Use `PredicateObligation`s instead of `Predicate`s

Keep more information about trait binding failures.

73 files changed, 185 insertions, 91 deletions

diff --git a/src/test/ui/associated-type-bounds/bad-bounds-on-assoc-in-trait.stderr b/src/test/ui/associated-type-bounds/bad-bounds-on-assoc-in-trait.stderr
index efd5a92a4fc..d5066e39ebc 100644
--- a/src/test/ui/associated-type-bounds/bad-bounds-on-assoc-in-trait.stderr
+++ b/src/test/ui/associated-type-bounds/bad-bounds-on-assoc-in-trait.stderr
@@ -20,7 +20,10 @@ error[E0277]: `<<T as Case1>::C as std::iter::Iterator>::Item` cannot be sent be
   --> $DIR/bad-bounds-on-assoc-in-trait.rs:36:20
    |
 LL | trait Case1 {
-   | ----------- required by `Case1`
+   |       -----
+LL |     type C: Clone + Iterator<Item:
+LL |         Send + Iterator<Item:
+   |         ---- required by this bound in `Case1`
 ...
 LL | fn assume_case1<T: Case1>() {
    |                    ^^^^^   - help: consider further restricting the associated type: `where <<T as Case1>::C as std::iter::Iterator>::Item: std::marker::Send`
@@ -33,7 +36,10 @@ error[E0277]: `<<T as Case1>::C as std::iter::Iterator>::Item` cannot be shared
   --> $DIR/bad-bounds-on-assoc-in-trait.rs:36:20
    |
 LL | trait Case1 {
-   | ----------- required by `Case1`
+   |       -----
+...
+LL |         > + Sync>;
+   |             ---- required by this bound in `Case1`
 ...
 LL | fn assume_case1<T: Case1>() {
    |                    ^^^^^   - help: consider further restricting the associated type: `where <<T as Case1>::C as std::iter::Iterator>::Item: std::marker::Sync`
@@ -46,7 +52,10 @@ error[E0277]: `<_ as Lam<&'a u8>>::App` doesn't implement `std::fmt::Debug`
   --> $DIR/bad-bounds-on-assoc-in-trait.rs:36:20
    |
 LL | trait Case1 {
-   | ----------- required by `Case1`
+   |       -----
+...
+LL |                 Debug
+   |                 ----- required by this bound in `Case1`
 ...
 LL | fn assume_case1<T: Case1>() {
    |                    ^^^^^ `<_ as Lam<&'a u8>>::App` cannot be formatted using `{:?}` because it doesn't implement `std::fmt::Debug`
diff --git a/src/test/ui/associated-types/associated-types-overridden-binding.stderr b/src/test/ui/associated-types/associated-types-overridden-binding.stderr
index 683a2ab21d9..76d00f9e6f2 100644
--- a/src/test/ui/associated-types/associated-types-overridden-binding.stderr
+++ b/src/test/ui/associated-types/associated-types-overridden-binding.stderr
@@ -2,7 +2,7 @@ error[E0284]: type annotations needed
   --> $DIR/associated-types-overridden-binding.rs:4:12
    |
 LL | trait Foo: Iterator<Item = i32> {}
-   | ------------------------------- required by `Foo`
+   |       ---           ---------- required by this bound in `Foo`
 LL | trait Bar: Foo<Item = u32> {}
    |            ^^^^^^^^^^^^^^^ cannot infer type for type parameter `Self`
    |
@@ -12,7 +12,7 @@ error[E0284]: type annotations needed
   --> $DIR/associated-types-overridden-binding.rs:7:21
    |
 LL | trait I32Iterator = Iterator<Item = i32>;
-   | ----------------------------------------- required by `I32Iterator`
+   |       -----------            ---------- required by this bound in `I32Iterator`
 LL | trait U32Iterator = I32Iterator<Item = u32>;
    |                     ^^^^^^^^^^^^^^^^^^^^^^^ cannot infer type for type parameter `Self`
    |
diff --git a/src/test/ui/associated-types/defaults-suitability.stderr b/src/test/ui/associated-types/defaults-suitability.stderr
index 54e39c4367d..3f6702da2a4 100644
--- a/src/test/ui/associated-types/defaults-suitability.stderr
+++ b/src/test/ui/associated-types/defaults-suitability.stderr
@@ -128,10 +128,14 @@ error[E0277]: the size for values of type `[u8]` cannot be known at compilation
    |
 LL |     type Ty = Vec<[u8]>;
    |     ^^^^^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time
+   | 
+  ::: $SRC_DIR/liballoc/vec.rs:LL:COL
+   |
+LL | pub struct Vec<T> {
+   |                - required by this bound in `std::vec::Vec`
    |
    = help: the trait `std::marker::Sized` is not implemented for `[u8]`
    = note: to learn more, visit <https://doc.rust-lang.org/book/ch19-04-advanced-types.html#dynamically-sized-types-and-the-sized-trait>
-   = note: required by `std::vec::Vec`
 
 error: aborting due to 11 previous errors
 
diff --git a/src/test/ui/bad/bad-sized.stderr b/src/test/ui/bad/bad-sized.stderr
index e9ded557281..5c169af4eb8 100644
--- a/src/test/ui/bad/bad-sized.stderr
+++ b/src/test/ui/bad/bad-sized.stderr
@@ -14,10 +14,14 @@ error[E0277]: the size for values of type `dyn Trait` cannot be known at compila
    |
 LL |     let x: Vec<dyn Trait + Sized> = Vec::new();
    |            ^^^^^^^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time
+   | 
+  ::: $SRC_DIR/liballoc/vec.rs:LL:COL
+   |
+LL | pub struct Vec<T> {
+   |                - required by this bound in `std::vec::Vec`
    |
    = help: the trait `std::marker::Sized` is not implemented for `dyn Trait`
    = note: to learn more, visit <https://doc.rust-lang.org/book/ch19-04-advanced-types.html#dynamically-sized-types-and-the-sized-trait>
-   = note: required by `std::vec::Vec`
 
 error[E0277]: the size for values of type `dyn Trait` cannot be known at compilation time
   --> $DIR/bad-sized.rs:4:37
diff --git a/src/test/ui/closures/closure-bounds-cant-promote-superkind-in-struct.stderr b/src/test/ui/closures/closure-bounds-cant-promote-superkind-in-struct.stderr
index f565948f479..06eca0f692d 100644
--- a/src/test/ui/closures/closure-bounds-cant-promote-superkind-in-struct.stderr
+++ b/src/test/ui/closures/closure-bounds-cant-promote-superkind-in-struct.stderr
@@ -2,7 +2,7 @@ error[E0277]: `F` cannot be sent between threads safely
   --> $DIR/closure-bounds-cant-promote-superkind-in-struct.rs:5:22
    |
 LL | struct X<F> where F: FnOnce() + 'static + Send {
-   | ---------------------------------------------- required by `X`
+   |        -                                  ---- required by this bound in `X`
 ...
 LL | fn foo<F>(blk: F) -> X<F> where F: FnOnce() + 'static {
    |                      ^^^^ `F` cannot be sent between threads safely
diff --git a/src/test/ui/consts/too_generic_eval_ice.stderr b/src/test/ui/consts/too_generic_eval_ice.stderr
index ffa28225b79..e188d981010 100644
--- a/src/test/ui/consts/too_generic_eval_ice.stderr
+++ b/src/test/ui/consts/too_generic_eval_ice.stderr
@@ -15,7 +15,7 @@ error[E0277]: the size for values of type `A` cannot be known at compilation tim
   --> $DIR/too_generic_eval_ice.rs:7:13
    |
 LL | pub struct Foo<A, B>(A, B);
-   | --------------------------- required by `Foo`
+   |            --- - required by this bound in `Foo`
 LL | 
 LL | impl<A, B> Foo<A, B> {
    |      - this type parameter needs to be `std::marker::Sized`
@@ -30,7 +30,7 @@ error[E0277]: the size for values of type `B` cannot be known at compilation tim
   --> $DIR/too_generic_eval_ice.rs:7:13
    |
 LL | pub struct Foo<A, B>(A, B);
-   | --------------------------- required by `Foo`
+   |            ---    - required by this bound in `Foo`
 LL | 
 LL | impl<A, B> Foo<A, B> {
    |         - this type parameter needs to be `std::marker::Sized`
diff --git a/src/test/ui/derives/derives-span-Eq-enum-struct-variant.stderr b/src/test/ui/derives/derives-span-Eq-enum-struct-variant.stderr
index 704825c7b38..3d7487a4d92 100644
--- a/src/test/ui/derives/derives-span-Eq-enum-struct-variant.stderr
+++ b/src/test/ui/derives/derives-span-Eq-enum-struct-variant.stderr
@@ -3,8 +3,12 @@ error[E0277]: the trait bound `Error: std::cmp::Eq` is not satisfied
    |
 LL |      x: Error
    |      ^^^^^^^^ the trait `std::cmp::Eq` is not implemented for `Error`
+   | 
+  ::: $SRC_DIR/libcore/cmp.rs:LL:COL
+   |
+LL | pub struct AssertParamIsEq<T: Eq + ?Sized> {
+   |                               -- required by this bound in `std::cmp::AssertParamIsEq`
    |
-   = note: required by `std::cmp::AssertParamIsEq`
    = note: this error originates in a derive macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: aborting due to previous error
diff --git a/src/test/ui/derives/derives-span-Eq-enum.stderr b/src/test/ui/derives/derives-span-Eq-enum.stderr
index 8d2499614d8..00345243cac 100644
--- a/src/test/ui/derives/derives-span-Eq-enum.stderr
+++ b/src/test/ui/derives/derives-span-Eq-enum.stderr
@@ -3,8 +3,12 @@ error[E0277]: the trait bound `Error: std::cmp::Eq` is not satisfied
    |
 LL |      Error
    |      ^^^^^ the trait `std::cmp::Eq` is not implemented for `Error`
+   | 
+  ::: $SRC_DIR/libcore/cmp.rs:LL:COL
+   |
+LL | pub struct AssertParamIsEq<T: Eq + ?Sized> {
+   |                               -- required by this bound in `std::cmp::AssertParamIsEq`
    |
-   = note: required by `std::cmp::AssertParamIsEq`
    = note: this error originates in a derive macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: aborting due to previous error
diff --git a/src/test/ui/derives/derives-span-Eq-struct.stderr b/src/test/ui/derives/derives-span-Eq-struct.stderr
index 22db0bf08b7..3d0efa1d147 100644
--- a/src/test/ui/derives/derives-span-Eq-struct.stderr
+++ b/src/test/ui/derives/derives-span-Eq-struct.stderr
@@ -3,8 +3,12 @@ error[E0277]: the trait bound `Error: std::cmp::Eq` is not satisfied
    |
 LL |     x: Error
    |     ^^^^^^^^ the trait `std::cmp::Eq` is not implemented for `Error`
+   | 
+  ::: $SRC_DIR/libcore/cmp.rs:LL:COL
+   |
+LL | pub struct AssertParamIsEq<T: Eq + ?Sized> {
+   |                               -- required by this bound in `std::cmp::AssertParamIsEq`
    |
-   = note: required by `std::cmp::AssertParamIsEq`
    = note: this error originates in a derive macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: aborting due to previous error
diff --git a/src/test/ui/derives/derives-span-Eq-tuple-struct.stderr b/src/test/ui/derives/derives-span-Eq-tuple-struct.stderr
index eaf14691ff0..2aec8ffdbe7 100644
--- a/src/test/ui/derives/derives-span-Eq-tuple-struct.stderr
+++ b/src/test/ui/derives/derives-span-Eq-tuple-struct.stderr
@@ -3,8 +3,12 @@ error[E0277]: the trait bound `Error: std::cmp::Eq` is not satisfied
    |
 LL |     Error
    |     ^^^^^ the trait `std::cmp::Eq` is not implemented for `Error`
+   | 
+  ::: $SRC_DIR/libcore/cmp.rs:LL:COL
+   |
+LL | pub struct AssertParamIsEq<T: Eq + ?Sized> {
+   |                               -- required by this bound in `std::cmp::AssertParamIsEq`
    |
-   = note: required by `std::cmp::AssertParamIsEq`
    = note: this error originates in a derive macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: aborting due to previous error
diff --git a/src/test/ui/error-codes/E0275.stderr b/src/test/ui/error-codes/E0275.stderr
index c551a00096e..a9fd0564ff5 100644
--- a/src/test/ui/error-codes/E0275.stderr
+++ b/src/test/ui/error-codes/E0275.stderr
@@ -2,7 +2,7 @@ error[E0275]: overflow evaluating the requirement `Bar<Bar<Bar<Bar<Bar<Bar<Bar<B
   --> $DIR/E0275.rs:5:33
    |
 LL | trait Foo {}
-   | --------- required by `Foo`
+   | --------- required by this bound in `Foo`
 ...
 LL | impl<T> Foo for T where Bar<T>: Foo {}
    |                                 ^^^
diff --git a/src/test/ui/generic-associated-types/issue-62326-parameter-out-of-range.stderr b/src/test/ui/generic-associated-types/issue-62326-parameter-out-of-range.stderr
index 68742396236..88b5c6a0a01 100644
--- a/src/test/ui/generic-associated-types/issue-62326-parameter-out-of-range.stderr
+++ b/src/test/ui/generic-associated-types/issue-62326-parameter-out-of-range.stderr
@@ -2,9 +2,9 @@ error[E0280]: the requirement `for<'a> <Self as Iterator>::Item<'a>: 'a` is not
   --> $DIR/issue-62326-parameter-out-of-range.rs:7:20
    |
 LL | trait Iterator {
-   | -------------- required by `Iterator`
+   |       --------
 LL |     type Item<'a>: 'a;
-   |                    ^^
+   |                    ^^ required by this bound in `Iterator`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/generic-associated-types/iterable.stderr b/src/test/ui/generic-associated-types/iterable.stderr
index b5bc0c76c2f..dc62ee53c06 100644
--- a/src/test/ui/generic-associated-types/iterable.stderr
+++ b/src/test/ui/generic-associated-types/iterable.stderr
@@ -38,7 +38,10 @@ error[E0271]: type mismatch resolving `for<'a> <<std::vec::Vec<T> as Iterable>::
   --> $DIR/iterable.rs:19:30
    |
 LL | trait Iterable {
-   | -------------- required by `Iterable`
+   |       --------
+LL |     type Item<'a> where Self: 'a;
+LL |     type Iter<'a>: Iterator<Item = Self::Item<'a>> where Self: 'a;
+   |                             --------------------- required by this bound in `Iterable`
 ...
 LL |     fn iter<'a>(&'a self) -> Self::Iter<'a> {
    |                              ^^^^^^^^^^^^^^ expected associated type, found reference
@@ -52,7 +55,10 @@ error[E0271]: type mismatch resolving `for<'a> <<[T] as Iterable>::Iter<'a> as s
   --> $DIR/iterable.rs:31:30
    |
 LL | trait Iterable {
-   | -------------- required by `Iterable`
+   |       --------
+LL |     type Item<'a> where Self: 'a;
+LL |     type Iter<'a>: Iterator<Item = Self::Item<'a>> where Self: 'a;
+   |                             --------------------- required by this bound in `Iterable`
 ...
 LL |     fn iter<'a>(&'a self) -> Self::Iter<'a> {
    |                              ^^^^^^^^^^^^^^ expected associated type, found reference
diff --git a/src/test/ui/issues/issue-18919.rs b/src/test/ui/issues/issue-18919.rs
index 91fbb13cd69..f06771e9ea5 100644
--- a/src/test/ui/issues/issue-18919.rs
+++ b/src/test/ui/issues/issue-18919.rs
@@ -4,4 +4,9 @@ fn ho_func(f: Option<FuncType>) {
     //~^ ERROR the size for values of type
 }
 
+enum Option<T> {
+    Some(T),
+    None,
+}
+
 fn main() {}
diff --git a/src/test/ui/issues/issue-18919.stderr b/src/test/ui/issues/issue-18919.stderr
index c8b9045efe6..db94d00b60c 100644
--- a/src/test/ui/issues/issue-18919.stderr
+++ b/src/test/ui/issues/issue-18919.stderr
@@ -3,10 +3,12 @@ error[E0277]: the size for values of type `dyn for<'r> std::ops::Fn(&'r isize) -
    |
 LL | fn ho_func(f: Option<FuncType>) {
    |               ^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time
+...
+LL | enum Option<T> {
+   |      ------ - required by this bound in `Option`
    |
    = help: the trait `std::marker::Sized` is not implemented for `dyn for<'r> std::ops::Fn(&'r isize) -> isize`
    = note: to learn more, visit <https://doc.rust-lang.org/book/ch19-04-advanced-types.html#dynamically-sized-types-and-the-sized-trait>
-   = note: required by `std::option::Option`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-20005.stderr b/src/test/ui/issues/issue-20005.stderr
index 529571a6b74..bcdebb2fa34 100644
--- a/src/test/ui/issues/issue-20005.stderr
+++ b/src/test/ui/issues/issue-20005.stderr
@@ -2,7 +2,7 @@ error[E0277]: the size for values of type `Self` cannot be known at compilation
   --> $DIR/issue-20005.rs:10:49
    |
 LL | trait From<Src> {
-   | --------------- required by `From`
+   |       ---- --- required by this bound in `From`
 ...
 LL |     ) -> <Dst as From<Self>>::Result where Dst: From<Self> {
    |                                                 ^^^^^^^^^^- help: consider further restricting `Self`: `, Self: std::marker::Sized`
diff --git a/src/test/ui/issues/issue-20413.stderr b/src/test/ui/issues/issue-20413.stderr
index 84e64ff74ae..ad33eef07cb 100644
--- a/src/test/ui/issues/issue-20413.stderr
+++ b/src/test/ui/issues/issue-20413.stderr
@@ -10,7 +10,7 @@ error[E0275]: overflow evaluating the requirement `NoData<NoData<NoData<NoData<N
   --> $DIR/issue-20413.rs:8:36
    |
 LL | trait Foo {
-   | --------- required by `Foo`
+   | --------- required by this bound in `Foo`
 ...
 LL | impl<T> Foo for T where NoData<T>: Foo {
    |                                    ^^^
@@ -148,7 +148,7 @@ error[E0275]: overflow evaluating the requirement `NoData<NoData<NoData<NoData<N
   --> $DIR/issue-20413.rs:8:36
    |
 LL | trait Foo {
-   | --------- required by `Foo`
+   | --------- required by this bound in `Foo`
 ...
 LL | impl<T> Foo for T where NoData<T>: Foo {
    |                                    ^^^
diff --git a/src/test/ui/issues/issue-20433.stderr b/src/test/ui/issues/issue-20433.stderr
index abd2290952b..1dab637e489 100644
--- a/src/test/ui/issues/issue-20433.stderr
+++ b/src/test/ui/issues/issue-20433.stderr
@@ -3,10 +3,14 @@ error[E0277]: the size for values of type `[i32]` cannot be known at compilation
    |
 LL |     fn iceman(c: Vec<[i32]>) {}
    |                  ^^^^^^^^^^ doesn't have a size known at compile-time
+   | 
+  ::: $SRC_DIR/liballoc/vec.rs:LL:COL
+   |
+LL | pub struct Vec<T> {
+   |                - required by this bound in `std::vec::Vec`
    |
    = help: the trait `std::marker::Sized` is not implemented for `[i32]`
    = note: to learn more, visit <https://doc.rust-lang.org/book/ch19-04-advanced-types.html#dynamically-sized-types-and-the-sized-trait>
-   = note: required by `std::vec::Vec`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-21837.stderr b/src/test/ui/issues/issue-21837.stderr
index ff0c1ca64e2..42a61995ad9 100644
--- a/src/test/ui/issues/issue-21837.stderr
+++ b/src/test/ui/issues/issue-21837.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `T: Bound` is not satisfied
   --> $DIR/issue-21837.rs:8:9
    |
 LL | pub struct Foo<T: Bound>(T);
-   | ---------------------------- required by `Foo`
+   |            ---    ----- required by this bound in `Foo`
 ...
 LL | impl<T> Trait2 for Foo<T> {}
    |         ^^^^^^ the trait `Bound` is not implemented for `T`
diff --git a/src/test/ui/issues/issue-21974.stderr b/src/test/ui/issues/issue-21974.stderr
index d36d0dad4a1..fea2c7d5d26 100644
--- a/src/test/ui/issues/issue-21974.stderr
+++ b/src/test/ui/issues/issue-21974.stderr
@@ -2,7 +2,7 @@ error[E0283]: type annotations needed
   --> $DIR/issue-21974.rs:11:19
    |
 LL | trait Foo {
-   | --------- required by `Foo`
+   | --------- required by this bound in `Foo`
 ...
 LL |     where &'a T : Foo,
    |                   ^^^ cannot infer type for reference `&'a T`
diff --git a/src/test/ui/issues/issue-23281.rs b/src/test/ui/issues/issue-23281.rs
index d5f74728862..72716896426 100644
--- a/src/test/ui/issues/issue-23281.rs
+++ b/src/test/ui/issues/issue-23281.rs
@@ -5,4 +5,8 @@ impl Struct {
     //~^ ERROR the size for values of type
 }
 
+struct Vec<T> {
+    t: T,
+}
+
 fn main() {}
diff --git a/src/test/ui/issues/issue-23281.stderr b/src/test/ui/issues/issue-23281.stderr
index 68a90c6d80f..6aa6051f98a 100644
--- a/src/test/ui/issues/issue-23281.stderr
+++ b/src/test/ui/issues/issue-23281.stderr
@@ -3,10 +3,12 @@ error[E0277]: the size for values of type `(dyn std::ops::Fn() + 'static)` canno
    |
 LL |     pub fn function(funs: Vec<dyn Fn() -> ()>) {}
    |                           ^^^^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time
+...
+LL | struct Vec<T> {
+   |        --- - required by this bound in `Vec`
    |
    = help: the trait `std::marker::Sized` is not implemented for `(dyn std::ops::Fn() + 'static)`
    = note: to learn more, visit <https://doc.rust-lang.org/book/ch19-04-advanced-types.html#dynamically-sized-types-and-the-sized-trait>
-   = note: required by `std::vec::Vec`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-24204.stderr b/src/test/ui/issues/issue-24204.stderr
index 2a714861da1..64d1b68cbed 100644
--- a/src/test/ui/issues/issue-24204.stderr
+++ b/src/test/ui/issues/issue-24204.stderr
@@ -2,7 +2,9 @@ error[E0271]: type mismatch resolving `<<T as Trait>::A as MultiDispatch<i32>>::
   --> $DIR/issue-24204.rs:14:12
    |
 LL | trait Trait: Sized {
-   | ------------------ required by `Trait`
+   |       -----
+LL |     type A: MultiDispatch<Self::B, O = Self>;
+   |                                    -------- required by this bound in `Trait`
 ...
 LL | fn test<T: Trait<B=i32>>(b: i32) -> T where T::A: MultiDispatch<i32> { T::new(b) }
    |            ^^^^^^^^^^^^ expected type parameter `T`, found associated type
diff --git a/src/test/ui/issues/issue-24424.stderr b/src/test/ui/issues/issue-24424.stderr
index f9338981408..9f5e934295b 100644
--- a/src/test/ui/issues/issue-24424.stderr
+++ b/src/test/ui/issues/issue-24424.stderr
@@ -2,7 +2,7 @@ error[E0283]: type annotations needed
   --> $DIR/issue-24424.rs:4:57
    |
 LL | trait Trait0<'l0>  {}
-   | ----------------- required by `Trait0`
+   | ----------------- required by this bound in `Trait0`
 LL | 
 LL | impl <'l0, 'l1, T0> Trait1<'l0, T0> for bool where T0 : Trait0<'l0>, T0 : Trait0<'l1> {}
    |                                                         ^^^^^^^^^^^ cannot infer type for type parameter `T0`
diff --git a/src/test/ui/iterators/bound.stderr b/src/test/ui/iterators/bound.stderr
index 92a91ff4cb1..db5949b692c 100644
--- a/src/test/ui/iterators/bound.stderr
+++ b/src/test/ui/iterators/bound.stderr
@@ -2,7 +2,7 @@ error[E0277]: `u8` is not an iterator
   --> $DIR/bound.rs:2:10
    |
 LL | struct S<I: Iterator>(I);
-   | ------------------------- required by `S`
+   |        -    -------- required by this bound in `S`
 LL | struct T(S<u8>);
    |          ^^^^^ `u8` is not an iterator
    |
diff --git a/src/test/ui/recursion/recursive-requirements.stderr b/src/test/ui/recursion/recursive-requirements.stderr
index 9846c938ba9..5a1ef37f734 100644
--- a/src/test/ui/recursion/recursive-requirements.stderr
+++ b/src/test/ui/recursion/recursive-requirements.stderr
@@ -2,7 +2,7 @@ error[E0277]: `*const Bar` cannot be shared between threads safely
   --> $DIR/recursive-requirements.rs:16:12
    |
 LL | struct AssertSync<T: Sync>(PhantomData<T>);
-   | ------------------------------------------- required by `AssertSync`
+   |        ----------    ---- required by this bound in `AssertSync`
 ...
 LL |     let _: AssertSync<Foo> = unimplemented!();
    |            ^^^^^^^^^^^^^^^ `*const Bar` cannot be shared between threads safely
@@ -14,7 +14,7 @@ error[E0277]: `*const Foo` cannot be shared between threads safely
   --> $DIR/recursive-requirements.rs:16:12
    |
 LL | struct AssertSync<T: Sync>(PhantomData<T>);
-   | ------------------------------------------- required by `AssertSync`
+   |        ----------    ---- required by this bound in `AssertSync`
 ...
 LL |     let _: AssertSync<Foo> = unimplemented!();
    |            ^^^^^^^^^^^^^^^ `*const Foo` cannot be shared between threads safely
diff --git a/src/test/ui/suggestions/missing-assoc-type-bound-restriction.stderr b/src/test/ui/suggestions/missing-assoc-type-bound-restriction.stderr
index 31d974ed43d..6b985edae9e 100644
--- a/src/test/ui/suggestions/missing-assoc-type-bound-restriction.stderr
+++ b/src/test/ui/suggestions/missing-assoc-type-bound-restriction.stderr
@@ -2,7 +2,10 @@ error[E0277]: the trait bound `<T as Parent>::Assoc: Child<A>` is not satisfied
   --> $DIR/missing-assoc-type-bound-restriction.rs:17:19
    |
 LL | trait Parent {
-   | ------------ required by `Parent`
+   |       ------
+LL |     type Ty;
+LL |     type Assoc: Child<Self::Ty>;
+   |                 --------------- required by this bound in `Parent`
 ...
 LL | impl<A, T: Parent<Ty = A>> Parent for ParentWrapper<T> {
    |                   ^^^^^^                              - help: consider further restricting the associated type: `where <T as Parent>::Assoc: Child<A>`
@@ -29,7 +32,10 @@ error[E0277]: the trait bound `<T as Parent>::Assoc: Child<A>` is not satisfied
   --> $DIR/missing-assoc-type-bound-restriction.rs:20:5
    |
 LL | trait Parent {
-   | ------------ required by `Parent`
+   |       ------
+LL |     type Ty;
+LL |     type Assoc: Child<Self::Ty>;
+   |                 --------------- required by this bound in `Parent`
 ...
 LL | impl<A, T: Parent<Ty = A>> Parent for ParentWrapper<T> {
    |                                                       - help: consider further restricting the associated type: `where <T as Parent>::Assoc: Child<A>`
diff --git a/src/test/ui/suggestions/mut-borrow-needed-by-trait.stderr b/src/test/ui/suggestions/mut-borrow-needed-by-trait.stderr
index 57a389cbb49..9ccddda45e2 100644
--- a/src/test/ui/suggestions/mut-borrow-needed-by-trait.stderr
+++ b/src/test/ui/suggestions/mut-borrow-needed-by-trait.stderr
@@ -12,18 +12,26 @@ error[E0277]: the trait bound `&dyn std::io::Write: std::io::Write` is not satis
    |
 LL |     let fp = BufWriter::new(fp);
    |              ^^^^^^^^^^^^^^ the trait `std::io::Write` is not implemented for `&dyn std::io::Write`
+   | 
+  ::: $SRC_DIR/libstd/io/buffered.rs:LL:COL
+   |
+LL | pub struct BufWriter<W: Write> {
+   |                         ----- required by this bound in `std::io::BufWriter`
    |
    = note: `std::io::Write` is implemented for `&mut dyn std::io::Write`, but not for `&dyn std::io::Write`
-   = note: required by `std::io::BufWriter`
 
 error[E0277]: the trait bound `&dyn std::io::Write: std::io::Write` is not satisfied
   --> $DIR/mut-borrow-needed-by-trait.rs:17:14
    |
 LL |     let fp = BufWriter::new(fp);
    |              ^^^^^^^^^^^^^^^^^^ the trait `std::io::Write` is not implemented for `&dyn std::io::Write`
+   | 
+  ::: $SRC_DIR/libstd/io/buffered.rs:LL:COL
+   |
+LL | pub struct BufWriter<W: Write> {
+   |                         ----- required by this bound in `std::io::BufWriter`
    |
    = note: `std::io::Write` is implemented for `&mut dyn std::io::Write`, but not for `&dyn std::io::Write`
-   = note: required by `std::io::BufWriter`
 
 error[E0599]: no method named `write_fmt` found for struct `std::io::BufWriter<&dyn std::io::Write>` in the current scope
   --> $DIR/mut-borrow-needed-by-trait.rs:22:5
diff --git a/src/test/ui/traits/negative-impls/negated-auto-traits-error.stderr b/src/test/ui/traits/negative-impls/negated-auto-traits-error.stderr
index 69a91b09e3e..ffed905eff2 100644
--- a/src/test/ui/traits/negative-impls/negated-auto-traits-error.stderr
+++ b/src/test/ui/traits/negative-impls/negated-auto-traits-error.stderr
@@ -13,7 +13,7 @@ error[E0277]: `dummy::TestType` cannot be sent between threads safely
   --> $DIR/negated-auto-traits-error.rs:23:5
    |
 LL | struct Outer<T: Send>(T);
-   | ------------------------- required by `Outer`
+   |        -----    ---- required by this bound in `Outer`
 ...
 LL |     Outer(TestType);
    |     ^^^^^^^^^^^^^^^ `dummy::TestType` cannot be sent between threads safely
diff --git a/src/test/ui/traits/trait-alias/trait-alias-wf.stderr b/src/test/ui/traits/trait-alias/trait-alias-wf.stderr
index ca4980ca305..84cde07ed89 100644
--- a/src/test/ui/traits/trait-alias/trait-alias-wf.stderr
+++ b/src/test/ui/traits/trait-alias/trait-alias-wf.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `T: Foo` is not satisfied
   --> $DIR/trait-alias-wf.rs:5:14
    |
 LL | trait A<T: Foo> {}
-   | --------------- required by `A`
+   |       -    --- required by this bound in `A`
 LL | trait B<T> = A<T>;
    |              ^^^^ the trait `Foo` is not implemented for `T`
    |
diff --git a/src/test/ui/traits/trait-bounds-on-structs-and-enums-in-fns.stderr b/src/test/ui/traits/trait-bounds-on-structs-and-enums-in-fns.stderr
index a2253021a7f..1b2511be6d0 100644
--- a/src/test/ui/traits/trait-bounds-on-structs-and-enums-in-fns.stderr
+++ b/src/test/ui/traits/trait-bounds-on-structs-and-enums-in-fns.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `u32: Trait` is not satisfied
   --> $DIR/trait-bounds-on-structs-and-enums-in-fns.rs:13:15
    |
 LL | struct Foo<T:Trait> {
-   | ------------------- required by `Foo`
+   |        ---   ----- required by this bound in `Foo`
 ...
 LL | fn explode(x: Foo<u32>) {}
    |               ^^^^^^^^ the trait `Trait` is not implemented for `u32`
@@ -11,7 +11,7 @@ error[E0277]: the trait bound `f32: Trait` is not satisfied
   --> $DIR/trait-bounds-on-structs-and-enums-in-fns.rs:16:14
    |
 LL | enum Bar<T:Trait> {
-   | ----------------- required by `Bar`
+   |      ---   ----- required by this bound in `Bar`
 ...
 LL | fn kaboom(y: Bar<f32>) {}
    |              ^^^^^^^^ the trait `Trait` is not implemented for `f32`
diff --git a/src/test/ui/traits/trait-bounds-on-structs-and-enums-in-impls.stderr b/src/test/ui/traits/trait-bounds-on-structs-and-enums-in-impls.stderr
index 7e8db610fe2..58dd68c1768 100644
--- a/src/test/ui/traits/trait-bounds-on-structs-and-enums-in-impls.stderr
+++ b/src/test/ui/traits/trait-bounds-on-structs-and-enums-in-impls.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `u16: Trait` is not satisfied
   --> $DIR/trait-bounds-on-structs-and-enums-in-impls.rs:20:6
    |
 LL | struct Foo<T:Trait> {
-   | ------------------- required by `Foo`
+   |        ---   ----- required by this bound in `Foo`
 ...
 LL | impl PolyTrait<Foo<u16>> for Struct {
    |      ^^^^^^^^^^^^^^^^^^^ the trait `Trait` is not implemented for `u16`
diff --git a/src/test/ui/traits/trait-bounds-on-structs-and-enums-locals.stderr b/src/test/ui/traits/trait-bounds-on-structs-and-enums-locals.stderr
index 070b7b013e5..f364fd1e14c 100644
--- a/src/test/ui/traits/trait-bounds-on-structs-and-enums-locals.stderr
+++ b/src/test/ui/traits/trait-bounds-on-structs-and-enums-locals.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `usize: Trait` is not satisfied
   --> $DIR/trait-bounds-on-structs-and-enums-locals.rs:15:14
    |
 LL | struct Foo<T:Trait> {
-   | ------------------- required by `Foo`
+   |        ---   ----- required by this bound in `Foo`
 ...
 LL |     let baz: Foo<usize> = loop { };
    |              ^^^^^^^^^^ the trait `Trait` is not implemented for `usize`
diff --git a/src/test/ui/traits/trait-bounds-on-structs-and-enums-static.stderr b/src/test/ui/traits/trait-bounds-on-structs-and-enums-static.stderr
index 722f01750cb..17b1288bc6a 100644
--- a/src/test/ui/traits/trait-bounds-on-structs-and-enums-static.stderr
+++ b/src/test/ui/traits/trait-bounds-on-structs-and-enums-static.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `usize: Trait` is not satisfied
   --> $DIR/trait-bounds-on-structs-and-enums-static.rs:9:11
    |
 LL | struct Foo<T:Trait> {
-   | ------------------- required by `Foo`
+   |        ---   ----- required by this bound in `Foo`
 ...
 LL | static X: Foo<usize> = Foo {
    |           ^^^^^^^^^^ the trait `Trait` is not implemented for `usize`
diff --git a/src/test/ui/traits/trait-bounds-on-structs-and-enums-xc.stderr b/src/test/ui/traits/trait-bounds-on-structs-and-enums-xc.stderr
index c5a7746afdf..d2fa211b487 100644
--- a/src/test/ui/traits/trait-bounds-on-structs-and-enums-xc.stderr
+++ b/src/test/ui/traits/trait-bounds-on-structs-and-enums-xc.stderr
@@ -3,16 +3,22 @@ error[E0277]: the trait bound `usize: trait_bounds_on_structs_and_enums_xc::Trai
    |
 LL | fn explode(x: Foo<usize>) {}
    |               ^^^^^^^^^^ the trait `trait_bounds_on_structs_and_enums_xc::Trait` is not implemented for `usize`
+   | 
+  ::: $DIR/auxiliary/trait_bounds_on_structs_and_enums_xc.rs:5:18
    |
-   = note: required by `trait_bounds_on_structs_and_enums_xc::Foo`
+LL | pub struct Foo<T:Trait> {
+   |                  ----- required by this bound in `trait_bounds_on_structs_and_enums_xc::Foo`
 
 error[E0277]: the trait bound `f32: trait_bounds_on_structs_and_enums_xc::Trait` is not satisfied
   --> $DIR/trait-bounds-on-structs-and-enums-xc.rs:10:14
    |
 LL | fn kaboom(y: Bar<f32>) {}
    |              ^^^^^^^^ the trait `trait_bounds_on_structs_and_enums_xc::Trait` is not implemented for `f32`
+   | 
+  ::: $DIR/auxiliary/trait_bounds_on_structs_and_enums_xc.rs:9:16
    |
-   = note: required by `trait_bounds_on_structs_and_enums_xc::Bar`
+LL | pub enum Bar<T:Trait> {
+   |                ----- required by this bound in `trait_bounds_on_structs_and_enums_xc::Bar`
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/traits/trait-bounds-on-structs-and-enums-xc1.stderr b/src/test/ui/traits/trait-bounds-on-structs-and-enums-xc1.stderr
index 57db65df5f3..ee3e755c953 100644
--- a/src/test/ui/traits/trait-bounds-on-structs-and-enums-xc1.stderr
+++ b/src/test/ui/traits/trait-bounds-on-structs-and-enums-xc1.stderr
@@ -3,8 +3,11 @@ error[E0277]: the trait bound `f64: trait_bounds_on_structs_and_enums_xc::Trait`
    |
 LL |     let bar: Bar<f64> = return;
    |              ^^^^^^^^ the trait `trait_bounds_on_structs_and_enums_xc::Trait` is not implemented for `f64`
+   | 
+  ::: $DIR/auxiliary/trait_bounds_on_structs_and_enums_xc.rs:9:16
    |
-   = note: required by `trait_bounds_on_structs_and_enums_xc::Bar`
+LL | pub enum Bar<T:Trait> {
+   |                ----- required by this bound in `trait_bounds_on_structs_and_enums_xc::Bar`
 
 error[E0277]: the trait bound `{integer}: trait_bounds_on_structs_and_enums_xc::Trait` is not satisfied
   --> $DIR/trait-bounds-on-structs-and-enums-xc1.rs:8:15
diff --git a/src/test/ui/traits/trait-bounds-on-structs-and-enums.stderr b/src/test/ui/traits/trait-bounds-on-structs-and-enums.stderr
index 9e8e5e08145..16dba294b6c 100644
--- a/src/test/ui/traits/trait-bounds-on-structs-and-enums.stderr
+++ b/src/test/ui/traits/trait-bounds-on-structs-and-enums.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `T: Trait` is not satisfied
   --> $DIR/trait-bounds-on-structs-and-enums.rs:13:9
    |
 LL | struct Foo<T:Trait> {
-   | ------------------- required by `Foo`
+   |        ---   ----- required by this bound in `Foo`
 ...
 LL | impl<T> Foo<T> {
    |         ^^^^^^ the trait `Trait` is not implemented for `T`
@@ -16,7 +16,7 @@ error[E0277]: the trait bound `isize: Trait` is not satisfied
   --> $DIR/trait-bounds-on-structs-and-enums.rs:19:5
    |
 LL | struct Foo<T:Trait> {
-   | ------------------- required by `Foo`
+   |        ---   ----- required by this bound in `Foo`
 ...
 LL |     a: Foo<isize>,
    |     ^^^^^^^^^^^^^ the trait `Trait` is not implemented for `isize`
@@ -25,7 +25,7 @@ error[E0277]: the trait bound `usize: Trait` is not satisfied
   --> $DIR/trait-bounds-on-structs-and-enums.rs:23:10
    |
 LL | enum Bar<T:Trait> {
-   | ----------------- required by `Bar`
+   |      ---   ----- required by this bound in `Bar`
 ...
 LL |     Quux(Bar<usize>),
    |          ^^^^^^^^^^ the trait `Trait` is not implemented for `usize`
@@ -34,7 +34,7 @@ error[E0277]: the trait bound `U: Trait` is not satisfied
   --> $DIR/trait-bounds-on-structs-and-enums.rs:27:5
    |
 LL | struct Foo<T:Trait> {
-   | ------------------- required by `Foo`
+   |        ---   ----- required by this bound in `Foo`
 ...
 LL |     b: Foo<U>,
    |     ^^^^^^^^^ the trait `Trait` is not implemented for `U`
@@ -48,7 +48,7 @@ error[E0277]: the trait bound `V: Trait` is not satisfied
   --> $DIR/trait-bounds-on-structs-and-enums.rs:31:21
    |
 LL | enum Bar<T:Trait> {
-   | ----------------- required by `Bar`
+   |      ---   ----- required by this bound in `Bar`
 ...
 LL |     EvenMoreBadness(Bar<V>),
    |                     ^^^^^^ the trait `Trait` is not implemented for `V`
@@ -62,7 +62,7 @@ error[E0277]: the trait bound `i32: Trait` is not satisfied
   --> $DIR/trait-bounds-on-structs-and-enums.rs:35:5
    |
 LL | struct Foo<T:Trait> {
-   | ------------------- required by `Foo`
+   |        ---   ----- required by this bound in `Foo`
 ...
 LL |     Foo<i32>,
    |     ^^^^^^^^ the trait `Trait` is not implemented for `i32`
@@ -71,7 +71,7 @@ error[E0277]: the trait bound `u8: Trait` is not satisfied
   --> $DIR/trait-bounds-on-structs-and-enums.rs:39:22
    |
 LL | enum Bar<T:Trait> {
-   | ----------------- required by `Bar`
+   |      ---   ----- required by this bound in `Bar`
 ...
 LL |     DictionaryLike { field: Bar<u8> },
    |                      ^^^^^^^^^^^^^^ the trait `Trait` is not implemented for `u8`
diff --git a/src/test/ui/type/type-check-defaults.stderr b/src/test/ui/type/type-check-defaults.stderr
index ca9b85bacba..4109bd70074 100644
--- a/src/test/ui/type/type-check-defaults.stderr
+++ b/src/test/ui/type/type-check-defaults.stderr
@@ -2,7 +2,7 @@ error[E0277]: a value of type `i32` cannot be built from an iterator over elemen
   --> $DIR/type-check-defaults.rs:6:19
    |
 LL | struct Foo<T, U: FromIterator<T>>(T, U);
-   | ---------------------------------------- required by `Foo`
+   |        ---       --------------- required by this bound in `Foo`
 LL | struct WellFormed<Z = Foo<i32, i32>>(Z);
    |                   ^ value of type `i32` cannot be built from `std::iter::Iterator<Item=i32>`
    |
@@ -12,7 +12,7 @@ error[E0277]: a value of type `i32` cannot be built from an iterator over elemen
   --> $DIR/type-check-defaults.rs:8:27
    |
 LL | struct Foo<T, U: FromIterator<T>>(T, U);
-   | ---------------------------------------- required by `Foo`
+   |        ---       --------------- required by this bound in `Foo`
 ...
 LL | struct WellFormedNoBounds<Z:?Sized = Foo<i32, i32>>(Z);
    |                           ^ value of type `i32` cannot be built from `std::iter::Iterator<Item=i32>`
@@ -50,7 +50,7 @@ error[E0277]: the trait bound `T: std::marker::Copy` is not satisfied
   --> $DIR/type-check-defaults.rs:21:25
    |
 LL | trait Super<T: Copy> { }
-   | -------------------- required by `Super`
+   |       -----    ---- required by this bound in `Super`
 LL | trait Base<T = String>: Super<T> { }
    |                         ^^^^^^^^ the trait `std::marker::Copy` is not implemented for `T`
    |
diff --git a/src/test/ui/type/type-check/issue-40294.stderr b/src/test/ui/type/type-check/issue-40294.stderr
index 7d81e0ce10c..ea7771a9c22 100644
--- a/src/test/ui/type/type-check/issue-40294.stderr
+++ b/src/test/ui/type/type-check/issue-40294.stderr
@@ -2,7 +2,7 @@ error[E0283]: type annotations needed
   --> $DIR/issue-40294.rs:6:19
    |
 LL | trait Foo: Sized {
-   | ---------------- required by `Foo`
+   | ---------------- required by this bound in `Foo`
 ...
 LL |     where &'a T : Foo,
    |                   ^^^ cannot infer type for reference `&'a T`
diff --git a/src/test/ui/union/union-derive-clone.stderr b/src/test/ui/union/union-derive-clone.stderr
index 66437611872..b536325810a 100644
--- a/src/test/ui/union/union-derive-clone.stderr
+++ b/src/test/ui/union/union-derive-clone.stderr
@@ -3,8 +3,12 @@ error[E0277]: the trait bound `U1: std::marker::Copy` is not satisfied
    |
 LL | #[derive(Clone)]
    |          ^^^^^ the trait `std::marker::Copy` is not implemented for `U1`
+   | 
+  ::: $SRC_DIR/libcore/clone.rs:LL:COL
+   |
+LL | pub struct AssertParamIsCopy<T: Copy + ?Sized> {
+   |                                 ---- required by this bound in `std::clone::AssertParamIsCopy`
    |
-   = note: required by `std::clone::AssertParamIsCopy`
    = note: this error originates in a derive macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0599]: no method named `clone` found for union `U5<CloneNoCopy>` in the current scope
diff --git a/src/test/ui/union/union-derive-eq.stderr b/src/test/ui/union/union-derive-eq.stderr
index 0955c161871..ae0cd5af4b0 100644
--- a/src/test/ui/union/union-derive-eq.stderr
+++ b/src/test/ui/union/union-derive-eq.stderr
@@ -3,8 +3,12 @@ error[E0277]: the trait bound `PartialEqNotEq: std::cmp::Eq` is not satisfied
    |
 LL |     a: PartialEqNotEq,
    |     ^^^^^^^^^^^^^^^^^ the trait `std::cmp::Eq` is not implemented for `PartialEqNotEq`
+   | 
+  ::: $SRC_DIR/libcore/cmp.rs:LL:COL
+   |
+LL | pub struct AssertParamIsEq<T: Eq + ?Sized> {
+   |                               -- required by this bound in `std::cmp::AssertParamIsEq`
    |
-   = note: required by `std::cmp::AssertParamIsEq`
    = note: this error originates in a derive macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: aborting due to previous error
diff --git a/src/test/ui/unsized/unsized-enum.stderr b/src/test/ui/unsized/unsized-enum.stderr
index 88f7b1f77ae..7f5ce5d02a5 100644
--- a/src/test/ui/unsized/unsized-enum.stderr
+++ b/src/test/ui/unsized/unsized-enum.stderr
@@ -2,7 +2,7 @@ error[E0277]: the size for values of type `T` cannot be known at compilation tim
   --> $DIR/unsized-enum.rs:6:36
    |
 LL | enum Foo<U> { FooSome(U), FooNone }
-   | ----------- required by `Foo`
+   |      --- - required by this bound in `Foo`
 LL | fn foo1<T>() { not_sized::<Foo<T>>() } // Hunky dory.
 LL | fn foo2<T: ?Sized>() { not_sized::<Foo<T>>() }
    |         -                          ^^^^^^ doesn't have a size known at compile-time
diff --git a/src/test/ui/unsized/unsized-inherent-impl-self-type.stderr b/src/test/ui/unsized/unsized-inherent-impl-self-type.stderr
index 5688ae5b89a..990cea97723 100644
--- a/src/test/ui/unsized/unsized-inherent-impl-self-type.stderr
+++ b/src/test/ui/unsized/unsized-inherent-impl-self-type.stderr
@@ -2,7 +2,7 @@ error[E0277]: the size for values of type `X` cannot be known at compilation tim
   --> $DIR/unsized-inherent-impl-self-type.rs:7:17
    |
 LL | struct S5<Y>(Y);
-   | ---------------- required by `S5`
+   |        -- - required by this bound in `S5`
 LL | 
 LL | impl<X: ?Sized> S5<X> {
    |      -          ^^^^^ doesn't have a size known at compile-time
diff --git a/src/test/ui/unsized/unsized-struct.stderr b/src/test/ui/unsized/unsized-struct.stderr
index 653fb5c1ae8..b9e226ccbf1 100644
--- a/src/test/ui/unsized/unsized-struct.stderr
+++ b/src/test/ui/unsized/unsized-struct.stderr
@@ -2,7 +2,7 @@ error[E0277]: the size for values of type `T` cannot be known at compilation tim
   --> $DIR/unsized-struct.rs:6:36
    |
 LL | struct Foo<T> { data: T }
-   | ------------- required by `Foo`
+   |        --- - required by this bound in `Foo`
 LL | fn foo1<T>() { not_sized::<Foo<T>>() } // Hunky dory.
 LL | fn foo2<T: ?Sized>() { not_sized::<Foo<T>>() }
    |         -                          ^^^^^^ doesn't have a size known at compile-time
diff --git a/src/test/ui/unsized/unsized-trait-impl-self-type.stderr b/src/test/ui/unsized/unsized-trait-impl-self-type.stderr
index 3597073e7e6..08ceabecb27 100644
--- a/src/test/ui/unsized/unsized-trait-impl-self-type.stderr
+++ b/src/test/ui/unsized/unsized-trait-impl-self-type.stderr
@@ -2,7 +2,7 @@ error[E0277]: the size for values of type `X` cannot be known at compilation tim
   --> $DIR/unsized-trait-impl-self-type.rs:10:17
    |
 LL | struct S5<Y>(Y);
-   | ---------------- required by `S5`
+   |        -- - required by this bound in `S5`
 LL | 
 LL | impl<X: ?Sized> T3<X> for S5<X> {
    |      -          ^^^^^ doesn't have a size known at compile-time
diff --git a/src/test/ui/wf/wf-const-type.stderr b/src/test/ui/wf/wf-const-type.stderr
index 531aadc25dd..22f31c9f79f 100644
--- a/src/test/ui/wf/wf-const-type.stderr
+++ b/src/test/ui/wf/wf-const-type.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `NotCopy: std::marker::Copy` is not satisfied
   --> $DIR/wf-const-type.rs:10:12
    |
 LL | struct IsCopy<T:Copy> { t: T }
-   | --------------------- required by `IsCopy`
+   |        ------   ---- required by this bound in `IsCopy`
 ...
 LL | const FOO: IsCopy<Option<NotCopy>> = IsCopy { t: None };
    |            ^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::marker::Copy` is not implemented for `NotCopy`
diff --git a/src/test/ui/wf/wf-enum-bound.stderr b/src/test/ui/wf/wf-enum-bound.stderr
index f70f67d414f..88d8c599022 100644
--- a/src/test/ui/wf/wf-enum-bound.stderr
+++ b/src/test/ui/wf/wf-enum-bound.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `U: std::marker::Copy` is not satisfied
   --> $DIR/wf-enum-bound.rs:10:14
    |
 LL | trait ExtraCopy<T:Copy> { }
-   | ----------------------- required by `ExtraCopy`
+   |       ---------   ---- required by this bound in `ExtraCopy`
 ...
 LL |     where T: ExtraCopy<U>
    |              ^^^^^^^^^^^^ the trait `std::marker::Copy` is not implemented for `U`
diff --git a/src/test/ui/wf/wf-enum-fields-struct-variant.stderr b/src/test/ui/wf/wf-enum-fields-struct-variant.stderr
index 8634b7dba5c..d45ab952987 100644
--- a/src/test/ui/wf/wf-enum-fields-struct-variant.stderr
+++ b/src/test/ui/wf/wf-enum-fields-struct-variant.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `A: std::marker::Copy` is not satisfied
   --> $DIR/wf-enum-fields-struct-variant.rs:13:9
    |
 LL | struct IsCopy<T:Copy> {
-   | --------------------- required by `IsCopy`
+   |        ------   ---- required by this bound in `IsCopy`
 ...
 LL |         f: IsCopy<A>
    |         ^^^^^^^^^^^^ the trait `std::marker::Copy` is not implemented for `A`
diff --git a/src/test/ui/wf/wf-enum-fields.stderr b/src/test/ui/wf/wf-enum-fields.stderr
index a22b2d11a91..013407bcc68 100644
--- a/src/test/ui/wf/wf-enum-fields.stderr
+++ b/src/test/ui/wf/wf-enum-fields.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `A: std::marker::Copy` is not satisfied
   --> $DIR/wf-enum-fields.rs:12:17
    |
 LL | struct IsCopy<T:Copy> {
-   | --------------------- required by `IsCopy`
+   |        ------   ---- required by this bound in `IsCopy`
 ...
 LL |     SomeVariant(IsCopy<A>)
    |                 ^^^^^^^^^ the trait `std::marker::Copy` is not implemented for `A`
diff --git a/src/test/ui/wf/wf-fn-where-clause.rs b/src/test/ui/wf/wf-fn-where-clause.rs
index 5fd567bd32d..adae536138b 100644
--- a/src/test/ui/wf/wf-fn-where-clause.rs
+++ b/src/test/ui/wf/wf-fn-where-clause.rs
@@ -13,5 +13,8 @@ fn bar() where Vec<dyn Copy>:, {}
 //~^ ERROR E0277
 //~| ERROR E0038
 
+struct Vec<T> {
+    t: T,
+}
 
 fn main() { }
diff --git a/src/test/ui/wf/wf-fn-where-clause.stderr b/src/test/ui/wf/wf-fn-where-clause.stderr
index cf1aeac7e3e..c5a7a5b0611 100644
--- a/src/test/ui/wf/wf-fn-where-clause.stderr
+++ b/src/test/ui/wf/wf-fn-where-clause.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `U: std::marker::Copy` is not satisfied
   --> $DIR/wf-fn-where-clause.rs:8:24
    |
 LL | trait ExtraCopy<T:Copy> { }
-   | ----------------------- required by `ExtraCopy`
+   |       ---------   ---- required by this bound in `ExtraCopy`
 LL | 
 LL | fn foo<T,U>() where T: ExtraCopy<U>
    |                        ^^^^^^^^^^^^ the trait `std::marker::Copy` is not implemented for `U`
@@ -17,10 +17,12 @@ error[E0277]: the size for values of type `(dyn std::marker::Copy + 'static)` ca
    |
 LL | fn bar() where Vec<dyn Copy>:, {}
    |                ^^^^^^^^^^^^^ doesn't have a size known at compile-time
+...
+LL | struct Vec<T> {
+   |        --- - required by this bound in `Vec`
    |
    = help: the trait `std::marker::Sized` is not implemented for `(dyn std::marker::Copy + 'static)`
    = note: to learn more, visit <https://doc.rust-lang.org/book/ch19-04-advanced-types.html#dynamically-sized-types-and-the-sized-trait>
-   = note: required by `std::vec::Vec`
 
 error[E0038]: the trait `std::marker::Copy` cannot be made into an object
   --> $DIR/wf-fn-where-clause.rs:12:16
diff --git a/src/test/ui/wf/wf-impl-associated-type-trait.stderr b/src/test/ui/wf/wf-impl-associated-type-trait.stderr
index d44a6f01a47..7312233aa54 100644
--- a/src/test/ui/wf/wf-impl-associated-type-trait.stderr
+++ b/src/test/ui/wf/wf-impl-associated-type-trait.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `T: MyHash` is not satisfied
   --> $DIR/wf-impl-associated-type-trait.rs:17:5
    |
 LL | pub struct MySet<T:MyHash> {
-   | -------------------------- required by `MySet`
+   |            -----   ------ required by this bound in `MySet`
 ...
 LL |     type Bar = MySet<T>;
    |     ^^^^^^^^^^^^^^^^^^^^ the trait `MyHash` is not implemented for `T`
diff --git a/src/test/ui/wf/wf-in-fn-arg.stderr b/src/test/ui/wf/wf-in-fn-arg.stderr
index 907701440aa..67a5562b6bc 100644
--- a/src/test/ui/wf/wf-in-fn-arg.stderr
+++ b/src/test/ui/wf/wf-in-fn-arg.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `T: std::marker::Copy` is not satisfied
   --> $DIR/wf-in-fn-arg.rs:10:14
    |
 LL | struct MustBeCopy<T:Copy> {
-   | ------------------------- required by `MustBeCopy`
+   |        ----------   ---- required by this bound in `MustBeCopy`
 ...
 LL | fn bar<T>(_: &MustBeCopy<T>)
    |              ^^^^^^^^^^^^^^ the trait `std::marker::Copy` is not implemented for `T`
diff --git a/src/test/ui/wf/wf-in-fn-ret.stderr b/src/test/ui/wf/wf-in-fn-ret.stderr
index 2ed4eecefe1..545ee559b3f 100644
--- a/src/test/ui/wf/wf-in-fn-ret.stderr
+++ b/src/test/ui/wf/wf-in-fn-ret.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `T: std::marker::Copy` is not satisfied
   --> $DIR/wf-in-fn-ret.rs:10:16
    |
 LL | struct MustBeCopy<T:Copy> {
-   | ------------------------- required by `MustBeCopy`
+   |        ----------   ---- required by this bound in `MustBeCopy`
 ...
 LL | fn bar<T>() -> MustBeCopy<T>
    |                ^^^^^^^^^^^^^ the trait `std::marker::Copy` is not implemented for `T`
diff --git a/src/test/ui/wf/wf-in-fn-type-arg.stderr b/src/test/ui/wf/wf-in-fn-type-arg.stderr
index 0c699838abd..0d8c6b14c56 100644
--- a/src/test/ui/wf/wf-in-fn-type-arg.stderr
+++ b/src/test/ui/wf/wf-in-fn-type-arg.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `T: std::marker::Copy` is not satisfied
   --> $DIR/wf-in-fn-type-arg.rs:9:5
    |
 LL | struct MustBeCopy<T:Copy> {
-   | ------------------------- required by `MustBeCopy`
+   |        ----------   ---- required by this bound in `MustBeCopy`
 ...
 LL |     x: fn(MustBeCopy<T>)
    |     ^^^^^^^^^^^^^^^^^^^^ the trait `std::marker::Copy` is not implemented for `T`
diff --git a/src/test/ui/wf/wf-in-fn-type-ret.stderr b/src/test/ui/wf/wf-in-fn-type-ret.stderr
index 3429ab89ffb..b7c8bf303f3 100644
--- a/src/test/ui/wf/wf-in-fn-type-ret.stderr
+++ b/src/test/ui/wf/wf-in-fn-type-ret.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `T: std::marker::Copy` is not satisfied
   --> $DIR/wf-in-fn-type-ret.rs:9:5
    |
 LL | struct MustBeCopy<T:Copy> {
-   | ------------------------- required by `MustBeCopy`
+   |        ----------   ---- required by this bound in `MustBeCopy`
 ...
 LL |     x: fn() -> MustBeCopy<T>
    |     ^^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::marker::Copy` is not implemented for `T`
diff --git a/src/test/ui/wf/wf-in-fn-where-clause.stderr b/src/test/ui/wf/wf-in-fn-where-clause.stderr
index d33749d795c..e54cc17ccbe 100644
--- a/src/test/ui/wf/wf-in-fn-where-clause.stderr
+++ b/src/test/ui/wf/wf-in-fn-where-clause.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `U: std::marker::Copy` is not satisfied
   --> $DIR/wf-in-fn-where-clause.rs:10:14
    |
 LL | trait MustBeCopy<T:Copy> {
-   | ------------------------ required by `MustBeCopy`
+   |       ----------   ---- required by this bound in `MustBeCopy`
 ...
 LL |     where T: MustBeCopy<U>
    |              ^^^^^^^^^^^^^ the trait `std::marker::Copy` is not implemented for `U`
diff --git a/src/test/ui/wf/wf-in-obj-type-trait.stderr b/src/test/ui/wf/wf-in-obj-type-trait.stderr
index 605dc497849..699c3fe1a63 100644
--- a/src/test/ui/wf/wf-in-obj-type-trait.stderr
+++ b/src/test/ui/wf/wf-in-obj-type-trait.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `T: std::marker::Copy` is not satisfied
   --> $DIR/wf-in-obj-type-trait.rs:11:5
    |
 LL | struct MustBeCopy<T:Copy> {
-   | ------------------------- required by `MustBeCopy`
+   |        ----------   ---- required by this bound in `MustBeCopy`
 ...
 LL |     x: dyn Object<MustBeCopy<T>>
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::marker::Copy` is not implemented for `T`
diff --git a/src/test/ui/wf/wf-inherent-impl-method-where-clause.stderr b/src/test/ui/wf/wf-inherent-impl-method-where-clause.stderr
index da2f8085a8a..172e763650a 100644
--- a/src/test/ui/wf/wf-inherent-impl-method-where-clause.stderr
+++ b/src/test/ui/wf/wf-inherent-impl-method-where-clause.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `U: std::marker::Copy` is not satisfied
   --> $DIR/wf-inherent-impl-method-where-clause.rs:12:27
    |
 LL | trait ExtraCopy<T:Copy> { }
-   | ----------------------- required by `ExtraCopy`
+   |       ---------   ---- required by this bound in `ExtraCopy`
 ...
 LL |     fn foo(self) where T: ExtraCopy<U>
    |                           ^^^^^^^^^^^^ the trait `std::marker::Copy` is not implemented for `U`
diff --git a/src/test/ui/wf/wf-inherent-impl-where-clause.stderr b/src/test/ui/wf/wf-inherent-impl-where-clause.stderr
index 28d5bc62556..1ac5aba3cad 100644
--- a/src/test/ui/wf/wf-inherent-impl-where-clause.stderr
+++ b/src/test/ui/wf/wf-inherent-impl-where-clause.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `U: std::marker::Copy` is not satisfied
   --> $DIR/wf-inherent-impl-where-clause.rs:11:29
    |
 LL | trait ExtraCopy<T:Copy> { }
-   | ----------------------- required by `ExtraCopy`
+   |       ---------   ---- required by this bound in `ExtraCopy`
 ...
 LL | impl<T,U> Foo<T,U> where T: ExtraCopy<U>
    |                             ^^^^^^^^^^^^ the trait `std::marker::Copy` is not implemented for `U`
diff --git a/src/test/ui/wf/wf-static-type.stderr b/src/test/ui/wf/wf-static-type.stderr
index 05a628d7c3e..ec31710e861 100644
--- a/src/test/ui/wf/wf-static-type.stderr
+++ b/src/test/ui/wf/wf-static-type.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `NotCopy: std::marker::Copy` is not satisfied
   --> $DIR/wf-static-type.rs:10:13
    |
 LL | struct IsCopy<T:Copy> { t: T }
-   | --------------------- required by `IsCopy`
+   |        ------   ---- required by this bound in `IsCopy`
 ...
 LL | static FOO: IsCopy<Option<NotCopy>> = IsCopy { t: None };
    |             ^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::marker::Copy` is not implemented for `NotCopy`
diff --git a/src/test/ui/wf/wf-struct-bound.stderr b/src/test/ui/wf/wf-struct-bound.stderr
index 07e569ddac1..848a2eb8bee 100644
--- a/src/test/ui/wf/wf-struct-bound.stderr
+++ b/src/test/ui/wf/wf-struct-bound.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `U: std::marker::Copy` is not satisfied
   --> $DIR/wf-struct-bound.rs:10:14
    |
 LL | trait ExtraCopy<T:Copy> { }
-   | ----------------------- required by `ExtraCopy`
+   |       ---------   ---- required by this bound in `ExtraCopy`
 ...
 LL |     where T: ExtraCopy<U>
    |              ^^^^^^^^^^^^ the trait `std::marker::Copy` is not implemented for `U`
diff --git a/src/test/ui/wf/wf-struct-field.stderr b/src/test/ui/wf/wf-struct-field.stderr
index f3bce24eace..a748a1c9c39 100644
--- a/src/test/ui/wf/wf-struct-field.stderr
+++ b/src/test/ui/wf/wf-struct-field.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `A: std::marker::Copy` is not satisfied
   --> $DIR/wf-struct-field.rs:12:5
    |
 LL | struct IsCopy<T:Copy> {
-   | --------------------- required by `IsCopy`
+   |        ------   ---- required by this bound in `IsCopy`
 ...
 LL |     data: IsCopy<A>
    |     ^^^^^^^^^^^^^^^ the trait `std::marker::Copy` is not implemented for `A`
diff --git a/src/test/ui/wf/wf-trait-associated-type-bound.stderr b/src/test/ui/wf/wf-trait-associated-type-bound.stderr
index 6cf7f2069b6..e568acabcd0 100644
--- a/src/test/ui/wf/wf-trait-associated-type-bound.stderr
+++ b/src/test/ui/wf/wf-trait-associated-type-bound.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `T: std::marker::Copy` is not satisfied
   --> $DIR/wf-trait-associated-type-bound.rs:10:17
    |
 LL | trait ExtraCopy<T:Copy> { }
-   | ----------------------- required by `ExtraCopy`
+   |       ---------   ---- required by this bound in `ExtraCopy`
 ...
 LL |     type Type1: ExtraCopy<T>;
    |                 ^^^^^^^^^^^^ the trait `std::marker::Copy` is not implemented for `T`
diff --git a/src/test/ui/wf/wf-trait-associated-type-trait.stderr b/src/test/ui/wf/wf-trait-associated-type-trait.stderr
index 93cb948cdbf..915f660f54d 100644
--- a/src/test/ui/wf/wf-trait-associated-type-trait.stderr
+++ b/src/test/ui/wf/wf-trait-associated-type-trait.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `<Self as SomeTrait>::Type1: std::marker::Copy` is
   --> $DIR/wf-trait-associated-type-trait.rs:11:5
    |
 LL | struct IsCopy<T:Copy> { x: T }
-   | --------------------- required by `IsCopy`
+   |        ------   ---- required by this bound in `IsCopy`
 LL | 
 LL | trait SomeTrait {
    |                - help: consider further restricting the associated type: `where <Self as SomeTrait>::Type1: std::marker::Copy`
diff --git a/src/test/ui/wf/wf-trait-bound.stderr b/src/test/ui/wf/wf-trait-bound.stderr
index b8ffad6d180..0db29621e31 100644
--- a/src/test/ui/wf/wf-trait-bound.stderr
+++ b/src/test/ui/wf/wf-trait-bound.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `U: std::marker::Copy` is not satisfied
   --> $DIR/wf-trait-bound.rs:10:14
    |
 LL | trait ExtraCopy<T:Copy> { }
-   | ----------------------- required by `ExtraCopy`
+   |       ---------   ---- required by this bound in `ExtraCopy`
 ...
 LL |     where T: ExtraCopy<U>
    |              ^^^^^^^^^^^^ the trait `std::marker::Copy` is not implemented for `U`
diff --git a/src/test/ui/wf/wf-trait-default-fn-arg.stderr b/src/test/ui/wf/wf-trait-default-fn-arg.stderr
index 6a97d31cf3e..55fc202ca51 100644
--- a/src/test/ui/wf/wf-trait-default-fn-arg.stderr
+++ b/src/test/ui/wf/wf-trait-default-fn-arg.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `Self: std::cmp::Eq` is not satisfied
   --> $DIR/wf-trait-default-fn-arg.rs:11:22
    |
 LL | struct Bar<T:Eq+?Sized> { value: Box<T> }
-   | ----------------------- required by `Bar`
+   |        ---   -- required by this bound in `Bar`
 ...
 LL |     fn bar(&self, x: &Bar<Self>) {
    |                      ^^^^^^^^^^ - help: consider further restricting `Self`: `where Self: std::cmp::Eq`
diff --git a/src/test/ui/wf/wf-trait-default-fn-ret.stderr b/src/test/ui/wf/wf-trait-default-fn-ret.stderr
index 36c1e486269..00b153317ab 100644
--- a/src/test/ui/wf/wf-trait-default-fn-ret.stderr
+++ b/src/test/ui/wf/wf-trait-default-fn-ret.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `Self: std::cmp::Eq` is not satisfied
   --> $DIR/wf-trait-default-fn-ret.rs:11:22
    |
 LL | struct Bar<T:Eq+?Sized> { value: Box<T> }
-   | ----------------------- required by `Bar`
+   |        ---   -- required by this bound in `Bar`
 ...
 LL |     fn bar(&self) -> Bar<Self> {
    |                      ^^^^^^^^^- help: consider further restricting `Self`: `where Self: std::cmp::Eq`
diff --git a/src/test/ui/wf/wf-trait-default-fn-where-clause.stderr b/src/test/ui/wf/wf-trait-default-fn-where-clause.stderr
index 6b63feaba89..97210a8aa6a 100644
--- a/src/test/ui/wf/wf-trait-default-fn-where-clause.stderr
+++ b/src/test/ui/wf/wf-trait-default-fn-where-clause.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `Self: std::cmp::Eq` is not satisfied
   --> $DIR/wf-trait-default-fn-where-clause.rs:11:31
    |
 LL | trait Bar<T:Eq+?Sized> { }
-   | ---------------------- required by `Bar`
+   |       ---   -- required by this bound in `Bar`
 ...
 LL |     fn bar<A>(&self) where A: Bar<Self> {
    |                               ^^^^^^^^^- help: consider further restricting `Self`: `, Self: std::cmp::Eq`
diff --git a/src/test/ui/wf/wf-trait-fn-arg.stderr b/src/test/ui/wf/wf-trait-fn-arg.stderr
index 69e2ab72912..190721492a2 100644
--- a/src/test/ui/wf/wf-trait-fn-arg.stderr
+++ b/src/test/ui/wf/wf-trait-fn-arg.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `Self: std::cmp::Eq` is not satisfied
   --> $DIR/wf-trait-fn-arg.rs:10:22
    |
 LL | struct Bar<T:Eq+?Sized> { value: Box<T> }
-   | ----------------------- required by `Bar`
+   |        ---   -- required by this bound in `Bar`
 ...
 LL |     fn bar(&self, x: &Bar<Self>);
    |                      ^^^^^^^^^^ - help: consider further restricting `Self`: `where Self: std::cmp::Eq`
diff --git a/src/test/ui/wf/wf-trait-fn-ret.stderr b/src/test/ui/wf/wf-trait-fn-ret.stderr
index bfc6265662e..b8d10f4f396 100644
--- a/src/test/ui/wf/wf-trait-fn-ret.stderr
+++ b/src/test/ui/wf/wf-trait-fn-ret.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `Self: std::cmp::Eq` is not satisfied
   --> $DIR/wf-trait-fn-ret.rs:10:22
    |
 LL | struct Bar<T:Eq+?Sized> { value: Box<T> }
-   | ----------------------- required by `Bar`
+   |        ---   -- required by this bound in `Bar`
 ...
 LL |     fn bar(&self) -> &Bar<Self>;
    |                      ^^^^^^^^^^- help: consider further restricting `Self`: `where Self: std::cmp::Eq`
diff --git a/src/test/ui/wf/wf-trait-fn-where-clause.stderr b/src/test/ui/wf/wf-trait-fn-where-clause.stderr
index ec8f02c9c4f..c138da032ce 100644
--- a/src/test/ui/wf/wf-trait-fn-where-clause.stderr
+++ b/src/test/ui/wf/wf-trait-fn-where-clause.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `Self: std::cmp::Eq` is not satisfied
   --> $DIR/wf-trait-fn-where-clause.rs:10:49
    |
 LL | struct Bar<T:Eq+?Sized> { value: Box<T> }
-   | ----------------------- required by `Bar`
+   |        ---   -- required by this bound in `Bar`
 ...
 LL |     fn bar(&self) where Self: Sized, Bar<Self>: Copy;
    |                                                 ^^^^- help: consider further restricting `Self`: `, Self: std::cmp::Eq`
diff --git a/src/test/ui/wf/wf-trait-superbound.stderr b/src/test/ui/wf/wf-trait-superbound.stderr
index 88b4bec0451..5310939af9c 100644
--- a/src/test/ui/wf/wf-trait-superbound.stderr
+++ b/src/test/ui/wf/wf-trait-superbound.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `T: std::marker::Copy` is not satisfied
   --> $DIR/wf-trait-superbound.rs:9:21
    |
 LL | trait ExtraCopy<T:Copy> { }
-   | ----------------------- required by `ExtraCopy`
+   |       ---------   ---- required by this bound in `ExtraCopy`
 LL | 
 LL | trait SomeTrait<T>: ExtraCopy<T> {
    |                     ^^^^^^^^^^^^ the trait `std::marker::Copy` is not implemented for `T`