When trait bounds are missing for return values, point at them

10 files changed, 74 insertions, 5 deletions

diff --git a/src/test/ui/async-await/issue-64130-4-async-move.stderr b/src/test/ui/async-await/issue-64130-4-async-move.stderr
index 77d0885c38d..f59dbc26384 100644
--- a/src/test/ui/async-await/issue-64130-4-async-move.stderr
+++ b/src/test/ui/async-await/issue-64130-4-async-move.stderr
@@ -1,8 +1,17 @@
 error: future cannot be sent between threads safely
   --> $DIR/issue-64130-4-async-move.rs:15:17
    |
-LL | pub fn foo() -> impl Future + Send {
-   |                 ^^^^^^^^^^^^^^^^^^ future returned by `foo` is not `Send`
+LL |   pub fn foo() -> impl Future + Send {
+   |                   ^^^^^^^^^^^^^^^^^^ future returned by `foo` is not `Send`
+...
+LL | /     async move {
+LL | |         match client.status() {
+LL | |             200 => {
+LL | |                 let _x = get().await;
+...  |
+LL | |         }
+LL | |     }
+   | |_____- this returned value is of type `impl std::future::Future`
    |
    = help: the trait `std::marker::Sync` is not implemented for `(dyn std::any::Any + std::marker::Send + 'static)`
 note: future is not `Send` as this value is used across an await
diff --git a/src/test/ui/const-generics/array-impls/alloc-traits-no-impls-length-33.stderr b/src/test/ui/const-generics/array-impls/alloc-traits-no-impls-length-33.stderr
index 5c37468130c..6e5afcdb8bb 100644
--- a/src/test/ui/const-generics/array-impls/alloc-traits-no-impls-length-33.stderr
+++ b/src/test/ui/const-generics/array-impls/alloc-traits-no-impls-length-33.stderr
@@ -3,6 +3,9 @@ error[E0277]: arrays only have std trait implementations for lengths 0..=32
    |
 LL | pub fn no_vec_partial_eq_array<A, B>() -> impl PartialEq<[B; 33]>
    |                                           ^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::array::LengthAtMost32` is not implemented for `[B; 33]`
+...
+LL |     Vec::<A>::new()
+   |     --------------- this returned value is of type `std::vec::Vec<A>`
    |
    = note: required because of the requirements on the impl of `std::cmp::PartialEq<[B; 33]>` for `std::vec::Vec<A>`
    = note: the return type of a function must have a statically known size
@@ -12,6 +15,9 @@ error[E0277]: arrays only have std trait implementations for lengths 0..=32
    |
 LL | pub fn no_vec_partial_eq_ref_array<'a, A, B>() -> impl PartialEq<&'a [B; 33]>
    |                                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::array::LengthAtMost32` is not implemented for `[B; 33]`
+...
+LL |     Vec::<A>::new()
+   |     --------------- this returned value is of type `std::vec::Vec<A>`
    |
    = note: required because of the requirements on the impl of `std::cmp::PartialEq<&'a [B; 33]>` for `std::vec::Vec<A>`
    = note: the return type of a function must have a statically known size
@@ -21,6 +27,9 @@ error[E0277]: arrays only have std trait implementations for lengths 0..=32
    |
 LL | pub fn no_vecdeque_partial_eq_array<A, B>() -> impl PartialEq<[B; 33]>
    |                                                ^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::array::LengthAtMost32` is not implemented for `[B; 33]`
+...
+LL |     VecDeque::<A>::new()
+   |     -------------------- this returned value is of type `std::collections::VecDeque<A>`
    |
    = note: required because of the requirements on the impl of `std::cmp::PartialEq<[B; 33]>` for `std::collections::VecDeque<A>`
    = note: the return type of a function must have a statically known size
@@ -30,6 +39,9 @@ error[E0277]: arrays only have std trait implementations for lengths 0..=32
    |
 LL | pub fn no_vecdeque_partial_eq_ref_array<'a, A, B>() -> impl PartialEq<&'a [B; 33]>
    |                                                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::array::LengthAtMost32` is not implemented for `[B; 33]`
+...
+LL |     VecDeque::<A>::new()
+   |     -------------------- this returned value is of type `std::collections::VecDeque<A>`
    |
    = note: required because of the requirements on the impl of `std::cmp::PartialEq<&'a [B; 33]>` for `std::collections::VecDeque<A>`
    = note: the return type of a function must have a statically known size
@@ -39,6 +51,9 @@ error[E0277]: arrays only have std trait implementations for lengths 0..=32
    |
 LL | pub fn no_vecdeque_partial_eq_ref_mut_array<'a, A, B>() -> impl PartialEq<&'a mut [B; 33]>
    |                                                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::array::LengthAtMost32` is not implemented for `[B; 33]`
+...
+LL |     VecDeque::<A>::new()
+   |     -------------------- this returned value is of type `std::collections::VecDeque<A>`
    |
    = note: required because of the requirements on the impl of `std::cmp::PartialEq<&'a mut [B; 33]>` for `std::collections::VecDeque<A>`
    = note: the return type of a function must have a statically known size
diff --git a/src/test/ui/const-generics/array-impls/into-iter-no-impls-length-33.stderr b/src/test/ui/const-generics/array-impls/into-iter-no-impls-length-33.stderr
index bfdff8e3bbe..e615e10bd5f 100644
--- a/src/test/ui/const-generics/array-impls/into-iter-no-impls-length-33.stderr
+++ b/src/test/ui/const-generics/array-impls/into-iter-no-impls-length-33.stderr
@@ -11,6 +11,9 @@ error[E0277]: arrays only have std trait implementations for lengths 0..=32
    |
 LL | pub fn no_iterator() -> impl Iterator<Item = i32> {
    |                         ^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::array::LengthAtMost32` is not implemented for `[i32; 33]`
+LL |
+LL |     IntoIter::new([0i32; 33])
+   |     ------------------------- this returned value is of type `std::array::IntoIter<_, _: usize>`
    |
    = note: required because of the requirements on the impl of `std::iter::Iterator` for `std::array::IntoIter<i32, 33usize>`
    = note: the return type of a function must have a statically known size
@@ -28,6 +31,9 @@ error[E0277]: arrays only have std trait implementations for lengths 0..=32
    |
 LL | pub fn no_double_ended_iterator() -> impl DoubleEndedIterator {
    |                                      ^^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::array::LengthAtMost32` is not implemented for `[i32; 33]`
+LL |
+LL |     IntoIter::new([0i32; 33])
+   |     ------------------------- this returned value is of type `std::array::IntoIter<_, _: usize>`
    |
    = note: required because of the requirements on the impl of `std::iter::DoubleEndedIterator` for `std::array::IntoIter<i32, 33usize>`
    = note: the return type of a function must have a statically known size
@@ -45,6 +51,9 @@ error[E0277]: arrays only have std trait implementations for lengths 0..=32
    |
 LL | pub fn no_exact_size_iterator() -> impl ExactSizeIterator {
    |                                    ^^^^^^^^^^^^^^^^^^^^^^ the trait `std::array::LengthAtMost32` is not implemented for `[i32; 33]`
+LL |
+LL |     IntoIter::new([0i32; 33])
+   |     ------------------------- this returned value is of type `std::array::IntoIter<_, _: usize>`
    |
    = note: required because of the requirements on the impl of `std::iter::ExactSizeIterator` for `std::array::IntoIter<i32, 33usize>`
    = note: the return type of a function must have a statically known size
@@ -62,6 +71,9 @@ error[E0277]: arrays only have std trait implementations for lengths 0..=32
    |
 LL | pub fn no_fused_iterator() -> impl FusedIterator {
    |                               ^^^^^^^^^^^^^^^^^^ the trait `std::array::LengthAtMost32` is not implemented for `[i32; 33]`
+LL |
+LL |     IntoIter::new([0i32; 33])
+   |     ------------------------- this returned value is of type `std::array::IntoIter<_, _: usize>`
    |
    = note: required because of the requirements on the impl of `std::iter::FusedIterator` for `std::array::IntoIter<i32, 33usize>`
    = note: the return type of a function must have a statically known size
@@ -79,6 +91,9 @@ error[E0277]: arrays only have std trait implementations for lengths 0..=32
    |
 LL | pub fn no_trusted_len() -> impl TrustedLen {
    |                            ^^^^^^^^^^^^^^^ the trait `std::array::LengthAtMost32` is not implemented for `[i32; 33]`
+LL |
+LL |     IntoIter::new([0i32; 33])
+   |     ------------------------- this returned value is of type `std::array::IntoIter<_, _: usize>`
    |
    = note: required because of the requirements on the impl of `std::iter::TrustedLen` for `std::array::IntoIter<i32, 33usize>`
    = note: the return type of a function must have a statically known size
@@ -96,6 +111,9 @@ error[E0277]: arrays only have std trait implementations for lengths 0..=32
    |
 LL | pub fn no_clone() -> impl Clone {
    |                      ^^^^^^^^^^ the trait `std::array::LengthAtMost32` is not implemented for `[i32; 33]`
+LL |
+LL |     IntoIter::new([0i32; 33])
+   |     ------------------------- this returned value is of type `std::array::IntoIter<_, _: usize>`
    |
    = note: required because of the requirements on the impl of `std::clone::Clone` for `std::array::IntoIter<i32, 33usize>`
    = note: the return type of a function must have a statically known size
@@ -113,6 +131,9 @@ error[E0277]: arrays only have std trait implementations for lengths 0..=32
    |
 LL | pub fn no_debug() -> impl Debug {
    |                      ^^^^^^^^^^ the trait `std::array::LengthAtMost32` is not implemented for `[i32; 33]`
+LL |
+LL |     IntoIter::new([0i32; 33])
+   |     ------------------------- this returned value is of type `std::array::IntoIter<_, _: usize>`
    |
    = note: required because of the requirements on the impl of `std::fmt::Debug` for `std::array::IntoIter<i32, 33usize>`
    = note: the return type of a function must have a statically known size
diff --git a/src/test/ui/generic-associated-types/impl_bounds.stderr b/src/test/ui/generic-associated-types/impl_bounds.stderr
index 01799007693..ca2350ff757 100644
--- a/src/test/ui/generic-associated-types/impl_bounds.stderr
+++ b/src/test/ui/generic-associated-types/impl_bounds.stderr
@@ -38,7 +38,7 @@ LL |     type C where Self: Copy = String;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::marker::Copy` is not implemented for `T`
    |
    = note: required because of the requirements on the impl of `std::marker::Copy` for `Fooy<T>`
-   = note: the requirement `Fooy<T>: std::marker::Copy` appears on the associated impl typebut not on the corresponding associated trait type
+   = note: the requirement `Fooy<T>: std::marker::Copy` appears on the associated impl type but not on the corresponding associated trait type
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/impl-trait/dyn-trait-return-should-be-impl-trait.stderr b/src/test/ui/impl-trait/dyn-trait-return-should-be-impl-trait.stderr
index a09ce2bb298..d51cd6aeae6 100644
--- a/src/test/ui/impl-trait/dyn-trait-return-should-be-impl-trait.stderr
+++ b/src/test/ui/impl-trait/dyn-trait-return-should-be-impl-trait.stderr
@@ -11,7 +11,9 @@ error[E0277]: the size for values of type `(dyn Trait + 'static)` cannot be know
   --> $DIR/dyn-trait-return-should-be-impl-trait.rs:7:13
    |
 LL | fn fuz() -> (usize, Trait) { (42, Struct) }
-   |             ^^^^^^^^^^^^^^ doesn't have a size known at compile-time
+   |             ^^^^^^^^^^^^^^   ------------ this returned value is of type `(usize, (dyn Trait + 'static))`
+   |             |
+   |             doesn't have a size known at compile-time
    |
    = help: within `(usize, (dyn Trait + 'static))`, the trait `std::marker::Sized` is not implemented for `(dyn Trait + 'static)`
    = note: to learn more, visit <https://doc.rust-lang.org/book/ch19-04-advanced-types.html#dynamically-sized-types-and-the-sized-trait>
@@ -31,7 +33,9 @@ error[E0277]: the size for values of type `(dyn Trait + 'static)` cannot be know
   --> $DIR/dyn-trait-return-should-be-impl-trait.rs:10:13
    |
 LL | fn bar() -> (usize, dyn Trait) { (42, Struct) }
-   |             ^^^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time
+   |             ^^^^^^^^^^^^^^^^^^   ------------ this returned value is of type `(usize, (dyn Trait + 'static))`
+   |             |
+   |             doesn't have a size known at compile-time
    |
    = help: within `(usize, (dyn Trait + 'static))`, the trait `std::marker::Sized` is not implemented for `(dyn Trait + 'static)`
    = note: to learn more, visit <https://doc.rust-lang.org/book/ch19-04-advanced-types.html#dynamically-sized-types-and-the-sized-trait>
diff --git a/src/test/ui/issues/issue-58344.stderr b/src/test/ui/issues/issue-58344.stderr
index 427d03b679d..9b07dbd7ab6 100644
--- a/src/test/ui/issues/issue-58344.stderr
+++ b/src/test/ui/issues/issue-58344.stderr
@@ -3,6 +3,9 @@ error[E0277]: the trait bound `impl Trait<<u32 as std::ops::Add>::Output>: Trait
    |
 LL | ) -> Either<impl Trait<<u32 as Add<u32>>::Output>, impl Trait<<u32 as Add<u32>>::Output>> {
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Trait<u32>` is not implemented for `impl Trait<<u32 as std::ops::Add>::Output>`
+...
+LL |     add_generic(value, 1u32)
+   |     ------------------------ this returned value is of type `Either<impl Trait<<_ as std::ops::Add<_>>::Output>, impl Trait<<_ as std::ops::Add<_>>::Output>>`
    |
    = note: the return type of a function must have a statically known size
 
@@ -11,6 +14,9 @@ error[E0277]: the trait bound `impl Trait<<u32 as std::ops::Add>::Output>: Trait
    |
 LL | ) -> Either<impl Trait<<u32 as Add<u32>>::Output>, impl Trait<<u32 as Add<u32>>::Output>> {
    |                                                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Trait<u32>` is not implemented for `impl Trait<<u32 as std::ops::Add>::Output>`
+...
+LL |     add_generic(value, 1u32)
+   |     ------------------------ this returned value is of type `Either<impl Trait<<_ as std::ops::Add<_>>::Output>, impl Trait<<_ as std::ops::Add<_>>::Output>>`
    |
    = note: the return type of a function must have a statically known size
 
diff --git a/src/test/ui/issues/issue-5883.stderr b/src/test/ui/issues/issue-5883.stderr
index c2de1d09550..d886ecc11d1 100644
--- a/src/test/ui/issues/issue-5883.stderr
+++ b/src/test/ui/issues/issue-5883.stderr
@@ -14,6 +14,9 @@ error[E0277]: the size for values of type `(dyn A + 'static)` cannot be known at
    |
 LL |     -> Struct {
    |        ^^^^^^ doesn't have a size known at compile-time
+LL |
+LL |     Struct { r: r }
+   |     --------------- this returned value is of type `Struct`
    |
    = help: within `Struct`, the trait `std::marker::Sized` is not implemented for `(dyn A + 'static)`
    = note: to learn more, visit <https://doc.rust-lang.org/book/ch19-04-advanced-types.html#dynamically-sized-types-and-the-sized-trait>
diff --git a/src/test/ui/lifetimes/lifetime-elision-return-type-trait.stderr b/src/test/ui/lifetimes/lifetime-elision-return-type-trait.stderr
index 228582d0001..49fa11c35ae 100644
--- a/src/test/ui/lifetimes/lifetime-elision-return-type-trait.stderr
+++ b/src/test/ui/lifetimes/lifetime-elision-return-type-trait.stderr
@@ -3,6 +3,9 @@ error[E0277]: the trait bound `std::result::Result<(), _>: Future` is not satisf
    |
 LL | fn foo() -> impl Future<Item=(), Error=Box<dyn Error>> {
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Future` is not implemented for `std::result::Result<(), _>`
+LL |
+LL |     Ok(())
+   |     ------ this returned value is of type `std::result::Result<_, _>`
    |
    = note: the return type of a function must have a statically known size
 
diff --git a/src/test/ui/never_type/feature-gate-never_type_fallback.stderr b/src/test/ui/never_type/feature-gate-never_type_fallback.stderr
index 837e90d6ceb..88bfed2b547 100644
--- a/src/test/ui/never_type/feature-gate-never_type_fallback.stderr
+++ b/src/test/ui/never_type/feature-gate-never_type_fallback.stderr
@@ -3,8 +3,12 @@ error[E0277]: the trait bound `(): T` is not satisfied
    |
 LL | fn should_ret_unit() -> impl T {
    |                         ^^^^^^ the trait `T` is not implemented for `()`
+LL |
+LL |     panic!()
+   |     -------- this returned value is of type `_`
    |
    = note: the return type of a function must have a statically known size
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/type-alias-impl-trait/generic_underconstrained2.stderr b/src/test/ui/type-alias-impl-trait/generic_underconstrained2.stderr
index d4c7c7c7452..9e8414f9c15 100644
--- a/src/test/ui/type-alias-impl-trait/generic_underconstrained2.stderr
+++ b/src/test/ui/type-alias-impl-trait/generic_underconstrained2.stderr
@@ -18,6 +18,8 @@ LL | type Underconstrained<T: std::fmt::Debug> = impl 'static;
 ...
 LL | fn underconstrained<U>(_: U) -> Underconstrained<U> {
    |                     - help: consider restricting this bound: `U: std::fmt::Debug`
+LL |     5u32
+   |     ---- this returned value is of type `u32`
    |
    = help: the trait `std::fmt::Debug` is not implemented for `U`
    = note: the return type of a function must have a statically known size
@@ -30,6 +32,8 @@ LL | type Underconstrained2<T: std::fmt::Debug> = impl 'static;
 ...
 LL | fn underconstrained2<U, V>(_: U, _: V) -> Underconstrained2<V> {
    |                         - help: consider restricting this bound: `V: std::fmt::Debug`
+LL |     5u32
+   |     ---- this returned value is of type `u32`
    |
    = help: the trait `std::fmt::Debug` is not implemented for `V`
    = note: the return type of a function must have a statically known size