From 80e09e2f910560a9944790ed73c3c23e9e0573a7 Mon Sep 17 00:00:00 2001
From: Felipe Pena <felipensp@gmail.com>
Date: Sun, 29 Sep 2024 02:02:38 -0300
Subject: [PATCH] checker: fix compiler panic, when calling an unknown function
 in `C.printf(c'%f\n', sin(2))` (fix #22343) (#22348)

---
 vlib/v/checker/fn.v                          | 2 +-
 vlib/v/checker/tests/unknown_fn_call_err.out | 6 ++++++
 vlib/v/checker/tests/unknown_fn_call_err.vv  | 5 +++++
 3 files changed, 12 insertions(+), 1 deletion(-)
 create mode 100644 vlib/v/checker/tests/unknown_fn_call_err.out
 create mode 100644 vlib/v/checker/tests/unknown_fn_call_err.vv

diff --git a/vlib/v/checker/fn.v b/vlib/v/checker/fn.v
index e224c3f2a..1b9108d16 100644
--- a/vlib/v/checker/fn.v
+++ b/vlib/v/checker/fn.v
@@ -1285,7 +1285,7 @@ fn (mut c Checker) fn_call(mut node ast.CallExpr, mut continue_check &bool) ast.
 				c.expected_type = expected_type
 			}
 			typ := if already_checked && mut call_arg.expr is ast.CallExpr {
-				call_arg.expr.return_type
+				node.args[i].typ
 			} else {
 				c.expr(mut call_arg.expr)
 			}
diff --git a/vlib/v/checker/tests/unknown_fn_call_err.out b/vlib/v/checker/tests/unknown_fn_call_err.out
new file mode 100644
index 000000000..8625c8ba3
--- /dev/null
+++ b/vlib/v/checker/tests/unknown_fn_call_err.out
@@ -0,0 +1,6 @@
+vlib/v/checker/tests/unknown_fn_call_err.vv:4:20: error: unknown function: sin
+    2 | 
+    3 | fn main() {
+    4 |     C.printf(c'%f\n', sin(2))
+      |                       ~~~~~~
+    5 | }
diff --git a/vlib/v/checker/tests/unknown_fn_call_err.vv b/vlib/v/checker/tests/unknown_fn_call_err.vv
new file mode 100644
index 000000000..f9fd00c92
--- /dev/null
+++ b/vlib/v/checker/tests/unknown_fn_call_err.vv
@@ -0,0 +1,5 @@
+module main
+
+fn main() {
+	C.printf(c'%f\n', sin(2))
+}
-- 
2.39.5