Do not mention associated items when they introduce an obligation

Author: estebank

compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs

@@ -1958,15 +1958,9 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
                     region, object_ty,
                 ));
             }
-            ObligationCauseCode::ItemObligation(item_def_id) => {
-                let item_name = tcx.def_path_str(item_def_id);
-                let msg = format!("required by `{}`", item_name);
-                let sp = tcx
-                    .hir()
-                    .span_if_local(item_def_id)
-                    .unwrap_or_else(|| tcx.def_span(item_def_id));
-                let sp = tcx.sess.source_map().guess_head_span(sp);
-                err.span_note(sp, &msg);
+            ObligationCauseCode::ItemObligation(_item_def_id) => {
+                // We hold the `DefId` of the item introducing the obligation, but displaying it
+                // doesn't add user usable information. It always point at an associated item.
             }
             ObligationCauseCode::BindingObligation(item_def_id, span) => {
                 let item_name = tcx.def_path_str(item_def_id);

compiler/rustc_typeck/src/check/compare_method.rs

@@ -232,7 +232,6 @@ fn compare_predicate_entailment<'tcx>(
                 span,
                 impl_m_hir_id,
                 ObligationCauseCode::CompareImplMethodObligation {
-                    item_name: impl_m.ident.name,
                     impl_item_def_id: impl_m.def_id,
                     trait_item_def_id: trait_m.def_id,
                 },

src/test/ui/allocator/not-an-allocator.stderr

@@ -6,11 +6,6 @@ LL | #[global_allocator]
 LL | static A: usize = 0;
    | ^^^^^^^^^^^^^^^^^^^^ the trait `GlobalAlloc` is not implemented for `usize`
    |
-note: required by `std::alloc::GlobalAlloc::alloc`
-  --> $SRC_DIR/core/src/alloc/global.rs:LL:COL
-   |
-LL |     unsafe fn alloc(&self, layout: Layout) -> *mut u8;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = note: this error originates in the attribute macro `global_allocator` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0277]: the trait bound `usize: GlobalAlloc` is not satisfied
@@ -21,11 +16,6 @@ LL | #[global_allocator]
 LL | static A: usize = 0;
    | ^^^^^^^^^^^^^^^^^^^^ the trait `GlobalAlloc` is not implemented for `usize`
    |
-note: required by `std::alloc::GlobalAlloc::dealloc`
-  --> $SRC_DIR/core/src/alloc/global.rs:LL:COL
-   |
-LL |     unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout);
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = note: this error originates in the attribute macro `global_allocator` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0277]: the trait bound `usize: GlobalAlloc` is not satisfied
@@ -36,11 +26,6 @@ LL | #[global_allocator]
 LL | static A: usize = 0;
    | ^^^^^^^^^^^^^^^^^^^^ the trait `GlobalAlloc` is not implemented for `usize`
    |
-note: required by `std::alloc::GlobalAlloc::realloc`
-  --> $SRC_DIR/core/src/alloc/global.rs:LL:COL
-   |
-LL |     unsafe fn realloc(&self, ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 {
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = note: this error originates in the attribute macro `global_allocator` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0277]: the trait bound `usize: GlobalAlloc` is not satisfied
@@ -51,11 +36,6 @@ LL | #[global_allocator]
 LL | static A: usize = 0;
    | ^^^^^^^^^^^^^^^^^^^^ the trait `GlobalAlloc` is not implemented for `usize`
    |
-note: required by `std::alloc::GlobalAlloc::alloc_zeroed`
-  --> $SRC_DIR/core/src/alloc/global.rs:LL:COL
-   |
-LL |     unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut u8 {
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = note: this error originates in the attribute macro `global_allocator` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: aborting due to 4 previous errors

src/test/ui/associated-consts/associated-const-array-len.stderr

@@ -3,12 +3,6 @@ error[E0277]: the trait bound `i32: Foo` is not satisfied
    |
 LL | const X: [i32; <i32 as Foo>::ID] = [0, 1, 2];
    |                ^^^^^^^^^^^^^^^^ the trait `Foo` is not implemented for `i32`
-   |
-note: required by `Foo::ID`
-  --> $DIR/associated-const-array-len.rs:2:5
-   |
-LL |     const ID: usize;
-   |     ^^^^^^^^^^^^^^^^
 
 error: aborting due to previous error
 

src/test/ui/associated-consts/issue-63496.stderr

@@ -9,11 +9,6 @@ LL |     fn f() -> ([u8; A::C], [u8; A::C]);
    |
    = note: cannot satisfy `_: A`
    = note: associated constants cannot be accessed directly on a `trait`, they can only be accessed through a specific `impl`
-note: required by `A::C`
-  --> $DIR/issue-63496.rs:2:5
-   |
-LL |     const C: usize;
-   |     ^^^^^^^^^^^^^^^
 
 error[E0283]: type annotations needed
   --> $DIR/issue-63496.rs:4:33
@@ -26,11 +21,6 @@ LL |     fn f() -> ([u8; A::C], [u8; A::C]);
    |
    = note: cannot satisfy `_: A`
    = note: associated constants cannot be accessed directly on a `trait`, they can only be accessed through a specific `impl`
-note: required by `A::C`
-  --> $DIR/issue-63496.rs:2:5
-   |
-LL |     const C: usize;
-   |     ^^^^^^^^^^^^^^^
 
 error: aborting due to 2 previous errors
 

src/test/ui/associated-item/issue-48027.stderr

@@ -9,11 +9,6 @@ LL |     fn return_n(&self) -> [u8; Bar::X];
    |
    = note: cannot satisfy `_: Bar`
    = note: associated constants cannot be accessed directly on a `trait`, they can only be accessed through a specific `impl`
-note: required by `Bar::X`
-  --> $DIR/issue-48027.rs:2:5
-   |
-LL |     const X: usize;
-   |     ^^^^^^^^^^^^^^^
 
 error[E0038]: the trait `Bar` cannot be made into an object
   --> $DIR/issue-48027.rs:6:6

src/test/ui/associated-types/associated-types-bound-failure.stderr

@@ -6,11 +6,6 @@ LL |     ToInt::to_int(&g.get())
    |     |
    |     required by a bound introduced by this call
    |
-note: required by `ToInt::to_int`
-  --> $DIR/associated-types-bound-failure.rs:6:5
-   |
-LL |     fn to_int(&self) -> isize;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
 help: consider further restricting the associated type
    |
 LL |     where G : GetToInt, <G as GetToInt>::R: ToInt

src/test/ui/associated-types/associated-types-unconstrained.stderr

@@ -5,11 +5,6 @@ LL |     let x: isize = Foo::bar();
    |                    ^^^^^^^^ cannot infer type
    |
    = note: cannot satisfy `_: Foo`
-note: required by `Foo::bar`
-  --> $DIR/associated-types-unconstrained.rs:5:5
-   |
-LL |     fn bar() -> isize;
-   |     ^^^^^^^^^^^^^^^^^^
 
 error: aborting due to previous error
 

src/test/ui/associated-types/issue-44153.stderr

@@ -9,11 +9,6 @@ note: required because of the requirements on the impl of `Visit` for `()`
    |
 LL | impl<'a> Visit for () where
    |          ^^^^^     ^^
-note: required by `Visit::visit`
-  --> $DIR/issue-44153.rs:6:5
-   |
-LL |     fn visit() {}
-   |     ^^^^^^^^^^
 
 error: aborting due to previous error
 

src/test/ui/async-await/issue-61076.rs

@@ -42,12 +42,10 @@ async fn bar() -> Result<(), ()> {
     foo()?; //~ ERROR the `?` operator can only be applied to values that implement `Try`
     //~^ NOTE the `?` operator cannot be applied to type `impl Future<Output = Result<(), ()>>`
     //~| HELP the trait `Try` is not implemented for `impl Future<Output = Result<(), ()>>`
-    //~| NOTE required by `branch`
     //~| HELP consider `await`ing on the `Future`
     //~| NOTE in this expansion of desugaring of operator `?`
     //~| NOTE in this expansion of desugaring of operator `?`
     //~| NOTE in this expansion of desugaring of operator `?`
-    //~| NOTE in this expansion of desugaring of operator `?`
     Ok(())
 }
 
@@ -67,12 +65,10 @@ async fn baz() -> Result<(), ()> {
     t?; //~ ERROR the `?` operator can only be applied to values that implement `Try`
     //~^ NOTE the `?` operator cannot be applied to type `T`
     //~| HELP the trait `Try` is not implemented for `T`
-    //~| NOTE required by `branch`
     //~| HELP consider `await`ing on the `Future`
     //~| NOTE in this expansion of desugaring of operator `?`
     //~| NOTE in this expansion of desugaring of operator `?`
     //~| NOTE in this expansion of desugaring of operator `?`
-    //~| NOTE in this expansion of desugaring of operator `?`
 
 
     let _: i32 = tuple().0; //~ ERROR no field `0`

src/test/ui/async-await/issue-61076.stderr

@@ -5,35 +5,25 @@ LL |     foo()?;
    |     ^^^^^^ the `?` operator cannot be applied to type `impl Future<Output = Result<(), ()>>`
    |
    = help: the trait `Try` is not implemented for `impl Future<Output = Result<(), ()>>`
-note: required by `branch`
-  --> $SRC_DIR/core/src/ops/try_trait.rs:LL:COL
-   |
-LL |     fn branch(self) -> ControlFlow<Self::Residual, Self::Output>;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 help: consider `await`ing on the `Future`
    |
 LL |     foo().await?;
    |          ++++++
 
 error[E0277]: the `?` operator can only be applied to values that implement `Try`
-  --> $DIR/issue-61076.rs:67:5
+  --> $DIR/issue-61076.rs:65:5
    |
 LL |     t?;
    |     ^^ the `?` operator cannot be applied to type `T`
    |
    = help: the trait `Try` is not implemented for `T`
-note: required by `branch`
-  --> $SRC_DIR/core/src/ops/try_trait.rs:LL:COL
-   |
-LL |     fn branch(self) -> ControlFlow<Self::Residual, Self::Output>;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 help: consider `await`ing on the `Future`
    |
 LL |     t.await?;
    |      ++++++
 
 error[E0609]: no field `0` on type `impl Future<Output = Tuple>`
-  --> $DIR/issue-61076.rs:78:26
+  --> $DIR/issue-61076.rs:74:26
    |
 LL |     let _: i32 = tuple().0;
    |                          ^ field not available in `impl Future`, but it is available in its `Output`
@@ -44,7 +34,7 @@ LL |     let _: i32 = tuple().await.0;
    |                         ++++++
 
 error[E0609]: no field `a` on type `impl Future<Output = Struct>`
-  --> $DIR/issue-61076.rs:82:28
+  --> $DIR/issue-61076.rs:78:28
    |
 LL |     let _: i32 = struct_().a;
    |                            ^ field not available in `impl Future`, but it is available in its `Output`
@@ -55,7 +45,7 @@ LL |     let _: i32 = struct_().await.a;
    |                           ++++++
 
 error[E0599]: no method named `method` found for opaque type `impl Future<Output = Struct>` in the current scope
-  --> $DIR/issue-61076.rs:86:15
+  --> $DIR/issue-61076.rs:82:15
    |
 LL |     struct_().method();
    |               ^^^^^^ method not found in `impl Future<Output = Struct>`
@@ -66,13 +56,13 @@ LL |     struct_().await.method();
    |               ++++++
 
 error[E0308]: mismatched types
-  --> $DIR/issue-61076.rs:94:9
+  --> $DIR/issue-61076.rs:90:9
    |
 LL |         Tuple(_) => {}
    |         ^^^^^^^^ expected opaque type, found struct `Tuple`
    |
 note: while checking the return type of the `async fn`
-  --> $DIR/issue-61076.rs:58:21
+  --> $DIR/issue-61076.rs:56:21
    |
 LL | async fn tuple() -> Tuple {
    |                     ^^^^^ checked the `Output` of this `async fn`, expected opaque type

src/test/ui/async-await/issue-70594.stderr

@@ -25,11 +25,6 @@ LL |     [1; ().await];
    |         ^^^^^^^^ `()` is not a future
    |
    = help: the trait `Future` is not implemented for `()`
-note: required by `poll`
-  --> $SRC_DIR/core/src/future/future.rs:LL:COL
-   |
-LL |     fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output>;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to 4 previous errors
 

src/test/ui/async-await/issue-84841.stderr

@@ -5,11 +5,6 @@ LL |     test()?;
    |     ^^^^^^^ the `?` operator cannot be applied to type `impl Future<Output = ()>`
    |
    = help: the trait `Try` is not implemented for `impl Future<Output = ()>`
-note: required by `branch`
-  --> $SRC_DIR/core/src/ops/try_trait.rs:LL:COL
-   |
-LL |     fn branch(self) -> ControlFlow<Self::Residual, Self::Output>;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0277]: the `?` operator can only be used in an async function that returns `Result` or `Option` (or another type that implements `FromResidual`)
   --> $DIR/issue-84841.rs:9:11
@@ -25,11 +20,6 @@ LL | | }
    | |_- this function should return `Result` or `Option` to accept `?`
    |
    = help: the trait `FromResidual<_>` is not implemented for `()`
-note: required by `from_residual`
-  --> $SRC_DIR/core/src/ops/try_trait.rs:LL:COL
-   |
-LL |     fn from_residual(residual: R) -> Self;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to 2 previous errors
 

src/test/ui/async-await/issues/issue-62009-1.stderr

@@ -34,11 +34,6 @@ LL |     (|_| 2333).await;
    |     ^^^^^^^^^^^^^^^^ `[closure@$DIR/issue-62009-1.rs:12:5: 12:15]` is not a future
    |
    = help: the trait `Future` is not implemented for `[closure@$DIR/issue-62009-1.rs:12:5: 12:15]`
-note: required by `poll`
-  --> $SRC_DIR/core/src/future/future.rs:LL:COL
-   |
-LL |     fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output>;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to 4 previous errors
 

src/test/ui/async-await/try-on-option-in-async.stderr

@@ -11,11 +11,6 @@ LL | |     }
    | |_____- this function should return `Result` or `Option` to accept `?`
    |
    = help: the trait `FromResidual<Option<Infallible>>` is not implemented for `{integer}`
-note: required by `from_residual`
-  --> $SRC_DIR/core/src/ops/try_trait.rs:LL:COL
-   |
-LL |     fn from_residual(residual: R) -> Self;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0277]: the `?` operator can only be used in an async closure that returns `Result` or `Option` (or another type that implements `FromResidual`)
   --> $DIR/try-on-option-in-async.rs:17:10
@@ -30,11 +25,6 @@ LL | |     };
    | |_____- this function should return `Result` or `Option` to accept `?`
    |
    = help: the trait `FromResidual<Option<Infallible>>` is not implemented for `u32`
-note: required by `from_residual`
-  --> $SRC_DIR/core/src/ops/try_trait.rs:LL:COL
-   |
-LL |     fn from_residual(residual: R) -> Self;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0277]: the `?` operator can only be used in an async function that returns `Result` or `Option` (or another type that implements `FromResidual`)
   --> $DIR/try-on-option-in-async.rs:26:6
@@ -49,11 +39,6 @@ LL | | }
    | |_- this function should return `Result` or `Option` to accept `?`
    |
    = help: the trait `FromResidual<Option<Infallible>>` is not implemented for `u32`
-note: required by `from_residual`
-  --> $SRC_DIR/core/src/ops/try_trait.rs:LL:COL
-   |
-LL |     fn from_residual(residual: R) -> Self;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to 3 previous errors
 

src/test/ui/const-generics/defaults/wfness.stderr

@@ -12,11 +12,6 @@ LL | struct WhereClause<const N: u8 = 2> where (): Trait<N>;
    |
    = help: the following implementations were found:
              <() as Trait<3_u8>>
-note: required by `WhereClause`
-  --> $DIR/wfness.rs:8:1
-   |
-LL | struct WhereClause<const N: u8 = 2> where (): Trait<N>;
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0277]: the trait bound `(): Trait<1_u8>` is not satisfied
   --> $DIR/wfness.rs:16:13

src/test/ui/const-generics/dont-evaluate-array-len-on-err-1.stderr

@@ -3,12 +3,6 @@ error[E0277]: the trait bound `[Adt; _]: Foo` is not satisfied
    |
 LL |         <[Adt; std::mem::size_of::<Self::Assoc>()] as Foo>::bar()
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Foo` is not implemented for `[Adt; _]`
-   |
-note: required by `Foo::bar`
-  --> $DIR/dont-evaluate-array-len-on-err-1.rs:19:5
-   |
-LL |     fn bar() {}
-   |     ^^^^^^^^
 
 error: aborting due to previous error
 

src/test/ui/const-generics/exhaustive-value.stderr

@@ -10,11 +10,6 @@ LL |     <() as Foo<N>>::test()
              <() as Foo<101_u8>>
              <() as Foo<102_u8>>
            and 252 others
-note: required by `Foo::test`
-  --> $DIR/exhaustive-value.rs:2:5
-   |
-LL |     fn test() {}
-   |     ^^^^^^^^^
 
 error: aborting due to previous error
 

src/test/ui/derives/derives-span-Clone-enum-struct-variant.stderr

@@ -7,11 +7,6 @@ LL | #[derive(Clone)]
 LL |      x: Error
    |      ^^^^^^^^ the trait `Clone` is not implemented for `Error`
    |
-note: required by `clone`
-  --> $SRC_DIR/core/src/clone.rs:LL:COL
-   |
-LL |     fn clone(&self) -> Self;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^
    = note: this error originates in the derive macro `Clone` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: aborting due to previous error