Rollup merge of #132828 - est31:let_chains_parsing_tests, r=compiler-errors

Additional tests to ensure let is rejected during parsing

In the original stabilization PR, @ `compiler-errors` has [pointed out](https://github.com/rust-lang/rust/pull/94927#issuecomment-1165156328) that #97295 wasn't enough to address the concerns about having `let` in expressions being rejected at parsing time, instead of later.

Thankfully, since then the situation has been greatly improved by #115677. This PR adds some additional tests to `disallowed-positions.rs`, and adds two additional revisions to the "normal" case which is now given the `feature` name:

* `no_feature`: Added to incorporate `disallowed-positions-without-feature-gate.rs` into the file, reducing duplication.
* `nothing`: like feature, but all functions are cfg'd out. Ensures that the errors are really emitted during parsing.

cc tracking issue #53667

tests/ui/rfcs/rfc-2497-if-let-chains/disallowed-positions-without-feature-gate.rs

@@ -1,340 +0,0 @@
-// Check that we don't suggest enabling a feature for code that's
-// not accepted even with that feature.
-
-#![allow(irrefutable_let_patterns)]
-
-use std::ops::Range;
-
-fn main() {}
-
-fn _if() {
-    if (let 0 = 1) {}
-    //~^ ERROR expected expression, found `let` statement
-
-    if (((let 0 = 1))) {}
-    //~^ ERROR expected expression, found `let` statement
-
-    if (let 0 = 1) && true {}
-    //~^ ERROR expected expression, found `let` statement
-
-    if true && (let 0 = 1) {}
-    //~^ ERROR expected expression, found `let` statement
-
-    if (let 0 = 1) && (let 0 = 1) {}
-    //~^ ERROR expected expression, found `let` statement
-    //~| ERROR expected expression, found `let` statement
-
-    if (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
-    //~^ ERROR expected expression, found `let` statement
-    //~| ERROR expected expression, found `let` statement
-    //~| ERROR expected expression, found `let` statement
-}
-
-fn _while() {
-    while (let 0 = 1) {}
-    //~^ ERROR expected expression, found `let` statement
-
-    while (((let 0 = 1))) {}
-    //~^ ERROR expected expression, found `let` statement
-
-    while (let 0 = 1) && true {}
-    //~^ ERROR expected expression, found `let` statement
-
-    while true && (let 0 = 1) {}
-    //~^ ERROR expected expression, found `let` statement
-
-    while (let 0 = 1) && (let 0 = 1) {}
-    //~^ ERROR expected expression, found `let` statement
-    //~| ERROR expected expression, found `let` statement
-
-    while (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
-    //~^ ERROR expected expression, found `let` statement
-    //~| ERROR expected expression, found `let` statement
-    //~| ERROR expected expression, found `let` statement
-}
-
-fn _macros() {
-    macro_rules! use_expr {
-        ($e:expr) => {
-            if $e {}
-            while $e {}
-        }
-    }
-    use_expr!((let 0 = 1 && 0 == 0));
-    //~^ ERROR expected expression, found `let` statement
-    use_expr!((let 0 = 1));
-    //~^ ERROR expected expression, found `let` statement
-}
-
-fn nested_within_if_expr() {
-    if &let 0 = 0 {}
-    //~^ ERROR expected expression, found `let` statement
-
-    if !let 0 = 0 {}
-    //~^ ERROR expected expression, found `let` statement
-    if *let 0 = 0 {}
-    //~^ ERROR expected expression, found `let` statement
-    if -let 0 = 0 {}
-    //~^ ERROR expected expression, found `let` statement
-
-    fn _check_try_binds_tighter() -> Result<(), ()> {
-        if let 0 = 0? {}
-        //~^ ERROR the `?` operator can only be applied to values that implement `Try`
-        Ok(())
-    }
-    if (let 0 = 0)? {}
-    //~^ ERROR expected expression, found `let` statement
-
-    if true || let 0 = 0 {}
-    //~^ ERROR expected expression, found `let` statement
-    if (true || let 0 = 0) {}
-    //~^ ERROR expected expression, found `let` statement
-    if true && (true || let 0 = 0) {}
-    //~^ ERROR expected expression, found `let` statement
-    if true || (true && let 0 = 0) {}
-    //~^ ERROR expected expression, found `let` statement
-
-    let mut x = true;
-    if x = let 0 = 0 {}
-    //~^ ERROR expected expression, found `let` statement
-
-    if true..(let 0 = 0) {}
-    //~^ ERROR expected expression, found `let` statement
-    //~| ERROR mismatched types
-    if ..(let 0 = 0) {}
-    //~^ ERROR expected expression, found `let` statement
-    if (let 0 = 0).. {}
-    //~^ ERROR expected expression, found `let` statement
-
-    // Binds as `(let ... = true)..true &&/|| false`.
-    if let Range { start: _, end: _ } = true..true && false {}
-    //~^ ERROR expected expression, found `let` statement
-    //~| ERROR mismatched types
-    if let Range { start: _, end: _ } = true..true || false {}
-    //~^ ERROR expected expression, found `let` statement
-    //~| ERROR mismatched types
-
-    // Binds as `(let Range { start: F, end } = F)..(|| true)`.
-    const F: fn() -> bool = || true;
-    if let Range { start: F, end } = F..|| true {}
-    //~^ ERROR expected expression, found `let` statement
-    //~| ERROR mismatched types
-
-    // Binds as `(let Range { start: true, end } = t)..(&&false)`.
-    let t = &&true;
-    if let Range { start: true, end } = t..&&false {}
-    //~^ ERROR expected expression, found `let` statement
-    //~| ERROR mismatched types
-
-    if let true = let true = true {}
-    //~^ ERROR expected expression, found `let` statement
-}
-
-fn nested_within_while_expr() {
-    while &let 0 = 0 {}
-    //~^ ERROR expected expression, found `let` statement
-
-    while !let 0 = 0 {}
-    //~^ ERROR expected expression, found `let` statement
-    while *let 0 = 0 {}
-    //~^ ERROR expected expression, found `let` statement
-    while -let 0 = 0 {}
-    //~^ ERROR expected expression, found `let` statement
-
-    fn _check_try_binds_tighter() -> Result<(), ()> {
-        while let 0 = 0? {}
-        //~^ ERROR the `?` operator can only be applied to values that implement `Try`
-        Ok(())
-    }
-    while (let 0 = 0)? {}
-    //~^ ERROR expected expression, found `let` statement
-
-    while true || let 0 = 0 {}
-    //~^ ERROR expected expression, found `let` statement
-    while (true || let 0 = 0) {}
-    //~^ ERROR expected expression, found `let` statement
-    while true && (true || let 0 = 0) {}
-    //~^ ERROR expected expression, found `let` statement
-    while true || (true && let 0 = 0) {}
-    //~^ ERROR expected expression, found `let` statement
-
-    let mut x = true;
-    while x = let 0 = 0 {}
-    //~^ ERROR expected expression, found `let` statement
-
-    while true..(let 0 = 0) {}
-    //~^ ERROR expected expression, found `let` statement
-    //~| ERROR mismatched types
-    while ..(let 0 = 0) {}
-    //~^ ERROR expected expression, found `let` statement
-    while (let 0 = 0).. {}
-    //~^ ERROR expected expression, found `let` statement
-
-    // Binds as `(let ... = true)..true &&/|| false`.
-    while let Range { start: _, end: _ } = true..true && false {}
-    //~^ ERROR expected expression, found `let` statement
-    //~| ERROR mismatched types
-    while let Range { start: _, end: _ } = true..true || false {}
-    //~^ ERROR expected expression, found `let` statement
-    //~| ERROR mismatched types
-
-    // Binds as `(let Range { start: F, end } = F)..(|| true)`.
-    const F: fn() -> bool = || true;
-    while let Range { start: F, end } = F..|| true {}
-    //~^ ERROR expected expression, found `let` statement
-    //~| ERROR mismatched types
-
-    // Binds as `(let Range { start: true, end } = t)..(&&false)`.
-    let t = &&true;
-    while let Range { start: true, end } = t..&&false {}
-    //~^ ERROR expected expression, found `let` statement
-    //~| ERROR mismatched types
-
-    while let true = let true = true {}
-    //~^ ERROR expected expression, found `let` statement
-}
-
-fn not_error_because_clarified_intent() {
-    if let Range { start: _, end: _ } = (true..true || false) { }
-
-    if let Range { start: _, end: _ } = (true..true && false) { }
-
-    while let Range { start: _, end: _ } = (true..true || false) { }
-
-    while let Range { start: _, end: _ } = (true..true && false) { }
-}
-
-fn outside_if_and_while_expr() {
-    &let 0 = 0;
-    //~^ ERROR expected expression, found `let` statement
-
-    !let 0 = 0;
-    //~^ ERROR expected expression, found `let` statement
-    *let 0 = 0;
-    //~^ ERROR expected expression, found `let` statement
-    -let 0 = 0;
-    //~^ ERROR expected expression, found `let` statement
-    let _ = let _ = 3;
-    //~^ ERROR expected expression, found `let` statement
-
-    fn _check_try_binds_tighter() -> Result<(), ()> {
-        let 0 = 0?;
-        //~^ ERROR the `?` operator can only be applied to values that implement `Try`
-        Ok(())
-    }
-    (let 0 = 0)?;
-    //~^ ERROR expected expression, found `let` statement
-
-    true || let 0 = 0;
-    //~^ ERROR expected expression, found `let` statement
-    (true || let 0 = 0);
-    //~^ ERROR expected expression, found `let` statement
-    true && (true || let 0 = 0);
-    //~^ ERROR expected expression, found `let` statement
-
-    let mut x = true;
-    x = let 0 = 0;
-    //~^ ERROR expected expression, found `let` statement
-
-    true..(let 0 = 0);
-    //~^ ERROR expected expression, found `let` statement
-    ..(let 0 = 0);
-    //~^ ERROR expected expression, found `let` statement
-    (let 0 = 0)..;
-    //~^ ERROR expected expression, found `let` statement
-
-    (let Range { start: _, end: _ } = true..true || false);
-    //~^ ERROR mismatched types
-    //~| ERROR expected expression, found `let` statement
-
-    (let true = let true = true);
-    //~^ ERROR expected expression, found `let` statement
-    //~| ERROR expected expression, found `let` statement
-
-    {
-        #[cfg(FALSE)]
-        let x = true && let y = 1;
-        //~^ ERROR expected expression, found `let` statement
-    }
-
-    #[cfg(FALSE)]
-    {
-        [1, 2, 3][let _ = ()]
-        //~^ ERROR expected expression, found `let` statement
-    }
-
-    // Check function tail position.
-    &let 0 = 0
-    //~^ ERROR expected expression, found `let` statement
-}
-
-// Let's make sure that `let` inside const generic arguments are considered.
-fn inside_const_generic_arguments() {
-    struct A<const B: bool>;
-    impl<const B: bool> A<{B}> { const O: u32 = 5; }
-
-    if let A::<{
-        true && let 1 = 1
-        //~^ ERROR expected expression, found `let` statement
-    }>::O = 5 {}
-
-    while let A::<{
-        true && let 1 = 1
-        //~^ ERROR expected expression, found `let` statement
-    }>::O = 5 {}
-
-    if A::<{
-        true && let 1 = 1
-        //~^ ERROR expected expression, found `let` statement
-    }>::O == 5 {}
-
-    // In the cases above we have `ExprKind::Block` to help us out.
-    // Below however, we would not have a block and so an implementation might go
-    // from visiting expressions to types without banning `let` expressions down the tree.
-    // This tests ensures that we are not caught by surprise should the parser
-    // admit non-IDENT expressions in const generic arguments.
-
-    if A::<
-        true && let 1 = 1
-        //~^ ERROR expressions must be enclosed in braces
-        //~| ERROR expected expression, found `let` statement
-    >::O == 5 {}
-}
-
-fn with_parenthesis() {
-    let opt = Some(Some(1i32));
-
-    if (let Some(a) = opt && true) {
-    //~^ ERROR expected expression, found `let` statement
-    }
-
-    if (let Some(a) = opt) && true {
-    //~^ ERROR expected expression, found `let` statement
-    }
-    if (let Some(a) = opt) && (let Some(b) = a) {
-    //~^ ERROR expected expression, found `let` statement
-    //~| ERROR expected expression, found `let` statement
-    }
-
-    if (let Some(a) = opt && (let Some(b) = a)) && b == 1 {
-    //~^ ERROR expected expression, found `let` statement
-    //~| ERROR expected expression, found `let` statement
-    }
-    if (let Some(a) = opt && (let Some(b) = a)) && true {
-    //~^ ERROR expected expression, found `let` statement
-    //~| ERROR expected expression, found `let` statement
-    }
-    if (let Some(a) = opt && (true)) && true {
-    //~^ ERROR expected expression, found `let` statement
-    }
-
-    #[cfg(FALSE)]
-    let x = (true && let y = 1);
-    //~^ ERROR expected expression, found `let` statement
-
-    #[cfg(FALSE)]
-    {
-        ([1, 2, 3][let _ = ()])
-        //~^ ERROR expected expression, found `let` statement
-    }
-}

tests/ui/rfcs/rfc-2497-if-let-chains/disallowed-positions.feature.stderr

@@ -1,239 +1,239 @@
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:11:9
+  --> $DIR/disallowed-positions.rs:33:9
    |
 LL |     if (let 0 = 1) {}
    |         ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions-without-feature-gate.rs:11:9
+  --> $DIR/disallowed-positions.rs:33:9
    |
 LL |     if (let 0 = 1) {}
    |         ^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:14:11
+  --> $DIR/disallowed-positions.rs:36:11
    |
 LL |     if (((let 0 = 1))) {}
    |           ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions-without-feature-gate.rs:14:11
+  --> $DIR/disallowed-positions.rs:36:11
    |
 LL |     if (((let 0 = 1))) {}
    |           ^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:17:9
+  --> $DIR/disallowed-positions.rs:39:9
    |
 LL |     if (let 0 = 1) && true {}
    |         ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions-without-feature-gate.rs:17:9
+  --> $DIR/disallowed-positions.rs:39:9
    |
 LL |     if (let 0 = 1) && true {}
    |         ^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:20:17
+  --> $DIR/disallowed-positions.rs:42:17
    |
 LL |     if true && (let 0 = 1) {}
    |                 ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions-without-feature-gate.rs:20:17
+  --> $DIR/disallowed-positions.rs:42:17
    |
 LL |     if true && (let 0 = 1) {}
    |                 ^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:23:9
+  --> $DIR/disallowed-positions.rs:45:9
    |
 LL |     if (let 0 = 1) && (let 0 = 1) {}
    |         ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions-without-feature-gate.rs:23:9
+  --> $DIR/disallowed-positions.rs:45:9
    |
 LL |     if (let 0 = 1) && (let 0 = 1) {}
    |         ^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:23:24
+  --> $DIR/disallowed-positions.rs:45:24
    |
 LL |     if (let 0 = 1) && (let 0 = 1) {}
    |                        ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions-without-feature-gate.rs:23:24
+  --> $DIR/disallowed-positions.rs:45:24
    |
 LL |     if (let 0 = 1) && (let 0 = 1) {}
    |                        ^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:27:9
+  --> $DIR/disallowed-positions.rs:49:35
    |
-LL |     if (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
-   |         ^^^^^^^^^
-   |
-   = note: only supported directly in conditions of `if` and `while` expressions
-note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions-without-feature-gate.rs:27:9
-   |
-LL |     if (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:27:22
-   |
-LL |     if (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
-   |                      ^^^^^^^^^
-   |
-   = note: only supported directly in conditions of `if` and `while` expressions
-note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions-without-feature-gate.rs:27:9
-   |
-LL |     if (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:27:35
-   |
-LL |     if (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
    |                                   ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions-without-feature-gate.rs:27:9
+  --> $DIR/disallowed-positions.rs:49:35
    |
-LL |     if (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:34:12
+  --> $DIR/disallowed-positions.rs:49:48
+   |
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                                ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:49:35
+   |
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:49:61
+   |
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                                             ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:49:35
+   |
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:59:12
    |
 LL |     while (let 0 = 1) {}
    |            ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions-without-feature-gate.rs:34:12
+  --> $DIR/disallowed-positions.rs:59:12
    |
 LL |     while (let 0 = 1) {}
    |            ^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:37:14
+  --> $DIR/disallowed-positions.rs:62:14
    |
 LL |     while (((let 0 = 1))) {}
    |              ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions-without-feature-gate.rs:37:14
+  --> $DIR/disallowed-positions.rs:62:14
    |
 LL |     while (((let 0 = 1))) {}
    |              ^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:40:12
+  --> $DIR/disallowed-positions.rs:65:12
    |
 LL |     while (let 0 = 1) && true {}
    |            ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions-without-feature-gate.rs:40:12
+  --> $DIR/disallowed-positions.rs:65:12
    |
 LL |     while (let 0 = 1) && true {}
    |            ^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:43:20
+  --> $DIR/disallowed-positions.rs:68:20
    |
 LL |     while true && (let 0 = 1) {}
    |                    ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions-without-feature-gate.rs:43:20
+  --> $DIR/disallowed-positions.rs:68:20
    |
 LL |     while true && (let 0 = 1) {}
    |                    ^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:46:12
+  --> $DIR/disallowed-positions.rs:71:12
    |
 LL |     while (let 0 = 1) && (let 0 = 1) {}
    |            ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions-without-feature-gate.rs:46:12
+  --> $DIR/disallowed-positions.rs:71:12
    |
 LL |     while (let 0 = 1) && (let 0 = 1) {}
    |            ^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:46:27
+  --> $DIR/disallowed-positions.rs:71:27
    |
 LL |     while (let 0 = 1) && (let 0 = 1) {}
    |                           ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions-without-feature-gate.rs:46:27
+  --> $DIR/disallowed-positions.rs:71:27
    |
 LL |     while (let 0 = 1) && (let 0 = 1) {}
    |                           ^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:50:12
+  --> $DIR/disallowed-positions.rs:75:38
    |
-LL |     while (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
-   |            ^^^^^^^^^
-   |
-   = note: only supported directly in conditions of `if` and `while` expressions
-note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions-without-feature-gate.rs:50:12
-   |
-LL |     while (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
-   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:50:25
-   |
-LL |     while (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
-   |                         ^^^^^^^^^
-   |
-   = note: only supported directly in conditions of `if` and `while` expressions
-note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions-without-feature-gate.rs:50:12
-   |
-LL |     while (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
-   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:50:38
-   |
-LL |     while (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
    |                                      ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions-without-feature-gate.rs:50:12
+  --> $DIR/disallowed-positions.rs:75:38
    |
-LL |     while (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
-   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:70:9
+  --> $DIR/disallowed-positions.rs:75:51
+   |
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                                   ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:75:38
+   |
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:75:64
+   |
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                                                ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:75:38
+   |
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:99:9
    |
 LL |     if &let 0 = 0 {}
    |         ^^^^^^^^^
@@ -241,7 +241,7 @@ LL |     if &let 0 = 0 {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:73:9
+  --> $DIR/disallowed-positions.rs:102:9
    |
 LL |     if !let 0 = 0 {}
    |         ^^^^^^^^^
@@ -249,7 +249,7 @@ LL |     if !let 0 = 0 {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:75:9
+  --> $DIR/disallowed-positions.rs:104:9
    |
 LL |     if *let 0 = 0 {}
    |         ^^^^^^^^^
@@ -257,7 +257,7 @@ LL |     if *let 0 = 0 {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:77:9
+  --> $DIR/disallowed-positions.rs:106:9
    |
 LL |     if -let 0 = 0 {}
    |         ^^^^^^^^^
@@ -265,7 +265,7 @@ LL |     if -let 0 = 0 {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:85:9
+  --> $DIR/disallowed-positions.rs:114:9
    |
 LL |     if (let 0 = 0)? {}
    |         ^^^^^^^^^
@@ -273,20 +273,20 @@ LL |     if (let 0 = 0)? {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:88:16
+  --> $DIR/disallowed-positions.rs:117:16
    |
 LL |     if true || let 0 = 0 {}
    |                ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `||` operators are not supported in let chain expressions
-  --> $DIR/disallowed-positions-without-feature-gate.rs:88:13
+  --> $DIR/disallowed-positions.rs:117:13
    |
 LL |     if true || let 0 = 0 {}
    |             ^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:90:17
+  --> $DIR/disallowed-positions.rs:119:17
    |
 LL |     if (true || let 0 = 0) {}
    |                 ^^^^^^^^^
@@ -294,7 +294,7 @@ LL |     if (true || let 0 = 0) {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:92:25
+  --> $DIR/disallowed-positions.rs:121:25
    |
 LL |     if true && (true || let 0 = 0) {}
    |                         ^^^^^^^^^
@@ -302,7 +302,7 @@ LL |     if true && (true || let 0 = 0) {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:94:25
+  --> $DIR/disallowed-positions.rs:123:25
    |
 LL |     if true || (true && let 0 = 0) {}
    |                         ^^^^^^^^^
@@ -310,7 +310,7 @@ LL |     if true || (true && let 0 = 0) {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:98:12
+  --> $DIR/disallowed-positions.rs:127:12
    |
 LL |     if x = let 0 = 0 {}
    |            ^^^
@@ -318,7 +318,7 @@ LL |     if x = let 0 = 0 {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:101:15
+  --> $DIR/disallowed-positions.rs:130:15
    |
 LL |     if true..(let 0 = 0) {}
    |               ^^^^^^^^^
@@ -326,7 +326,7 @@ LL |     if true..(let 0 = 0) {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:104:11
+  --> $DIR/disallowed-positions.rs:133:11
    |
 LL |     if ..(let 0 = 0) {}
    |           ^^^^^^^^^
@@ -334,7 +334,7 @@ LL |     if ..(let 0 = 0) {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:106:9
+  --> $DIR/disallowed-positions.rs:135:9
    |
 LL |     if (let 0 = 0).. {}
    |         ^^^^^^^^^
@@ -342,7 +342,7 @@ LL |     if (let 0 = 0).. {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:110:8
+  --> $DIR/disallowed-positions.rs:139:8
    |
 LL |     if let Range { start: _, end: _ } = true..true && false {}
    |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -350,7 +350,7 @@ LL |     if let Range { start: _, end: _ } = true..true && false {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:113:8
+  --> $DIR/disallowed-positions.rs:142:8
    |
 LL |     if let Range { start: _, end: _ } = true..true || false {}
    |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -358,7 +358,7 @@ LL |     if let Range { start: _, end: _ } = true..true || false {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:119:8
+  --> $DIR/disallowed-positions.rs:148:8
    |
 LL |     if let Range { start: F, end } = F..|| true {}
    |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -366,7 +366,7 @@ LL |     if let Range { start: F, end } = F..|| true {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:125:8
+  --> $DIR/disallowed-positions.rs:154:8
    |
 LL |     if let Range { start: true, end } = t..&&false {}
    |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -374,7 +374,7 @@ LL |     if let Range { start: true, end } = t..&&false {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:129:19
+  --> $DIR/disallowed-positions.rs:158:19
    |
 LL |     if let true = let true = true {}
    |                   ^^^
@@ -382,7 +382,71 @@ LL |     if let true = let true = true {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:134:12
+  --> $DIR/disallowed-positions.rs:161:15
+   |
+LL |     if return let 0 = 0 {}
+   |               ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:164:21
+   |
+LL |     loop { if break let 0 = 0 {} }
+   |                     ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:167:15
+   |
+LL |     if (match let 0 = 0 { _ => { false } }) {}
+   |               ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:170:9
+   |
+LL |     if (let 0 = 0, false).1 {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:173:9
+   |
+LL |     if (let 0 = 0,) {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:177:13
+   |
+LL |         if (let 0 = 0).await {}
+   |             ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:181:12
+   |
+LL |     if (|| let 0 = 0) {}
+   |            ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:184:9
+   |
+LL |     if (let 0 = 0)() {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:190:12
    |
 LL |     while &let 0 = 0 {}
    |            ^^^^^^^^^
@@ -390,7 +454,7 @@ LL |     while &let 0 = 0 {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:137:12
+  --> $DIR/disallowed-positions.rs:193:12
    |
 LL |     while !let 0 = 0 {}
    |            ^^^^^^^^^
@@ -398,7 +462,7 @@ LL |     while !let 0 = 0 {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:139:12
+  --> $DIR/disallowed-positions.rs:195:12
    |
 LL |     while *let 0 = 0 {}
    |            ^^^^^^^^^
@@ -406,7 +470,7 @@ LL |     while *let 0 = 0 {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:141:12
+  --> $DIR/disallowed-positions.rs:197:12
    |
 LL |     while -let 0 = 0 {}
    |            ^^^^^^^^^
@@ -414,7 +478,7 @@ LL |     while -let 0 = 0 {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:149:12
+  --> $DIR/disallowed-positions.rs:205:12
    |
 LL |     while (let 0 = 0)? {}
    |            ^^^^^^^^^
@@ -422,20 +486,20 @@ LL |     while (let 0 = 0)? {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:152:19
+  --> $DIR/disallowed-positions.rs:208:19
    |
 LL |     while true || let 0 = 0 {}
    |                   ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `||` operators are not supported in let chain expressions
-  --> $DIR/disallowed-positions-without-feature-gate.rs:152:16
+  --> $DIR/disallowed-positions.rs:208:16
    |
 LL |     while true || let 0 = 0 {}
    |                ^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:154:20
+  --> $DIR/disallowed-positions.rs:210:20
    |
 LL |     while (true || let 0 = 0) {}
    |                    ^^^^^^^^^
@@ -443,7 +507,7 @@ LL |     while (true || let 0 = 0) {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:156:28
+  --> $DIR/disallowed-positions.rs:212:28
    |
 LL |     while true && (true || let 0 = 0) {}
    |                            ^^^^^^^^^
@@ -451,7 +515,7 @@ LL |     while true && (true || let 0 = 0) {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:158:28
+  --> $DIR/disallowed-positions.rs:214:28
    |
 LL |     while true || (true && let 0 = 0) {}
    |                            ^^^^^^^^^
@@ -459,7 +523,7 @@ LL |     while true || (true && let 0 = 0) {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:162:15
+  --> $DIR/disallowed-positions.rs:218:15
    |
 LL |     while x = let 0 = 0 {}
    |               ^^^
@@ -467,7 +531,7 @@ LL |     while x = let 0 = 0 {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:165:18
+  --> $DIR/disallowed-positions.rs:221:18
    |
 LL |     while true..(let 0 = 0) {}
    |                  ^^^^^^^^^
@@ -475,7 +539,7 @@ LL |     while true..(let 0 = 0) {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:168:14
+  --> $DIR/disallowed-positions.rs:224:14
    |
 LL |     while ..(let 0 = 0) {}
    |              ^^^^^^^^^
@@ -483,7 +547,7 @@ LL |     while ..(let 0 = 0) {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:170:12
+  --> $DIR/disallowed-positions.rs:226:12
    |
 LL |     while (let 0 = 0).. {}
    |            ^^^^^^^^^
@@ -491,7 +555,7 @@ LL |     while (let 0 = 0).. {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:174:11
+  --> $DIR/disallowed-positions.rs:230:11
    |
 LL |     while let Range { start: _, end: _ } = true..true && false {}
    |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -499,7 +563,7 @@ LL |     while let Range { start: _, end: _ } = true..true && false {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:177:11
+  --> $DIR/disallowed-positions.rs:233:11
    |
 LL |     while let Range { start: _, end: _ } = true..true || false {}
    |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -507,7 +571,7 @@ LL |     while let Range { start: _, end: _ } = true..true || false {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:183:11
+  --> $DIR/disallowed-positions.rs:239:11
    |
 LL |     while let Range { start: F, end } = F..|| true {}
    |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -515,7 +579,7 @@ LL |     while let Range { start: F, end } = F..|| true {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:189:11
+  --> $DIR/disallowed-positions.rs:245:11
    |
 LL |     while let Range { start: true, end } = t..&&false {}
    |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -523,7 +587,7 @@ LL |     while let Range { start: true, end } = t..&&false {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:193:22
+  --> $DIR/disallowed-positions.rs:249:22
    |
 LL |     while let true = let true = true {}
    |                      ^^^
@@ -531,7 +595,71 @@ LL |     while let true = let true = true {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:208:6
+  --> $DIR/disallowed-positions.rs:252:18
+   |
+LL |     while return let 0 = 0 {}
+   |                  ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:255:39
+   |
+LL |     'outer: loop { while break 'outer let 0 = 0 {} }
+   |                                       ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:258:18
+   |
+LL |     while (match let 0 = 0 { _ => { false } }) {}
+   |                  ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:261:12
+   |
+LL |     while (let 0 = 0, false).1 {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:264:12
+   |
+LL |     while (let 0 = 0,) {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:268:16
+   |
+LL |         while (let 0 = 0).await {}
+   |                ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:272:15
+   |
+LL |     while (|| let 0 = 0) {}
+   |               ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:275:12
+   |
+LL |     while (let 0 = 0)() {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:292:6
    |
 LL |     &let 0 = 0;
    |      ^^^
@@ -539,7 +667,7 @@ LL |     &let 0 = 0;
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:211:6
+  --> $DIR/disallowed-positions.rs:295:6
    |
 LL |     !let 0 = 0;
    |      ^^^
@@ -547,7 +675,7 @@ LL |     !let 0 = 0;
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:213:6
+  --> $DIR/disallowed-positions.rs:297:6
    |
 LL |     *let 0 = 0;
    |      ^^^
@@ -555,7 +683,7 @@ LL |     *let 0 = 0;
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:215:6
+  --> $DIR/disallowed-positions.rs:299:6
    |
 LL |     -let 0 = 0;
    |      ^^^
@@ -563,7 +691,7 @@ LL |     -let 0 = 0;
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:217:13
+  --> $DIR/disallowed-positions.rs:301:13
    |
 LL |     let _ = let _ = 3;
    |             ^^^
@@ -571,7 +699,7 @@ LL |     let _ = let _ = 3;
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:225:6
+  --> $DIR/disallowed-positions.rs:309:6
    |
 LL |     (let 0 = 0)?;
    |      ^^^
@@ -579,7 +707,7 @@ LL |     (let 0 = 0)?;
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:228:13
+  --> $DIR/disallowed-positions.rs:312:13
    |
 LL |     true || let 0 = 0;
    |             ^^^
@@ -587,7 +715,7 @@ LL |     true || let 0 = 0;
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:230:14
+  --> $DIR/disallowed-positions.rs:314:14
    |
 LL |     (true || let 0 = 0);
    |              ^^^
@@ -595,7 +723,7 @@ LL |     (true || let 0 = 0);
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:232:22
+  --> $DIR/disallowed-positions.rs:316:22
    |
 LL |     true && (true || let 0 = 0);
    |                      ^^^
@@ -603,7 +731,7 @@ LL |     true && (true || let 0 = 0);
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:236:9
+  --> $DIR/disallowed-positions.rs:320:9
    |
 LL |     x = let 0 = 0;
    |         ^^^
@@ -611,7 +739,7 @@ LL |     x = let 0 = 0;
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:239:12
+  --> $DIR/disallowed-positions.rs:323:12
    |
 LL |     true..(let 0 = 0);
    |            ^^^
@@ -619,7 +747,7 @@ LL |     true..(let 0 = 0);
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:241:8
+  --> $DIR/disallowed-positions.rs:325:8
    |
 LL |     ..(let 0 = 0);
    |        ^^^
@@ -627,7 +755,7 @@ LL |     ..(let 0 = 0);
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:243:6
+  --> $DIR/disallowed-positions.rs:327:6
    |
 LL |     (let 0 = 0)..;
    |      ^^^
@@ -635,7 +763,7 @@ LL |     (let 0 = 0)..;
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:246:6
+  --> $DIR/disallowed-positions.rs:330:6
    |
 LL |     (let Range { start: _, end: _ } = true..true || false);
    |      ^^^
@@ -643,7 +771,7 @@ LL |     (let Range { start: _, end: _ } = true..true || false);
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:250:6
+  --> $DIR/disallowed-positions.rs:334:6
    |
 LL |     (let true = let true = true);
    |      ^^^
@@ -651,7 +779,7 @@ LL |     (let true = let true = true);
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:250:17
+  --> $DIR/disallowed-positions.rs:334:17
    |
 LL |     (let true = let true = true);
    |                 ^^^
@@ -659,7 +787,7 @@ LL |     (let true = let true = true);
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:256:25
+  --> $DIR/disallowed-positions.rs:340:25
    |
 LL |         let x = true && let y = 1;
    |                         ^^^
@@ -667,7 +795,7 @@ LL |         let x = true && let y = 1;
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:262:19
+  --> $DIR/disallowed-positions.rs:346:19
    |
 LL |         [1, 2, 3][let _ = ()]
    |                   ^^^
@@ -675,7 +803,7 @@ LL |         [1, 2, 3][let _ = ()]
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:267:6
+  --> $DIR/disallowed-positions.rs:351:6
    |
 LL |     &let 0 = 0
    |      ^^^
@@ -683,7 +811,7 @@ LL |     &let 0 = 0
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:277:17
+  --> $DIR/disallowed-positions.rs:362:17
    |
 LL |         true && let 1 = 1
    |                 ^^^
@@ -691,7 +819,7 @@ LL |         true && let 1 = 1
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:282:17
+  --> $DIR/disallowed-positions.rs:367:17
    |
 LL |         true && let 1 = 1
    |                 ^^^
@@ -699,7 +827,7 @@ LL |         true && let 1 = 1
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:287:17
+  --> $DIR/disallowed-positions.rs:372:17
    |
 LL |         true && let 1 = 1
    |                 ^^^
@@ -707,7 +835,7 @@ LL |         true && let 1 = 1
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:298:17
+  --> $DIR/disallowed-positions.rs:383:17
    |
 LL |         true && let 1 = 1
    |                 ^^^
@@ -715,7 +843,7 @@ LL |         true && let 1 = 1
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expressions must be enclosed in braces to be used as const generic arguments
-  --> $DIR/disallowed-positions-without-feature-gate.rs:298:9
+  --> $DIR/disallowed-positions.rs:383:9
    |
 LL |         true && let 1 = 1
    |         ^^^^^^^^^^^^^^^^^
@@ -726,124 +854,124 @@ LL |         { true && let 1 = 1 }
    |         +                   +
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:307:9
+  --> $DIR/disallowed-positions.rs:393:9
    |
 LL |     if (let Some(a) = opt && true) {
    |         ^^^^^^^^^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions-without-feature-gate.rs:307:9
+  --> $DIR/disallowed-positions.rs:393:9
    |
 LL |     if (let Some(a) = opt && true) {
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:311:9
+  --> $DIR/disallowed-positions.rs:397:9
    |
 LL |     if (let Some(a) = opt) && true {
    |         ^^^^^^^^^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions-without-feature-gate.rs:311:9
+  --> $DIR/disallowed-positions.rs:397:9
    |
 LL |     if (let Some(a) = opt) && true {
    |         ^^^^^^^^^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:314:9
+  --> $DIR/disallowed-positions.rs:400:9
    |
 LL |     if (let Some(a) = opt) && (let Some(b) = a) {
    |         ^^^^^^^^^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions-without-feature-gate.rs:314:9
+  --> $DIR/disallowed-positions.rs:400:9
    |
 LL |     if (let Some(a) = opt) && (let Some(b) = a) {
    |         ^^^^^^^^^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:314:32
+  --> $DIR/disallowed-positions.rs:400:32
    |
 LL |     if (let Some(a) = opt) && (let Some(b) = a) {
    |                                ^^^^^^^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions-without-feature-gate.rs:314:32
+  --> $DIR/disallowed-positions.rs:400:32
    |
 LL |     if (let Some(a) = opt) && (let Some(b) = a) {
    |                                ^^^^^^^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:319:9
+  --> $DIR/disallowed-positions.rs:408:9
    |
 LL |     if (let Some(a) = opt && (let Some(b) = a)) && b == 1 {
    |         ^^^^^^^^^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions-without-feature-gate.rs:319:9
+  --> $DIR/disallowed-positions.rs:408:9
    |
 LL |     if (let Some(a) = opt && (let Some(b) = a)) && b == 1 {
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:319:31
+  --> $DIR/disallowed-positions.rs:408:31
    |
 LL |     if (let Some(a) = opt && (let Some(b) = a)) && b == 1 {
    |                               ^^^^^^^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions-without-feature-gate.rs:319:31
+  --> $DIR/disallowed-positions.rs:408:31
    |
 LL |     if (let Some(a) = opt && (let Some(b) = a)) && b == 1 {
    |                               ^^^^^^^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:323:9
+  --> $DIR/disallowed-positions.rs:412:9
    |
 LL |     if (let Some(a) = opt && (let Some(b) = a)) && true {
    |         ^^^^^^^^^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions-without-feature-gate.rs:323:9
+  --> $DIR/disallowed-positions.rs:412:9
    |
 LL |     if (let Some(a) = opt && (let Some(b) = a)) && true {
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:323:31
+  --> $DIR/disallowed-positions.rs:412:31
    |
 LL |     if (let Some(a) = opt && (let Some(b) = a)) && true {
    |                               ^^^^^^^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions-without-feature-gate.rs:323:31
+  --> $DIR/disallowed-positions.rs:412:31
    |
 LL |     if (let Some(a) = opt && (let Some(b) = a)) && true {
    |                               ^^^^^^^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:327:9
+  --> $DIR/disallowed-positions.rs:416:9
    |
 LL |     if (let Some(a) = opt && (true)) && true {
    |         ^^^^^^^^^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions-without-feature-gate.rs:327:9
+  --> $DIR/disallowed-positions.rs:416:9
    |
 LL |     if (let Some(a) = opt && (true)) && true {
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:332:22
+  --> $DIR/disallowed-positions.rs:436:22
    |
 LL |     let x = (true && let y = 1);
    |                      ^^^
@@ -851,7 +979,7 @@ LL |     let x = (true && let y = 1);
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:337:20
+  --> $DIR/disallowed-positions.rs:441:20
    |
 LL |         ([1, 2, 3][let _ = ()])
    |                    ^^^
@@ -859,7 +987,7 @@ LL |         ([1, 2, 3][let _ = ()])
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:63:16
+  --> $DIR/disallowed-positions.rs:91:16
    |
 LL |     use_expr!((let 0 = 1 && 0 == 0));
    |                ^^^
@@ -867,7 +995,7 @@ LL |     use_expr!((let 0 = 1 && 0 == 0));
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions-without-feature-gate.rs:65:16
+  --> $DIR/disallowed-positions.rs:93:16
    |
 LL |     use_expr!((let 0 = 1));
    |                ^^^
@@ -875,7 +1003,7 @@ LL |     use_expr!((let 0 = 1));
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions-without-feature-gate.rs:101:8
+  --> $DIR/disallowed-positions.rs:130:8
    |
 LL |     if true..(let 0 = 0) {}
    |        ^^^^^^^^^^^^^^^^^ expected `bool`, found `Range<bool>`
@@ -884,7 +1012,7 @@ LL |     if true..(let 0 = 0) {}
             found struct `std::ops::Range<bool>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions-without-feature-gate.rs:110:12
+  --> $DIR/disallowed-positions.rs:139:12
    |
 LL |     if let Range { start: _, end: _ } = true..true && false {}
    |            ^^^^^^^^^^^^^^^^^^^^^^^^^^   ---- this expression has type `bool`
@@ -895,7 +1023,7 @@ LL |     if let Range { start: _, end: _ } = true..true && false {}
             found struct `std::ops::Range<_>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions-without-feature-gate.rs:113:12
+  --> $DIR/disallowed-positions.rs:142:12
    |
 LL |     if let Range { start: _, end: _ } = true..true || false {}
    |            ^^^^^^^^^^^^^^^^^^^^^^^^^^   ---- this expression has type `bool`
@@ -906,7 +1034,7 @@ LL |     if let Range { start: _, end: _ } = true..true || false {}
             found struct `std::ops::Range<_>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions-without-feature-gate.rs:119:12
+  --> $DIR/disallowed-positions.rs:148:12
    |
 LL |     if let Range { start: F, end } = F..|| true {}
    |            ^^^^^^^^^^^^^^^^^^^^^^^   - this expression has type `fn() -> bool`
@@ -917,7 +1045,7 @@ LL |     if let Range { start: F, end } = F..|| true {}
                   found struct `std::ops::Range<_>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions-without-feature-gate.rs:125:12
+  --> $DIR/disallowed-positions.rs:154:12
    |
 LL |     if let Range { start: true, end } = t..&&false {}
    |            ^^^^^^^^^^^^^^^^^^^^^^^^^^   - this expression has type `&&bool`
@@ -928,7 +1056,7 @@ LL |     if let Range { start: true, end } = t..&&false {}
             found struct `std::ops::Range<_>`
 
 error[E0277]: the `?` operator can only be applied to values that implement `Try`
-  --> $DIR/disallowed-positions-without-feature-gate.rs:81:20
+  --> $DIR/disallowed-positions.rs:110:20
    |
 LL |         if let 0 = 0? {}
    |                    ^^ the `?` operator cannot be applied to type `{integer}`
@@ -936,7 +1064,7 @@ LL |         if let 0 = 0? {}
    = help: the trait `Try` is not implemented for `{integer}`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions-without-feature-gate.rs:165:11
+  --> $DIR/disallowed-positions.rs:221:11
    |
 LL |     while true..(let 0 = 0) {}
    |           ^^^^^^^^^^^^^^^^^ expected `bool`, found `Range<bool>`
@@ -945,7 +1073,7 @@ LL |     while true..(let 0 = 0) {}
             found struct `std::ops::Range<bool>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions-without-feature-gate.rs:174:15
+  --> $DIR/disallowed-positions.rs:230:15
    |
 LL |     while let Range { start: _, end: _ } = true..true && false {}
    |               ^^^^^^^^^^^^^^^^^^^^^^^^^^   ---- this expression has type `bool`
@@ -956,7 +1084,7 @@ LL |     while let Range { start: _, end: _ } = true..true && false {}
             found struct `std::ops::Range<_>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions-without-feature-gate.rs:177:15
+  --> $DIR/disallowed-positions.rs:233:15
    |
 LL |     while let Range { start: _, end: _ } = true..true || false {}
    |               ^^^^^^^^^^^^^^^^^^^^^^^^^^   ---- this expression has type `bool`
@@ -967,7 +1095,7 @@ LL |     while let Range { start: _, end: _ } = true..true || false {}
             found struct `std::ops::Range<_>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions-without-feature-gate.rs:183:15
+  --> $DIR/disallowed-positions.rs:239:15
    |
 LL |     while let Range { start: F, end } = F..|| true {}
    |               ^^^^^^^^^^^^^^^^^^^^^^^   - this expression has type `fn() -> bool`
@@ -978,7 +1106,7 @@ LL |     while let Range { start: F, end } = F..|| true {}
                   found struct `std::ops::Range<_>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions-without-feature-gate.rs:189:15
+  --> $DIR/disallowed-positions.rs:245:15
    |
 LL |     while let Range { start: true, end } = t..&&false {}
    |               ^^^^^^^^^^^^^^^^^^^^^^^^^^   - this expression has type `&&bool`
@@ -989,7 +1117,7 @@ LL |     while let Range { start: true, end } = t..&&false {}
             found struct `std::ops::Range<_>`
 
 error[E0277]: the `?` operator can only be applied to values that implement `Try`
-  --> $DIR/disallowed-positions-without-feature-gate.rs:145:23
+  --> $DIR/disallowed-positions.rs:201:23
    |
 LL |         while let 0 = 0? {}
    |                       ^^ the `?` operator cannot be applied to type `{integer}`
@@ -997,7 +1125,7 @@ LL |         while let 0 = 0? {}
    = help: the trait `Try` is not implemented for `{integer}`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions-without-feature-gate.rs:246:10
+  --> $DIR/disallowed-positions.rs:330:10
    |
 LL |     (let Range { start: _, end: _ } = true..true || false);
    |          ^^^^^^^^^^^^^^^^^^^^^^^^^^   ---- this expression has type `bool`
@@ -1008,14 +1136,14 @@ LL |     (let Range { start: _, end: _ } = true..true || false);
             found struct `std::ops::Range<_>`
 
 error[E0277]: the `?` operator can only be applied to values that implement `Try`
-  --> $DIR/disallowed-positions-without-feature-gate.rs:221:17
+  --> $DIR/disallowed-positions.rs:305:17
    |
 LL |         let 0 = 0?;
    |                 ^^ the `?` operator cannot be applied to type `{integer}`
    |
    = help: the trait `Try` is not implemented for `{integer}`
 
-error: aborting due to 105 previous errors
+error: aborting due to 121 previous errors
 
 Some errors have detailed explanations: E0277, E0308.
 For more information about an error, try `rustc --explain E0277`.

tests/ui/rfcs/rfc-2497-if-let-chains/disallowed-positions.no_feature.stderr

@@ -0,0 +1,1239 @@
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:33:9
+   |
+LL |     if (let 0 = 1) {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:33:9
+   |
+LL |     if (let 0 = 1) {}
+   |         ^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:36:11
+   |
+LL |     if (((let 0 = 1))) {}
+   |           ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:36:11
+   |
+LL |     if (((let 0 = 1))) {}
+   |           ^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:39:9
+   |
+LL |     if (let 0 = 1) && true {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:39:9
+   |
+LL |     if (let 0 = 1) && true {}
+   |         ^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:42:17
+   |
+LL |     if true && (let 0 = 1) {}
+   |                 ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:42:17
+   |
+LL |     if true && (let 0 = 1) {}
+   |                 ^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:45:9
+   |
+LL |     if (let 0 = 1) && (let 0 = 1) {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:45:9
+   |
+LL |     if (let 0 = 1) && (let 0 = 1) {}
+   |         ^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:45:24
+   |
+LL |     if (let 0 = 1) && (let 0 = 1) {}
+   |                        ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:45:24
+   |
+LL |     if (let 0 = 1) && (let 0 = 1) {}
+   |                        ^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:49:35
+   |
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                   ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:49:35
+   |
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:49:48
+   |
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                                ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:49:35
+   |
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:49:61
+   |
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                                             ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:49:35
+   |
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:59:12
+   |
+LL |     while (let 0 = 1) {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:59:12
+   |
+LL |     while (let 0 = 1) {}
+   |            ^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:62:14
+   |
+LL |     while (((let 0 = 1))) {}
+   |              ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:62:14
+   |
+LL |     while (((let 0 = 1))) {}
+   |              ^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:65:12
+   |
+LL |     while (let 0 = 1) && true {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:65:12
+   |
+LL |     while (let 0 = 1) && true {}
+   |            ^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:68:20
+   |
+LL |     while true && (let 0 = 1) {}
+   |                    ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:68:20
+   |
+LL |     while true && (let 0 = 1) {}
+   |                    ^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:71:12
+   |
+LL |     while (let 0 = 1) && (let 0 = 1) {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:71:12
+   |
+LL |     while (let 0 = 1) && (let 0 = 1) {}
+   |            ^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:71:27
+   |
+LL |     while (let 0 = 1) && (let 0 = 1) {}
+   |                           ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:71:27
+   |
+LL |     while (let 0 = 1) && (let 0 = 1) {}
+   |                           ^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:75:38
+   |
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                      ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:75:38
+   |
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:75:51
+   |
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                                   ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:75:38
+   |
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:75:64
+   |
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                                                ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:75:38
+   |
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:99:9
+   |
+LL |     if &let 0 = 0 {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:102:9
+   |
+LL |     if !let 0 = 0 {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:104:9
+   |
+LL |     if *let 0 = 0 {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:106:9
+   |
+LL |     if -let 0 = 0 {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:114:9
+   |
+LL |     if (let 0 = 0)? {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:117:16
+   |
+LL |     if true || let 0 = 0 {}
+   |                ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `||` operators are not supported in let chain expressions
+  --> $DIR/disallowed-positions.rs:117:13
+   |
+LL |     if true || let 0 = 0 {}
+   |             ^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:119:17
+   |
+LL |     if (true || let 0 = 0) {}
+   |                 ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:121:25
+   |
+LL |     if true && (true || let 0 = 0) {}
+   |                         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:123:25
+   |
+LL |     if true || (true && let 0 = 0) {}
+   |                         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:127:12
+   |
+LL |     if x = let 0 = 0 {}
+   |            ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:130:15
+   |
+LL |     if true..(let 0 = 0) {}
+   |               ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:133:11
+   |
+LL |     if ..(let 0 = 0) {}
+   |           ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:135:9
+   |
+LL |     if (let 0 = 0).. {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:139:8
+   |
+LL |     if let Range { start: _, end: _ } = true..true && false {}
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:142:8
+   |
+LL |     if let Range { start: _, end: _ } = true..true || false {}
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:148:8
+   |
+LL |     if let Range { start: F, end } = F..|| true {}
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:154:8
+   |
+LL |     if let Range { start: true, end } = t..&&false {}
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:158:19
+   |
+LL |     if let true = let true = true {}
+   |                   ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:161:15
+   |
+LL |     if return let 0 = 0 {}
+   |               ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:164:21
+   |
+LL |     loop { if break let 0 = 0 {} }
+   |                     ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:167:15
+   |
+LL |     if (match let 0 = 0 { _ => { false } }) {}
+   |               ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:170:9
+   |
+LL |     if (let 0 = 0, false).1 {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:173:9
+   |
+LL |     if (let 0 = 0,) {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:177:13
+   |
+LL |         if (let 0 = 0).await {}
+   |             ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:181:12
+   |
+LL |     if (|| let 0 = 0) {}
+   |            ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:184:9
+   |
+LL |     if (let 0 = 0)() {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:190:12
+   |
+LL |     while &let 0 = 0 {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:193:12
+   |
+LL |     while !let 0 = 0 {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:195:12
+   |
+LL |     while *let 0 = 0 {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:197:12
+   |
+LL |     while -let 0 = 0 {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:205:12
+   |
+LL |     while (let 0 = 0)? {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:208:19
+   |
+LL |     while true || let 0 = 0 {}
+   |                   ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `||` operators are not supported in let chain expressions
+  --> $DIR/disallowed-positions.rs:208:16
+   |
+LL |     while true || let 0 = 0 {}
+   |                ^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:210:20
+   |
+LL |     while (true || let 0 = 0) {}
+   |                    ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:212:28
+   |
+LL |     while true && (true || let 0 = 0) {}
+   |                            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:214:28
+   |
+LL |     while true || (true && let 0 = 0) {}
+   |                            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:218:15
+   |
+LL |     while x = let 0 = 0 {}
+   |               ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:221:18
+   |
+LL |     while true..(let 0 = 0) {}
+   |                  ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:224:14
+   |
+LL |     while ..(let 0 = 0) {}
+   |              ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:226:12
+   |
+LL |     while (let 0 = 0).. {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:230:11
+   |
+LL |     while let Range { start: _, end: _ } = true..true && false {}
+   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:233:11
+   |
+LL |     while let Range { start: _, end: _ } = true..true || false {}
+   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:239:11
+   |
+LL |     while let Range { start: F, end } = F..|| true {}
+   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:245:11
+   |
+LL |     while let Range { start: true, end } = t..&&false {}
+   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:249:22
+   |
+LL |     while let true = let true = true {}
+   |                      ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:252:18
+   |
+LL |     while return let 0 = 0 {}
+   |                  ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:255:39
+   |
+LL |     'outer: loop { while break 'outer let 0 = 0 {} }
+   |                                       ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:258:18
+   |
+LL |     while (match let 0 = 0 { _ => { false } }) {}
+   |                  ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:261:12
+   |
+LL |     while (let 0 = 0, false).1 {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:264:12
+   |
+LL |     while (let 0 = 0,) {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:268:16
+   |
+LL |         while (let 0 = 0).await {}
+   |                ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:272:15
+   |
+LL |     while (|| let 0 = 0) {}
+   |               ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:275:12
+   |
+LL |     while (let 0 = 0)() {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:292:6
+   |
+LL |     &let 0 = 0;
+   |      ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:295:6
+   |
+LL |     !let 0 = 0;
+   |      ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:297:6
+   |
+LL |     *let 0 = 0;
+   |      ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:299:6
+   |
+LL |     -let 0 = 0;
+   |      ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:301:13
+   |
+LL |     let _ = let _ = 3;
+   |             ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:309:6
+   |
+LL |     (let 0 = 0)?;
+   |      ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:312:13
+   |
+LL |     true || let 0 = 0;
+   |             ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:314:14
+   |
+LL |     (true || let 0 = 0);
+   |              ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:316:22
+   |
+LL |     true && (true || let 0 = 0);
+   |                      ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:320:9
+   |
+LL |     x = let 0 = 0;
+   |         ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:323:12
+   |
+LL |     true..(let 0 = 0);
+   |            ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:325:8
+   |
+LL |     ..(let 0 = 0);
+   |        ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:327:6
+   |
+LL |     (let 0 = 0)..;
+   |      ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:330:6
+   |
+LL |     (let Range { start: _, end: _ } = true..true || false);
+   |      ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:334:6
+   |
+LL |     (let true = let true = true);
+   |      ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:334:17
+   |
+LL |     (let true = let true = true);
+   |                 ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:340:25
+   |
+LL |         let x = true && let y = 1;
+   |                         ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:346:19
+   |
+LL |         [1, 2, 3][let _ = ()]
+   |                   ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:351:6
+   |
+LL |     &let 0 = 0
+   |      ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:362:17
+   |
+LL |         true && let 1 = 1
+   |                 ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:367:17
+   |
+LL |         true && let 1 = 1
+   |                 ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:372:17
+   |
+LL |         true && let 1 = 1
+   |                 ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:383:17
+   |
+LL |         true && let 1 = 1
+   |                 ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expressions must be enclosed in braces to be used as const generic arguments
+  --> $DIR/disallowed-positions.rs:383:9
+   |
+LL |         true && let 1 = 1
+   |         ^^^^^^^^^^^^^^^^^
+   |
+help: enclose the `const` expression in braces
+   |
+LL |         { true && let 1 = 1 }
+   |         +                   +
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:393:9
+   |
+LL |     if (let Some(a) = opt && true) {
+   |         ^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:393:9
+   |
+LL |     if (let Some(a) = opt && true) {
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:397:9
+   |
+LL |     if (let Some(a) = opt) && true {
+   |         ^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:397:9
+   |
+LL |     if (let Some(a) = opt) && true {
+   |         ^^^^^^^^^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:400:9
+   |
+LL |     if (let Some(a) = opt) && (let Some(b) = a) {
+   |         ^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:400:9
+   |
+LL |     if (let Some(a) = opt) && (let Some(b) = a) {
+   |         ^^^^^^^^^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:400:32
+   |
+LL |     if (let Some(a) = opt) && (let Some(b) = a) {
+   |                                ^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:400:32
+   |
+LL |     if (let Some(a) = opt) && (let Some(b) = a) {
+   |                                ^^^^^^^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:408:9
+   |
+LL |     if (let Some(a) = opt && (let Some(b) = a)) && b == 1 {
+   |         ^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:408:9
+   |
+LL |     if (let Some(a) = opt && (let Some(b) = a)) && b == 1 {
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:408:31
+   |
+LL |     if (let Some(a) = opt && (let Some(b) = a)) && b == 1 {
+   |                               ^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:408:31
+   |
+LL |     if (let Some(a) = opt && (let Some(b) = a)) && b == 1 {
+   |                               ^^^^^^^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:412:9
+   |
+LL |     if (let Some(a) = opt && (let Some(b) = a)) && true {
+   |         ^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:412:9
+   |
+LL |     if (let Some(a) = opt && (let Some(b) = a)) && true {
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:412:31
+   |
+LL |     if (let Some(a) = opt && (let Some(b) = a)) && true {
+   |                               ^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:412:31
+   |
+LL |     if (let Some(a) = opt && (let Some(b) = a)) && true {
+   |                               ^^^^^^^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:416:9
+   |
+LL |     if (let Some(a) = opt && (true)) && true {
+   |         ^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:416:9
+   |
+LL |     if (let Some(a) = opt && (true)) && true {
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:436:22
+   |
+LL |     let x = (true && let y = 1);
+   |                      ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:441:20
+   |
+LL |         ([1, 2, 3][let _ = ()])
+   |                    ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:91:16
+   |
+LL |     use_expr!((let 0 = 1 && 0 == 0));
+   |                ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:93:16
+   |
+LL |     use_expr!((let 0 = 1));
+   |                ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error[E0658]: `let` expressions in this position are unstable
+  --> $DIR/disallowed-positions.rs:49:8
+   |
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |        ^^^^^^^^^
+   |
+   = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
+   = help: add `#![feature(let_chains)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error[E0658]: `let` expressions in this position are unstable
+  --> $DIR/disallowed-positions.rs:49:21
+   |
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                     ^^^^^^^^^
+   |
+   = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
+   = help: add `#![feature(let_chains)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error[E0658]: `let` expressions in this position are unstable
+  --> $DIR/disallowed-positions.rs:75:11
+   |
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |           ^^^^^^^^^
+   |
+   = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
+   = help: add `#![feature(let_chains)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error[E0658]: `let` expressions in this position are unstable
+  --> $DIR/disallowed-positions.rs:75:24
+   |
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                        ^^^^^^^^^
+   |
+   = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
+   = help: add `#![feature(let_chains)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error[E0658]: `let` expressions in this position are unstable
+  --> $DIR/disallowed-positions.rs:404:8
+   |
+LL |     if let Some(a) = opt && (true && true) {
+   |        ^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
+   = help: add `#![feature(let_chains)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error[E0658]: `let` expressions in this position are unstable
+  --> $DIR/disallowed-positions.rs:420:28
+   |
+LL |     if (true && (true)) && let Some(a) = opt {
+   |                            ^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
+   = help: add `#![feature(let_chains)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error[E0658]: `let` expressions in this position are unstable
+  --> $DIR/disallowed-positions.rs:423:18
+   |
+LL |     if (true) && let Some(a) = opt {
+   |                  ^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
+   = help: add `#![feature(let_chains)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error[E0658]: `let` expressions in this position are unstable
+  --> $DIR/disallowed-positions.rs:426:16
+   |
+LL |     if true && let Some(a) = opt {
+   |                ^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
+   = help: add `#![feature(let_chains)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error[E0658]: `let` expressions in this position are unstable
+  --> $DIR/disallowed-positions.rs:431:8
+   |
+LL |     if let true = (true && fun()) && (true) {
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
+   = help: add `#![feature(let_chains)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:130:8
+   |
+LL |     if true..(let 0 = 0) {}
+   |        ^^^^^^^^^^^^^^^^^ expected `bool`, found `Range<bool>`
+   |
+   = note: expected type `bool`
+            found struct `std::ops::Range<bool>`
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:139:12
+   |
+LL |     if let Range { start: _, end: _ } = true..true && false {}
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^   ---- this expression has type `bool`
+   |            |
+   |            expected `bool`, found `Range<_>`
+   |
+   = note: expected type `bool`
+            found struct `std::ops::Range<_>`
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:142:12
+   |
+LL |     if let Range { start: _, end: _ } = true..true || false {}
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^   ---- this expression has type `bool`
+   |            |
+   |            expected `bool`, found `Range<_>`
+   |
+   = note: expected type `bool`
+            found struct `std::ops::Range<_>`
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:148:12
+   |
+LL |     if let Range { start: F, end } = F..|| true {}
+   |            ^^^^^^^^^^^^^^^^^^^^^^^   - this expression has type `fn() -> bool`
+   |            |
+   |            expected fn pointer, found `Range<_>`
+   |
+   = note: expected fn pointer `fn() -> bool`
+                  found struct `std::ops::Range<_>`
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:154:12
+   |
+LL |     if let Range { start: true, end } = t..&&false {}
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^   - this expression has type `&&bool`
+   |            |
+   |            expected `bool`, found `Range<_>`
+   |
+   = note: expected type `bool`
+            found struct `std::ops::Range<_>`
+
+error[E0277]: the `?` operator can only be applied to values that implement `Try`
+  --> $DIR/disallowed-positions.rs:110:20
+   |
+LL |         if let 0 = 0? {}
+   |                    ^^ the `?` operator cannot be applied to type `{integer}`
+   |
+   = help: the trait `Try` is not implemented for `{integer}`
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:221:11
+   |
+LL |     while true..(let 0 = 0) {}
+   |           ^^^^^^^^^^^^^^^^^ expected `bool`, found `Range<bool>`
+   |
+   = note: expected type `bool`
+            found struct `std::ops::Range<bool>`
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:230:15
+   |
+LL |     while let Range { start: _, end: _ } = true..true && false {}
+   |               ^^^^^^^^^^^^^^^^^^^^^^^^^^   ---- this expression has type `bool`
+   |               |
+   |               expected `bool`, found `Range<_>`
+   |
+   = note: expected type `bool`
+            found struct `std::ops::Range<_>`
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:233:15
+   |
+LL |     while let Range { start: _, end: _ } = true..true || false {}
+   |               ^^^^^^^^^^^^^^^^^^^^^^^^^^   ---- this expression has type `bool`
+   |               |
+   |               expected `bool`, found `Range<_>`
+   |
+   = note: expected type `bool`
+            found struct `std::ops::Range<_>`
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:239:15
+   |
+LL |     while let Range { start: F, end } = F..|| true {}
+   |               ^^^^^^^^^^^^^^^^^^^^^^^   - this expression has type `fn() -> bool`
+   |               |
+   |               expected fn pointer, found `Range<_>`
+   |
+   = note: expected fn pointer `fn() -> bool`
+                  found struct `std::ops::Range<_>`
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:245:15
+   |
+LL |     while let Range { start: true, end } = t..&&false {}
+   |               ^^^^^^^^^^^^^^^^^^^^^^^^^^   - this expression has type `&&bool`
+   |               |
+   |               expected `bool`, found `Range<_>`
+   |
+   = note: expected type `bool`
+            found struct `std::ops::Range<_>`
+
+error[E0277]: the `?` operator can only be applied to values that implement `Try`
+  --> $DIR/disallowed-positions.rs:201:23
+   |
+LL |         while let 0 = 0? {}
+   |                       ^^ the `?` operator cannot be applied to type `{integer}`
+   |
+   = help: the trait `Try` is not implemented for `{integer}`
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:330:10
+   |
+LL |     (let Range { start: _, end: _ } = true..true || false);
+   |          ^^^^^^^^^^^^^^^^^^^^^^^^^^   ---- this expression has type `bool`
+   |          |
+   |          expected `bool`, found `Range<_>`
+   |
+   = note: expected type `bool`
+            found struct `std::ops::Range<_>`
+
+error[E0277]: the `?` operator can only be applied to values that implement `Try`
+  --> $DIR/disallowed-positions.rs:305:17
+   |
+LL |         let 0 = 0?;
+   |                 ^^ the `?` operator cannot be applied to type `{integer}`
+   |
+   = help: the trait `Try` is not implemented for `{integer}`
+
+error: aborting due to 130 previous errors
+
+Some errors have detailed explanations: E0277, E0308, E0658.
+For more information about an error, try `rustc --explain E0277`.

tests/ui/rfcs/rfc-2497-if-let-chains/disallowed-positions.nofeature.stderr

@@ -1,239 +1,239 @@
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:29:9
+  --> $DIR/disallowed-positions.rs:31:9
    |
 LL |     if (let 0 = 1) {}
    |         ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions.rs:29:9
+  --> $DIR/disallowed-positions.rs:31:9
    |
 LL |     if (let 0 = 1) {}
    |         ^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:32:11
+  --> $DIR/disallowed-positions.rs:34:11
    |
 LL |     if (((let 0 = 1))) {}
    |           ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions.rs:32:11
+  --> $DIR/disallowed-positions.rs:34:11
    |
 LL |     if (((let 0 = 1))) {}
    |           ^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:35:9
+  --> $DIR/disallowed-positions.rs:37:9
    |
 LL |     if (let 0 = 1) && true {}
    |         ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions.rs:35:9
+  --> $DIR/disallowed-positions.rs:37:9
    |
 LL |     if (let 0 = 1) && true {}
    |         ^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:38:17
+  --> $DIR/disallowed-positions.rs:40:17
    |
 LL |     if true && (let 0 = 1) {}
    |                 ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions.rs:38:17
+  --> $DIR/disallowed-positions.rs:40:17
    |
 LL |     if true && (let 0 = 1) {}
    |                 ^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:41:9
+  --> $DIR/disallowed-positions.rs:43:9
    |
 LL |     if (let 0 = 1) && (let 0 = 1) {}
    |         ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions.rs:41:9
+  --> $DIR/disallowed-positions.rs:43:9
    |
 LL |     if (let 0 = 1) && (let 0 = 1) {}
    |         ^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:41:24
+  --> $DIR/disallowed-positions.rs:43:24
    |
 LL |     if (let 0 = 1) && (let 0 = 1) {}
    |                        ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions.rs:41:24
+  --> $DIR/disallowed-positions.rs:43:24
    |
 LL |     if (let 0 = 1) && (let 0 = 1) {}
    |                        ^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:45:35
+  --> $DIR/disallowed-positions.rs:47:35
    |
 LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
    |                                   ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions.rs:45:35
+  --> $DIR/disallowed-positions.rs:47:35
    |
 LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
    |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:45:48
+  --> $DIR/disallowed-positions.rs:47:48
    |
 LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
    |                                                ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions.rs:45:35
+  --> $DIR/disallowed-positions.rs:47:35
    |
 LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
    |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:45:61
+  --> $DIR/disallowed-positions.rs:47:61
    |
 LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
    |                                                             ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions.rs:45:35
+  --> $DIR/disallowed-positions.rs:47:35
    |
 LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
    |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:52:12
+  --> $DIR/disallowed-positions.rs:56:12
    |
 LL |     while (let 0 = 1) {}
    |            ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions.rs:52:12
+  --> $DIR/disallowed-positions.rs:56:12
    |
 LL |     while (let 0 = 1) {}
    |            ^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:55:14
+  --> $DIR/disallowed-positions.rs:59:14
    |
 LL |     while (((let 0 = 1))) {}
    |              ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions.rs:55:14
+  --> $DIR/disallowed-positions.rs:59:14
    |
 LL |     while (((let 0 = 1))) {}
    |              ^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:58:12
+  --> $DIR/disallowed-positions.rs:62:12
    |
 LL |     while (let 0 = 1) && true {}
    |            ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions.rs:58:12
+  --> $DIR/disallowed-positions.rs:62:12
    |
 LL |     while (let 0 = 1) && true {}
    |            ^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:61:20
+  --> $DIR/disallowed-positions.rs:65:20
    |
 LL |     while true && (let 0 = 1) {}
    |                    ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions.rs:61:20
+  --> $DIR/disallowed-positions.rs:65:20
    |
 LL |     while true && (let 0 = 1) {}
    |                    ^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:64:12
+  --> $DIR/disallowed-positions.rs:68:12
    |
 LL |     while (let 0 = 1) && (let 0 = 1) {}
    |            ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions.rs:64:12
+  --> $DIR/disallowed-positions.rs:68:12
    |
 LL |     while (let 0 = 1) && (let 0 = 1) {}
    |            ^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:64:27
+  --> $DIR/disallowed-positions.rs:68:27
    |
 LL |     while (let 0 = 1) && (let 0 = 1) {}
    |                           ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions.rs:64:27
+  --> $DIR/disallowed-positions.rs:68:27
    |
 LL |     while (let 0 = 1) && (let 0 = 1) {}
    |                           ^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:68:38
+  --> $DIR/disallowed-positions.rs:72:38
    |
 LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
    |                                      ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions.rs:68:38
+  --> $DIR/disallowed-positions.rs:72:38
    |
 LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
    |                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:68:51
+  --> $DIR/disallowed-positions.rs:72:51
    |
 LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
    |                                                   ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions.rs:68:38
+  --> $DIR/disallowed-positions.rs:72:38
    |
 LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
    |                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:68:64
+  --> $DIR/disallowed-positions.rs:72:64
    |
 LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
    |                                                                ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions.rs:68:38
+  --> $DIR/disallowed-positions.rs:72:38
    |
 LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
    |                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:88:9
+  --> $DIR/disallowed-positions.rs:95:9
    |
 LL |     if &let 0 = 0 {}
    |         ^^^^^^^^^
@@ -241,7 +241,7 @@ LL |     if &let 0 = 0 {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:91:9
+  --> $DIR/disallowed-positions.rs:98:9
    |
 LL |     if !let 0 = 0 {}
    |         ^^^^^^^^^
@@ -249,7 +249,7 @@ LL |     if !let 0 = 0 {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:93:9
+  --> $DIR/disallowed-positions.rs:100:9
    |
 LL |     if *let 0 = 0 {}
    |         ^^^^^^^^^
@@ -257,7 +257,7 @@ LL |     if *let 0 = 0 {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:95:9
+  --> $DIR/disallowed-positions.rs:102:9
    |
 LL |     if -let 0 = 0 {}
    |         ^^^^^^^^^
@@ -265,7 +265,7 @@ LL |     if -let 0 = 0 {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:103:9
+  --> $DIR/disallowed-positions.rs:110:9
    |
 LL |     if (let 0 = 0)? {}
    |         ^^^^^^^^^
@@ -273,20 +273,20 @@ LL |     if (let 0 = 0)? {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:106:16
+  --> $DIR/disallowed-positions.rs:113:16
    |
 LL |     if true || let 0 = 0 {}
    |                ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `||` operators are not supported in let chain expressions
-  --> $DIR/disallowed-positions.rs:106:13
+  --> $DIR/disallowed-positions.rs:113:13
    |
 LL |     if true || let 0 = 0 {}
    |             ^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:108:17
+  --> $DIR/disallowed-positions.rs:115:17
    |
 LL |     if (true || let 0 = 0) {}
    |                 ^^^^^^^^^
@@ -294,7 +294,7 @@ LL |     if (true || let 0 = 0) {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:110:25
+  --> $DIR/disallowed-positions.rs:117:25
    |
 LL |     if true && (true || let 0 = 0) {}
    |                         ^^^^^^^^^
@@ -302,7 +302,7 @@ LL |     if true && (true || let 0 = 0) {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:112:25
+  --> $DIR/disallowed-positions.rs:119:25
    |
 LL |     if true || (true && let 0 = 0) {}
    |                         ^^^^^^^^^
@@ -310,7 +310,7 @@ LL |     if true || (true && let 0 = 0) {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:116:12
+  --> $DIR/disallowed-positions.rs:123:12
    |
 LL |     if x = let 0 = 0 {}
    |            ^^^
@@ -318,7 +318,7 @@ LL |     if x = let 0 = 0 {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:119:15
+  --> $DIR/disallowed-positions.rs:126:15
    |
 LL |     if true..(let 0 = 0) {}
    |               ^^^^^^^^^
@@ -326,7 +326,7 @@ LL |     if true..(let 0 = 0) {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:122:11
+  --> $DIR/disallowed-positions.rs:129:11
    |
 LL |     if ..(let 0 = 0) {}
    |           ^^^^^^^^^
@@ -334,7 +334,7 @@ LL |     if ..(let 0 = 0) {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:124:9
+  --> $DIR/disallowed-positions.rs:131:9
    |
 LL |     if (let 0 = 0).. {}
    |         ^^^^^^^^^
@@ -342,7 +342,7 @@ LL |     if (let 0 = 0).. {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:128:8
+  --> $DIR/disallowed-positions.rs:135:8
    |
 LL |     if let Range { start: _, end: _ } = true..true && false {}
    |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -350,7 +350,7 @@ LL |     if let Range { start: _, end: _ } = true..true && false {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:131:8
+  --> $DIR/disallowed-positions.rs:138:8
    |
 LL |     if let Range { start: _, end: _ } = true..true || false {}
    |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -358,7 +358,7 @@ LL |     if let Range { start: _, end: _ } = true..true || false {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:137:8
+  --> $DIR/disallowed-positions.rs:144:8
    |
 LL |     if let Range { start: F, end } = F..|| true {}
    |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -366,7 +366,7 @@ LL |     if let Range { start: F, end } = F..|| true {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:143:8
+  --> $DIR/disallowed-positions.rs:150:8
    |
 LL |     if let Range { start: true, end } = t..&&false {}
    |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -374,7 +374,7 @@ LL |     if let Range { start: true, end } = t..&&false {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:147:19
+  --> $DIR/disallowed-positions.rs:154:19
    |
 LL |     if let true = let true = true {}
    |                   ^^^
@@ -382,7 +382,7 @@ LL |     if let true = let true = true {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:152:12
+  --> $DIR/disallowed-positions.rs:160:12
    |
 LL |     while &let 0 = 0 {}
    |            ^^^^^^^^^
@@ -390,7 +390,7 @@ LL |     while &let 0 = 0 {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:155:12
+  --> $DIR/disallowed-positions.rs:163:12
    |
 LL |     while !let 0 = 0 {}
    |            ^^^^^^^^^
@@ -398,7 +398,7 @@ LL |     while !let 0 = 0 {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:157:12
+  --> $DIR/disallowed-positions.rs:165:12
    |
 LL |     while *let 0 = 0 {}
    |            ^^^^^^^^^
@@ -406,7 +406,7 @@ LL |     while *let 0 = 0 {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:159:12
+  --> $DIR/disallowed-positions.rs:167:12
    |
 LL |     while -let 0 = 0 {}
    |            ^^^^^^^^^
@@ -414,7 +414,7 @@ LL |     while -let 0 = 0 {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:167:12
+  --> $DIR/disallowed-positions.rs:175:12
    |
 LL |     while (let 0 = 0)? {}
    |            ^^^^^^^^^
@@ -422,20 +422,20 @@ LL |     while (let 0 = 0)? {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:170:19
+  --> $DIR/disallowed-positions.rs:178:19
    |
 LL |     while true || let 0 = 0 {}
    |                   ^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `||` operators are not supported in let chain expressions
-  --> $DIR/disallowed-positions.rs:170:16
+  --> $DIR/disallowed-positions.rs:178:16
    |
 LL |     while true || let 0 = 0 {}
    |                ^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:172:20
+  --> $DIR/disallowed-positions.rs:180:20
    |
 LL |     while (true || let 0 = 0) {}
    |                    ^^^^^^^^^
@@ -443,7 +443,7 @@ LL |     while (true || let 0 = 0) {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:174:28
+  --> $DIR/disallowed-positions.rs:182:28
    |
 LL |     while true && (true || let 0 = 0) {}
    |                            ^^^^^^^^^
@@ -451,7 +451,7 @@ LL |     while true && (true || let 0 = 0) {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:176:28
+  --> $DIR/disallowed-positions.rs:184:28
    |
 LL |     while true || (true && let 0 = 0) {}
    |                            ^^^^^^^^^
@@ -459,7 +459,7 @@ LL |     while true || (true && let 0 = 0) {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:180:15
+  --> $DIR/disallowed-positions.rs:188:15
    |
 LL |     while x = let 0 = 0 {}
    |               ^^^
@@ -467,7 +467,7 @@ LL |     while x = let 0 = 0 {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:183:18
+  --> $DIR/disallowed-positions.rs:191:18
    |
 LL |     while true..(let 0 = 0) {}
    |                  ^^^^^^^^^
@@ -475,7 +475,7 @@ LL |     while true..(let 0 = 0) {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:186:14
+  --> $DIR/disallowed-positions.rs:194:14
    |
 LL |     while ..(let 0 = 0) {}
    |              ^^^^^^^^^
@@ -483,7 +483,7 @@ LL |     while ..(let 0 = 0) {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:188:12
+  --> $DIR/disallowed-positions.rs:196:12
    |
 LL |     while (let 0 = 0).. {}
    |            ^^^^^^^^^
@@ -491,7 +491,7 @@ LL |     while (let 0 = 0).. {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:192:11
+  --> $DIR/disallowed-positions.rs:200:11
    |
 LL |     while let Range { start: _, end: _ } = true..true && false {}
    |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -499,7 +499,7 @@ LL |     while let Range { start: _, end: _ } = true..true && false {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:195:11
+  --> $DIR/disallowed-positions.rs:203:11
    |
 LL |     while let Range { start: _, end: _ } = true..true || false {}
    |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -507,7 +507,7 @@ LL |     while let Range { start: _, end: _ } = true..true || false {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:201:11
+  --> $DIR/disallowed-positions.rs:209:11
    |
 LL |     while let Range { start: F, end } = F..|| true {}
    |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -515,7 +515,7 @@ LL |     while let Range { start: F, end } = F..|| true {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:207:11
+  --> $DIR/disallowed-positions.rs:215:11
    |
 LL |     while let Range { start: true, end } = t..&&false {}
    |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -523,7 +523,7 @@ LL |     while let Range { start: true, end } = t..&&false {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:211:22
+  --> $DIR/disallowed-positions.rs:219:22
    |
 LL |     while let true = let true = true {}
    |                      ^^^
@@ -531,7 +531,7 @@ LL |     while let true = let true = true {}
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:226:6
+  --> $DIR/disallowed-positions.rs:236:6
    |
 LL |     &let 0 = 0;
    |      ^^^
@@ -539,7 +539,7 @@ LL |     &let 0 = 0;
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:229:6
+  --> $DIR/disallowed-positions.rs:239:6
    |
 LL |     !let 0 = 0;
    |      ^^^
@@ -547,7 +547,7 @@ LL |     !let 0 = 0;
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:231:6
+  --> $DIR/disallowed-positions.rs:241:6
    |
 LL |     *let 0 = 0;
    |      ^^^
@@ -555,7 +555,7 @@ LL |     *let 0 = 0;
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:233:6
+  --> $DIR/disallowed-positions.rs:243:6
    |
 LL |     -let 0 = 0;
    |      ^^^
@@ -563,7 +563,15 @@ LL |     -let 0 = 0;
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:241:6
+  --> $DIR/disallowed-positions.rs:245:13
+   |
+LL |     let _ = let _ = 3;
+   |             ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:253:6
    |
 LL |     (let 0 = 0)?;
    |      ^^^
@@ -571,7 +579,7 @@ LL |     (let 0 = 0)?;
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:244:13
+  --> $DIR/disallowed-positions.rs:256:13
    |
 LL |     true || let 0 = 0;
    |             ^^^
@@ -579,7 +587,7 @@ LL |     true || let 0 = 0;
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:246:14
+  --> $DIR/disallowed-positions.rs:258:14
    |
 LL |     (true || let 0 = 0);
    |              ^^^
@@ -587,7 +595,7 @@ LL |     (true || let 0 = 0);
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:248:22
+  --> $DIR/disallowed-positions.rs:260:22
    |
 LL |     true && (true || let 0 = 0);
    |                      ^^^
@@ -595,7 +603,7 @@ LL |     true && (true || let 0 = 0);
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:252:9
+  --> $DIR/disallowed-positions.rs:264:9
    |
 LL |     x = let 0 = 0;
    |         ^^^
@@ -603,7 +611,7 @@ LL |     x = let 0 = 0;
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:255:12
+  --> $DIR/disallowed-positions.rs:267:12
    |
 LL |     true..(let 0 = 0);
    |            ^^^
@@ -611,7 +619,7 @@ LL |     true..(let 0 = 0);
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:257:8
+  --> $DIR/disallowed-positions.rs:269:8
    |
 LL |     ..(let 0 = 0);
    |        ^^^
@@ -619,7 +627,7 @@ LL |     ..(let 0 = 0);
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:259:6
+  --> $DIR/disallowed-positions.rs:271:6
    |
 LL |     (let 0 = 0)..;
    |      ^^^
@@ -627,7 +635,7 @@ LL |     (let 0 = 0)..;
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:262:6
+  --> $DIR/disallowed-positions.rs:274:6
    |
 LL |     (let Range { start: _, end: _ } = true..true || false);
    |      ^^^
@@ -635,7 +643,7 @@ LL |     (let Range { start: _, end: _ } = true..true || false);
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:266:6
+  --> $DIR/disallowed-positions.rs:278:6
    |
 LL |     (let true = let true = true);
    |      ^^^
@@ -643,7 +651,7 @@ LL |     (let true = let true = true);
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:266:17
+  --> $DIR/disallowed-positions.rs:278:17
    |
 LL |     (let true = let true = true);
    |                 ^^^
@@ -651,7 +659,7 @@ LL |     (let true = let true = true);
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:272:25
+  --> $DIR/disallowed-positions.rs:284:25
    |
 LL |         let x = true && let y = 1;
    |                         ^^^
@@ -659,7 +667,7 @@ LL |         let x = true && let y = 1;
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:278:19
+  --> $DIR/disallowed-positions.rs:290:19
    |
 LL |         [1, 2, 3][let _ = ()]
    |                   ^^^
@@ -667,7 +675,7 @@ LL |         [1, 2, 3][let _ = ()]
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:283:6
+  --> $DIR/disallowed-positions.rs:295:6
    |
 LL |     &let 0 = 0
    |      ^^^
@@ -675,7 +683,7 @@ LL |     &let 0 = 0
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:293:17
+  --> $DIR/disallowed-positions.rs:306:17
    |
 LL |         true && let 1 = 1
    |                 ^^^
@@ -683,7 +691,7 @@ LL |         true && let 1 = 1
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:298:17
+  --> $DIR/disallowed-positions.rs:311:17
    |
 LL |         true && let 1 = 1
    |                 ^^^
@@ -691,7 +699,7 @@ LL |         true && let 1 = 1
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:303:17
+  --> $DIR/disallowed-positions.rs:316:17
    |
 LL |         true && let 1 = 1
    |                 ^^^
@@ -699,7 +707,7 @@ LL |         true && let 1 = 1
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:314:17
+  --> $DIR/disallowed-positions.rs:327:17
    |
 LL |         true && let 1 = 1
    |                 ^^^
@@ -707,7 +715,7 @@ LL |         true && let 1 = 1
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expressions must be enclosed in braces to be used as const generic arguments
-  --> $DIR/disallowed-positions.rs:314:9
+  --> $DIR/disallowed-positions.rs:327:9
    |
 LL |         true && let 1 = 1
    |         ^^^^^^^^^^^^^^^^^
@@ -718,124 +726,124 @@ LL |         { true && let 1 = 1 }
    |         +                   +
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:323:9
+  --> $DIR/disallowed-positions.rs:337:9
    |
 LL |     if (let Some(a) = opt && true) {
    |         ^^^^^^^^^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions.rs:323:9
+  --> $DIR/disallowed-positions.rs:337:9
    |
 LL |     if (let Some(a) = opt && true) {
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:327:9
+  --> $DIR/disallowed-positions.rs:341:9
    |
 LL |     if (let Some(a) = opt) && true {
    |         ^^^^^^^^^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions.rs:327:9
+  --> $DIR/disallowed-positions.rs:341:9
    |
 LL |     if (let Some(a) = opt) && true {
    |         ^^^^^^^^^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:330:9
+  --> $DIR/disallowed-positions.rs:344:9
    |
 LL |     if (let Some(a) = opt) && (let Some(b) = a) {
    |         ^^^^^^^^^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions.rs:330:9
+  --> $DIR/disallowed-positions.rs:344:9
    |
 LL |     if (let Some(a) = opt) && (let Some(b) = a) {
    |         ^^^^^^^^^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:330:32
+  --> $DIR/disallowed-positions.rs:344:32
    |
 LL |     if (let Some(a) = opt) && (let Some(b) = a) {
    |                                ^^^^^^^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions.rs:330:32
+  --> $DIR/disallowed-positions.rs:344:32
    |
 LL |     if (let Some(a) = opt) && (let Some(b) = a) {
    |                                ^^^^^^^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:337:9
+  --> $DIR/disallowed-positions.rs:351:9
    |
 LL |     if (let Some(a) = opt && (let Some(b) = a)) && b == 1 {
    |         ^^^^^^^^^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions.rs:337:9
+  --> $DIR/disallowed-positions.rs:351:9
    |
 LL |     if (let Some(a) = opt && (let Some(b) = a)) && b == 1 {
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:337:31
+  --> $DIR/disallowed-positions.rs:351:31
    |
 LL |     if (let Some(a) = opt && (let Some(b) = a)) && b == 1 {
    |                               ^^^^^^^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions.rs:337:31
+  --> $DIR/disallowed-positions.rs:351:31
    |
 LL |     if (let Some(a) = opt && (let Some(b) = a)) && b == 1 {
    |                               ^^^^^^^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:341:9
+  --> $DIR/disallowed-positions.rs:355:9
    |
 LL |     if (let Some(a) = opt && (let Some(b) = a)) && true {
    |         ^^^^^^^^^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions.rs:341:9
+  --> $DIR/disallowed-positions.rs:355:9
    |
 LL |     if (let Some(a) = opt && (let Some(b) = a)) && true {
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:341:31
+  --> $DIR/disallowed-positions.rs:355:31
    |
 LL |     if (let Some(a) = opt && (let Some(b) = a)) && true {
    |                               ^^^^^^^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions.rs:341:31
+  --> $DIR/disallowed-positions.rs:355:31
    |
 LL |     if (let Some(a) = opt && (let Some(b) = a)) && true {
    |                               ^^^^^^^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:345:9
+  --> $DIR/disallowed-positions.rs:359:9
    |
 LL |     if (let Some(a) = opt && (true)) && true {
    |         ^^^^^^^^^^^^^^^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 note: `let`s wrapped in parentheses are not supported in a context with let chains
-  --> $DIR/disallowed-positions.rs:345:9
+  --> $DIR/disallowed-positions.rs:359:9
    |
 LL |     if (let Some(a) = opt && (true)) && true {
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:361:22
+  --> $DIR/disallowed-positions.rs:375:22
    |
 LL |     let x = (true && let y = 1);
    |                      ^^^
@@ -843,7 +851,7 @@ LL |     let x = (true && let y = 1);
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:366:20
+  --> $DIR/disallowed-positions.rs:380:20
    |
 LL |         ([1, 2, 3][let _ = ()])
    |                    ^^^
@@ -851,7 +859,7 @@ LL |         ([1, 2, 3][let _ = ()])
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:81:16
+  --> $DIR/disallowed-positions.rs:87:16
    |
 LL |     use_expr!((let 0 = 1 && 0 == 0));
    |                ^^^
@@ -859,15 +867,105 @@ LL |     use_expr!((let 0 = 1 && 0 == 0));
    = note: only supported directly in conditions of `if` and `while` expressions
 
 error: expected expression, found `let` statement
-  --> $DIR/disallowed-positions.rs:83:16
+  --> $DIR/disallowed-positions.rs:89:16
    |
 LL |     use_expr!((let 0 = 1));
    |                ^^^
    |
    = note: only supported directly in conditions of `if` and `while` expressions
 
+error[E0658]: `let` expressions in this position are unstable
+  --> $DIR/disallowed-positions.rs:47:8
+   |
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |        ^^^^^^^^^
+   |
+   = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
+   = help: add `#![feature(let_chains)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error[E0658]: `let` expressions in this position are unstable
+  --> $DIR/disallowed-positions.rs:47:21
+   |
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                     ^^^^^^^^^
+   |
+   = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
+   = help: add `#![feature(let_chains)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error[E0658]: `let` expressions in this position are unstable
+  --> $DIR/disallowed-positions.rs:72:11
+   |
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |           ^^^^^^^^^
+   |
+   = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
+   = help: add `#![feature(let_chains)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error[E0658]: `let` expressions in this position are unstable
+  --> $DIR/disallowed-positions.rs:72:24
+   |
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                        ^^^^^^^^^
+   |
+   = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
+   = help: add `#![feature(let_chains)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error[E0658]: `let` expressions in this position are unstable
+  --> $DIR/disallowed-positions.rs:348:8
+   |
+LL |     if let Some(a) = opt && (true && true) {
+   |        ^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
+   = help: add `#![feature(let_chains)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error[E0658]: `let` expressions in this position are unstable
+  --> $DIR/disallowed-positions.rs:363:28
+   |
+LL |     if (true && (true)) && let Some(a) = opt {
+   |                            ^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
+   = help: add `#![feature(let_chains)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error[E0658]: `let` expressions in this position are unstable
+  --> $DIR/disallowed-positions.rs:365:18
+   |
+LL |     if (true) && let Some(a) = opt {
+   |                  ^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
+   = help: add `#![feature(let_chains)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error[E0658]: `let` expressions in this position are unstable
+  --> $DIR/disallowed-positions.rs:367:16
+   |
+LL |     if true && let Some(a) = opt {
+   |                ^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
+   = help: add `#![feature(let_chains)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error[E0658]: `let` expressions in this position are unstable
+  --> $DIR/disallowed-positions.rs:371:8
+   |
+LL |     if let true = (true && fun()) && (true) {
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
+   = help: add `#![feature(let_chains)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:119:8
+  --> $DIR/disallowed-positions.rs:126:8
    |
 LL |     if true..(let 0 = 0) {}
    |        ^^^^^^^^^^^^^^^^^ expected `bool`, found `Range<bool>`
@@ -876,7 +974,7 @@ LL |     if true..(let 0 = 0) {}
             found struct `std::ops::Range<bool>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:128:12
+  --> $DIR/disallowed-positions.rs:135:12
    |
 LL |     if let Range { start: _, end: _ } = true..true && false {}
    |            ^^^^^^^^^^^^^^^^^^^^^^^^^^   ---- this expression has type `bool`
@@ -887,7 +985,7 @@ LL |     if let Range { start: _, end: _ } = true..true && false {}
             found struct `std::ops::Range<_>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:131:12
+  --> $DIR/disallowed-positions.rs:138:12
    |
 LL |     if let Range { start: _, end: _ } = true..true || false {}
    |            ^^^^^^^^^^^^^^^^^^^^^^^^^^   ---- this expression has type `bool`
@@ -898,7 +996,7 @@ LL |     if let Range { start: _, end: _ } = true..true || false {}
             found struct `std::ops::Range<_>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:137:12
+  --> $DIR/disallowed-positions.rs:144:12
    |
 LL |     if let Range { start: F, end } = F..|| true {}
    |            ^^^^^^^^^^^^^^^^^^^^^^^   - this expression has type `fn() -> bool`
@@ -909,7 +1007,7 @@ LL |     if let Range { start: F, end } = F..|| true {}
                   found struct `std::ops::Range<_>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:143:12
+  --> $DIR/disallowed-positions.rs:150:12
    |
 LL |     if let Range { start: true, end } = t..&&false {}
    |            ^^^^^^^^^^^^^^^^^^^^^^^^^^   - this expression has type `&&bool`
@@ -920,7 +1018,7 @@ LL |     if let Range { start: true, end } = t..&&false {}
             found struct `std::ops::Range<_>`
 
 error[E0277]: the `?` operator can only be applied to values that implement `Try`
-  --> $DIR/disallowed-positions.rs:99:20
+  --> $DIR/disallowed-positions.rs:106:20
    |
 LL |         if let 0 = 0? {}
    |                    ^^ the `?` operator cannot be applied to type `{integer}`
@@ -928,7 +1026,7 @@ LL |         if let 0 = 0? {}
    = help: the trait `Try` is not implemented for `{integer}`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:183:11
+  --> $DIR/disallowed-positions.rs:191:11
    |
 LL |     while true..(let 0 = 0) {}
    |           ^^^^^^^^^^^^^^^^^ expected `bool`, found `Range<bool>`
@@ -937,7 +1035,7 @@ LL |     while true..(let 0 = 0) {}
             found struct `std::ops::Range<bool>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:192:15
+  --> $DIR/disallowed-positions.rs:200:15
    |
 LL |     while let Range { start: _, end: _ } = true..true && false {}
    |               ^^^^^^^^^^^^^^^^^^^^^^^^^^   ---- this expression has type `bool`
@@ -948,7 +1046,7 @@ LL |     while let Range { start: _, end: _ } = true..true && false {}
             found struct `std::ops::Range<_>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:195:15
+  --> $DIR/disallowed-positions.rs:203:15
    |
 LL |     while let Range { start: _, end: _ } = true..true || false {}
    |               ^^^^^^^^^^^^^^^^^^^^^^^^^^   ---- this expression has type `bool`
@@ -959,7 +1057,7 @@ LL |     while let Range { start: _, end: _ } = true..true || false {}
             found struct `std::ops::Range<_>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:201:15
+  --> $DIR/disallowed-positions.rs:209:15
    |
 LL |     while let Range { start: F, end } = F..|| true {}
    |               ^^^^^^^^^^^^^^^^^^^^^^^   - this expression has type `fn() -> bool`
@@ -970,7 +1068,7 @@ LL |     while let Range { start: F, end } = F..|| true {}
                   found struct `std::ops::Range<_>`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:207:15
+  --> $DIR/disallowed-positions.rs:215:15
    |
 LL |     while let Range { start: true, end } = t..&&false {}
    |               ^^^^^^^^^^^^^^^^^^^^^^^^^^   - this expression has type `&&bool`
@@ -981,7 +1079,7 @@ LL |     while let Range { start: true, end } = t..&&false {}
             found struct `std::ops::Range<_>`
 
 error[E0277]: the `?` operator can only be applied to values that implement `Try`
-  --> $DIR/disallowed-positions.rs:163:23
+  --> $DIR/disallowed-positions.rs:171:23
    |
 LL |         while let 0 = 0? {}
    |                       ^^ the `?` operator cannot be applied to type `{integer}`
@@ -989,7 +1087,7 @@ LL |         while let 0 = 0? {}
    = help: the trait `Try` is not implemented for `{integer}`
 
 error[E0308]: mismatched types
-  --> $DIR/disallowed-positions.rs:262:10
+  --> $DIR/disallowed-positions.rs:274:10
    |
 LL |     (let Range { start: _, end: _ } = true..true || false);
    |          ^^^^^^^^^^^^^^^^^^^^^^^^^^   ---- this expression has type `bool`
@@ -1000,14 +1098,14 @@ LL |     (let Range { start: _, end: _ } = true..true || false);
             found struct `std::ops::Range<_>`
 
 error[E0277]: the `?` operator can only be applied to values that implement `Try`
-  --> $DIR/disallowed-positions.rs:237:17
+  --> $DIR/disallowed-positions.rs:249:17
    |
 LL |         let 0 = 0?;
    |                 ^^ the `?` operator cannot be applied to type `{integer}`
    |
    = help: the trait `Try` is not implemented for `{integer}`
 
-error: aborting due to 104 previous errors
+error: aborting due to 114 previous errors
 
-Some errors have detailed explanations: E0277, E0308.
+Some errors have detailed explanations: E0277, E0308, E0658.
 For more information about an error, try `rustc --explain E0277`.

tests/ui/rfcs/rfc-2497-if-let-chains/disallowed-positions.nothing.stderr

@@ -0,0 +1,990 @@
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:33:9
+   |
+LL |     if (let 0 = 1) {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:33:9
+   |
+LL |     if (let 0 = 1) {}
+   |         ^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:36:11
+   |
+LL |     if (((let 0 = 1))) {}
+   |           ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:36:11
+   |
+LL |     if (((let 0 = 1))) {}
+   |           ^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:39:9
+   |
+LL |     if (let 0 = 1) && true {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:39:9
+   |
+LL |     if (let 0 = 1) && true {}
+   |         ^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:42:17
+   |
+LL |     if true && (let 0 = 1) {}
+   |                 ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:42:17
+   |
+LL |     if true && (let 0 = 1) {}
+   |                 ^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:45:9
+   |
+LL |     if (let 0 = 1) && (let 0 = 1) {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:45:9
+   |
+LL |     if (let 0 = 1) && (let 0 = 1) {}
+   |         ^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:45:24
+   |
+LL |     if (let 0 = 1) && (let 0 = 1) {}
+   |                        ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:45:24
+   |
+LL |     if (let 0 = 1) && (let 0 = 1) {}
+   |                        ^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:49:35
+   |
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                   ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:49:35
+   |
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:49:48
+   |
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                                ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:49:35
+   |
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:49:61
+   |
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                                             ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:49:35
+   |
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:59:12
+   |
+LL |     while (let 0 = 1) {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:59:12
+   |
+LL |     while (let 0 = 1) {}
+   |            ^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:62:14
+   |
+LL |     while (((let 0 = 1))) {}
+   |              ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:62:14
+   |
+LL |     while (((let 0 = 1))) {}
+   |              ^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:65:12
+   |
+LL |     while (let 0 = 1) && true {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:65:12
+   |
+LL |     while (let 0 = 1) && true {}
+   |            ^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:68:20
+   |
+LL |     while true && (let 0 = 1) {}
+   |                    ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:68:20
+   |
+LL |     while true && (let 0 = 1) {}
+   |                    ^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:71:12
+   |
+LL |     while (let 0 = 1) && (let 0 = 1) {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:71:12
+   |
+LL |     while (let 0 = 1) && (let 0 = 1) {}
+   |            ^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:71:27
+   |
+LL |     while (let 0 = 1) && (let 0 = 1) {}
+   |                           ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:71:27
+   |
+LL |     while (let 0 = 1) && (let 0 = 1) {}
+   |                           ^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:75:38
+   |
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                      ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:75:38
+   |
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:75:51
+   |
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                                   ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:75:38
+   |
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:75:64
+   |
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                                                ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:75:38
+   |
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:99:9
+   |
+LL |     if &let 0 = 0 {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:102:9
+   |
+LL |     if !let 0 = 0 {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:104:9
+   |
+LL |     if *let 0 = 0 {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:106:9
+   |
+LL |     if -let 0 = 0 {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:114:9
+   |
+LL |     if (let 0 = 0)? {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:117:16
+   |
+LL |     if true || let 0 = 0 {}
+   |                ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `||` operators are not supported in let chain expressions
+  --> $DIR/disallowed-positions.rs:117:13
+   |
+LL |     if true || let 0 = 0 {}
+   |             ^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:119:17
+   |
+LL |     if (true || let 0 = 0) {}
+   |                 ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:121:25
+   |
+LL |     if true && (true || let 0 = 0) {}
+   |                         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:123:25
+   |
+LL |     if true || (true && let 0 = 0) {}
+   |                         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:127:12
+   |
+LL |     if x = let 0 = 0 {}
+   |            ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:130:15
+   |
+LL |     if true..(let 0 = 0) {}
+   |               ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:133:11
+   |
+LL |     if ..(let 0 = 0) {}
+   |           ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:135:9
+   |
+LL |     if (let 0 = 0).. {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:139:8
+   |
+LL |     if let Range { start: _, end: _ } = true..true && false {}
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:142:8
+   |
+LL |     if let Range { start: _, end: _ } = true..true || false {}
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:148:8
+   |
+LL |     if let Range { start: F, end } = F..|| true {}
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:154:8
+   |
+LL |     if let Range { start: true, end } = t..&&false {}
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:158:19
+   |
+LL |     if let true = let true = true {}
+   |                   ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:161:15
+   |
+LL |     if return let 0 = 0 {}
+   |               ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:164:21
+   |
+LL |     loop { if break let 0 = 0 {} }
+   |                     ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:167:15
+   |
+LL |     if (match let 0 = 0 { _ => { false } }) {}
+   |               ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:170:9
+   |
+LL |     if (let 0 = 0, false).1 {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:173:9
+   |
+LL |     if (let 0 = 0,) {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:177:13
+   |
+LL |         if (let 0 = 0).await {}
+   |             ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:181:12
+   |
+LL |     if (|| let 0 = 0) {}
+   |            ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:184:9
+   |
+LL |     if (let 0 = 0)() {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:190:12
+   |
+LL |     while &let 0 = 0 {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:193:12
+   |
+LL |     while !let 0 = 0 {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:195:12
+   |
+LL |     while *let 0 = 0 {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:197:12
+   |
+LL |     while -let 0 = 0 {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:205:12
+   |
+LL |     while (let 0 = 0)? {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:208:19
+   |
+LL |     while true || let 0 = 0 {}
+   |                   ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `||` operators are not supported in let chain expressions
+  --> $DIR/disallowed-positions.rs:208:16
+   |
+LL |     while true || let 0 = 0 {}
+   |                ^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:210:20
+   |
+LL |     while (true || let 0 = 0) {}
+   |                    ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:212:28
+   |
+LL |     while true && (true || let 0 = 0) {}
+   |                            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:214:28
+   |
+LL |     while true || (true && let 0 = 0) {}
+   |                            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:218:15
+   |
+LL |     while x = let 0 = 0 {}
+   |               ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:221:18
+   |
+LL |     while true..(let 0 = 0) {}
+   |                  ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:224:14
+   |
+LL |     while ..(let 0 = 0) {}
+   |              ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:226:12
+   |
+LL |     while (let 0 = 0).. {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:230:11
+   |
+LL |     while let Range { start: _, end: _ } = true..true && false {}
+   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:233:11
+   |
+LL |     while let Range { start: _, end: _ } = true..true || false {}
+   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:239:11
+   |
+LL |     while let Range { start: F, end } = F..|| true {}
+   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:245:11
+   |
+LL |     while let Range { start: true, end } = t..&&false {}
+   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:249:22
+   |
+LL |     while let true = let true = true {}
+   |                      ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:252:18
+   |
+LL |     while return let 0 = 0 {}
+   |                  ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:255:39
+   |
+LL |     'outer: loop { while break 'outer let 0 = 0 {} }
+   |                                       ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:258:18
+   |
+LL |     while (match let 0 = 0 { _ => { false } }) {}
+   |                  ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:261:12
+   |
+LL |     while (let 0 = 0, false).1 {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:264:12
+   |
+LL |     while (let 0 = 0,) {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:268:16
+   |
+LL |         while (let 0 = 0).await {}
+   |                ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:272:15
+   |
+LL |     while (|| let 0 = 0) {}
+   |               ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:275:12
+   |
+LL |     while (let 0 = 0)() {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:292:6
+   |
+LL |     &let 0 = 0;
+   |      ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:295:6
+   |
+LL |     !let 0 = 0;
+   |      ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:297:6
+   |
+LL |     *let 0 = 0;
+   |      ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:299:6
+   |
+LL |     -let 0 = 0;
+   |      ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:301:13
+   |
+LL |     let _ = let _ = 3;
+   |             ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:309:6
+   |
+LL |     (let 0 = 0)?;
+   |      ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:312:13
+   |
+LL |     true || let 0 = 0;
+   |             ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:314:14
+   |
+LL |     (true || let 0 = 0);
+   |              ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:316:22
+   |
+LL |     true && (true || let 0 = 0);
+   |                      ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:320:9
+   |
+LL |     x = let 0 = 0;
+   |         ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:323:12
+   |
+LL |     true..(let 0 = 0);
+   |            ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:325:8
+   |
+LL |     ..(let 0 = 0);
+   |        ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:327:6
+   |
+LL |     (let 0 = 0)..;
+   |      ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:330:6
+   |
+LL |     (let Range { start: _, end: _ } = true..true || false);
+   |      ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:334:6
+   |
+LL |     (let true = let true = true);
+   |      ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:334:17
+   |
+LL |     (let true = let true = true);
+   |                 ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:340:25
+   |
+LL |         let x = true && let y = 1;
+   |                         ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:346:19
+   |
+LL |         [1, 2, 3][let _ = ()]
+   |                   ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:351:6
+   |
+LL |     &let 0 = 0
+   |      ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:362:17
+   |
+LL |         true && let 1 = 1
+   |                 ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:367:17
+   |
+LL |         true && let 1 = 1
+   |                 ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:372:17
+   |
+LL |         true && let 1 = 1
+   |                 ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:383:17
+   |
+LL |         true && let 1 = 1
+   |                 ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expressions must be enclosed in braces to be used as const generic arguments
+  --> $DIR/disallowed-positions.rs:383:9
+   |
+LL |         true && let 1 = 1
+   |         ^^^^^^^^^^^^^^^^^
+   |
+help: enclose the `const` expression in braces
+   |
+LL |         { true && let 1 = 1 }
+   |         +                   +
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:393:9
+   |
+LL |     if (let Some(a) = opt && true) {
+   |         ^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:393:9
+   |
+LL |     if (let Some(a) = opt && true) {
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:397:9
+   |
+LL |     if (let Some(a) = opt) && true {
+   |         ^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:397:9
+   |
+LL |     if (let Some(a) = opt) && true {
+   |         ^^^^^^^^^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:400:9
+   |
+LL |     if (let Some(a) = opt) && (let Some(b) = a) {
+   |         ^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:400:9
+   |
+LL |     if (let Some(a) = opt) && (let Some(b) = a) {
+   |         ^^^^^^^^^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:400:32
+   |
+LL |     if (let Some(a) = opt) && (let Some(b) = a) {
+   |                                ^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:400:32
+   |
+LL |     if (let Some(a) = opt) && (let Some(b) = a) {
+   |                                ^^^^^^^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:408:9
+   |
+LL |     if (let Some(a) = opt && (let Some(b) = a)) && b == 1 {
+   |         ^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:408:9
+   |
+LL |     if (let Some(a) = opt && (let Some(b) = a)) && b == 1 {
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:408:31
+   |
+LL |     if (let Some(a) = opt && (let Some(b) = a)) && b == 1 {
+   |                               ^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:408:31
+   |
+LL |     if (let Some(a) = opt && (let Some(b) = a)) && b == 1 {
+   |                               ^^^^^^^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:412:9
+   |
+LL |     if (let Some(a) = opt && (let Some(b) = a)) && true {
+   |         ^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:412:9
+   |
+LL |     if (let Some(a) = opt && (let Some(b) = a)) && true {
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:412:31
+   |
+LL |     if (let Some(a) = opt && (let Some(b) = a)) && true {
+   |                               ^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:412:31
+   |
+LL |     if (let Some(a) = opt && (let Some(b) = a)) && true {
+   |                               ^^^^^^^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:416:9
+   |
+LL |     if (let Some(a) = opt && (true)) && true {
+   |         ^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:416:9
+   |
+LL |     if (let Some(a) = opt && (true)) && true {
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:436:22
+   |
+LL |     let x = (true && let y = 1);
+   |                      ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:441:20
+   |
+LL |         ([1, 2, 3][let _ = ()])
+   |                    ^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: aborting due to 105 previous errors
+

tests/ui/rfcs/rfc-2497-if-let-chains/disallowed-positions.rs

@@ -1,3 +1,5 @@
+//@ revisions: no_feature feature nothing
+//@ edition: 2021
 // Here we test that `lowering` behaves correctly wrt. `let $pats = $expr` expressions.
 //
 // We want to make sure that `let` is banned in situations other than:
@@ -17,7 +19,8 @@
 //
 // To that end, we check some positions which is not part of the language above.
 
-#![feature(let_chains)] // Avoid inflating `.stderr` with overzealous gates in this test.
+// Avoid inflating `.stderr` with overzealous gates (or test what happens if you disable the gate)
+#![cfg_attr(not(no_feature), feature(let_chains))]
 
 #![allow(irrefutable_let_patterns)]
 
@@ -25,6 +28,7 @@
 
 fn main() {}
 
+#[cfg(not(nothing))]
 fn _if() {
     if (let 0 = 1) {}
     //~^ ERROR expected expression, found `let` statement
@@ -46,8 +50,11 @@ fn _if() {
     //~^ ERROR expected expression, found `let` statement
     //~| ERROR expected expression, found `let` statement
     //~| ERROR expected expression, found `let` statement
+    //[no_feature]~| ERROR `let` expressions in this position are unstable
+    //[no_feature]~| ERROR `let` expressions in this position are unstable
 }
 
+#[cfg(not(nothing))]
 fn _while() {
     while (let 0 = 1) {}
     //~^ ERROR expected expression, found `let` statement
@@ -69,8 +76,11 @@ fn _while() {
     //~^ ERROR expected expression, found `let` statement
     //~| ERROR expected expression, found `let` statement
     //~| ERROR expected expression, found `let` statement
+    //[no_feature]~| ERROR `let` expressions in this position are unstable
+    //[no_feature]~| ERROR `let` expressions in this position are unstable
 }
 
+#[cfg(not(nothing))]
 fn _macros() {
     macro_rules! use_expr {
         ($e:expr) => {
@@ -79,11 +89,12 @@ macro_rules! use_expr {
         }
     }
     use_expr!((let 0 = 1 && 0 == 0));
-    //~^ ERROR expected expression, found `let` statement
+    //[feature,no_feature]~^ ERROR expected expression, found `let` statement
     use_expr!((let 0 = 1));
-    //~^ ERROR expected expression, found `let` statement
+    //[feature,no_feature]~^ ERROR expected expression, found `let` statement
 }
 
+#[cfg(not(nothing))]
 fn nested_within_if_expr() {
     if &let 0 = 0 {}
     //~^ ERROR expected expression, found `let` statement
@@ -97,7 +108,7 @@ fn nested_within_if_expr() {
 
     fn _check_try_binds_tighter() -> Result<(), ()> {
         if let 0 = 0? {}
-        //~^ ERROR the `?` operator can only be applied to values that implement `Try`
+        //[feature,no_feature]~^ ERROR the `?` operator can only be applied to values that implement `Try`
         Ok(())
     }
     if (let 0 = 0)? {}
@@ -118,7 +129,7 @@ fn _check_try_binds_tighter() -> Result<(), ()> {
 
     if true..(let 0 = 0) {}
     //~^ ERROR expected expression, found `let` statement
-    //~| ERROR mismatched types
+    //[feature,no_feature]~| ERROR mismatched types
     if ..(let 0 = 0) {}
     //~^ ERROR expected expression, found `let` statement
     if (let 0 = 0).. {}
@@ -127,27 +138,54 @@ fn _check_try_binds_tighter() -> Result<(), ()> {
     // Binds as `(let ... = true)..true &&/|| false`.
     if let Range { start: _, end: _ } = true..true && false {}
     //~^ ERROR expected expression, found `let` statement
-    //~| ERROR mismatched types
+    //[feature,no_feature]~| ERROR mismatched types
     if let Range { start: _, end: _ } = true..true || false {}
     //~^ ERROR expected expression, found `let` statement
-    //~| ERROR mismatched types
+    //[feature,no_feature]~| ERROR mismatched types
 
     // Binds as `(let Range { start: F, end } = F)..(|| true)`.
     const F: fn() -> bool = || true;
     if let Range { start: F, end } = F..|| true {}
     //~^ ERROR expected expression, found `let` statement
-    //~| ERROR mismatched types
+    //[feature,no_feature]~| ERROR mismatched types
 
     // Binds as `(let Range { start: true, end } = t)..(&&false)`.
     let t = &&true;
     if let Range { start: true, end } = t..&&false {}
     //~^ ERROR expected expression, found `let` statement
-    //~| ERROR mismatched types
+    //[feature,no_feature]~| ERROR mismatched types
 
     if let true = let true = true {}
     //~^ ERROR expected expression, found `let` statement
+
+    if return let 0 = 0 {}
+    //~^ ERROR expected expression, found `let` statement
+
+    loop { if break let 0 = 0 {} }
+    //~^ ERROR expected expression, found `let` statement
+
+    if (match let 0 = 0 { _ => { false } }) {}
+    //~^ ERROR expected expression, found `let` statement
+
+    if (let 0 = 0, false).1 {}
+    //~^ ERROR expected expression, found `let` statement
+
+    if (let 0 = 0,) {}
+    //~^ ERROR expected expression, found `let` statement
+
+    async fn foo() {
+        if (let 0 = 0).await {}
+        //~^ ERROR expected expression, found `let` statement
+    }
+
+    if (|| let 0 = 0) {}
+    //~^ ERROR expected expression, found `let` statement
+
+    if (let 0 = 0)() {}
+    //~^ ERROR expected expression, found `let` statement
 }
 
+#[cfg(not(nothing))]
 fn nested_within_while_expr() {
     while &let 0 = 0 {}
     //~^ ERROR expected expression, found `let` statement
@@ -161,7 +199,7 @@ fn nested_within_while_expr() {
 
     fn _check_try_binds_tighter() -> Result<(), ()> {
         while let 0 = 0? {}
-        //~^ ERROR the `?` operator can only be applied to values that implement `Try`
+        //[feature,no_feature]~^ ERROR the `?` operator can only be applied to values that implement `Try`
         Ok(())
     }
     while (let 0 = 0)? {}
@@ -182,7 +220,7 @@ fn _check_try_binds_tighter() -> Result<(), ()> {
 
     while true..(let 0 = 0) {}
     //~^ ERROR expected expression, found `let` statement
-    //~| ERROR mismatched types
+    //[feature,no_feature]~| ERROR mismatched types
     while ..(let 0 = 0) {}
     //~^ ERROR expected expression, found `let` statement
     while (let 0 = 0).. {}
@@ -191,27 +229,54 @@ fn _check_try_binds_tighter() -> Result<(), ()> {
     // Binds as `(let ... = true)..true &&/|| false`.
     while let Range { start: _, end: _ } = true..true && false {}
     //~^ ERROR expected expression, found `let` statement
-    //~| ERROR mismatched types
+    //[feature,no_feature]~| ERROR mismatched types
     while let Range { start: _, end: _ } = true..true || false {}
     //~^ ERROR expected expression, found `let` statement
-    //~| ERROR mismatched types
+    //[feature,no_feature]~| ERROR mismatched types
 
     // Binds as `(let Range { start: F, end } = F)..(|| true)`.
     const F: fn() -> bool = || true;
     while let Range { start: F, end } = F..|| true {}
     //~^ ERROR expected expression, found `let` statement
-    //~| ERROR mismatched types
+    //[feature,no_feature]~| ERROR mismatched types
 
     // Binds as `(let Range { start: true, end } = t)..(&&false)`.
     let t = &&true;
     while let Range { start: true, end } = t..&&false {}
     //~^ ERROR expected expression, found `let` statement
-    //~| ERROR mismatched types
+    //[feature,no_feature]~| ERROR mismatched types
 
     while let true = let true = true {}
     //~^ ERROR expected expression, found `let` statement
+
+    while return let 0 = 0 {}
+    //~^ ERROR expected expression, found `let` statement
+
+    'outer: loop { while break 'outer let 0 = 0 {} }
+    //~^ ERROR expected expression, found `let` statement
+
+    while (match let 0 = 0 { _ => { false } }) {}
+    //~^ ERROR expected expression, found `let` statement
+
+    while (let 0 = 0, false).1 {}
+    //~^ ERROR expected expression, found `let` statement
+
+    while (let 0 = 0,) {}
+    //~^ ERROR expected expression, found `let` statement
+
+    async fn foo() {
+        while (let 0 = 0).await {}
+        //~^ ERROR expected expression, found `let` statement
+    }
+
+    while (|| let 0 = 0) {}
+    //~^ ERROR expected expression, found `let` statement
+
+    while (let 0 = 0)() {}
+    //~^ ERROR expected expression, found `let` statement
 }
 
+#[cfg(not(nothing))]
 fn not_error_because_clarified_intent() {
     if let Range { start: _, end: _ } = (true..true || false) { }
 
@@ -222,6 +287,7 @@ fn not_error_because_clarified_intent() {
     while let Range { start: _, end: _ } = (true..true && false) { }
 }
 
+#[cfg(not(nothing))]
 fn outside_if_and_while_expr() {
     &let 0 = 0;
     //~^ ERROR expected expression, found `let` statement
@@ -232,10 +298,12 @@ fn outside_if_and_while_expr() {
     //~^ ERROR expected expression, found `let` statement
     -let 0 = 0;
     //~^ ERROR expected expression, found `let` statement
+    let _ = let _ = 3;
+    //~^ ERROR expected expression, found `let` statement
 
     fn _check_try_binds_tighter() -> Result<(), ()> {
         let 0 = 0?;
-        //~^ ERROR the `?` operator can only be applied to values that implement `Try`
+        //[feature,no_feature]~^ ERROR the `?` operator can only be applied to values that implement `Try`
         Ok(())
     }
     (let 0 = 0)?;
@@ -260,8 +328,8 @@ fn _check_try_binds_tighter() -> Result<(), ()> {
     //~^ ERROR expected expression, found `let` statement
 
     (let Range { start: _, end: _ } = true..true || false);
-    //~^ ERROR mismatched types
-    //~| ERROR expected expression, found `let` statement
+    //~^ ERROR expected expression, found `let` statement
+    //[feature,no_feature]~| ERROR mismatched types
 
     (let true = let true = true);
     //~^ ERROR expected expression, found `let` statement
@@ -285,6 +353,7 @@ fn _check_try_binds_tighter() -> Result<(), ()> {
 }
 
 // Let's make sure that `let` inside const generic arguments are considered.
+#[cfg(not(nothing))]
 fn inside_const_generic_arguments() {
     struct A<const B: bool>;
     impl<const B: bool> A<{B}> { const O: u32 = 5; }
@@ -317,6 +386,7 @@ fn inside_const_generic_arguments() {
     >::O == 5 {}
 }
 
+#[cfg(not(nothing))]
 fn with_parenthesis() {
     let opt = Some(Some(1i32));
 
@@ -332,6 +402,7 @@ fn with_parenthesis() {
     //~| ERROR expected expression, found `let` statement
     }
     if let Some(a) = opt && (true && true) {
+    //[no_feature]~^ ERROR `let` expressions in this position are unstable
     }
 
     if (let Some(a) = opt && (let Some(b) = a)) && b == 1 {
@@ -347,14 +418,18 @@ fn with_parenthesis() {
     }
 
     if (true && (true)) && let Some(a) = opt {
+    //[no_feature]~^ ERROR `let` expressions in this position are unstable
     }
     if (true) && let Some(a) = opt {
+    //[no_feature]~^ ERROR `let` expressions in this position are unstable
     }
     if true && let Some(a) = opt {
+    //[no_feature]~^ ERROR `let` expressions in this position are unstable
     }
 
     let fun = || true;
     if let true = (true && fun()) && (true) {
+    //[no_feature]~^ ERROR `let` expressions in this position are unstable
     }
 
     #[cfg(FALSE)]