Add testcase to showcase unused record field false positive

Summary:
The test case highlights the fact we don't expand macros when looking for record fields (among other things), as originally reported [here](#51).

This will be fixed later in the stack.

Reviewed By: michalmuskala, alanz

Differential Revision: D62128559

fbshipit-source-id: 43e9fa57b534ecbbb9357d12f91085a37b008993

crates/ide/src/diagnostics/unused_record_field.rs

@@ -149,4 +149,18 @@ main(#a{a1 = #b{b2 = B2}} = A) ->
         "#,
         );
     }
+
+    #[test]
+    fn test_unused_record_macro_name() {
+        // https://github.com/WhatsApp/erlang-language-platform/issues/51
+        check_diagnostics(
+            r#"
+-module(main).
+-export([ test/0 ]).
+-record(?MODULE, {queue :: term()}).
+               %% ^^^^^^^^^^^^^^^ warning: Unused record field ([missing name].queue)
+test() -> #?MODULE{queue = ok}.
+            "#,
+        );
+    }
 }