Add function pointer types to syntax tree
diff --git a/syntax/check.rs b/syntax/check.rs
index ef3faff..be61226 100644
--- a/syntax/check.rs
+++ b/syntax/check.rs
@@ -167,6 +167,7 @@
         Type::UniquePtr(_) => "unique_ptr".to_owned(),
         Type::Ref(_) => "reference".to_owned(),
         Type::Str(_) => "&str".to_owned(),
+        Type::Fn(_) => "function pointer".to_owned(),
         Type::Void(_) => "()".to_owned(),
     }
 }