From bc7a844a64dee290855b603297918e72d3cb0ecc Mon Sep 17 00:00:00 2001
From: Felipe Pena <felipensp@gmail.com>
Date: Mon, 9 Dec 2024 15:34:18 -0300
Subject: [PATCH] v: allow option array element comparison `==` and `!=` (fix
 #23108) (#23113)

---
 vlib/v/checker/infix.v                          |  6 +++---
 vlib/v/gen/c/infix.v                            | 16 +++++++++++++++-
 vlib/v/tests/options/option_indexexpr_eq_test.v |  7 +++++++
 3 files changed, 25 insertions(+), 4 deletions(-)
 create mode 100644 vlib/v/tests/options/option_indexexpr_eq_test.v

diff --git a/vlib/v/checker/infix.v b/vlib/v/checker/infix.v
index 8e63a122d..fbbde3a3e 100644
--- a/vlib/v/checker/infix.v
+++ b/vlib/v/checker/infix.v
@@ -897,9 +897,9 @@ fn (mut c Checker) infix_expr(mut node ast.InfixExpr) ast.Type {
 	right_is_option := right_type.has_flag(.option)
 	if left_is_option || right_is_option {
 		opt_infix_pos := if left_is_option { left_pos } else { right_pos }
-		if (node.left !in [ast.Ident, ast.SelectorExpr, ast.ComptimeSelector]
-			|| node.op in [.eq, .ne, .lt, .gt, .le, .ge]) && right_sym.kind != .none
-			&& !c.inside_sql {
+		if (node.left !in [ast.Ident, ast.IndexExpr, ast.SelectorExpr, ast.ComptimeSelector]
+			|| (node.op in [.eq, .ne] && !right_is_option)
+			|| node.op in [.lt, .gt, .le, .ge]) && right_sym.kind != .none && !c.inside_sql {
 			c.error('unwrapped Option cannot be used in an infix expression', opt_infix_pos)
 		}
 	}
diff --git a/vlib/v/gen/c/infix.v b/vlib/v/gen/c/infix.v
index 50a05be6d..9a50f45c6 100644
--- a/vlib/v/gen/c/infix.v
+++ b/vlib/v/gen/c/infix.v
@@ -112,7 +112,9 @@ fn (mut g Gen) infix_expr_eq_op(node ast.InfixExpr) {
 		g.gen_plain_infix_expr(node)
 		return
 	}
-	is_none_check := left_type.has_flag(.option) && node.right is ast.None
+	left_is_option := left_type.has_flag(.option)
+	right_is_option := right_type.has_flag(.option)
+	is_none_check := left_is_option && node.right is ast.None
 	if is_none_check {
 		g.gen_is_none_check(node)
 	} else if (left.typ.is_ptr() && right.typ.is_int())
@@ -367,6 +369,18 @@ fn (mut g Gen) infix_expr_eq_op(node ast.InfixExpr) {
 			signed_type:   left.unaliased
 			signed_expr:   node.left
 		)
+	} else if left_is_option && right_is_option {
+		old_inside_opt_or_res := g.inside_opt_or_res
+		g.inside_opt_or_res = true
+		if node.op == .eq {
+			g.write('!')
+		}
+		g.write('memcmp(')
+		g.expr(node.left)
+		g.write('.data, ')
+		g.expr(node.right)
+		g.write('.data, sizeof(${g.base_type(left_type)}))')
+		g.inside_opt_or_res = old_inside_opt_or_res
 	} else {
 		g.gen_plain_infix_expr(node)
 	}
diff --git a/vlib/v/tests/options/option_indexexpr_eq_test.v b/vlib/v/tests/options/option_indexexpr_eq_test.v
new file mode 100644
index 000000000..b5ebf53ac
--- /dev/null
+++ b/vlib/v/tests/options/option_indexexpr_eq_test.v
@@ -0,0 +1,7 @@
+fn test_main() {
+	x := []?int{len: 5, init: 1}
+	assert x[0] == x[1]
+
+	y := []?int{len: 4, init: 2}
+	assert !(x[0] == y[1])
+}
-- 
2.39.5