diff --git a/vlib/v/ast/str.v b/vlib/v/ast/str.v
index 9ef7494d07..baae9e6382 100644
--- a/vlib/v/ast/str.v
+++ b/vlib/v/ast/str.v
@@ -303,7 +303,13 @@ pub fn (x Expr) str() string {
 		}
 		CallExpr {
 			sargs := args2str(x.args)
-			propagate_suffix := if x.or_block.kind == .propagate_option { ' ?' } else { '' }
+			propagate_suffix := if x.or_block.kind == .propagate_option {
+				'?'
+			} else if x.or_block.kind == .propagate_result {
+				'!'
+			} else {
+				''
+			}
 			if x.is_method {
 				return '${x.left.str()}.${x.name}($sargs)$propagate_suffix'
 			}
diff --git a/vlib/v/checker/tests/fn_call_arg_mismatch_err_c.out b/vlib/v/checker/tests/fn_call_arg_mismatch_err_c.out
index b89d84279c..58cff628b8 100644
--- a/vlib/v/checker/tests/fn_call_arg_mismatch_err_c.out
+++ b/vlib/v/checker/tests/fn_call_arg_mismatch_err_c.out
@@ -1,4 +1,4 @@
-vlib/v/checker/tests/fn_call_arg_mismatch_err_c.vv:13:18: error: `os.chdir(files) ?` (no value) used as value in argument 1 to `os.ls`
+vlib/v/checker/tests/fn_call_arg_mismatch_err_c.vv:13:18: error: `os.chdir(files)?` (no value) used as value in argument 1 to `os.ls`
    11 |             println(files)
    12 |         } else {
    13 |             println(os.ls(os.chdir(files)?)?)