Rollup merge of #97818 - compiler-errors:rpit-error-spanned, r=oli-obk

Point at return expression for RPIT-related error

Certainly this needs some diagnostic refining, but I wanted to show that it was possible first and foremost. Not sure if this is the right approach. Open to feedback.

Fixes #80583

6 files changed, 27 insertions, 0 deletions

diff --git a/src/test/ui/associated-types/impl-trait-return-missing-constraint.stderr b/src/test/ui/associated-types/impl-trait-return-missing-constraint.stderr
index bd8c8a4414c..fbd76a64c1e 100644
--- a/src/test/ui/associated-types/impl-trait-return-missing-constraint.stderr
+++ b/src/test/ui/associated-types/impl-trait-return-missing-constraint.stderr
@@ -6,6 +6,9 @@ LL | fn bar() -> impl Bar {
 ...
 LL | fn baz() -> impl Bar<Item = i32> {
    |             ^^^^^^^^^^^^^^^^^^^^ expected associated type, found `i32`
+LL |
+LL |     bar()
+   |     ----- return type was inferred to be `impl Bar` here
    |
    = note: expected associated type `<impl Bar as Foo>::Item`
                          found type `i32`
diff --git a/src/test/ui/const-generics/defaults/rp_impl_trait_fail.stderr b/src/test/ui/const-generics/defaults/rp_impl_trait_fail.stderr
index cbe4a4ac0d6..cbc7b93f3a9 100644
--- a/src/test/ui/const-generics/defaults/rp_impl_trait_fail.stderr
+++ b/src/test/ui/const-generics/defaults/rp_impl_trait_fail.stderr
@@ -3,6 +3,9 @@ error[E0277]: the trait bound `Uwu<10_u32, 12_u32>: Trait` is not satisfied
    |
 LL | fn rawr() -> impl Trait {
    |              ^^^^^^^^^^ the trait `Trait` is not implemented for `Uwu<10_u32, 12_u32>`
+LL |
+LL |     Uwu::<10, 12>
+   |     ------------- return type was inferred to be `Uwu<10_u32, 12_u32>` here
    |
    = help: the trait `Trait` is implemented for `Uwu<N>`
 
@@ -11,6 +14,9 @@ error[E0277]: the trait bound `u32: Traitor<N>` is not satisfied
    |
 LL | fn uwu<const N: u8>() -> impl Traitor<N> {
    |                          ^^^^^^^^^^^^^^^ the trait `Traitor<N>` is not implemented for `u32`
+LL |
+LL |     1_u32
+   |     ----- return type was inferred to be `u32` here
    |
    = help: the following other types implement trait `Traitor<N, M>`:
              <u32 as Traitor<N, 2_u8>>
@@ -21,6 +27,9 @@ error[E0277]: the trait bound `u64: Traitor` is not satisfied
    |
 LL | fn owo() -> impl Traitor {
    |             ^^^^^^^^^^^^ the trait `Traitor` is not implemented for `u64`
+LL |
+LL |     1_u64
+   |     ----- return type was inferred to be `u64` here
    |
    = help: the following other types implement trait `Traitor<N, M>`:
              <u32 as Traitor<N, 2_u8>>
diff --git a/src/test/ui/impl-trait/bound-normalization-fail.stderr b/src/test/ui/impl-trait/bound-normalization-fail.stderr
index eac7e6b315e..bd8d3d3d24e 100644
--- a/src/test/ui/impl-trait/bound-normalization-fail.stderr
+++ b/src/test/ui/impl-trait/bound-normalization-fail.stderr
@@ -3,6 +3,9 @@ error[E0271]: type mismatch resolving `<Foo<()> as FooLike>::Output == <T as imp
    |
 LL |     fn foo_fail<T: Trait>() -> impl FooLike<Output = T::Assoc> {
    |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type mismatch resolving `<Foo<()> as FooLike>::Output == <T as impl_trait::Trait>::Assoc`
+LL |
+LL |         Foo(())
+   |         ------- return type was inferred to be `Foo<()>` here
    |
 note: expected this to be `()`
   --> $DIR/bound-normalization-fail.rs:14:19
@@ -27,6 +30,9 @@ error[E0271]: type mismatch resolving `<Foo<()> as FooLike>::Output == <T as lif
    |
 LL |     fn foo2_fail<'a, T: Trait<'a>>() -> impl FooLike<Output = T::Assoc> {
    |                                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type mismatch resolving `<Foo<()> as FooLike>::Output == <T as lifetimes::Trait<'static>>::Assoc`
+...
+LL |         Foo(())
+   |         ------- return type was inferred to be `Foo<()>` here
    |
 note: expected this to be `()`
   --> $DIR/bound-normalization-fail.rs:14:19
diff --git a/src/test/ui/issues-71798.stderr b/src/test/ui/issues-71798.stderr
index ab72c3e41af..829d0a02ec9 100644
--- a/src/test/ui/issues-71798.stderr
+++ b/src/test/ui/issues-71798.stderr
@@ -9,6 +9,9 @@ error[E0277]: `u32` is not a future
    |
 LL | fn test_ref(x: &u32) -> impl std::future::Future<Output = u32> + '_ {
    |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `u32` is not a future
+LL |
+LL |     *x
+   |     -- return type was inferred to be `u32` here
    |
    = help: the trait `Future` is not implemented for `u32`
    = note: u32 must be a future or must implement `IntoFuture` to be awaited
diff --git a/src/test/ui/type-alias-impl-trait/nested-tait-inference.stderr b/src/test/ui/type-alias-impl-trait/nested-tait-inference.stderr
index f98da9f7f92..62db019ed6a 100644
--- a/src/test/ui/type-alias-impl-trait/nested-tait-inference.stderr
+++ b/src/test/ui/type-alias-impl-trait/nested-tait-inference.stderr
@@ -3,6 +3,9 @@ error[E0277]: the trait bound `(): Foo<FooX>` is not satisfied
    |
 LL | fn foo() -> impl Foo<FooX> {
    |             ^^^^^^^^^^^^^^ the trait `Foo<FooX>` is not implemented for `()`
+...
+LL |     ()
+   |     -- return type was inferred to be `()` here
    |
    = help: the trait `Foo<()>` is implemented for `()`
 
diff --git a/src/test/ui/type-alias-impl-trait/nested-tait-inference2.stderr b/src/test/ui/type-alias-impl-trait/nested-tait-inference2.stderr
index 54f571ad3e3..f4d96038d91 100644
--- a/src/test/ui/type-alias-impl-trait/nested-tait-inference2.stderr
+++ b/src/test/ui/type-alias-impl-trait/nested-tait-inference2.stderr
@@ -3,6 +3,9 @@ error[E0277]: the trait bound `(): Foo<FooX>` is not satisfied
    |
 LL | fn foo() -> impl Foo<FooX> {
    |             ^^^^^^^^^^^^^^ the trait `Foo<FooX>` is not implemented for `()`
+LL |
+LL |     ()
+   |     -- return type was inferred to be `()` here
    |
    = help: the following other types implement trait `Foo<A>`:
              <() as Foo<()>>