Skip recording resolution for duplicated generic params.

compiler/rustc_resolve/src/late.rs

@@ -2360,8 +2360,8 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
                     if let GenericParamKind::Lifetime = param.kind {
                         // Record lifetime res, so lowering knows there is something fishy.
                         self.record_lifetime_param(param.id, LifetimeRes::Error);
-                        continue;
                     }
+                    continue;
                 }
                 Entry::Vacant(entry) => {
                     entry.insert(param.ident.span);

src/test/ui/const-generics/defaults/self-referential.rs

@@ -0,0 +1,4 @@
+trait Foo<const M: u8, const M: u8 = M> {}
+//~^ ERROR the name `M` is already used for a generic parameter in this item's generic parameters
+impl Foo<2> for () {}
+fn main() {}

src/test/ui/const-generics/defaults/self-referential.stderr

@@ -0,0 +1,11 @@
+error[E0403]: the name `M` is already used for a generic parameter in this item's generic parameters
+  --> $DIR/self-referential.rs:1:30
+   |
+LL | trait Foo<const M: u8, const M: u8 = M> {}
+   |                 -            ^ already used
+   |                 |
+   |                 first use of `M`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0403`.

src/test/ui/duplicate/duplicate-type-parameter.stderr

@@ -55,10 +55,10 @@ LL | impl<T,T> Qux<T,T> for Option<T> {}
    |      first use of `T`
 
 error[E0207]: the type parameter `T` is not constrained by the impl trait, self type, or predicates
-  --> $DIR/duplicate-type-parameter.rs:24:6
+  --> $DIR/duplicate-type-parameter.rs:24:8
    |
 LL | impl<T,T> Qux<T,T> for Option<T> {}
-   |      ^ unconstrained type parameter
+   |        ^ unconstrained type parameter
 
 error: aborting due to 8 previous errors