diff --git a/src/stage1/parser.cpp b/src/stage1/parser.cpp
index d57277cd5136..f152f245b756 100644
--- a/src/stage1/parser.cpp
+++ b/src/stage1/parser.cpp
@@ -825,7 +825,16 @@ static AstNode *ast_parse_fn_proto(ParseContext *pc) {
     AstNode *return_type = nullptr;
     if (anytype == nullptr) {
         exmark = eat_token_if(pc, TokenIdBang);
-        return_type = ast_expect(pc, ast_parse_type_expr);
+        return_type = ast_parse_type_expr(pc);
+        if (return_type == nullptr) {
+            Token *next = peek_token(pc);
+            ast_error(
+                pc,
+                next,
+                "expected return type (use 'void' to return nothing), found: '%s'",
+                token_name(next->id)
+            );
+        }
     }
 
     AstNode *res = ast_create_node(pc, NodeTypeFnProto, first);