Auto merge of #144087 - cuviper:beta-next, r=cuviper

[beta] backports

- Taint body on invalid call ABI rust-lang/rust#142983
- Fix rustdoc not correctly showing attributes with re-exports rust-lang/rust#143083
- trait_sel: `MetaSized` always holds temporarily rust-lang/rust#144016
- Ensure home directory exists rust-lang/rust#144003

r? cuviper

.github/workflows/ci.yml

@@ -190,6 +190,11 @@ jobs:
       - name: install MinGW
         run: src/ci/scripts/install-mingw.sh
 
+      # Workaround for spurious ci failures after mingw install
+      # see https://rust-lang.zulipchat.com/#narrow/channel/242791-t-infra/topic/Spurious.20bors.20CI.20failures/near/528915775
+      - name: ensure home dir exists
+        run: mkdir -p ~
+
       - name: install ninja
         run: src/ci/scripts/install-ninja.sh
 

compiler/rustc_abi/src/extern_abi.rs

@@ -36,6 +36,10 @@ pub enum ExternAbi {
     /// Stronger than just `#[cold]` because `fn` pointers might be incompatible.
     RustCold,
 
+    /// An always-invalid ABI that's used to test "this ABI is not supported by this platform"
+    /// in a platform-agnostic way.
+    RustInvalid,
+
     /// Unstable impl detail that directly uses Rust types to describe the ABI to LLVM.
     /// Even normally-compatible Rust types can become ABI-incompatible with this ABI!
     Unadjusted,
@@ -157,6 +161,7 @@ fn from_str(s: &str) -> Result<$e_name, Self::Err> {
             RiscvInterruptS =><= "riscv-interrupt-s",
             RustCall =><= "rust-call",
             RustCold =><= "rust-cold",
+            RustInvalid =><= "rust-invalid",
             Stdcall { unwind: false } =><= "stdcall",
             Stdcall { unwind: true } =><= "stdcall-unwind",
             System { unwind: false } =><= "system",

compiler/rustc_ast_lowering/src/stability.rs

@@ -96,6 +96,9 @@ pub fn extern_abi_stability(abi: ExternAbi) -> Result<(), UnstableAbi> {
         ExternAbi::RustCold => {
             Err(UnstableAbi { abi, feature: sym::rust_cold_cc, explain: GateReason::Experimental })
         }
+        ExternAbi::RustInvalid => {
+            Err(UnstableAbi { abi, feature: sym::rustc_attrs, explain: GateReason::ImplDetail })
+        }
         ExternAbi::GpuKernel => Err(UnstableAbi {
             abi,
             feature: sym::abi_gpu_kernel,

compiler/rustc_hir_typeck/src/callee.rs

@@ -156,7 +156,16 @@ pub(crate) fn check_expr_call(
     pub(crate) fn check_call_abi(&self, abi: ExternAbi, span: Span) {
         let canon_abi = match AbiMap::from_target(&self.sess().target).canonize_abi(abi, false) {
             AbiMapping::Direct(canon_abi) | AbiMapping::Deprecated(canon_abi) => canon_abi,
-            AbiMapping::Invalid => return,
+            AbiMapping::Invalid => {
+                // This should be reported elsewhere, but we want to taint this body
+                // so that we don't try to evaluate calls to ABIs that are invalid.
+                let guar = self.dcx().span_delayed_bug(
+                    span,
+                    format!("invalid abi for platform should have reported an error: {abi}"),
+                );
+                self.set_tainted_by_errors(guar);
+                return;
+            }
         };
 
         let valid = match canon_abi {

compiler/rustc_middle/src/ty/layout.rs

@@ -1253,7 +1253,8 @@ pub fn fn_can_unwind(tcx: TyCtxt<'_>, fn_def_id: Option<DefId>, abi: ExternAbi)
         | CCmseNonSecureCall
         | CCmseNonSecureEntry
         | Custom
-        | Unadjusted => false,
+        | Unadjusted
+        | RustInvalid => false,
         Rust | RustCall | RustCold => tcx.sess.panic_strategy() == PanicStrategy::Unwind,
     }
 }

compiler/rustc_smir/src/rustc_internal/internal.rs

@@ -494,6 +494,7 @@ fn internal<'tcx>(&self, _tables: &mut Tables<'_>, _tcx: TyCtxt<'tcx>) -> Self::
             Abi::RustCall => rustc_abi::ExternAbi::RustCall,
             Abi::Unadjusted => rustc_abi::ExternAbi::Unadjusted,
             Abi::RustCold => rustc_abi::ExternAbi::RustCold,
+            Abi::RustInvalid => rustc_abi::ExternAbi::RustInvalid,
             Abi::RiscvInterruptM => rustc_abi::ExternAbi::RiscvInterruptM,
             Abi::RiscvInterruptS => rustc_abi::ExternAbi::RiscvInterruptS,
             Abi::Custom => rustc_abi::ExternAbi::Custom,

compiler/rustc_smir/src/rustc_smir/convert/ty.rs

@@ -877,6 +877,7 @@ fn stable(&self, _: &mut Tables<'_>) -> Self::T {
             ExternAbi::RustCall => Abi::RustCall,
             ExternAbi::Unadjusted => Abi::Unadjusted,
             ExternAbi::RustCold => Abi::RustCold,
+            ExternAbi::RustInvalid => Abi::RustInvalid,
             ExternAbi::RiscvInterruptM => Abi::RiscvInterruptM,
             ExternAbi::RiscvInterruptS => Abi::RiscvInterruptS,
             ExternAbi::Custom => Abi::Custom,

compiler/rustc_smir/src/stable_mir/ty.rs

@@ -1126,6 +1126,7 @@ pub enum Abi {
     RustCold,
     RiscvInterruptM,
     RiscvInterruptS,
+    RustInvalid,
     Custom,
 }
 

compiler/rustc_target/src/spec/abi_map.rs

@@ -156,7 +156,8 @@ pub fn canonize_abi(&self, extern_abi: ExternAbi, has_c_varargs: bool) -> AbiMap
                 | ExternAbi::Msp430Interrupt
                 | ExternAbi::RiscvInterruptM
                 | ExternAbi::RiscvInterruptS
-                | ExternAbi::X86Interrupt,
+                | ExternAbi::X86Interrupt
+                | ExternAbi::RustInvalid,
                 _,
             ) => return AbiMapping::Invalid,
         };

compiler/rustc_trait_selection/src/traits/util.rs

@@ -377,6 +377,13 @@ pub fn sizedness_fast_path<'tcx>(tcx: TyCtxt<'tcx>, predicate: ty::Predicate<'tc
             _ => return false,
         };
 
+        // FIXME(sized_hierarchy): this temporarily reverts the `sized_hierarchy` feature
+        // while a proper fix for `tests/ui/sized-hierarchy/incomplete-inference-issue-143992.rs`
+        // is pending a proper fix
+        if !tcx.features().sized_hierarchy() && matches!(sizedness, SizedTraitKind::MetaSized) {
+            return true;
+        }
+
         if trait_ref.self_ty().has_trivial_sizedness(tcx, sizedness) {
             debug!("fast path -- trivial sizedness");
             return true;

src/librustdoc/clean/mod.rs

@@ -2746,7 +2746,8 @@ fn add_without_unwanted_attributes<'hir>(
                     attrs.push((Cow::Owned(attr), import_parent));
                 }
             }
-            hir::Attribute::Parsed(..) if is_inline => {
+            // FIXME: make sure to exclude `#[cfg_trace]` here when it is ported to the new parsers
+            hir::Attribute::Parsed(..) => {
                 attrs.push((Cow::Owned(attr), import_parent));
             }
             _ => {}

tests/rustdoc/attributes-re-export.rs

@@ -0,0 +1,13 @@
+// Tests that attributes are correctly copied onto a re-exported item.
+//@ edition:2021
+#![crate_name = "re_export"]
+
+//@ has 're_export/fn.thingy2.html' '//pre[@class="rust item-decl"]' '#[no_mangle]'
+pub use thingymod::thingy as thingy2;
+
+mod thingymod {
+    #[no_mangle]
+    pub fn thingy() {
+
+    }
+}

tests/ui/abi/invalid-call-abi-ctfe.rs

@@ -0,0 +1,14 @@
+// Fix for #142969 where an invalid ABI in a signature still had its call ABI computed
+// because CTFE tried to evaluate it, despite previous errors during AST-to-HIR lowering.
+
+#![feature(rustc_attrs)]
+
+const extern "rust-invalid" fn foo() {
+    //~^ ERROR `"rust-invalid"` is not a supported ABI for the current target
+    panic!()
+}
+
+const _: () = foo();
+
+
+fn main() {}

tests/ui/abi/invalid-call-abi-ctfe.stderr

@@ -0,0 +1,9 @@
+error[E0570]: `"rust-invalid"` is not a supported ABI for the current target
+  --> $DIR/invalid-call-abi-ctfe.rs:6:1
+   |
+LL | const extern "rust-invalid" fn foo() {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0570`.

tests/ui/abi/invalid-call-abi.rs

@@ -0,0 +1,12 @@
+// Tests the `"rustc-invalid"` ABI, which is never canonizable.
+
+#![feature(rustc_attrs)]
+
+const extern "rust-invalid" fn foo() {
+    //~^ ERROR `"rust-invalid"` is not a supported ABI for the current target
+    panic!()
+}
+
+fn main() {
+    foo();
+}

tests/ui/abi/invalid-call-abi.stderr

@@ -0,0 +1,9 @@
+error[E0570]: `"rust-invalid"` is not a supported ABI for the current target
+  --> $DIR/invalid-call-abi.rs:5:1
+   |
+LL | const extern "rust-invalid" fn foo() {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0570`.

tests/ui/consts/const-size_of_val-align_of_val-extern-type.rs

@@ -8,8 +8,8 @@
 }
 
 const _SIZE: usize = unsafe { size_of_val(&4 as *const i32 as *const Opaque) };
-//~^ ERROR the size for values of type `Opaque` cannot be known
+//~^ ERROR `extern type` does not have known layout
 const _ALIGN: usize = unsafe { align_of_val(&4 as *const i32 as *const Opaque) };
-//~^ ERROR the size for values of type `Opaque` cannot be known
+//~^ ERROR `extern type` does not have known layout
 
 fn main() {}

tests/ui/consts/const-size_of_val-align_of_val-extern-type.stderr

@@ -1,27 +1,15 @@
-error[E0277]: the size for values of type `Opaque` cannot be known
-  --> $DIR/const-size_of_val-align_of_val-extern-type.rs:10:43
+error[E0080]: `extern type` does not have known layout
+  --> $DIR/const-size_of_val-align_of_val-extern-type.rs:10:31
    |
 LL | const _SIZE: usize = unsafe { size_of_val(&4 as *const i32 as *const Opaque) };
-   |                               ----------- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ doesn't have a known size
-   |                               |
-   |                               required by a bound introduced by this call
-   |
-   = help: the trait `MetaSized` is not implemented for `Opaque`
-note: required by a bound in `std::intrinsics::size_of_val`
-  --> $SRC_DIR/core/src/intrinsics/mod.rs:LL:COL
+   |                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ evaluation of `_SIZE` failed here
 
-error[E0277]: the size for values of type `Opaque` cannot be known
-  --> $DIR/const-size_of_val-align_of_val-extern-type.rs:12:45
+error[E0080]: `extern type` does not have known layout
+  --> $DIR/const-size_of_val-align_of_val-extern-type.rs:12:32
    |
 LL | const _ALIGN: usize = unsafe { align_of_val(&4 as *const i32 as *const Opaque) };
-   |                                ------------ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ doesn't have a known size
-   |                                |
-   |                                required by a bound introduced by this call
-   |
-   = help: the trait `MetaSized` is not implemented for `Opaque`
-note: required by a bound in `std::intrinsics::align_of_val`
-  --> $SRC_DIR/core/src/intrinsics/mod.rs:LL:COL
+   |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ evaluation of `_ALIGN` failed here
 
 error: aborting due to 2 previous errors
 
-For more information about this error, try `rustc --explain E0277`.
+For more information about this error, try `rustc --explain E0080`.

tests/ui/extern/extern-types-size_of_val.rs

@@ -1,4 +1,4 @@
-//@ check-fail
+//@ check-pass
 #![feature(extern_types)]
 
 use std::mem::{align_of_val, size_of_val};
@@ -11,7 +11,5 @@ fn main() {
     let x: &A = unsafe { &*(1usize as *const A) };
 
     size_of_val(x);
-    //~^ ERROR the size for values of type `A` cannot be known
     align_of_val(x);
-    //~^ ERROR the size for values of type `A` cannot be known
 }

tests/ui/extern/extern-types-size_of_val.stderr

@@ -1,39 +0,0 @@
-error[E0277]: the size for values of type `A` cannot be known
-  --> $DIR/extern-types-size_of_val.rs:13:17
-   |
-LL |     size_of_val(x);
-   |     ----------- ^ the trait `MetaSized` is not implemented for `A`
-   |     |
-   |     required by a bound introduced by this call
-   |
-   = note: the trait bound `A: MetaSized` is not satisfied
-note: required by a bound in `std::mem::size_of_val`
-  --> $SRC_DIR/core/src/mem/mod.rs:LL:COL
-help: consider borrowing here
-   |
-LL |     size_of_val(&x);
-   |                 +
-LL |     size_of_val(&mut x);
-   |                 ++++
-
-error[E0277]: the size for values of type `A` cannot be known
-  --> $DIR/extern-types-size_of_val.rs:15:18
-   |
-LL |     align_of_val(x);
-   |     ------------ ^ the trait `MetaSized` is not implemented for `A`
-   |     |
-   |     required by a bound introduced by this call
-   |
-   = note: the trait bound `A: MetaSized` is not satisfied
-note: required by a bound in `std::mem::align_of_val`
-  --> $SRC_DIR/core/src/mem/mod.rs:LL:COL
-help: consider borrowing here
-   |
-LL |     align_of_val(&x);
-   |                  +
-LL |     align_of_val(&mut x);
-   |                  ++++
-
-error: aborting due to 2 previous errors
-
-For more information about this error, try `rustc --explain E0277`.

tests/ui/extern/extern-types-unsized.rs

@@ -27,9 +27,7 @@ fn main() {
 
     assert_sized::<Bar<A>>();
     //~^ ERROR the size for values of type
-    //~| ERROR the size for values of type
 
     assert_sized::<Bar<Bar<A>>>();
     //~^ ERROR the size for values of type
-    //~| ERROR the size for values of type
 }

tests/ui/extern/extern-types-unsized.stderr

@@ -59,21 +59,8 @@ help: consider relaxing the implicit `Sized` restriction
 LL | fn assert_sized<T: ?Sized>() {}
    |                  ++++++++
 
-error[E0277]: the size for values of type `A` cannot be known
-  --> $DIR/extern-types-unsized.rs:28:20
-   |
-LL |     assert_sized::<Bar<A>>();
-   |                    ^^^^^^ doesn't have a known size
-   |
-   = help: the trait `MetaSized` is not implemented for `A`
-note: required by a bound in `Bar`
-  --> $DIR/extern-types-unsized.rs:14:12
-   |
-LL | struct Bar<T: ?Sized> {
-   |            ^ required by this bound in `Bar`
-
 error[E0277]: the size for values of type `A` cannot be known at compilation time
-  --> $DIR/extern-types-unsized.rs:32:20
+  --> $DIR/extern-types-unsized.rs:31:20
    |
 LL |     assert_sized::<Bar<Bar<A>>>();
    |                    ^^^^^^^^^^^ doesn't have a size known at compile-time
@@ -94,19 +81,6 @@ help: consider relaxing the implicit `Sized` restriction
 LL | fn assert_sized<T: ?Sized>() {}
    |                  ++++++++
 
-error[E0277]: the size for values of type `A` cannot be known
-  --> $DIR/extern-types-unsized.rs:32:20
-   |
-LL |     assert_sized::<Bar<Bar<A>>>();
-   |                    ^^^^^^^^^^^ doesn't have a known size
-   |
-   = help: the trait `MetaSized` is not implemented for `A`
-note: required by a bound in `Bar`
-  --> $DIR/extern-types-unsized.rs:14:12
-   |
-LL | struct Bar<T: ?Sized> {
-   |            ^ required by this bound in `Bar`
-
-error: aborting due to 6 previous errors
+error: aborting due to 4 previous errors
 
 For more information about this error, try `rustc --explain E0277`.

tests/ui/extern/unsized-extern-derefmove.rs

@@ -7,14 +7,10 @@
 }
 
 unsafe fn make_device() -> Box<Device> {
-//~^ ERROR the size for values of type `Device` cannot be known
     Box::from_raw(0 as *mut _)
-//~^ ERROR the size for values of type `Device` cannot be known
-//~| ERROR the size for values of type `Device` cannot be known
 }
 
 fn main() {
     let d: Device = unsafe { *make_device() };
 //~^ ERROR the size for values of type `Device` cannot be known
-//~| ERROR the size for values of type `Device` cannot be known
 }

tests/ui/extern/unsized-extern-derefmove.stderr

@@ -1,43 +1,5 @@
-error[E0277]: the size for values of type `Device` cannot be known
-  --> $DIR/unsized-extern-derefmove.rs:9:28
-   |
-LL | unsafe fn make_device() -> Box<Device> {
-   |                            ^^^^^^^^^^^ doesn't have a known size
-   |
-   = help: the trait `MetaSized` is not implemented for `Device`
-note: required by a bound in `Box`
-  --> $SRC_DIR/alloc/src/boxed.rs:LL:COL
-
-error[E0277]: the size for values of type `Device` cannot be known
-  --> $DIR/unsized-extern-derefmove.rs:11:19
-   |
-LL |     Box::from_raw(0 as *mut _)
-   |     ------------- ^^^^^^^^^^^ the trait `MetaSized` is not implemented for `Device`
-   |     |
-   |     required by a bound introduced by this call
-   |
-   = note: the trait bound `Device: MetaSized` is not satisfied
-note: required by a bound in `Box::<T>::from_raw`
-  --> $SRC_DIR/alloc/src/boxed.rs:LL:COL
-help: consider borrowing here
-   |
-LL |     Box::from_raw(&0 as *mut _)
-   |                   +
-LL |     Box::from_raw(&mut 0 as *mut _)
-   |                   ++++
-
-error[E0277]: the size for values of type `Device` cannot be known
-  --> $DIR/unsized-extern-derefmove.rs:11:5
-   |
-LL |     Box::from_raw(0 as *mut _)
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^ doesn't have a known size
-   |
-   = help: the trait `MetaSized` is not implemented for `Device`
-note: required by a bound in `Box`
-  --> $SRC_DIR/alloc/src/boxed.rs:LL:COL
-
 error[E0277]: the size for values of type `Device` cannot be known at compilation time
-  --> $DIR/unsized-extern-derefmove.rs:17:9
+  --> $DIR/unsized-extern-derefmove.rs:14:9
    |
 LL |     let d: Device = unsafe { *make_device() };
    |         ^ doesn't have a size known at compile-time
@@ -49,16 +11,6 @@ help: consider borrowing here
 LL |     let d: &Device = unsafe { *make_device() };
    |            +
 
-error[E0277]: the size for values of type `Device` cannot be known
-  --> $DIR/unsized-extern-derefmove.rs:17:31
-   |
-LL |     let d: Device = unsafe { *make_device() };
-   |                               ^^^^^^^^^^^^^ doesn't have a known size
-   |
-   = help: the trait `MetaSized` is not implemented for `Device`
-note: required by a bound in `Box`
-  --> $SRC_DIR/alloc/src/boxed.rs:LL:COL
-
-error: aborting due to 5 previous errors
+error: aborting due to 1 previous error
 
 For more information about this error, try `rustc --explain E0277`.

tests/ui/layout/unconstrained-param-ice-137308.rs

@@ -17,4 +17,3 @@ impl<C: ?Sized> A for u8 { //~ ERROR: the type parameter `C` is not constrained
 #[rustc_layout(debug)]
 struct S([u8; <u8 as A>::B]);
 //~^ ERROR: the type has an unknown layout
-//~| ERROR: type annotations needed

tests/ui/layout/unconstrained-param-ice-137308.stderr

@@ -4,19 +4,12 @@ error[E0207]: the type parameter `C` is not constrained by the impl trait, self
 LL | impl<C: ?Sized> A for u8 {
    |      ^ unconstrained type parameter
 
-error[E0282]: type annotations needed
-  --> $DIR/unconstrained-param-ice-137308.rs:18:16
-   |
-LL | struct S([u8; <u8 as A>::B]);
-   |                ^^ cannot infer type for type parameter `C`
-
 error: the type has an unknown layout
   --> $DIR/unconstrained-param-ice-137308.rs:18:1
    |
 LL | struct S([u8; <u8 as A>::B]);
    | ^^^^^^^^
 
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 
-Some errors have detailed explanations: E0207, E0282.
-For more information about an error, try `rustc --explain E0207`.
+For more information about this error, try `rustc --explain E0207`.

tests/ui/nll/issue-50716.rs

@@ -5,7 +5,7 @@ trait A {
     type X: ?Sized;
 }
 
-fn foo<'a, T: 'static>(s: Box<<&'a T as A>::X>) //~ ERROR
+fn foo<'a, T: 'static>(s: Box<<&'a T as A>::X>)
 where
     for<'b> &'b T: A,
     <&'static T as A>::X: Sized

tests/ui/nll/issue-50716.stderr

@@ -1,18 +1,3 @@
-error[E0308]: mismatched types
-  --> $DIR/issue-50716.rs:8:27
-   |
-LL | fn foo<'a, T: 'static>(s: Box<<&'a T as A>::X>)
-   |                           ^^^^^^^^^^^^^^^^^^^^ lifetime mismatch
-   |
-   = note: expected trait `<<&'a T as A>::X as MetaSized>`
-              found trait `<<&'static T as A>::X as MetaSized>`
-note: the lifetime `'a` as defined here...
-  --> $DIR/issue-50716.rs:8:8
-   |
-LL | fn foo<'a, T: 'static>(s: Box<<&'a T as A>::X>)
-   |        ^^
-   = note: ...does not necessarily outlive the static lifetime
-
 error: lifetime may not live long enough
   --> $DIR/issue-50716.rs:13:14
    |
@@ -22,6 +7,5 @@ LL | fn foo<'a, T: 'static>(s: Box<<&'a T as A>::X>)
 LL |     let _x = *s;
    |              ^^ proving this value is `Sized` requires that `'a` must outlive `'static`
 
-error: aborting due to 2 previous errors
+error: aborting due to 1 previous error
 
-For more information about this error, try `rustc --explain E0308`.

tests/ui/print-calling-conventions.stdout

@@ -20,6 +20,7 @@ riscv-interrupt-m
 riscv-interrupt-s
 rust-call
 rust-cold
+rust-invalid
 stdcall
 stdcall-unwind
 system

tests/ui/sized-hierarchy/incomplete-inference-issue-143992.next.stderr

@@ -0,0 +1,17 @@
+error[E0308]: mismatched types
+  --> $DIR/incomplete-inference-issue-143992.rs:27:28
+   |
+LL |     let _x = T::Assoc::new(());
+   |              ------------- ^^ expected `[u32; 1]`, found `()`
+   |              |
+   |              arguments to this function are incorrect
+   |
+note: associated function defined here
+  --> $DIR/incomplete-inference-issue-143992.rs:18:8
+   |
+LL |     fn new(r: R) -> R {
+   |        ^^^ ----
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0308`.

tests/ui/sized-hierarchy/incomplete-inference-issue-143992.rs

@@ -0,0 +1,29 @@
+//@ compile-flags: --crate-type=lib
+//@ revisions: current next
+//@ ignore-compare-mode-next-solver (explicit revisions)
+//@[current] check-pass
+//@[next] compile-flags: -Znext-solver
+//@[next] check-fail
+
+// Test that we avoid incomplete inference when normalizing. Without this,
+// `Trait`'s implicit `MetaSized` supertrait requires proving `T::Assoc<_>: MetaSized`
+// before checking the `new` arguments, resulting in eagerly constraining the inference
+// var to `u32`. This is undesirable and would breaking code.
+
+pub trait Trait {
+    type Assoc<G>: OtherTrait<G>;
+}
+
+pub trait OtherTrait<R> {
+    fn new(r: R) -> R {
+        r
+    }
+}
+
+pub fn function<T: Trait>()
+where
+    T::Assoc<[u32; 1]>: Clone,
+{
+    let _x = T::Assoc::new(());
+//[next]~^ ERROR mismatched types
+}

tests/ui/sized-hierarchy/overflow.current.stderr

@@ -1,45 +0,0 @@
-error[E0275]: overflow evaluating the requirement `Element: MetaSized`
-  --> $DIR/overflow.rs:16:16
-   |
-LL | struct Element(<Box<Box<Element>> as ParseTokens>::Output);
-   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-note: required for `Box<Element>` to implement `ParseTokens`
-  --> $DIR/overflow.rs:12:31
-   |
-LL | impl<T: ParseTokens + ?Sized> ParseTokens for Box<T> {
-   |      -                        ^^^^^^^^^^^     ^^^^^^
-   |      |
-   |      unsatisfied trait bound introduced here
-   = note: 1 redundant requirement hidden
-   = note: required for `Box<Box<Element>>` to implement `ParseTokens`
-
-error[E0275]: overflow evaluating the requirement `Box<Element>: ParseTokens`
-  --> $DIR/overflow.rs:18:22
-   |
-LL | impl ParseTokens for Element {
-   |                      ^^^^^^^
-   |
-note: required for `Box<Box<Element>>` to implement `ParseTokens`
-  --> $DIR/overflow.rs:12:31
-   |
-LL | impl<T: ParseTokens + ?Sized> ParseTokens for Box<T> {
-   |         -----------           ^^^^^^^^^^^     ^^^^^^
-   |         |
-   |         unsatisfied trait bound introduced here
-note: required because it appears within the type `Element`
-  --> $DIR/overflow.rs:16:8
-   |
-LL | struct Element(<Box<Box<Element>> as ParseTokens>::Output);
-   |        ^^^^^^^
-note: required by a bound in `ParseTokens`
-  --> $DIR/overflow.rs:9:1
-   |
-LL | / trait ParseTokens {
-LL | |     type Output;
-LL | | }
-   | |_^ required by this bound in `ParseTokens`
-
-error: aborting due to 2 previous errors
-
-For more information about this error, try `rustc --explain E0275`.

tests/ui/sized-hierarchy/overflow.rs

@@ -1,9 +1,13 @@
 //@ compile-flags: --crate-type=lib
 //@ revisions: current next
 //@ ignore-compare-mode-next-solver (explicit revisions)
+//@[current] check-pass
 //@[next] check-pass
 //@[next] compile-flags: -Znext-solver
 
+// FIXME(sized_hierarchy): this is expected to fail in the old solver when there
+// isn't a temporary revert of the `sized_hierarchy` feature
+
 use std::marker::PhantomData;
 
 trait ParseTokens {
@@ -14,8 +18,6 @@ impl<T: ParseTokens + ?Sized> ParseTokens for Box<T> {
 }
 
 struct Element(<Box<Box<Element>> as ParseTokens>::Output);
-//[current]~^ ERROR overflow evaluating
 impl ParseTokens for Element {
-//[current]~^ ERROR overflow evaluating
     type Output = ();
 }

tests/ui/traits/resolve-impl-before-constrain-check.rs

@@ -15,7 +15,6 @@ fn call() {}
 
 fn test() -> impl Sized {
     <() as Callable>::call()
-//~^ ERROR: type annotations needed
 }
 
 fn main() {}

tests/ui/traits/resolve-impl-before-constrain-check.stderr

@@ -4,13 +4,6 @@ error[E0207]: the type parameter `V` is not constrained by the impl trait, self
 LL |     impl<V: ?Sized> Callable for () {
    |          ^ unconstrained type parameter
 
-error[E0282]: type annotations needed
-  --> $DIR/resolve-impl-before-constrain-check.rs:17:6
-   |
-LL |     <() as Callable>::call()
-   |      ^^ cannot infer type for type parameter `V`
+error: aborting due to 1 previous error
 
-error: aborting due to 2 previous errors
-
-Some errors have detailed explanations: E0207, E0282.
-For more information about an error, try `rustc --explain E0207`.
+For more information about this error, try `rustc --explain E0207`.