late resolve, visit_fn: bail early if there's no body.

src/test/ui/resolve/issue-69401-trait-fn-no-body-ty-local.rs

@@ -0,0 +1,6 @@
+fn main() {}
+
+trait Foo {
+    fn fn_with_type_named_same_as_local_in_param(b: b);
+    //~^ ERROR cannot find type `b` in this scope
+}

src/test/ui/resolve/issue-69401-trait-fn-no-body-ty-local.stderr

@@ -0,0 +1,9 @@
+error[E0412]: cannot find type `b` in this scope
+  --> $DIR/issue-69401-trait-fn-no-body-ty-local.rs:4:53
+   |
+LL |     fn fn_with_type_named_same_as_local_in_param(b: b);
+   |                                                     ^ not found in this scope
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0412`.