diff --git a/src/main/wacc/parser.scala b/src/main/wacc/parser.scala
index 8098e84..5403060 100644
--- a/src/main/wacc/parser.scala
+++ b/src/main/wacc/parser.scala
@@ -119,7 +119,7 @@ object parser {
     "begin" ~> many(
       atomic(`<type>`.label("function declaration") <~> `<ident>` <~ "(") <**> `<partial-func-decl>`
     ).label("function declaration"),
-    (atomic(`<ident>` <~ "(") ~> fail("function is missing return type") | `<stmt>`.label(
+    (atomic(`<ident>` <~ "(").verifiedExplain("function is missing return type") | `<stmt>`.label(
       "main program body"
     )) <~ "end"
   )