Propagate Expectation around binop typeck code to construct more precise trait obligations for binops.

src/test/ui/generic-associated-types/missing-bounds.fixed

@@ -0,0 +1,46 @@
+// run-rustfix
+
+use std::ops::Add;
+
+struct A<B>(B);
+
+impl<B> Add for A<B> where B: Add + Add<Output = B> {
+    type Output = Self;
+
+    fn add(self, rhs: Self) -> Self {
+        A(self.0 + rhs.0) //~ ERROR mismatched types
+    }
+}
+
+struct C<B>(B);
+
+impl<B: Add + Add<Output = B>> Add for C<B> {
+    type Output = Self;
+
+    fn add(self, rhs: Self) -> Self {
+        Self(self.0 + rhs.0) //~ ERROR mismatched types
+    }
+}
+
+struct D<B>(B);
+
+impl<B: std::ops::Add<Output=B>> Add for D<B> {
+    type Output = Self;
+
+    fn add(self, rhs: Self) -> Self {
+        Self(self.0 + rhs.0) //~ ERROR cannot add `B` to `B`
+    }
+}
+
+struct E<B>(B);
+
+impl<B: Add + Add<Output = B>> Add for E<B> where B: Add<Output = B> {
+    //~^ ERROR equality constraints are not yet supported in `where` clauses
+    type Output = Self;
+
+    fn add(self, rhs: Self) -> Self {
+        Self(self.0 + rhs.0) //~ ERROR mismatched types
+    }
+}
+
+fn main() {}

src/test/ui/generic-associated-types/missing-bounds.rs

@@ -1,3 +1,5 @@
+// run-rustfix
+
 use std::ops::Add;
 
 struct A<B>(B);

src/test/ui/generic-associated-types/missing-bounds.stderr

@@ -1,5 +1,5 @@
 error: equality constraints are not yet supported in `where` clauses
-  --> $DIR/missing-bounds.rs:35:33
+  --> $DIR/missing-bounds.rs:37:33
    |
 LL | impl<B: Add> Add for E<B> where <B as Add>::Output = B {
    |                                 ^^^^^^^^^^^^^^^^^^^^^^ not supported
@@ -11,7 +11,7 @@ LL | impl<B: Add> Add for E<B> where B: Add<Output = B> {
    |                                 ~~~~~~~~~~~~~~~~~~
 
 error[E0308]: mismatched types
-  --> $DIR/missing-bounds.rs:9:11
+  --> $DIR/missing-bounds.rs:11:11
    |
 LL | impl<B> Add for A<B> where B: Add {
    |      - this type parameter
@@ -24,7 +24,7 @@ LL |         A(self.0 + rhs.0)
    = note: expected type parameter `B`
              found associated type `<B as Add>::Output`
 note: tuple struct defined here
-  --> $DIR/missing-bounds.rs:3:8
+  --> $DIR/missing-bounds.rs:5:8
    |
 LL | struct A<B>(B);
    |        ^
@@ -34,7 +34,7 @@ LL | impl<B> Add for A<B> where B: Add + Add<Output = B> {
    |                                   +++++++++++++++++
 
 error[E0308]: mismatched types
-  --> $DIR/missing-bounds.rs:19:14
+  --> $DIR/missing-bounds.rs:21:14
    |
 LL | impl<B: Add> Add for C<B> {
    |      - this type parameter
@@ -47,7 +47,7 @@ LL |         Self(self.0 + rhs.0)
    = note: expected type parameter `B`
              found associated type `<B as Add>::Output`
 note: tuple struct defined here
-  --> $DIR/missing-bounds.rs:13:8
+  --> $DIR/missing-bounds.rs:15:8
    |
 LL | struct C<B>(B);
    |        ^
@@ -57,7 +57,7 @@ LL | impl<B: Add + Add<Output = B>> Add for C<B> {
    |             +++++++++++++++++
 
 error[E0369]: cannot add `B` to `B`
-  --> $DIR/missing-bounds.rs:29:21
+  --> $DIR/missing-bounds.rs:31:21
    |
 LL |         Self(self.0 + rhs.0)
    |              ------ ^ ----- B
@@ -66,11 +66,11 @@ LL |         Self(self.0 + rhs.0)
    |
 help: consider restricting type parameter `B`
    |
-LL | impl<B: std::ops::Add> Add for D<B> {
-   |       +++++++++++++++
+LL | impl<B: std::ops::Add<Output=B>> Add for D<B> {
+   |       +++++++++++++++++++++++++
 
 error[E0308]: mismatched types
-  --> $DIR/missing-bounds.rs:40:14
+  --> $DIR/missing-bounds.rs:42:14
    |
 LL | impl<B: Add> Add for E<B> where <B as Add>::Output = B {
    |      - this type parameter
@@ -83,7 +83,7 @@ LL |         Self(self.0 + rhs.0)
    = note: expected type parameter `B`
              found associated type `<B as Add>::Output`
 note: tuple struct defined here
-  --> $DIR/missing-bounds.rs:33:8
+  --> $DIR/missing-bounds.rs:35:8
    |
 LL | struct E<B>(B);
    |        ^

src/test/ui/suggestions/issue-97677.stderr

@@ -8,8 +8,8 @@ LL |     n + 10
    |
 help: consider restricting type parameter `N`
    |
-LL | fn add_ten<N: std::ops::Add<i32>>(n: N) -> N {
-   |             ++++++++++++++++++++
+LL | fn add_ten<N: std::ops::Add<i32><Output=N>>(n: N) -> N {
+   |             ++++++++++++++++++++++++++++++
 
 error: aborting due to previous error