From 39bf02ea68c0ffa8d172cb7ae327a80f666afa41 Mon Sep 17 00:00:00 2001
From: Swastik Baranwal <swstkbaranwal@gmail.com>
Date: Fri, 28 Aug 2020 13:38:07 +0530
Subject: [PATCH] checker: add error for arr1 <,>,>=,<= arr2 (#6243)

---
 vlib/v/checker/checker.v               |  5 +++++
 vlib/v/checker/tests/array_cmp_err.out | 26 ++++++++++++++++++++++++++
 vlib/v/checker/tests/array_cmp_err.vv  |  6 ++++++
 3 files changed, 37 insertions(+)
 create mode 100644 vlib/v/checker/tests/array_cmp_err.out
 create mode 100644 vlib/v/checker/tests/array_cmp_err.vv

diff --git a/vlib/v/checker/checker.v b/vlib/v/checker/checker.v
index f351305b4e..725120bb61 100644
--- a/vlib/v/checker/checker.v
+++ b/vlib/v/checker/checker.v
@@ -593,6 +593,11 @@ pub fn (mut c Checker) infix_expr(mut infix_expr ast.InfixExpr) table.Type {
 				return_type = promoted_type
 			}
 		}
+		.gt, .lt, .ge, .le {
+			if left.kind in [.array, .array_fixed] && right.kind in [.array, .array_fixed] {
+				c.error('only `==` and `!=` are defined on arrays', infix_expr.pos)
+			}
+		}
 		.left_shift {
 			if left.kind == .array {
 				// `array << elm`
diff --git a/vlib/v/checker/tests/array_cmp_err.out b/vlib/v/checker/tests/array_cmp_err.out
new file mode 100644
index 0000000000..885a514d9c
--- /dev/null
+++ b/vlib/v/checker/tests/array_cmp_err.out
@@ -0,0 +1,26 @@
+vlib/v/checker/tests/array_cmp_err.vv:2:26: error: only `==` and `!=` are defined on arrays
+    1 | fn main() {
+    2 |     println([2, 3, 4, 6] < [2, 5])
+      |                          ^
+    3 |     println([2, 3, 4, 6] > [2, 5])
+    4 |     println([2, 3, 1, 6] >= [3, 5, 7])
+vlib/v/checker/tests/array_cmp_err.vv:3:26: error: only `==` and `!=` are defined on arrays
+    1 | fn main() {
+    2 |     println([2, 3, 4, 6] < [2, 5])
+    3 |     println([2, 3, 4, 6] > [2, 5])
+      |                          ^
+    4 |     println([2, 3, 1, 6] >= [3, 5, 7])
+    5 |     println([2, 3, 6, 8] <= [2, 5, 8, 9])
+vlib/v/checker/tests/array_cmp_err.vv:4:26: error: only `==` and `!=` are defined on arrays
+    2 |     println([2, 3, 4, 6] < [2, 5])
+    3 |     println([2, 3, 4, 6] > [2, 5])
+    4 |     println([2, 3, 1, 6] >= [3, 5, 7])
+      |                          ~~
+    5 |     println([2, 3, 6, 8] <= [2, 5, 8, 9])
+    6 | }
+vlib/v/checker/tests/array_cmp_err.vv:5:26: error: only `==` and `!=` are defined on arrays
+    3 |     println([2, 3, 4, 6] > [2, 5])
+    4 |     println([2, 3, 1, 6] >= [3, 5, 7])
+    5 |     println([2, 3, 6, 8] <= [2, 5, 8, 9])
+      |                          ~~
+    6 | }
diff --git a/vlib/v/checker/tests/array_cmp_err.vv b/vlib/v/checker/tests/array_cmp_err.vv
new file mode 100644
index 0000000000..ec60eb90f7
--- /dev/null
+++ b/vlib/v/checker/tests/array_cmp_err.vv
@@ -0,0 +1,6 @@
+fn main() {
+    println([2, 3, 4, 6] < [2, 5])
+    println([2, 3, 4, 6] > [2, 5])
+    println([2, 3, 1, 6] >= [3, 5, 7])
+    println([2, 3, 6, 8] <= [2, 5, 8, 9])
+}