From 65fb977e8934e9ecc8ce789120ec9573b5dd9332 Mon Sep 17 00:00:00 2001
From: Christoffer Lerno <christoffer@aegik.com>
Date: Fri, 4 Apr 2025 13:21:53 +0200
Subject: [PATCH] Clearer errors when using a &ref parameter with type.

---
 src/compiler/parse_global.c               | 5 -----
 src/compiler/sema_decls.c                 | 9 +++++++++
 test/test_suite/functions/ref_param_fn.c3 | 9 +++++++++
 3 files changed, 18 insertions(+), 5 deletions(-)
 create mode 100644 test/test_suite/functions/ref_param_fn.c3

diff --git a/src/compiler/parse_global.c b/src/compiler/parse_global.c
index 84e876e95..833b021e3 100644
--- a/src/compiler/parse_global.c
+++ b/src/compiler/parse_global.c
@@ -1443,11 +1443,6 @@ bool parse_parameters(ParseContext *c, Decl ***params_ref, Variadic *variadic, i
 					PRINT_ERROR_LAST("'&foo' parameters may not be followed by '...’");
 					return false;
 				}
-				if (type)
-				{
-					PRINT_ERROR_LAST("'&foo' should be untyped.");
-					return false;
-				}
 
 				// Span includes the "&"
 				span = extend_span_with_token(span, c->span);
diff --git a/src/compiler/sema_decls.c b/src/compiler/sema_decls.c
index f8c102605..432bb6090 100755
--- a/src/compiler/sema_decls.c
+++ b/src/compiler/sema_decls.c
@@ -1145,6 +1145,15 @@ static inline bool sema_analyse_signature(SemaContext *context, Signature *sig,
 		if (!sema_resolve_type_info(context, method_parent,
 		                            is_macro ? RESOLVE_TYPE_MACRO_METHOD : RESOLVE_TYPE_FUNC_METHOD)) return false;
 	}
+
+	if (params && params[0] && params[0]->var.self_addr && params[0]->var.type_info)
+	{
+		if (method_parent)
+		{
+			RETURN_SEMA_ERROR(type_infoptr(params[0]->var.type_info), "A ref parameter should always be untyped, please remove the type here.");
+		}
+		RETURN_SEMA_ERROR(params[0], "Ref parameters are only allowed on methods.");
+	}
 	// Fill in the type if the first parameter is lacking a type.
 	if (method_parent && params && params[0] && !params[0]->var.type_info)
 	{
diff --git a/test/test_suite/functions/ref_param_fn.c3 b/test/test_suite/functions/ref_param_fn.c3
new file mode 100644
index 000000000..42abd554e
--- /dev/null
+++ b/test/test_suite/functions/ref_param_fn.c3
@@ -0,0 +1,9 @@
+fn String str(int& element) // #error: A ref parameter should always be untyped
+{
+	return "abc";
+}
+
+fn String int.str(int& element) // #error: Ref parameters are only allowed on methods
+{
+	return "abc";
+}