From 923ef733c023a302a98dd02bd0da9258c673dde1 Mon Sep 17 00:00:00 2001
From: yuyi <yuyi98@163.com>
Date: Sat, 4 Sep 2021 19:34:29 +0800
Subject: [PATCH] checker: disallow array sort with fancy args for now (#11388)

---
 vlib/v/checker/checker.v                      | 9 +++++++++
 vlib/v/checker/tests/array_fancy_sort_err.out | 8 ++++++++
 vlib/v/checker/tests/array_fancy_sort_err.vv  | 8 ++++++++
 3 files changed, 25 insertions(+)
 create mode 100644 vlib/v/checker/tests/array_fancy_sort_err.out
 create mode 100644 vlib/v/checker/tests/array_fancy_sort_err.vv

diff --git a/vlib/v/checker/checker.v b/vlib/v/checker/checker.v
index 2542a03c88..c6ec90b7e1 100644
--- a/vlib/v/checker/checker.v
+++ b/vlib/v/checker/checker.v
@@ -2555,6 +2555,15 @@ fn (mut c Checker) array_builtin_method_call(mut node ast.CallExpr, left_type as
 				} else if left_name == right_name {
 					c.error('`.sort()` cannot use same argument', node.pos)
 				}
+				if (node.args[0].expr.left !is ast.Ident
+					&& node.args[0].expr.left !is ast.SelectorExpr
+					&& node.args[0].expr.left !is ast.IndexExpr)
+					|| (node.args[0].expr.right !is ast.Ident
+					&& node.args[0].expr.right !is ast.SelectorExpr
+					&& node.args[0].expr.right !is ast.IndexExpr) {
+					c.error('`.sort()` can only use ident, index or selector as argument, \ne.g. `arr.sort(a < b)`, `arr.sort(a.id < b.id)`, `arr.sort(a[0] < b[0])`',
+						node.pos)
+				}
 			} else {
 				c.error(
 					'`.sort()` requires a `<` or `>` comparison as the first and only argument' +
diff --git a/vlib/v/checker/tests/array_fancy_sort_err.out b/vlib/v/checker/tests/array_fancy_sort_err.out
new file mode 100644
index 0000000000..c61409c1aa
--- /dev/null
+++ b/vlib/v/checker/tests/array_fancy_sort_err.out
@@ -0,0 +1,8 @@
+vlib/v/checker/tests/array_fancy_sort_err.vv:6:8: error: `.sort()` can only use ident, index or selector as argument,
+e.g. `arr.sort(a < b)`, `arr.sort(a.id < b.id)`, `arr.sort(a[0] < b[0])`
+    4 |     text := os.read_file(os.args[0]) ?
+    5 |     mut lines := text.split_into_lines()
+    6 |     lines.sort(a.split('/').last() < b.split('/').last())
+      |           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+    7 |     println(lines.join('\n'))
+    8 | }
diff --git a/vlib/v/checker/tests/array_fancy_sort_err.vv b/vlib/v/checker/tests/array_fancy_sort_err.vv
new file mode 100644
index 0000000000..3c05a5e6bb
--- /dev/null
+++ b/vlib/v/checker/tests/array_fancy_sort_err.vv
@@ -0,0 +1,8 @@
+import os
+
+fn main() {
+	text := os.read_file(os.args[0]) ?
+	mut lines := text.split_into_lines()
+	lines.sort(a.split('/').last() < b.split('/').last())
+	println(lines.join('\n'))
+}