Prohibit raw vaargs in regular functions with a function body.

releasenotes.md

@@ -48,6 +48,7 @@
 - Assert on add to uninitialized ct variable #1765.
 - Dynamic function lookup fails after changing type without dummy anycast #1761
 - $vasplat was allowed inside of a function when passed as an argument to a function.
+- Prohibit raw vaargs in regular functions with a function body.
 
 ### Stdlib changes
 - Increase BitWriter.write_bits limit up to 32 bits.

src/compiler/sema_stmts.c

@@ -3161,6 +3161,12 @@ bool sema_analyse_function_body(SemaContext *context, Decl *func)
 	if (!decl_ok(func)) return false;
 
 	Signature *signature = &func->func_decl.signature;
+	if (signature->variadic == VARIADIC_RAW)
+	{
+		RETURN_SEMA_ERROR(func, "C-style variadic arguments '...' are not supported for regular functions,"
+						  " please use typed vaargs on the form 'int... args' or "
+						  "untyped vaargs on the form 'args...' instead.");
+	}
 	FunctionPrototype *prototype = func->type->function.prototype;
 	ASSERT0(prototype);
 	context->original_inline_line = 0;

test/test_suite/functions/vaarg_raw.c3

@@ -0,0 +1,8 @@
+import std;
+
+fn void main()
+{}
+
+fn void bohoo(...) // #error: C-style variadic arguments
+{
+}

test/test_suite/macros/vasplat_function_call.c3

@@ -1,7 +1,7 @@
 import std;
 
 def IList = List(<int>);
-fn IList IList.new(...) @operator(construct)
+fn IList IList.new() @operator(construct)
 {
   IList l;
   l.new_init($vasplat); // #error: can only be used inside