Remove redundant explanatory note for type parameters

src/librustc_trait_selection/traits/error_reporting/mod.rs

@@ -376,7 +376,12 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
                             // If it has a custom `#[rustc_on_unimplemented]`
                             // error message, let's display it as the label!
                             err.span_label(span, s.as_str());
-                            err.help(&explanation);
+                            if !matches!(trait_ref.skip_binder().self_ty().kind, ty::Param(_)) {
+                                // When the self type is a type param We don't need to "the trait
+                                // `std::marker::Sized` is not implemented for `T`" as we will point
+                                // at the type param with a label to suggest constraining it.
+                                err.help(&explanation);
+                            }
                         } else {
                             err.span_label(span, explanation);
                         }

src/test/ui/associated-types/defaults-unsound-62211-1.stderr

@@ -21,7 +21,6 @@ LL | trait UncheckedCopy: Sized {
 LL |     + AddAssign<&'static str>
    |       ^^^^^^^^^^^^^^^^^^^^^^^ no implementation for `Self += &'static str`
    |
-   = help: the trait `std::ops::AddAssign<&'static str>` is not implemented for `Self`
 help: consider further restricting `Self`
    |
 LL | trait UncheckedCopy: Sized + std::ops::AddAssign<&'static str> {
@@ -50,7 +49,6 @@ LL | trait UncheckedCopy: Sized {
 LL |     + Display = Self;
    |       ^^^^^^^ `Self` cannot be formatted with the default formatter
    |
-   = help: the trait `std::fmt::Display` is not implemented for `Self`
    = note: in format strings you may be able to use `{:?}` (or {:#?} for pretty-print) instead
 help: consider further restricting `Self`
    |
@@ -69,7 +67,6 @@ LL |     + Display = Self;
 LL | impl<T> UncheckedCopy for T {}
    |         ^^^^^^^^^^^^^ `T` cannot be formatted with the default formatter
    |
-   = help: the trait `std::fmt::Display` is not implemented for `T`
    = note: in format strings you may be able to use `{:?}` (or {:#?} for pretty-print) instead
 help: consider restricting type parameter `T`
    |
@@ -105,7 +102,6 @@ LL |     + AddAssign<&'static str>
 LL | impl<T> UncheckedCopy for T {}
    |         ^^^^^^^^^^^^^ no implementation for `T += &'static str`
    |
-   = help: the trait `std::ops::AddAssign<&'static str>` is not implemented for `T`
 help: consider restricting type parameter `T`
    |
 LL | impl<T: std::ops::AddAssign<&'static str>> UncheckedCopy for T {}

src/test/ui/associated-types/defaults-unsound-62211-2.stderr

@@ -21,7 +21,6 @@ LL | trait UncheckedCopy: Sized {
 LL |     + AddAssign<&'static str>
    |       ^^^^^^^^^^^^^^^^^^^^^^^ no implementation for `Self += &'static str`
    |
-   = help: the trait `std::ops::AddAssign<&'static str>` is not implemented for `Self`
 help: consider further restricting `Self`
    |
 LL | trait UncheckedCopy: Sized + std::ops::AddAssign<&'static str> {
@@ -50,7 +49,6 @@ LL | trait UncheckedCopy: Sized {
 LL |     + Display = Self;
    |       ^^^^^^^ `Self` cannot be formatted with the default formatter
    |
-   = help: the trait `std::fmt::Display` is not implemented for `Self`
    = note: in format strings you may be able to use `{:?}` (or {:#?} for pretty-print) instead
 help: consider further restricting `Self`
    |
@@ -69,7 +67,6 @@ LL |     + Display = Self;
 LL | impl<T> UncheckedCopy for T {}
    |         ^^^^^^^^^^^^^ `T` cannot be formatted with the default formatter
    |
-   = help: the trait `std::fmt::Display` is not implemented for `T`
    = note: in format strings you may be able to use `{:?}` (or {:#?} for pretty-print) instead
 help: consider restricting type parameter `T`
    |
@@ -105,7 +102,6 @@ LL |     + AddAssign<&'static str>
 LL | impl<T> UncheckedCopy for T {}
    |         ^^^^^^^^^^^^^ no implementation for `T += &'static str`
    |
-   = help: the trait `std::ops::AddAssign<&'static str>` is not implemented for `T`
 help: consider restricting type parameter `T`
    |
 LL | impl<T: std::ops::AddAssign<&'static str>> UncheckedCopy for T {}

src/test/ui/associated-types/issue-63593.stderr

@@ -6,7 +6,6 @@ LL | trait MyTrait {
 LL |     type This = Self;
    |     ^^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time
    |
-   = help: the trait `std::marker::Sized` is not implemented for `Self`
 help: consider further restricting `Self`
    |
 LL | trait MyTrait: std::marker::Sized {

src/test/ui/associated-types/trait-with-supertraits-needing-sized-self.stderr

@@ -9,7 +9,6 @@ LL | trait ArithmeticOps: Add<Output=Self> + Sub<Output=Self> + Mul<Output=Self>
 LL | pub trait Add<Rhs = Self> {
    |               --- required by this bound in `std::ops::Add`
    |
-   = help: the trait `std::marker::Sized` is not implemented for `Self`
 help: consider further restricting `Self`
    |
 LL | trait ArithmeticOps: Add<Output=Self> + Sub<Output=Self> + Mul<Output=Self> + Div<Output=Self> + std::marker::Sized {}

src/test/ui/async-await/issue-70818.stderr

@@ -7,7 +7,6 @@ LL |
 LL |     async { (ty, ty1) }
    |     ------------------- this returned value is of type `impl std::future::Future`
    |
-   = help: within `impl std::future::Future`, the trait `std::marker::Send` is not implemented for `U`
 note: captured value is not `Send`
   --> $DIR/issue-70818.rs:6:18
    |

src/test/ui/bad/bad-method-typaram-kind.stderr

@@ -4,7 +4,6 @@ error[E0277]: `T` cannot be sent between threads safely
 LL |     1.bar::<T>();
    |       ^^^ `T` cannot be sent between threads safely
    |
-   = help: the trait `std::marker::Send` is not implemented for `T`
 help: consider further restricting this bound
    |
 LL | fn foo<T:'static + std::marker::Send>() {

src/test/ui/bound-suggestions.stderr

@@ -4,7 +4,6 @@ error[E0277]: `impl Sized` doesn't implement `std::fmt::Debug`
 LL |     println!("{:?}", t);
    |                      ^ `impl Sized` cannot be formatted using `{:?}` because it doesn't implement `std::fmt::Debug`
    |
-   = help: the trait `std::fmt::Debug` is not implemented for `impl Sized`
    = note: required by `std::fmt::Debug::fmt`
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 help: consider further restricting this bound
@@ -18,7 +17,6 @@ error[E0277]: `T` doesn't implement `std::fmt::Debug`
 LL |     println!("{:?}", t);
    |                      ^ `T` cannot be formatted using `{:?}` because it doesn't implement `std::fmt::Debug`
    |
-   = help: the trait `std::fmt::Debug` is not implemented for `T`
    = note: required by `std::fmt::Debug::fmt`
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 help: consider restricting type parameter `T`
@@ -32,7 +30,6 @@ error[E0277]: `T` doesn't implement `std::fmt::Debug`
 LL |     println!("{:?}", t);
    |                      ^ `T` cannot be formatted using `{:?}` because it doesn't implement `std::fmt::Debug`
    |
-   = help: the trait `std::fmt::Debug` is not implemented for `T`
    = note: required by `std::fmt::Debug::fmt`
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 help: consider further restricting this bound
@@ -46,7 +43,6 @@ error[E0277]: `Y` doesn't implement `std::fmt::Debug`
 LL |     println!("{:?} {:?}", x, y);
    |                              ^ `Y` cannot be formatted using `{:?}` because it doesn't implement `std::fmt::Debug`
    |
-   = help: the trait `std::fmt::Debug` is not implemented for `Y`
    = note: required by `std::fmt::Debug::fmt`
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 help: consider further restricting type parameter `Y`
@@ -60,7 +56,6 @@ error[E0277]: `X` doesn't implement `std::fmt::Debug`
 LL |     println!("{:?}", x);
    |                      ^ `X` cannot be formatted using `{:?}` because it doesn't implement `std::fmt::Debug`
    |
-   = help: the trait `std::fmt::Debug` is not implemented for `X`
    = note: required by `std::fmt::Debug::fmt`
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 help: consider further restricting this bound
@@ -74,7 +69,6 @@ error[E0277]: `X` doesn't implement `std::fmt::Debug`
 LL |     println!("{:?}", x);
    |                      ^ `X` cannot be formatted using `{:?}` because it doesn't implement `std::fmt::Debug`
    |
-   = help: the trait `std::fmt::Debug` is not implemented for `X`
    = note: required by `std::fmt::Debug::fmt`
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 help: consider further restricting type parameter `X`

src/test/ui/builtin-superkinds/builtin-superkinds-double-superkind.stderr

@@ -7,7 +7,6 @@ LL |
 LL | impl <T: Sync+'static> Foo for (T,) { }
    |                        ^^^ `T` cannot be sent between threads safely
    |
-   = help: within `(T,)`, the trait `std::marker::Send` is not implemented for `T`
    = note: required because it appears within the type `(T,)`
 help: consider further restricting this bound
    |
@@ -23,7 +22,6 @@ LL | trait Foo : Send+Sync { }
 LL | impl <T: Send> Foo for (T,T) { }
    |                ^^^ `T` cannot be shared between threads safely
    |
-   = help: within `(T, T)`, the trait `std::marker::Sync` is not implemented for `T`
    = note: required because it appears within the type `(T, T)`
 help: consider further restricting this bound
    |

src/test/ui/builtin-superkinds/builtin-superkinds-in-metadata.stderr

@@ -9,7 +9,6 @@ LL | impl <T:Sync+'static> RequiresRequiresShareAndSend for X<T> { }
 LL | pub trait RequiresRequiresShareAndSend : RequiresShare + Send { }
    |                                                          ---- required by this bound in `trait_superkinds_in_metadata::RequiresRequiresShareAndSend`
    |
-   = help: within `X<T>`, the trait `std::marker::Send` is not implemented for `T`
    = note: required because it appears within the type `X<T>`
 help: consider further restricting this bound
    |

src/test/ui/builtin-superkinds/builtin-superkinds-typaram-not-send.stderr

@@ -7,7 +7,6 @@ LL |
 LL | impl <T: Sync+'static> Foo for T { }
    |                        ^^^ `T` cannot be sent between threads safely
    |
-   = help: the trait `std::marker::Send` is not implemented for `T`
 help: consider further restricting this bound
    |
 LL | impl <T: Sync+'static + std::marker::Send> Foo for T { }

src/test/ui/closures/closure-bounds-cant-promote-superkind-in-struct.stderr

@@ -7,7 +7,6 @@ LL | struct X<F> where F: FnOnce() + 'static + Send {
 LL | fn foo<F>(blk: F) -> X<F> where F: FnOnce() + 'static {
    |                      ^^^^ `F` cannot be sent between threads safely
    |
-   = help: the trait `std::marker::Send` is not implemented for `F`
 help: consider further restricting this bound
    |
 LL | fn foo<F>(blk: F) -> X<F> where F: FnOnce() + 'static + std::marker::Send {

src/test/ui/closures/closure-bounds-subtype.stderr

@@ -7,7 +7,6 @@ LL | fn take_const_owned<F>(_: F) where F: FnOnce() + Sync + Send {
 LL |     take_const_owned(f);
    |                      ^ `F` cannot be shared between threads safely
    |
-   = help: the trait `std::marker::Sync` is not implemented for `F`
 help: consider further restricting this bound
    |
 LL | fn give_owned<F>(f: F) where F: FnOnce() + Send + std::marker::Sync {

src/test/ui/dst/dst-object-from-unsized-type.stderr

@@ -6,7 +6,6 @@ LL | fn test1<T: ?Sized + Foo>(t: &T) {
 LL |     let u: &dyn Foo = t;
    |                       ^ doesn't have a size known at compile-time
    |
-   = help: the trait `std::marker::Sized` is not implemented for `T`
    = note: required for the cast to the object type `dyn Foo`
 
 error[E0277]: the size for values of type `T` cannot be known at compilation time
@@ -17,7 +16,6 @@ LL | fn test2<T: ?Sized + Foo>(t: &T) {
 LL |     let v: &dyn Foo = t as &dyn Foo;
    |                       ^ doesn't have a size known at compile-time
    |
-   = help: the trait `std::marker::Sized` is not implemented for `T`
    = note: required for the cast to the object type `dyn Foo`
 
 error[E0277]: the size for values of type `str` cannot be known at compilation time

src/test/ui/generic-associated-types/issue-68642-broken-llvm-ir.stderr

@@ -16,7 +16,6 @@ LL |     type F<'a>: Fn() -> u32;
 LL |     type F<'a> = Self;
    |     ^^^^^^^^^^^^^^^^^^ expected an `Fn<()>` closure, found `T`
    |
-   = help: the trait `std::ops::Fn<()>` is not implemented for `T`
    = note: wrap the `T` in a closure with no arguments: `|| { /* code */ }
 help: consider restricting type parameter `T`
    |

src/test/ui/generic-associated-types/issue-68643-broken-mir.stderr

@@ -16,7 +16,6 @@ LL |     type F<'a>: Fn() -> u32;
 LL |     type F<'a> = Self;
    |     ^^^^^^^^^^^^^^^^^^ expected an `Fn<()>` closure, found `T`
    |
-   = help: the trait `std::ops::Fn<()>` is not implemented for `T`
    = note: wrap the `T` in a closure with no arguments: `|| { /* code */ }
 help: consider restricting type parameter `T`
    |

src/test/ui/generic-associated-types/issue-68644-codegen-selection.stderr

@@ -16,7 +16,6 @@ LL |     type F<'a>: Fn() -> u32;
 LL |     type F<'a> = Self;
    |     ^^^^^^^^^^^^^^^^^^ expected an `Fn<()>` closure, found `T`
    |
-   = help: the trait `std::ops::Fn<()>` is not implemented for `T`
    = note: wrap the `T` in a closure with no arguments: `|| { /* code */ }
 help: consider restricting type parameter `T`
    |

src/test/ui/generic-associated-types/issue-68645-codegen-fulfillment.stderr

@@ -16,7 +16,6 @@ LL |     type F<'a>: Fn() -> u32;
 LL |     type F<'a> = Self;
    |     ^^^^^^^^^^^^^^^^^^ expected an `Fn<()>` closure, found `T`
    |
-   = help: the trait `std::ops::Fn<()>` is not implemented for `T`
    = note: wrap the `T` in a closure with no arguments: `|| { /* code */ }
 help: consider restricting type parameter `T`
    |

src/test/ui/issues/issue-20005.stderr

@@ -7,7 +7,6 @@ LL | trait From<Src> {
 LL |     ) -> <Dst as From<Self>>::Result where Dst: From<Self> {
    |                                                 ^^^^^^^^^^ doesn't have a size known at compile-time
    |
-   = help: the trait `std::marker::Sized` is not implemented for `Self`
 help: consider further restricting `Self`
    |
 LL |     ) -> <Dst as From<Self>>::Result where Dst: From<Self>, Self: std::marker::Sized {

src/test/ui/issues/issue-27060-2.stderr

@@ -6,7 +6,6 @@ LL | pub struct Bad<T: ?Sized> {
 LL |     data: T,
    |           ^ doesn't have a size known at compile-time
    |
-   = help: the trait `std::marker::Sized` is not implemented for `T`
    = note: the last field of a packed struct may only have a dynamically sized type if it does not need drop to be run
    = help: change the field's type to have a statically known size
 help: borrowed types always have a statically known size

src/test/ui/issues/issue-27078.stderr

@@ -4,7 +4,6 @@ error[E0277]: the size for values of type `Self` cannot be known at compilation
 LL |     fn foo(self) -> &'static i32 {
    |            ^^^^ doesn't have a size known at compile-time
    |
-   = help: the trait `std::marker::Sized` is not implemented for `Self`
    = help: unsized locals are gated as an unstable feature
 help: consider further restricting `Self`
    |

src/test/ui/kindck/kindck-impl-type-params.nll.stderr

@@ -4,7 +4,6 @@ error[E0277]: `T` cannot be sent between threads safely
 LL |     let a = &t as &dyn Gettable<T>;
    |             ^^ `T` cannot be sent between threads safely
    |
-   = help: the trait `std::marker::Send` is not implemented for `T`
    = note: required because of the requirements on the impl of `Gettable<T>` for `S<T>`
    = note: required for the cast to the object type `dyn Gettable<T>`
 help: consider restricting type parameter `T`
@@ -31,7 +30,6 @@ error[E0277]: `T` cannot be sent between threads safely
 LL |     let a: &dyn Gettable<T> = &t;
    |                               ^^ `T` cannot be sent between threads safely
    |
-   = help: the trait `std::marker::Send` is not implemented for `T`
    = note: required because of the requirements on the impl of `Gettable<T>` for `S<T>`
    = note: required for the cast to the object type `dyn Gettable<T>`
 help: consider restricting type parameter `T`

src/test/ui/kindck/kindck-impl-type-params.stderr

@@ -4,7 +4,6 @@ error[E0277]: `T` cannot be sent between threads safely
 LL |     let a = &t as &dyn Gettable<T>;
    |             ^^ `T` cannot be sent between threads safely
    |
-   = help: the trait `std::marker::Send` is not implemented for `T`
    = note: required because of the requirements on the impl of `Gettable<T>` for `S<T>`
    = note: required for the cast to the object type `dyn Gettable<T>`
 help: consider restricting type parameter `T`
@@ -31,7 +30,6 @@ error[E0277]: `T` cannot be sent between threads safely
 LL |     let a: &dyn Gettable<T> = &t;
    |                               ^^ `T` cannot be sent between threads safely
    |
-   = help: the trait `std::marker::Send` is not implemented for `T`
    = note: required because of the requirements on the impl of `Gettable<T>` for `S<T>`
    = note: required for the cast to the object type `dyn Gettable<T>`
 help: consider restricting type parameter `T`

src/test/ui/lazy_normalization_consts/feature-gate-lazy_normalization_consts.stderr

@@ -9,7 +9,6 @@ LL | fn test<T>() {
 LL |     let _: [u8; sof::<T>()];
    |                       ^ doesn't have a size known at compile-time
    |
-   = help: the trait `std::marker::Sized` is not implemented for `T`
 help: consider relaxing the implicit `Sized` restriction
    |
 LL | pub const fn sof<T: ?Sized>() -> usize {

src/test/ui/phantom-oibit.stderr

@@ -7,7 +7,6 @@ LL | fn is_zen<T: Zen>(_: T) {}
 LL |     is_zen(x)
    |            ^ `T` cannot be shared between threads safely
    |
-   = help: the trait `std::marker::Sync` is not implemented for `T`
    = note: required because of the requirements on the impl of `Zen` for `&T`
    = note: required because it appears within the type `std::marker::PhantomData<&T>`
    = note: required because it appears within the type `Guard<'_, T>`
@@ -25,7 +24,6 @@ LL | fn is_zen<T: Zen>(_: T) {}
 LL |     is_zen(x)
    |            ^ `T` cannot be shared between threads safely
    |
-   = help: the trait `std::marker::Sync` is not implemented for `T`
    = note: required because of the requirements on the impl of `Zen` for `&T`
    = note: required because it appears within the type `std::marker::PhantomData<&T>`
    = note: required because it appears within the type `Guard<'_, T>`

src/test/ui/specialization/deafult-generic-associated-type-bound.stderr

@@ -24,7 +24,6 @@ LL |     type U<'a>: PartialEq<&'a Self>;
 LL |     default type U<'a> = &'a T;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^ no implementation for `T == T`
    |
-   = help: the trait `std::cmp::PartialEq` is not implemented for `T`
    = note: required because of the requirements on the impl of `std::cmp::PartialEq` for `&'a T`
 help: consider further restricting this bound
    |

src/test/ui/suggestions/adt-param-with-implicit-sized-bound.stderr

@@ -9,7 +9,6 @@ LL | struct Struct5<T: ?Sized>{
 LL |     _t: X<T>,
    |         ^^^^ doesn't have a size known at compile-time
    |
-   = help: the trait `std::marker::Sized` is not implemented for `T`
 help: you could relax the implicit `Sized` bound on `T` if it were used through indirection like `&T` or `Box<T>`
   --> $DIR/adt-param-with-implicit-sized-bound.rs:18:10
    |
@@ -27,7 +26,6 @@ LL |     fn func1() -> Struct1<Self>;
 LL | struct Struct1<T>{
    |                - required by this bound in `Struct1`
    |
-   = help: the trait `std::marker::Sized` is not implemented for `Self`
 help: consider further restricting `Self`
    |
 LL |     fn func1() -> Struct1<Self> where Self: std::marker::Sized;
@@ -46,7 +44,6 @@ LL |     fn func2<'a>() -> Struct2<'a, Self>;
 LL | struct Struct2<'a, T>{
    |                    - required by this bound in `Struct2`
    |
-   = help: the trait `std::marker::Sized` is not implemented for `Self`
 help: consider further restricting `Self`
    |
 LL |     fn func2<'a>() -> Struct2<'a, Self> where Self: std::marker::Sized;
@@ -65,7 +62,6 @@ LL |     fn func3() -> Struct3<Self>;
 LL | struct Struct3<T>{
    |                - required by this bound in `Struct3`
    |
-   = help: the trait `std::marker::Sized` is not implemented for `Self`
 help: you could relax the implicit `Sized` bound on `T` if it were used through indirection like `&T` or `Box<T>`
   --> $DIR/adt-param-with-implicit-sized-bound.rs:14:16
    |
@@ -87,7 +83,6 @@ LL |     fn func4() -> Struct4<Self>;
 LL | struct Struct4<T>{
    |                - required by this bound in `Struct4`
    |
-   = help: the trait `std::marker::Sized` is not implemented for `Self`
 help: consider further restricting `Self`
    |
 LL |     fn func4() -> Struct4<Self> where Self: std::marker::Sized;