Don't suggest dyn as parameter to add

Author: compiler-errors

Diff for: compiler/rustc_resolve/src/late/diagnostics.rs

@@ -2065,7 +2065,11 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
         path: &[Segment],
     ) -> Option<(Span, &'static str, String, Applicability)> {
         let (ident, span) = match path {
-            [segment] if !segment.has_generic_args && segment.ident.name != kw::SelfUpper => {
+            [segment]
+                if !segment.has_generic_args
+                    && segment.ident.name != kw::SelfUpper
+                    && segment.ident.name != kw::Dyn =>
+            {
                 (segment.ident.to_string(), segment.ident.span)
             }
             _ => return None,

Diff for: src/tools/clippy/tests/ui/crashes/ice-6252.stderr

@@ -17,9 +17,12 @@ error[E0412]: cannot find type `VAL` in this scope
   --> $DIR/ice-6252.rs:10:63
    |
 LL | impl<N, M> TypeVal<usize> for Multiply<N, M> where N: TypeVal<VAL> {}
-   |          -                                                    ^^^ not found in this scope
-   |          |
-   |          help: you might be missing a type parameter: `, VAL`
+   |                                                               ^^^ not found in this scope
+   |
+help: you might be missing a type parameter
+   |
+LL | impl<N, M, VAL> TypeVal<usize> for Multiply<N, M> where N: TypeVal<VAL> {}
+   |          +++++
 
 error[E0046]: not all trait items implemented, missing: `VAL`
   --> $DIR/ice-6252.rs:10:1

Diff for: tests/ui/issues/issue-86756.stderr

@@ -11,11 +11,6 @@ error[E0412]: cannot find type `dyn` in this scope
    |
 LL |     eq::<dyn, Foo>
    |          ^^^ not found in this scope
-   |
-help: you might be missing a type parameter
-   |
-LL | fn eq<A, B, dyn>() {
-   |           +++++
 
 warning: trait objects without an explicit `dyn` are deprecated
   --> $DIR/issue-86756.rs:5:15

Diff for: tests/ui/parser/dyn-trait-compatibility.stderr

@@ -27,22 +27,12 @@ error[E0412]: cannot find type `dyn` in this scope
    |
 LL | type A2 = dyn<dyn, dyn>;
    |               ^^^ not found in this scope
-   |
-help: you might be missing a type parameter
-   |
-LL | type A2<dyn> = dyn<dyn, dyn>;
-   |        +++++
 
 error[E0412]: cannot find type `dyn` in this scope
   --> $DIR/dyn-trait-compatibility.rs:5:20
    |
 LL | type A2 = dyn<dyn, dyn>;
    |                    ^^^ not found in this scope
-   |
-help: you might be missing a type parameter
-   |
-LL | type A2<dyn> = dyn<dyn, dyn>;
-   |        +++++
 
 error[E0412]: cannot find type `dyn` in this scope
   --> $DIR/dyn-trait-compatibility.rs:9:11
@@ -55,11 +45,6 @@ error[E0412]: cannot find type `dyn` in this scope
    |
 LL | type A3 = dyn<<dyn as dyn>::dyn>;
    |                ^^^ not found in this scope
-   |
-help: you might be missing a type parameter
-   |
-LL | type A3<dyn> = dyn<<dyn as dyn>::dyn>;
-   |        +++++
 
 error: aborting due to 8 previous errors