From fde0d9fa91cfaffd656ae69bd626aa854d8b9501 Mon Sep 17 00:00:00 2001
From: yuyi <yuyi98@163.com>
Date: Thu, 27 Jul 2023 17:36:44 +0800
Subject: [PATCH] checker: fix compiling 'f(g()!)' with -autofree (#18979)

---
 vlib/v/checker/fn.v                             |  7 +++++--
 vlib/v/slow_tests/valgrind/fn_call_result_arg.v | 11 +++++++++++
 2 files changed, 16 insertions(+), 2 deletions(-)
 create mode 100644 vlib/v/slow_tests/valgrind/fn_call_result_arg.v

diff --git a/vlib/v/checker/fn.v b/vlib/v/checker/fn.v
index 70b36976bdbb54..874559339e9934 100644
--- a/vlib/v/checker/fn.v
+++ b/vlib/v/checker/fn.v
@@ -507,8 +507,11 @@ fn (mut c Checker) call_expr(mut node ast.CallExpr) ast.Type {
 	c.inside_fn_arg = old_inside_fn_arg
 	// autofree: mark args that have to be freed (after saving them in tmp exprs)
 	free_tmp_arg_vars := c.pref.autofree && !c.is_builtin_mod && node.args.len > 0
-		&& !node.args[0].typ.has_flag(.option) && !node.args[0].typ.has_flag(.result)
-	if free_tmp_arg_vars && !c.inside_const {
+		&& !c.inside_const && !node.args[0].typ.has_flag(.option)
+		&& !node.args[0].typ.has_flag(.result) && !(node.args[0].expr is ast.CallExpr
+		&& (node.args[0].expr.return_type.has_flag(.option)
+		|| node.args[0].expr.return_type.has_flag(.result)))
+	if free_tmp_arg_vars {
 		for i, arg in node.args {
 			if arg.typ != ast.string_type {
 				continue
diff --git a/vlib/v/slow_tests/valgrind/fn_call_result_arg.v b/vlib/v/slow_tests/valgrind/fn_call_result_arg.v
new file mode 100644
index 00000000000000..971a8ae58a496c
--- /dev/null
+++ b/vlib/v/slow_tests/valgrind/fn_call_result_arg.v
@@ -0,0 +1,11 @@
+fn f() !string {
+	return 'abc'
+}
+
+fn g(s string) {
+	println(s)
+}
+
+fn main() {
+	g(f()!)
+}