Add test

src/test/ui/type/closure-with-wrong-borrows.rs

@@ -0,0 +1,10 @@
+struct S<'a>(&'a str);
+
+fn f(inner: fn(&str, &S)) {
+}
+
+#[allow(unreachable_code)]
+fn main() {
+    let inner: fn(_, _) = unimplemented!();
+    f(inner); //~ ERROR mismatched types
+}

src/test/ui/type/closure-with-wrong-borrows.stderr

@@ -0,0 +1,23 @@
+error[E0308]: mismatched types
+  --> $DIR/closure-with-wrong-borrows.rs:9:7
+   |
+LL |     f(inner);
+   |     - ^^^^^ one type is more general than the other
+   |     |
+   |     arguments to this function are incorrect
+   |
+   = note: expected fn pointer `for<'a, 'b, 'c> fn(&'a str, &'b S<'c>)`
+              found fn pointer `fn(_, _)`
+note: function defined here
+  --> $DIR/closure-with-wrong-borrows.rs:3:4
+   |
+LL | fn f(inner: fn(&str, &S)) {
+   |    ^ -------------------
+help: consider removing the ``
+   |
+LL |     f(inner);
+   |
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.