Print opaque types from type aliases via their path

44 files changed, 153 insertions, 77 deletions

diff --git a/compiler/rustc_middle/src/ty/print/pretty.rs b/compiler/rustc_middle/src/ty/print/pretty.rs
index 11a3ee53629..6521957ec94 100644
--- a/compiler/rustc_middle/src/ty/print/pretty.rs
+++ b/compiler/rustc_middle/src/ty/print/pretty.rs
@@ -644,18 +644,23 @@ pub trait PrettyPrinter<'tcx>:
                     return Ok(self);
                 }
 
-                let def_key = self.tcx().def_key(def_id);
-                if let Some(name) = def_key.disambiguated_data.data.get_opt_name() {
-                    p!(write("{}", name));
-                    // FIXME(eddyb) print this with `print_def_path`.
-                    if !substs.is_empty() {
-                        p!("::");
-                        p!(generic_delimiters(|cx| cx.comma_sep(substs.iter())));
+                let parent = self.tcx().parent(def_id).expect("opaque types always have a parent");
+                match self.tcx().def_kind(parent) {
+                    DefKind::TyAlias | DefKind::AssocTy => {
+                        if let ty::Opaque(d, _) = *self.tcx().type_of(parent).kind() {
+                            if d == def_id {
+                                // If the type alias directly starts with the `impl` of the
+                                // opaque type we're printing, then skip the `::{opaque#1}`.
+                                p!(print_def_path(parent, substs));
+                                return Ok(self);
+                            }
+                        }
+                        // Complex opaque type, e.g. `type Foo = (i32, impl Debug);`
+                        p!(print_def_path(def_id, substs));
+                        return Ok(self);
                     }
-                    return Ok(self);
+                    _ => return self.pretty_print_opaque_impl_type(def_id, substs),
                 }
-
-                return self.pretty_print_opaque_impl_type(def_id, substs);
             }
             ty::Str => p!("str"),
             ty::Generator(did, substs, movability) => {
@@ -898,15 +903,6 @@ pub trait PrettyPrinter<'tcx>:
                     if !first {
                         p!(", ");
                     }
-                    if let GenericArgKind::Type(ty) = ty.unpack() {
-                        if let ty::Opaque(d, substs) = *ty.kind() {
-                            if d == def_id {
-                                p!(print_def_path(d, substs));
-                                first = false;
-                                continue;
-                            }
-                        }
-                    }
                     p!(print(trait_ref.rebind(*ty)));
                     first = false;
                 }
diff --git a/src/test/ui/associated-type-bounds/assoc-type-eq-with-dyn-atb-fail.stderr b/src/test/ui/associated-type-bounds/assoc-type-eq-with-dyn-atb-fail.stderr
index be4bfa6272b..f1dcd34066d 100644
--- a/src/test/ui/associated-type-bounds/assoc-type-eq-with-dyn-atb-fail.stderr
+++ b/src/test/ui/associated-type-bounds/assoc-type-eq-with-dyn-atb-fail.stderr
@@ -4,7 +4,7 @@ error[E0277]: the trait bound `String: Copy` is not satisfied
 LL |         Box::new(AssocNoCopy)
    |         ^^^^^^^^^^^^^^^^^^^^^ the trait `Copy` is not implemented for `String`
    |
-   = note: required for the cast to the object type `dyn Bar<Assoc = impl Copy>`
+   = note: required for the cast to the object type `dyn Bar<Assoc = <AssocNoCopy as Thing>::Out::{opaque#0}>`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/impl-trait/auto-trait.rs b/src/test/ui/impl-trait/auto-trait.rs
index cf2773f4ef5..35994e4a5ba 100644
--- a/src/test/ui/impl-trait/auto-trait.rs
+++ b/src/test/ui/impl-trait/auto-trait.rs
@@ -19,7 +19,7 @@ impl<T: Send> AnotherTrait for T {}
 // (We treat opaque types as "foreign types" that could grow more impls
 // in the future.)
 impl AnotherTrait for D<OpaqueType> {
-    //~^ ERROR conflicting implementations of trait `AnotherTrait` for type `D<impl OpaqueTrait>`
+    //~^ ERROR conflicting implementations of trait `AnotherTrait` for type `D<OpaqueType>`
 }
 
 fn main() {}
diff --git a/src/test/ui/impl-trait/auto-trait.stderr b/src/test/ui/impl-trait/auto-trait.stderr
index 26cd8fb6a9b..81009413c9a 100644
--- a/src/test/ui/impl-trait/auto-trait.stderr
+++ b/src/test/ui/impl-trait/auto-trait.stderr
@@ -1,11 +1,11 @@
-error[E0119]: conflicting implementations of trait `AnotherTrait` for type `D<impl OpaqueTrait>`
+error[E0119]: conflicting implementations of trait `AnotherTrait` for type `D<OpaqueType>`
   --> $DIR/auto-trait.rs:21:1
    |
 LL | impl<T: Send> AnotherTrait for T {}
    | -------------------------------- first implementation here
 ...
 LL | impl AnotherTrait for D<OpaqueType> {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `D<impl OpaqueTrait>`
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `D<OpaqueType>`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/impl-trait/negative-reasoning.rs b/src/test/ui/impl-trait/negative-reasoning.rs
index d173fe83fb7..70e24a3a9d0 100644
--- a/src/test/ui/impl-trait/negative-reasoning.rs
+++ b/src/test/ui/impl-trait/negative-reasoning.rs
@@ -17,7 +17,7 @@ impl<T: std::fmt::Debug> AnotherTrait for T {}
 
 // This is in error, because we cannot assume that `OpaqueType: !Debug`
 impl AnotherTrait for D<OpaqueType> {
-    //~^ ERROR conflicting implementations of trait `AnotherTrait` for type `D<impl OpaqueTrait>`
+    //~^ ERROR conflicting implementations of trait `AnotherTrait` for type `D<OpaqueType>`
 }
 
 fn main() {}
diff --git a/src/test/ui/impl-trait/negative-reasoning.stderr b/src/test/ui/impl-trait/negative-reasoning.stderr
index e39a8e53f79..6b8cc9e7374 100644
--- a/src/test/ui/impl-trait/negative-reasoning.stderr
+++ b/src/test/ui/impl-trait/negative-reasoning.stderr
@@ -1,13 +1,13 @@
-error[E0119]: conflicting implementations of trait `AnotherTrait` for type `D<impl OpaqueTrait>`
+error[E0119]: conflicting implementations of trait `AnotherTrait` for type `D<OpaqueType>`
   --> $DIR/negative-reasoning.rs:19:1
    |
 LL | impl<T: std::fmt::Debug> AnotherTrait for T {}
    | ------------------------------------------- first implementation here
 ...
 LL | impl AnotherTrait for D<OpaqueType> {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `D<impl OpaqueTrait>`
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `D<OpaqueType>`
    |
-   = note: upstream crates may add a new impl of trait `std::fmt::Debug` for type `impl OpaqueTrait` in future versions
+   = note: upstream crates may add a new impl of trait `std::fmt::Debug` for type `OpaqueType` in future versions
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/lint/lint-ctypes-73249-2.rs b/src/test/ui/lint/lint-ctypes-73249-2.rs
index fe578f51b63..691047c8a40 100644
--- a/src/test/ui/lint/lint-ctypes-73249-2.rs
+++ b/src/test/ui/lint/lint-ctypes-73249-2.rs
@@ -23,7 +23,7 @@ pub struct A<T: Foo> {
 }
 
 extern "C" {
-    pub fn lint_me() -> A<()>; //~ ERROR: uses type `impl Baz`
+    pub fn lint_me() -> A<()>; //~ ERROR: uses type `Qux`
 }
 
 fn main() {}
diff --git a/src/test/ui/lint/lint-ctypes-73249-2.stderr b/src/test/ui/lint/lint-ctypes-73249-2.stderr
index 36dbe3217d7..7c85e9fa85c 100644
--- a/src/test/ui/lint/lint-ctypes-73249-2.stderr
+++ b/src/test/ui/lint/lint-ctypes-73249-2.stderr
@@ -1,4 +1,4 @@
-error: `extern` block uses type `impl Baz`, which is not FFI-safe
+error: `extern` block uses type `Qux`, which is not FFI-safe
   --> $DIR/lint-ctypes-73249-2.rs:26:25
    |
 LL |     pub fn lint_me() -> A<()>;
diff --git a/src/test/ui/lint/lint-ctypes-73249-3.rs b/src/test/ui/lint/lint-ctypes-73249-3.rs
index ec12de00739..ef8ab7e03d2 100644
--- a/src/test/ui/lint/lint-ctypes-73249-3.rs
+++ b/src/test/ui/lint/lint-ctypes-73249-3.rs
@@ -17,7 +17,7 @@ pub struct A {
 }
 
 extern "C" {
-    pub fn lint_me() -> A; //~ ERROR: uses type `impl Baz`
+    pub fn lint_me() -> A; //~ ERROR: uses type `Qux`
 }
 
 fn main() {}
diff --git a/src/test/ui/lint/lint-ctypes-73249-3.stderr b/src/test/ui/lint/lint-ctypes-73249-3.stderr
index e987ec90228..83e2a233c43 100644
--- a/src/test/ui/lint/lint-ctypes-73249-3.stderr
+++ b/src/test/ui/lint/lint-ctypes-73249-3.stderr
@@ -1,4 +1,4 @@
-error: `extern` block uses type `impl Baz`, which is not FFI-safe
+error: `extern` block uses type `Qux`, which is not FFI-safe
   --> $DIR/lint-ctypes-73249-3.rs:20:25
    |
 LL |     pub fn lint_me() -> A;
diff --git a/src/test/ui/lint/lint-ctypes-73249-5.rs b/src/test/ui/lint/lint-ctypes-73249-5.rs
index 58c2d7a501a..083fb6c5fb1 100644
--- a/src/test/ui/lint/lint-ctypes-73249-5.rs
+++ b/src/test/ui/lint/lint-ctypes-73249-5.rs
@@ -17,7 +17,7 @@ pub struct A {
 }
 
 extern "C" {
-    pub fn lint_me() -> A; //~ ERROR: uses type `impl Baz`
+    pub fn lint_me() -> A; //~ ERROR: uses type `Qux`
 }
 
 fn main() {}
diff --git a/src/test/ui/lint/lint-ctypes-73249-5.stderr b/src/test/ui/lint/lint-ctypes-73249-5.stderr
index 749714c7df8..37781d78cf2 100644
--- a/src/test/ui/lint/lint-ctypes-73249-5.stderr
+++ b/src/test/ui/lint/lint-ctypes-73249-5.stderr
@@ -1,4 +1,4 @@
-error: `extern` block uses type `impl Baz`, which is not FFI-safe
+error: `extern` block uses type `Qux`, which is not FFI-safe
   --> $DIR/lint-ctypes-73249-5.rs:20:25
    |
 LL |     pub fn lint_me() -> A;
diff --git a/src/test/ui/lint/lint-ctypes-73251-1.rs b/src/test/ui/lint/lint-ctypes-73251-1.rs
index dc4c7efd7ef..145ba784f7c 100644
--- a/src/test/ui/lint/lint-ctypes-73251-1.rs
+++ b/src/test/ui/lint/lint-ctypes-73251-1.rs
@@ -20,7 +20,7 @@ fn assign() -> Qux {
 }
 
 extern "C" {
-    pub fn lint_me() -> <u32 as Foo>::Assoc; //~ ERROR: uses type `impl Baz`
+    pub fn lint_me() -> <u32 as Foo>::Assoc; //~ ERROR: uses type `Qux`
 }
 
 fn main() {}
diff --git a/src/test/ui/lint/lint-ctypes-73251-1.stderr b/src/test/ui/lint/lint-ctypes-73251-1.stderr
index 505ccd5a930..76b19d37e21 100644
--- a/src/test/ui/lint/lint-ctypes-73251-1.stderr
+++ b/src/test/ui/lint/lint-ctypes-73251-1.stderr
@@ -1,4 +1,4 @@
-error: `extern` block uses type `impl Baz`, which is not FFI-safe
+error: `extern` block uses type `Qux`, which is not FFI-safe
   --> $DIR/lint-ctypes-73251-1.rs:23:25
    |
 LL |     pub fn lint_me() -> <u32 as Foo>::Assoc;
diff --git a/src/test/ui/lint/lint-ctypes-73251-2.rs b/src/test/ui/lint/lint-ctypes-73251-2.rs
index 717ca4986f7..df71a945796 100644
--- a/src/test/ui/lint/lint-ctypes-73251-2.rs
+++ b/src/test/ui/lint/lint-ctypes-73251-2.rs
@@ -33,7 +33,7 @@ fn use_of_b() -> AliasB {
 }
 
 extern "C" {
-    pub fn lint_me() -> <AliasB as TraitB>::Assoc; //~ ERROR: uses type `impl TraitA<Assoc = u32>`
+    pub fn lint_me() -> <AliasB as TraitB>::Assoc; //~ ERROR: uses type `AliasA`
 }
 
 fn main() {}
diff --git a/src/test/ui/lint/lint-ctypes-73251-2.stderr b/src/test/ui/lint/lint-ctypes-73251-2.stderr
index d7e10db441e..64f0fb2d892 100644
--- a/src/test/ui/lint/lint-ctypes-73251-2.stderr
+++ b/src/test/ui/lint/lint-ctypes-73251-2.stderr
@@ -1,4 +1,4 @@
-error: `extern` block uses type `impl TraitA<Assoc = u32>`, which is not FFI-safe
+error: `extern` block uses type `AliasA`, which is not FFI-safe
   --> $DIR/lint-ctypes-73251-2.rs:36:25
    |
 LL |     pub fn lint_me() -> <AliasB as TraitB>::Assoc;
diff --git a/src/test/ui/lint/opaque-ty-ffi-unsafe.rs b/src/test/ui/lint/opaque-ty-ffi-unsafe.rs
index 3a62b6a21a5..b7cc38e99fc 100644
--- a/src/test/ui/lint/opaque-ty-ffi-unsafe.rs
+++ b/src/test/ui/lint/opaque-ty-ffi-unsafe.rs
@@ -9,7 +9,7 @@ pub fn ret_closure() -> A {
 
 extern "C" {
     pub fn a(_: A);
-    //~^ ERROR `extern` block uses type `impl Fn()`, which is not FFI-safe [improper_ctypes]
+    //~^ ERROR `extern` block uses type `A`, which is not FFI-safe [improper_ctypes]
 }
 
 fn main() {}
diff --git a/src/test/ui/lint/opaque-ty-ffi-unsafe.stderr b/src/test/ui/lint/opaque-ty-ffi-unsafe.stderr
index 5afbef778b3..62d00fd6835 100644
--- a/src/test/ui/lint/opaque-ty-ffi-unsafe.stderr
+++ b/src/test/ui/lint/opaque-ty-ffi-unsafe.stderr
@@ -1,4 +1,4 @@
-error: `extern` block uses type `impl Fn()`, which is not FFI-safe
+error: `extern` block uses type `A`, which is not FFI-safe
   --> $DIR/opaque-ty-ffi-unsafe.rs:11:17
    |
 LL |     pub fn a(_: A);
diff --git a/src/test/ui/traits/alias/issue-83613.rs b/src/test/ui/traits/alias/issue-83613.rs
index 0013d5d66f1..04320e72076 100644
--- a/src/test/ui/traits/alias/issue-83613.rs
+++ b/src/test/ui/traits/alias/issue-83613.rs
@@ -8,6 +8,6 @@ fn mk_opaque() -> OpaqueType {
 trait AnotherTrait {}
 impl<T: Send> AnotherTrait for T {}
 impl AnotherTrait for OpaqueType {}
-//~^ ERROR conflicting implementations of trait `AnotherTrait` for type `impl OpaqueTrait`
+//~^ ERROR conflicting implementations of trait `AnotherTrait` for type `OpaqueType`
 //~| ERROR cannot implement trait on type alias impl trait
 fn main() {}
diff --git a/src/test/ui/traits/alias/issue-83613.stderr b/src/test/ui/traits/alias/issue-83613.stderr
index 6a3498a3893..4f19e6607c8 100644
--- a/src/test/ui/traits/alias/issue-83613.stderr
+++ b/src/test/ui/traits/alias/issue-83613.stderr
@@ -10,13 +10,13 @@ note: type alias impl trait defined here
 LL | type OpaqueType = impl OpaqueTrait;
    |                   ^^^^^^^^^^^^^^^^
 
-error[E0119]: conflicting implementations of trait `AnotherTrait` for type `impl OpaqueTrait`
+error[E0119]: conflicting implementations of trait `AnotherTrait` for type `OpaqueType`
   --> $DIR/issue-83613.rs:10:1
    |
 LL | impl<T: Send> AnotherTrait for T {}
    | -------------------------------- first implementation here
 LL | impl AnotherTrait for OpaqueType {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `impl OpaqueTrait`
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `OpaqueType`
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/type-alias-impl-trait/auto-trait-leakage2.stderr b/src/test/ui/type-alias-impl-trait/auto-trait-leakage2.stderr
index 4a49d6e4ab8..0664275b2ad 100644
--- a/src/test/ui/type-alias-impl-trait/auto-trait-leakage2.stderr
+++ b/src/test/ui/type-alias-impl-trait/auto-trait-leakage2.stderr
@@ -2,15 +2,15 @@ error[E0277]: `Rc<u32>` cannot be sent between threads safely
   --> $DIR/auto-trait-leakage2.rs:17:13
    |
 LL |     type Foo = impl std::fmt::Debug;
-   |                -------------------- within this `impl Debug`
+   |                -------------------- within this `Foo`
 ...
 LL |     is_send(m::foo());
    |     ------- ^^^^^^^^ `Rc<u32>` cannot be sent between threads safely
    |     |
    |     required by a bound introduced by this call
    |
-   = help: within `impl Debug`, the trait `Send` is not implemented for `Rc<u32>`
-   = note: required because it appears within the type `impl Debug`
+   = help: within `Foo`, the trait `Send` is not implemented for `Rc<u32>`
+   = note: required because it appears within the type `Foo`
 note: required by a bound in `is_send`
   --> $DIR/auto-trait-leakage2.rs:14:15
    |
diff --git a/src/test/ui/type-alias-impl-trait/declared_but_not_defined_in_scope.stderr b/src/test/ui/type-alias-impl-trait/declared_but_not_defined_in_scope.stderr
index d61561d3ea9..26308c6ff6b 100644
--- a/src/test/ui/type-alias-impl-trait/declared_but_not_defined_in_scope.stderr
+++ b/src/test/ui/type-alias-impl-trait/declared_but_not_defined_in_scope.stderr
@@ -15,7 +15,7 @@ LL |     pub type Boo = impl ::std::fmt::Debug;
 LL |     ""
    |     ^^ expected opaque type, found `&str`
    |
-   = note: expected opaque type `impl Debug`
+   = note: expected opaque type `Boo`
                 found reference `&str`
 
 error: aborting due to 2 previous errors
diff --git a/src/test/ui/type-alias-impl-trait/issue-63279.stderr b/src/test/ui/type-alias-impl-trait/issue-63279.stderr
index 950d9bbf245..4b7dbbd6a56 100644
--- a/src/test/ui/type-alias-impl-trait/issue-63279.stderr
+++ b/src/test/ui/type-alias-impl-trait/issue-63279.stderr
@@ -25,7 +25,7 @@ LL | type Closure = impl FnOnce();
 LL |     || -> Closure { || () }
    |     ^^^^^^^^^^^^^^^^^^^^^^^ expected `()`, found closure
    |
-   = note: expected opaque type `impl FnOnce()`
+   = note: expected opaque type `Closure`
                   found closure `[closure@$DIR/issue-63279.rs:8:5: 8:28]`
 
 error: aborting due to 3 previous errors
diff --git a/src/test/ui/type-alias-impl-trait/issue-74280.stderr b/src/test/ui/type-alias-impl-trait/issue-74280.stderr
index c11585db077..38591e37f53 100644
--- a/src/test/ui/type-alias-impl-trait/issue-74280.stderr
+++ b/src/test/ui/type-alias-impl-trait/issue-74280.stderr
@@ -7,7 +7,7 @@ LL | type Test = impl Copy;
 LL |     7
    |     ^ expected `()`, found integer
    |
-   = note: expected opaque type `impl Copy`
+   = note: expected opaque type `Test`
                      found type `{integer}`
 
 error: aborting due to previous error
diff --git a/src/test/ui/type-alias-impl-trait/issue-77179.stderr b/src/test/ui/type-alias-impl-trait/issue-77179.stderr
index 9e742a25500..053546e4b92 100644
--- a/src/test/ui/type-alias-impl-trait/issue-77179.stderr
+++ b/src/test/ui/type-alias-impl-trait/issue-77179.stderr
@@ -5,7 +5,7 @@ LL | fn test() -> Pointer<_> {
    |              --------^-
    |              |       |
    |              |       not allowed in type signatures
-   |              help: replace with the correct return type: `impl Deref<Target = i32>`
+   |              help: replace with the correct return type: `Pointer<i32>`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/type-alias-impl-trait/multiple-def-uses-in-one-fn3.stderr b/src/test/ui/type-alias-impl-trait/multiple-def-uses-in-one-fn3.stderr
index 20da37ec9a1..db4b60461ef 100644
--- a/src/test/ui/type-alias-impl-trait/multiple-def-uses-in-one-fn3.stderr
+++ b/src/test/ui/type-alias-impl-trait/multiple-def-uses-in-one-fn3.stderr
@@ -11,7 +11,7 @@ LL | fn g<A: ToString + Clone, B: ToString + Clone>(a: A, b: B) -> (X<A, B>, X<A
 LL |     (a, b)
    |         ^ expected type parameter `A`, found type parameter `B`
    |
-   = note: expected opaque type `impl ToString`
+   = note: expected opaque type `X<A, B>`
            found type parameter `B`
    = note: a type parameter was expected, but a different one was found; you might be missing a type parameter or trait bound
    = note: for more information, visit https://doc.rust-lang.org/book/ch10-02-traits.html#traits-as-parameters
diff --git a/src/test/ui/type-alias-impl-trait/nested-tait-inference.rs b/src/test/ui/type-alias-impl-trait/nested-tait-inference.rs
index d51c4185fbc..784a6c75886 100644
--- a/src/test/ui/type-alias-impl-trait/nested-tait-inference.rs
+++ b/src/test/ui/type-alias-impl-trait/nested-tait-inference.rs
@@ -12,7 +12,7 @@ impl Foo<()> for () { }
 fn foo() -> impl Foo<FooX> {
     // FIXME(type-alias-impl-trait): We could probably make this work.
     ()
-    //~^ ERROR: the trait bound `(): Foo<impl Debug>` is not satisfied
+    //~^ ERROR: the trait bound `(): Foo<FooX>` is not satisfied
 }
 
 fn main() { }
diff --git a/src/test/ui/type-alias-impl-trait/nested-tait-inference.stderr b/src/test/ui/type-alias-impl-trait/nested-tait-inference.stderr
index 630328afc52..9472cac6355 100644
--- a/src/test/ui/type-alias-impl-trait/nested-tait-inference.stderr
+++ b/src/test/ui/type-alias-impl-trait/nested-tait-inference.stderr
@@ -1,8 +1,8 @@
-error[E0277]: the trait bound `(): Foo<impl Debug>` is not satisfied
+error[E0277]: the trait bound `(): Foo<FooX>` is not satisfied
   --> $DIR/nested-tait-inference.rs:14:5
    |
 LL |     ()
-   |     ^^ the trait `Foo<impl Debug>` is not implemented for `()`
+   |     ^^ the trait `Foo<FooX>` is not implemented for `()`
    |
    = help: the following implementations were found:
              <() as Foo<()>>
diff --git a/src/test/ui/type-alias-impl-trait/nested-tait-inference2.rs b/src/test/ui/type-alias-impl-trait/nested-tait-inference2.rs
index 00d835d3ca7..00bd44c493c 100644
--- a/src/test/ui/type-alias-impl-trait/nested-tait-inference2.rs
+++ b/src/test/ui/type-alias-impl-trait/nested-tait-inference2.rs
@@ -12,7 +12,7 @@ impl Foo<u32> for () {}
 
 fn foo() -> impl Foo<FooX> {
     ()
-    //~^ ERROR: the trait bound `(): Foo<impl Debug>` is not satisfied
+    //~^ ERROR: the trait bound `(): Foo<FooX>` is not satisfied
 }
 
 fn main() {}
diff --git a/src/test/ui/type-alias-impl-trait/nested-tait-inference2.stderr b/src/test/ui/type-alias-impl-trait/nested-tait-inference2.stderr
index 1b04ea2bf16..ec1b4642d08 100644
--- a/src/test/ui/type-alias-impl-trait/nested-tait-inference2.stderr
+++ b/src/test/ui/type-alias-impl-trait/nested-tait-inference2.stderr
@@ -1,8 +1,8 @@
-error[E0277]: the trait bound `(): Foo<impl Debug>` is not satisfied
+error[E0277]: the trait bound `(): Foo<FooX>` is not satisfied
   --> $DIR/nested-tait-inference2.rs:14:5
    |
 LL |     ()
-   |     ^^ the trait `Foo<impl Debug>` is not implemented for `()`
+   |     ^^ the trait `Foo<FooX>` is not implemented for `()`
    |
    = help: the following implementations were found:
              <() as Foo<()>>
diff --git a/src/test/ui/type-alias-impl-trait/nested.rs b/src/test/ui/type-alias-impl-trait/nested.rs
index e55fe3a3aaf..6b866be7d17 100644
--- a/src/test/ui/type-alias-impl-trait/nested.rs
+++ b/src/test/ui/type-alias-impl-trait/nested.rs
@@ -13,5 +13,5 @@ fn bar() -> Bar {
 
 fn main() {
     println!("{:?}", bar());
-    //~^ ERROR `impl Trait<impl Debug>` doesn't implement `Debug`
+    //~^ ERROR `Bar` doesn't implement `Debug`
 }
diff --git a/src/test/ui/type-alias-impl-trait/nested.stderr b/src/test/ui/type-alias-impl-trait/nested.stderr
index eff56e3b76d..cf4d23656e0 100644
--- a/src/test/ui/type-alias-impl-trait/nested.stderr
+++ b/src/test/ui/type-alias-impl-trait/nested.stderr
@@ -1,10 +1,10 @@
-error[E0277]: `impl Trait<impl Debug>` doesn't implement `Debug`
+error[E0277]: `Bar` doesn't implement `Debug`
   --> $DIR/nested.rs:15:22
    |
 LL |     println!("{:?}", bar());
-   |                      ^^^^^ `impl Trait<impl Debug>` cannot be formatted using `{:?}` because it doesn't implement `Debug`
+   |                      ^^^^^ `Bar` cannot be formatted using `{:?}` because it doesn't implement `Debug`
    |
-   = help: the trait `Debug` is not implemented for `impl Trait<impl Debug>`
+   = help: the trait `Debug` is not implemented for `Bar`
    = note: this error originates in the macro `$crate::format_args_nl` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: aborting due to previous error
diff --git a/src/test/ui/type-alias-impl-trait/no_revealing_outside_defining_module.stderr b/src/test/ui/type-alias-impl-trait/no_revealing_outside_defining_module.stderr
index d12160a9793..e691d8781c0 100644
--- a/src/test/ui/type-alias-impl-trait/no_revealing_outside_defining_module.stderr
+++ b/src/test/ui/type-alias-impl-trait/no_revealing_outside_defining_module.stderr
@@ -8,7 +8,7 @@ LL |     let _: &str = bomp();
    |                   ^^^^^^ expected `&str`, found opaque type
    |
    = note: expected reference `&str`
-            found opaque type `impl Debug`
+            found opaque type `Boo`
 
 error[E0308]: mismatched types
   --> $DIR/no_revealing_outside_defining_module.rs:19:5
@@ -19,7 +19,7 @@ LL |     pub type Boo = impl ::std::fmt::Debug;
 LL |     ""
    |     ^^ expected opaque type, found `&str`
    |
-   = note: expected opaque type `impl Debug`
+   = note: expected opaque type `Boo`
                 found reference `&str`
 
 error: aborting due to 2 previous errors
diff --git a/src/test/ui/type-alias-impl-trait/self-referential-2.rs b/src/test/ui/type-alias-impl-trait/self-referential-2.rs
index e9ace992c8b..dc7054da5ec 100644
--- a/src/test/ui/type-alias-impl-trait/self-referential-2.rs
+++ b/src/test/ui/type-alias-impl-trait/self-referential-2.rs
@@ -4,7 +4,7 @@ type Foo = impl std::fmt::Debug;
 type Bar = impl PartialEq<Foo>;
 
 fn bar() -> Bar {
-    42_i32 //~ ERROR can't compare `i32` with `impl Debug`
+    42_i32 //~ ERROR can't compare `i32` with `Foo`
 }
 
 fn main() {}
diff --git a/src/test/ui/type-alias-impl-trait/self-referential-2.stderr b/src/test/ui/type-alias-impl-trait/self-referential-2.stderr
index 2c3630dc394..6997676260d 100644
--- a/src/test/ui/type-alias-impl-trait/self-referential-2.stderr
+++ b/src/test/ui/type-alias-impl-trait/self-referential-2.stderr
@@ -1,10 +1,10 @@
-error[E0277]: can't compare `i32` with `impl Debug`
+error[E0277]: can't compare `i32` with `Foo`
   --> $DIR/self-referential-2.rs:7:5
    |
 LL |     42_i32
-   |     ^^^^^^ no implementation for `i32 == impl Debug`
+   |     ^^^^^^ no implementation for `i32 == Foo`
    |
-   = help: the trait `PartialEq<impl Debug>` is not implemented for `i32`
+   = help: the trait `PartialEq<Foo>` is not implemented for `i32`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/type-alias-impl-trait/self-referential-4.rs b/src/test/ui/type-alias-impl-trait/self-referential-4.rs
new file mode 100644
index 00000000000..697ec56825a
--- /dev/null
+++ b/src/test/ui/type-alias-impl-trait/self-referential-4.rs
@@ -0,0 +1,25 @@
+#![feature(type_alias_impl_trait)]
+
+type Bar<'a, 'b> = impl PartialEq<Bar<'b, 'static>> + std::fmt::Debug;
+
+fn bar<'a, 'b>(i: &'a i32) -> Bar<'a, 'b> {
+    i //~ ERROR can't compare `&i32` with `Bar<'b, 'static>`
+}
+
+type Foo<'a, 'b> = impl PartialEq<Foo<'static, 'b>> + std::fmt::Debug;
+
+fn foo<'a, 'b>(i: &'a i32) -> Foo<'a, 'b> {
+    i //~ ERROR can't compare `&i32` with `Foo<'static, 'b>`
+}
+
+type Moo<'a, 'b> = impl PartialEq<Moo<'static, 'a>> + std::fmt::Debug;
+
+fn moo<'a, 'b>(i: &'a i32) -> Moo<'a, 'b> {
+    i //~ ERROR can't compare `&i32` with `Moo<'static, 'a>`
+}
+
+fn main() {
+    let meh = 42;
+    let muh = 69;
+    assert_eq!(bar(&meh), bar(&meh));
+}
diff --git a/src/test/ui/type-alias-impl-trait/self-referential-4.stderr b/src/test/ui/type-alias-impl-trait/self-referential-4.stderr
new file mode 100644
index 00000000000..4a6ee2f9279
--- /dev/null
+++ b/src/test/ui/type-alias-impl-trait/self-referential-4.stderr
@@ -0,0 +1,27 @@
+error[E0277]: can't compare `&i32` with `Bar<'b, 'static>`
+  --> $DIR/self-referential-4.rs:6:5
+   |
+LL |     i
+   |     ^ no implementation for `&i32 == Bar<'b, 'static>`
+   |
+   = help: the trait `PartialEq<Bar<'b, 'static>>` is not implemented for `&i32`
+
+error[E0277]: can't compare `&i32` with `Foo<'static, 'b>`
+  --> $DIR/self-referential-4.rs:12:5
+   |
+LL |     i
+   |     ^ no implementation for `&i32 == Foo<'static, 'b>`
+   |
+   = help: the trait `PartialEq<Foo<'static, 'b>>` is not implemented for `&i32`
+
+error[E0277]: can't compare `&i32` with `Moo<'static, 'a>`
+  --> $DIR/self-referential-4.rs:18:5
+   |
+LL |     i
+   |     ^ no implementation for `&i32 == Moo<'static, 'a>`
+   |
+   = help: the trait `PartialEq<Moo<'static, 'a>>` is not implemented for `&i32`
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/type-alias-impl-trait/self-referential.rs b/src/test/ui/type-alias-impl-trait/self-referential.rs
index 46468bc98b9..4974ac72dad 100644
--- a/src/test/ui/type-alias-impl-trait/self-referential.rs
+++ b/src/test/ui/type-alias-impl-trait/self-referential.rs
@@ -3,7 +3,19 @@
 type Bar<'a, 'b> = impl PartialEq<Bar<'b, 'a>> + std::fmt::Debug;
 
 fn bar<'a, 'b>(i: &'a i32) -> Bar<'a, 'b> {
-    i //~ ERROR can't compare `&i32` with `impl PartialEq<Bar<'a, 'b>
+    i //~ ERROR can't compare `&i32` with `Bar<'b, 'a>`
+}
+
+type Foo<'a, 'b> = (i32, impl PartialEq<Foo<'a, 'b>> + std::fmt::Debug);
+
+fn foo<'a, 'b>(i: &'a i32) -> Foo<'a, 'b> {
+    (42, i) //~ ERROR can't compare `&i32` with `(i32, &i32)`
+}
+
+type Moo<'a, 'b> = (i32, impl PartialEq<Moo<'b, 'a>> + std::fmt::Debug);
+
+fn moo<'a, 'b>(i: &'a i32) -> Moo<'a, 'b> {
+    (42, i) //~ ERROR can't compare `&i32` with `(i32, Moo<'b, 'a>::{opaque#0})`
 }
 
 fn main() {
diff --git a/src/test/ui/type-alias-impl-trait/self-referential.stderr b/src/test/ui/type-alias-impl-trait/self-referential.stderr
index 29f1e0bec08..0626e6be0d5 100644
--- a/src/test/ui/type-alias-impl-trait/self-referential.stderr
+++ b/src/test/ui/type-alias-impl-trait/self-referential.stderr
@@ -1,11 +1,27 @@
-error[E0277]: can't compare `&i32` with `impl PartialEq<Bar<'a, 'b>::{opaque#0}> + Debug`
+error[E0277]: can't compare `&i32` with `Bar<'b, 'a>`
   --> $DIR/self-referential.rs:6:5
    |
 LL |     i
-   |     ^ no implementation for `&i32 == impl PartialEq<Bar<'a, 'b>::{opaque#0}> + Debug`
+   |     ^ no implementation for `&i32 == Bar<'b, 'a>`
    |
-   = help: the trait `PartialEq<impl PartialEq<Bar<'a, 'b>::{opaque#0}> + Debug>` is not implemented for `&i32`
+   = help: the trait `PartialEq<Bar<'b, 'a>>` is not implemented for `&i32`
 
-error: aborting due to previous error
+error[E0277]: can't compare `&i32` with `(i32, &i32)`
+  --> $DIR/self-referential.rs:12:10
+   |
+LL |     (42, i)
+   |          ^ no implementation for `&i32 == (i32, &i32)`
+   |
+   = help: the trait `PartialEq<(i32, &i32)>` is not implemented for `&i32`
+
+error[E0277]: can't compare `&i32` with `(i32, Moo<'b, 'a>::{opaque#0})`
+  --> $DIR/self-referential.rs:18:10
+   |
+LL |     (42, i)
+   |          ^ no implementation for `&i32 == (i32, Moo<'b, 'a>::{opaque#0})`
+   |
+   = help: the trait `PartialEq<(i32, Moo<'b, 'a>::{opaque#0})>` is not implemented for `&i32`
+
+error: aborting due to 3 previous errors
 
 For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/type-alias-impl-trait/structural-match-no-leak.rs b/src/test/ui/type-alias-impl-trait/structural-match-no-leak.rs
index e0d24146179..cab742d23f5 100644
--- a/src/test/ui/type-alias-impl-trait/structural-match-no-leak.rs
+++ b/src/test/ui/type-alias-impl-trait/structural-match-no-leak.rs
@@ -13,7 +13,7 @@ const LEAK_FREE: Bar = leak_free();
 fn leak_free_test() {
     match LEAK_FREE {
         LEAK_FREE => (),
-        //~^ `impl Send` cannot be used in patterns
+        //~^ `Bar` cannot be used in patterns
         _ => (),
     }
 }
diff --git a/src/test/ui/type-alias-impl-trait/structural-match-no-leak.stderr b/src/test/ui/type-alias-impl-trait/structural-match-no-leak.stderr
index 7e41b374452..aacc0cc7aa6 100644
--- a/src/test/ui/type-alias-impl-trait/structural-match-no-leak.stderr
+++ b/src/test/ui/type-alias-impl-trait/structural-match-no-leak.stderr
@@ -1,4 +1,4 @@
-error: `impl Send` cannot be used in patterns
+error: `Bar` cannot be used in patterns
   --> $DIR/structural-match-no-leak.rs:15:9
    |
 LL |         LEAK_FREE => (),
diff --git a/src/test/ui/type-alias-impl-trait/structural-match.rs b/src/test/ui/type-alias-impl-trait/structural-match.rs
index 1a2c373bac1..c8825c68e33 100644
--- a/src/test/ui/type-alias-impl-trait/structural-match.rs
+++ b/src/test/ui/type-alias-impl-trait/structural-match.rs
@@ -14,7 +14,7 @@ const VALUE: Foo = value();
 fn test() {
     match VALUE {
         VALUE => (),
-        //~^ `impl Send` cannot be used in patterns
+        //~^ `Foo` cannot be used in patterns
         _ => (),
     }
 }
diff --git a/src/test/ui/type-alias-impl-trait/structural-match.stderr b/src/test/ui/type-alias-impl-trait/structural-match.stderr
index b43f2148dea..28ae9c212d9 100644
--- a/src/test/ui/type-alias-impl-trait/structural-match.stderr
+++ b/src/test/ui/type-alias-impl-trait/structural-match.stderr
@@ -1,4 +1,4 @@
-error: `impl Send` cannot be used in patterns
+error: `Foo` cannot be used in patterns
   --> $DIR/structural-match.rs:16:9
    |
 LL |         VALUE => (),
diff --git a/src/test/ui/type-alias-impl-trait/type_of_a_let.stderr b/src/test/ui/type-alias-impl-trait/type_of_a_let.stderr
index eccd3f9048f..1dabe4586c5 100644
--- a/src/test/ui/type-alias-impl-trait/type_of_a_let.stderr
+++ b/src/test/ui/type-alias-impl-trait/type_of_a_let.stderr
@@ -2,7 +2,7 @@ error[E0382]: use of moved value: `x`
   --> $DIR/type_of_a_let.rs:16:16
    |
 LL |     let x: Foo = 22_u32;
-   |         - move occurs because `x` has type `impl Debug`, which does not implement the `Copy` trait
+   |         - move occurs because `x` has type `Foo`, which does not implement the `Copy` trait
 LL |     let y: Foo = x;
    |                  - value moved here
 LL |     same_type((x, y));
@@ -12,7 +12,7 @@ error[E0382]: use of moved value: `y`
   --> $DIR/type_of_a_let.rs:17:5
    |
 LL |     let y: Foo = x;
-   |         - move occurs because `y` has type `impl Debug`, which does not implement the `Copy` trait
+   |         - move occurs because `y` has type `Foo`, which does not implement the `Copy` trait
 LL |     same_type((x, y));
    |                   - value moved here
 LL |     y