gen: add argument names to compile-time method struct (#9174)

vlib/builtin/builtin.v

@@ -88,7 +88,8 @@ fn __print_assert_failure(i &VAssertMetaInfo) {
 // MethodArgs holds type information for function and/or method arguments.
 pub struct MethodArgs {
 pub:
-	typ int
+	typ  int
+	name string
 }
 
 // FunctionData holds information about a parsed function.

vlib/v/gen/c/comptime.v

@@ -336,7 +336,7 @@ fn (mut g Gen) comp_for(node ast.CompFor) {
 				// Skip receiver arg
 				for j, arg in method.params[1..] {
 					typ := arg.typ.idx()
-					g.write(typ.str())
+					g.write('{$typ.str(), _SLIT("$arg.name")}')
 					if j < len - 1 {
 						g.write(', ')
 					}

vlib/v/tests/comptime_method_args_test.v

@@ -0,0 +1,14 @@
+struct TestStruct {}
+
+fn (t TestStruct) test(arg1 string, arg2 string, arg3 string) {}
+
+fn test_comptime_method_names() {
+	$for method in TestStruct.methods {
+		if method.name == 'test' {
+			args := method.args
+			assert args[0].name == 'arg1'
+			assert args[1].name == 'arg2'
+			assert args[2].name == 'arg3'
+		}
+	}
+}