implied_bounds: clarify our assumptions

16 files changed, 95 insertions, 44 deletions

diff --git a/src/test/ui/associated-types/associated-types-for-unimpl-trait.stderr b/src/test/ui/associated-types/associated-types-for-unimpl-trait.stderr
index 6552c8be780..389cc7beddd 100644
--- a/src/test/ui/associated-types/associated-types-for-unimpl-trait.stderr
+++ b/src/test/ui/associated-types/associated-types-for-unimpl-trait.stderr
@@ -1,8 +1,8 @@
 error[E0277]: the trait bound `Self: Get` is not satisfied
-  --> $DIR/associated-types-for-unimpl-trait.rs:10:40
+  --> $DIR/associated-types-for-unimpl-trait.rs:10:5
    |
 LL |     fn uhoh<U:Get>(&self, foo: U, bar: <Self as Get>::Value) {}
-   |                                        ^^^^^^^^^^^^^^^^^^^^ the trait `Get` is not implemented for `Self`
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Get` is not implemented for `Self`
    |
 help: consider further restricting `Self`
    |
diff --git a/src/test/ui/associated-types/associated-types-no-suitable-bound.stderr b/src/test/ui/associated-types/associated-types-no-suitable-bound.stderr
index b2ee1b5e6d0..1feaa612ee6 100644
--- a/src/test/ui/associated-types/associated-types-no-suitable-bound.stderr
+++ b/src/test/ui/associated-types/associated-types-no-suitable-bound.stderr
@@ -1,8 +1,8 @@
 error[E0277]: the trait bound `T: Get` is not satisfied
-  --> $DIR/associated-types-no-suitable-bound.rs:11:21
+  --> $DIR/associated-types-no-suitable-bound.rs:11:5
    |
 LL |     fn uhoh<T>(foo: <T as Get>::Value) {}
-   |                     ^^^^^^^^^^^^^^^^^ the trait `Get` is not implemented for `T`
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Get` is not implemented for `T`
    |
 help: consider restricting type parameter `T`
    |
diff --git a/src/test/ui/associated-types/associated-types-no-suitable-supertrait-2.stderr b/src/test/ui/associated-types/associated-types-no-suitable-supertrait-2.stderr
index 2e40dbd065d..cc3ed556115 100644
--- a/src/test/ui/associated-types/associated-types-no-suitable-supertrait-2.stderr
+++ b/src/test/ui/associated-types/associated-types-no-suitable-supertrait-2.stderr
@@ -1,8 +1,8 @@
 error[E0277]: the trait bound `Self: Get` is not satisfied
-  --> $DIR/associated-types-no-suitable-supertrait-2.rs:17:40
+  --> $DIR/associated-types-no-suitable-supertrait-2.rs:17:5
    |
 LL |     fn uhoh<U:Get>(&self, foo: U, bar: <Self as Get>::Value) {}
-   |                                        ^^^^^^^^^^^^^^^^^^^^ the trait `Get` is not implemented for `Self`
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Get` is not implemented for `Self`
    |
 help: consider further restricting `Self`
    |
diff --git a/src/test/ui/associated-types/associated-types-no-suitable-supertrait.stderr b/src/test/ui/associated-types/associated-types-no-suitable-supertrait.stderr
index bd3ee2abd2c..18f2830d8b2 100644
--- a/src/test/ui/associated-types/associated-types-no-suitable-supertrait.stderr
+++ b/src/test/ui/associated-types/associated-types-no-suitable-supertrait.stderr
@@ -1,14 +1,14 @@
 error[E0277]: the trait bound `(T, U): Get` is not satisfied
-  --> $DIR/associated-types-no-suitable-supertrait.rs:22:40
+  --> $DIR/associated-types-no-suitable-supertrait.rs:22:5
    |
 LL |     fn uhoh<U:Get>(&self, foo: U, bar: <(T, U) as Get>::Value) {}
-   |                                        ^^^^^^^^^^^^^^^^^^^^^^ the trait `Get` is not implemented for `(T, U)`
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Get` is not implemented for `(T, U)`
 
 error[E0277]: the trait bound `Self: Get` is not satisfied
-  --> $DIR/associated-types-no-suitable-supertrait.rs:17:40
+  --> $DIR/associated-types-no-suitable-supertrait.rs:17:5
    |
 LL |     fn uhoh<U:Get>(&self, foo: U, bar: <Self as Get>::Value) {}
-   |                                        ^^^^^^^^^^^^^^^^^^^^ the trait `Get` is not implemented for `Self`
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Get` is not implemented for `Self`
    |
 help: consider further restricting `Self`
    |
diff --git a/src/test/ui/associated-types/associated-types-projection-to-unrelated-trait-in-method-without-default.stderr b/src/test/ui/associated-types/associated-types-projection-to-unrelated-trait-in-method-without-default.stderr
index 2e67c21940f..66d59bccdbb 100644
--- a/src/test/ui/associated-types/associated-types-projection-to-unrelated-trait-in-method-without-default.stderr
+++ b/src/test/ui/associated-types/associated-types-projection-to-unrelated-trait-in-method-without-default.stderr
@@ -1,8 +1,8 @@
 error[E0277]: the trait bound `Self: Get` is not satisfied
-  --> $DIR/associated-types-projection-to-unrelated-trait-in-method-without-default.rs:10:40
+  --> $DIR/associated-types-projection-to-unrelated-trait-in-method-without-default.rs:10:5
    |
 LL |     fn okay<U:Get>(&self, foo: U, bar: <Self as Get>::Value);
-   |                                        ^^^^^^^^^^^^^^^^^^^^ the trait `Get` is not implemented for `Self`
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Get` is not implemented for `Self`
    |
 help: consider further restricting `Self`
    |
diff --git a/src/test/ui/associated-types/issue-59324.stderr b/src/test/ui/associated-types/issue-59324.stderr
index dd5ec7175b5..62cf1f37a77 100644
--- a/src/test/ui/associated-types/issue-59324.stderr
+++ b/src/test/ui/associated-types/issue-59324.stderr
@@ -45,16 +45,20 @@ LL | pub trait ThriftService<Bug: NotFoo + Foo>:
    |                                     +++++
 
 error[E0277]: the trait bound `(): Foo` is not satisfied
-  --> $DIR/issue-59324.rs:23:29
+  --> $DIR/issue-59324.rs:23:1
    |
 LL | fn with_factory<H>(factory: dyn ThriftService<()>) {}
-   |                             ^^^^^^^^^^^^^^^^^^^^^ the trait `Foo` is not implemented for `()`
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Foo` is not implemented for `()`
 
 error[E0277]: the trait bound `Bug: Foo` is not satisfied
-  --> $DIR/issue-59324.rs:16:8
+  --> $DIR/issue-59324.rs:16:5
    |
-LL |     fn get_service(
-   |        ^^^^^^^^^^^ the trait `Foo` is not implemented for `Bug`
+LL | /     fn get_service(
+LL | |
+LL | |
+LL | |         &self,
+LL | |     ) -> Self::AssocType;
+   | |_________________________^ the trait `Foo` is not implemented for `Bug`
    |
 help: consider further restricting this bound
    |
diff --git a/src/test/ui/issues/issue-18611.stderr b/src/test/ui/issues/issue-18611.stderr
index bd18d46223e..22c3470b61e 100644
--- a/src/test/ui/issues/issue-18611.stderr
+++ b/src/test/ui/issues/issue-18611.stderr
@@ -1,8 +1,10 @@
 error[E0277]: the trait bound `isize: HasState` is not satisfied
-  --> $DIR/issue-18611.rs:1:18
+  --> $DIR/issue-18611.rs:1:1
    |
-LL | fn add_state(op: <isize as HasState>::State) {
-   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `HasState` is not implemented for `isize`
+LL | / fn add_state(op: <isize as HasState>::State) {
+LL | |
+LL | | }
+   | |_^ the trait `HasState` is not implemented for `isize`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-20831-debruijn.stderr b/src/test/ui/issues/issue-20831-debruijn.stderr
index 57f9575bdbd..ef62dece836 100644
--- a/src/test/ui/issues/issue-20831-debruijn.stderr
+++ b/src/test/ui/issues/issue-20831-debruijn.stderr
@@ -1,8 +1,14 @@
 error[E0495]: cannot infer an appropriate lifetime for lifetime parameter `'a` due to conflicting requirements
-  --> $DIR/issue-20831-debruijn.rs:28:8
+  --> $DIR/issue-20831-debruijn.rs:28:5
    |
-LL |     fn subscribe(&mut self, t : Box<dyn Subscriber<Input=<Self as Publisher>::Output> + 'a>) {
-   |        ^^^^^^^^^
+LL | /     fn subscribe(&mut self, t : Box<dyn Subscriber<Input=<Self as Publisher>::Output> + 'a>) {
+LL | |         // Not obvious, but there is an implicit lifetime here -------^
+LL | |
+LL | |         //
+...  |
+LL | |         self.sub = t;
+LL | |     }
+   | |_____^
    |
 note: first, the lifetime cannot outlive the anonymous lifetime defined here...
   --> $DIR/issue-20831-debruijn.rs:28:58
@@ -15,10 +21,16 @@ note: ...but the lifetime must also be valid for the lifetime `'a` as defined he
 LL | impl<'a> Publisher<'a> for MyStruct<'a> {
    |      ^^
 note: ...so that the types are compatible
-  --> $DIR/issue-20831-debruijn.rs:28:8
+  --> $DIR/issue-20831-debruijn.rs:28:5
    |
-LL |     fn subscribe(&mut self, t : Box<dyn Subscriber<Input=<Self as Publisher>::Output> + 'a>) {
-   |        ^^^^^^^^^
+LL | /     fn subscribe(&mut self, t : Box<dyn Subscriber<Input=<Self as Publisher>::Output> + 'a>) {
+LL | |         // Not obvious, but there is an implicit lifetime here -------^
+LL | |
+LL | |         //
+...  |
+LL | |         self.sub = t;
+LL | |     }
+   | |_____^
    = note: expected `<MyStruct<'a> as Publisher<'_>>`
               found `<MyStruct<'_> as Publisher<'_>>`
 
diff --git a/src/test/ui/issues/issue-35570.rs b/src/test/ui/issues/issue-35570.rs
index 42cef9a47f2..a2b0222d4f3 100644
--- a/src/test/ui/issues/issue-35570.rs
+++ b/src/test/ui/issues/issue-35570.rs
@@ -6,7 +6,8 @@ trait Trait2<'a> {
 }
 
 fn _ice(param: Box<dyn for <'a> Trait1<<() as Trait2<'a>>::Ty>>) {
-//~^ the trait bound `for<'a> (): Trait2<'a>` is not satisfied
+    //~^ ERROR the trait bound `for<'a> (): Trait2<'a>` is not satisfied
+    //~| ERROR the trait bound `for<'a> (): Trait2<'a>` is not satisfied
     let _e: (usize, usize) = unsafe{mem::transmute(param)};
 }
 
diff --git a/src/test/ui/issues/issue-35570.stderr b/src/test/ui/issues/issue-35570.stderr
index 2697d46bdb2..ebc40f6786f 100644
--- a/src/test/ui/issues/issue-35570.stderr
+++ b/src/test/ui/issues/issue-35570.stderr
@@ -1,9 +1,19 @@
 error[E0277]: the trait bound `for<'a> (): Trait2<'a>` is not satisfied
+  --> $DIR/issue-35570.rs:8:1
+   |
+LL | / fn _ice(param: Box<dyn for <'a> Trait1<<() as Trait2<'a>>::Ty>>) {
+LL | |
+LL | |
+LL | |     let _e: (usize, usize) = unsafe{mem::transmute(param)};
+LL | | }
+   | |_^ the trait `for<'a> Trait2<'a>` is not implemented for `()`
+
+error[E0277]: the trait bound `for<'a> (): Trait2<'a>` is not satisfied
   --> $DIR/issue-35570.rs:8:40
    |
 LL | fn _ice(param: Box<dyn for <'a> Trait1<<() as Trait2<'a>>::Ty>>) {
    |                                        ^^^^^^^^^^^^^^^^^^^^^^ the trait `for<'a> Trait2<'a>` is not implemented for `()`
 
-error: aborting due to previous error
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/nll/normalization-bounds-error.stderr b/src/test/ui/nll/normalization-bounds-error.stderr
index 6da3d5d9692..6abe53127c3 100644
--- a/src/test/ui/nll/normalization-bounds-error.stderr
+++ b/src/test/ui/nll/normalization-bounds-error.stderr
@@ -1,8 +1,8 @@
 error[E0495]: cannot infer an appropriate lifetime for lifetime parameter `'d` due to conflicting requirements
-  --> $DIR/normalization-bounds-error.rs:12:4
+  --> $DIR/normalization-bounds-error.rs:12:1
    |
 LL | fn visit_seq<'d, 'a: 'd>() -> <&'a () as Visitor<'d>>::Value {}
-   |    ^^^^^^^^^
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
 note: first, the lifetime cannot outlive the lifetime `'d` as defined here...
   --> $DIR/normalization-bounds-error.rs:12:14
@@ -15,10 +15,10 @@ note: ...but the lifetime must also be valid for the lifetime `'a` as defined he
 LL | fn visit_seq<'d, 'a: 'd>() -> <&'a () as Visitor<'d>>::Value {}
    |                  ^^
 note: ...so that the types are compatible
-  --> $DIR/normalization-bounds-error.rs:12:4
+  --> $DIR/normalization-bounds-error.rs:12:1
    |
 LL | fn visit_seq<'d, 'a: 'd>() -> <&'a () as Visitor<'d>>::Value {}
-   |    ^^^^^^^^^
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = note: expected `Visitor<'d>`
               found `Visitor<'_>`
 
diff --git a/src/test/ui/regions/regions-implied-bounds-projection-gap-hr-1.rs b/src/test/ui/regions/regions-implied-bounds-projection-gap-hr-1.rs
index c1dab6086ef..1106352037a 100644
--- a/src/test/ui/regions/regions-implied-bounds-projection-gap-hr-1.rs
+++ b/src/test/ui/regions/regions-implied-bounds-projection-gap-hr-1.rs
@@ -19,7 +19,8 @@ trait Trait2<'a, 'b> {
 // since for it to be WF, we would need to know that `'y: 'x`, but we
 // do not infer that.
 fn callee<'x, 'y, T>(t: &'x dyn for<'z> Trait1< <T as Trait2<'y, 'z>>::Foo >)
-    //~^ the trait bound `for<'z> T: Trait2<'y, 'z>` is not satisfied
+    //~^ ERROR the trait bound `for<'z> T: Trait2<'y, 'z>` is not satisfied
+    //~| ERROR the trait bound `for<'z> T: Trait2<'y, 'z>` is not satisfied
 {
 }
 
diff --git a/src/test/ui/regions/regions-implied-bounds-projection-gap-hr-1.stderr b/src/test/ui/regions/regions-implied-bounds-projection-gap-hr-1.stderr
index 6844e866532..66f592c34dd 100644
--- a/src/test/ui/regions/regions-implied-bounds-projection-gap-hr-1.stderr
+++ b/src/test/ui/regions/regions-implied-bounds-projection-gap-hr-1.stderr
@@ -1,4 +1,19 @@
 error[E0277]: the trait bound `for<'z> T: Trait2<'y, 'z>` is not satisfied
+  --> $DIR/regions-implied-bounds-projection-gap-hr-1.rs:21:1
+   |
+LL | / fn callee<'x, 'y, T>(t: &'x dyn for<'z> Trait1< <T as Trait2<'y, 'z>>::Foo >)
+LL | |
+LL | |
+LL | | {
+LL | | }
+   | |_^ the trait `for<'z> Trait2<'y, 'z>` is not implemented for `T`
+   |
+help: consider restricting type parameter `T`
+   |
+LL | fn callee<'x, 'y, T: for<'z> Trait2<'y, 'z>>(t: &'x dyn for<'z> Trait1< <T as Trait2<'y, 'z>>::Foo >)
+   |                    ++++++++++++++++++++++++
+
+error[E0277]: the trait bound `for<'z> T: Trait2<'y, 'z>` is not satisfied
   --> $DIR/regions-implied-bounds-projection-gap-hr-1.rs:21:49
    |
 LL | fn callee<'x, 'y, T>(t: &'x dyn for<'z> Trait1< <T as Trait2<'y, 'z>>::Foo >)
@@ -9,6 +24,6 @@ help: consider restricting type parameter `T`
 LL | fn callee<'x, 'y, T: for<'z> Trait2<'y, 'z>>(t: &'x dyn for<'z> Trait1< <T as Trait2<'y, 'z>>::Foo >)
    |                    ++++++++++++++++++++++++
 
-error: aborting due to previous error
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/specialization/min_specialization/issue-79224.stderr b/src/test/ui/specialization/min_specialization/issue-79224.stderr
index cfb9007c7a2..b395d93f097 100644
--- a/src/test/ui/specialization/min_specialization/issue-79224.stderr
+++ b/src/test/ui/specialization/min_specialization/issue-79224.stderr
@@ -1,8 +1,12 @@
 error[E0277]: the trait bound `B: Clone` is not satisfied
-  --> $DIR/issue-79224.rs:18:17
+  --> $DIR/issue-79224.rs:18:1
    |
-LL | impl<B: ?Sized> Display for Cow<'_, B> {
-   |                 ^^^^^^^ the trait `Clone` is not implemented for `B`
+LL | / impl<B: ?Sized> Display for Cow<'_, B> {
+LL | |     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+LL | |         write!(f, "foo")
+LL | |     }
+LL | | }
+   | |_^ the trait `Clone` is not implemented for `B`
    |
    = note: required because of the requirements on the impl of `ToOwned` for `B`
 help: consider further restricting this bound
@@ -11,10 +15,12 @@ LL | impl<B: ?Sized + std::clone::Clone> Display for Cow<'_, B> {
    |                +++++++++++++++++++
 
 error[E0277]: the trait bound `B: Clone` is not satisfied
-  --> $DIR/issue-79224.rs:19:12
+  --> $DIR/issue-79224.rs:19:5
    |
-LL |     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-   |            ^^^^^ the trait `Clone` is not implemented for `B`
+LL | /     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+LL | |         write!(f, "foo")
+LL | |     }
+   | |_____^ the trait `Clone` is not implemented for `B`
    |
    = note: required because of the requirements on the impl of `ToOwned` for `B`
 help: consider further restricting this bound
diff --git a/src/test/ui/traits/issue-91594.stderr b/src/test/ui/traits/issue-91594.stderr
index f2b3de13beb..b9f1d8c6a2e 100644
--- a/src/test/ui/traits/issue-91594.stderr
+++ b/src/test/ui/traits/issue-91594.stderr
@@ -1,8 +1,8 @@
 error[E0277]: the trait bound `Foo: HasComponent<()>` is not satisfied
-  --> $DIR/issue-91594.rs:10:6
+  --> $DIR/issue-91594.rs:10:1
    |
 LL | impl HasComponent<<Foo as Component<Foo>>::Interface> for Foo {}
-   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `HasComponent<()>` is not implemented for `Foo`
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `HasComponent<()>` is not implemented for `Foo`
    |
    = help: the trait `HasComponent<<Foo as Component<Foo>>::Interface>` is implemented for `Foo`
 note: required because of the requirements on the impl of `Component<Foo>` for `Foo`
diff --git a/src/test/ui/wf/wf-foreign-fn-decl-ret.stderr b/src/test/ui/wf/wf-foreign-fn-decl-ret.stderr
index b03023b5fd1..78312a09105 100644
--- a/src/test/ui/wf/wf-foreign-fn-decl-ret.stderr
+++ b/src/test/ui/wf/wf-foreign-fn-decl-ret.stderr
@@ -1,8 +1,8 @@
 error[E0277]: the trait bound `(): Foo` is not satisfied
-  --> $DIR/wf-foreign-fn-decl-ret.rs:11:25
+  --> $DIR/wf-foreign-fn-decl-ret.rs:11:5
    |
 LL |     pub fn lint_me() -> <() as Foo>::Assoc;
-   |                         ^^^^^^^^^^^^^^^^^^ the trait `Foo` is not implemented for `()`
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Foo` is not implemented for `()`
 
 error[E0277]: the trait bound `u32: Unsatisfied` is not satisfied
   --> $DIR/wf-foreign-fn-decl-ret.rs:14:32