4 files changed, 28 insertions, 7 deletions
diff --git a/tests/ui/generics/issue-79605.rs b/tests/ui/generics/issue-79605.rs
new file mode 100644
index 000000000..6f4c31e57
--- /dev/null
+++ b/tests/ui/generics/issue-79605.rs
@@ -0,0 +1,6 @@
+struct X<'a, T>(&'a T);
+
+impl X<'_, _> {}
+//~^ ERROR the placeholder `_` is not allowed within types on item signatures for implementations
+
+fn main() {}
diff --git a/tests/ui/generics/issue-79605.stderr b/tests/ui/generics/issue-79605.stderr
new file mode 100644
index 000000000..c5584962d
--- /dev/null
+++ b/tests/ui/generics/issue-79605.stderr
@@ -0,0 +1,14 @@
+error[E0121]: the placeholder `_` is not allowed within types on item signatures for implementations
+  --> $DIR/issue-79605.rs:3:12
+   |
+LL | impl X<'_, _> {}
+   |            ^ not allowed in type signatures
+   |
+help: use type parameters instead
+   |
+LL | impl<T> X<'_, T> {}
+   |     +++       ~
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0121`.
diff --git a/tests/ui/generics/single-colon-path-not-const-generics.rs b/tests/ui/generics/single-colon-path-not-const-generics.rs
index 55a7ae0bb..dff00b0b7 100644
--- a/tests/ui/generics/single-colon-path-not-const-generics.rs
+++ b/tests/ui/generics/single-colon-path-not-const-generics.rs
@@ -6,8 +6,8 @@ pub mod foo {
 
 pub struct Foo {
   a: Vec<foo::bar:A>,
-  //~^ ERROR expected
-  //~| HELP path separator
+  //~^ ERROR path separator must be a double colon
+  //~| HELP use a double colon instead
 }
 
 fn main() {}
diff --git a/tests/ui/generics/single-colon-path-not-const-generics.stderr b/tests/ui/generics/single-colon-path-not-const-generics.stderr
index 3eafa9fa5..96f07e190 100644
--- a/tests/ui/generics/single-colon-path-not-const-generics.stderr
+++ b/tests/ui/generics/single-colon-path-not-const-generics.stderr
@@ -1,11 +1,12 @@
-error: expected one of `,` or `>`, found `:`
+error: path separator must be a double colon
   --> $DIR/single-colon-path-not-const-generics.rs:8:18
    |
+LL | pub struct Foo {
+   |            --- while parsing this struct
 LL |   a: Vec<foo::bar:A>,
-   |                  ^
-   |                  |
-   |                  expected one of `,` or `>`
-   |                  help: write a path separator here: `::`
+   |                  ^ help: use a double colon instead: `::`
+   |
+   = note: if you meant to annotate an expression with a type, the type ascription syntax has been removed, see issue #101728 <https://github.com/rust-lang/rust/issues/101728>
 
 error: aborting due to previous error