From 42d5c0b2e7231ebde9992d902ec747e974c57cd7 Mon Sep 17 00:00:00 2001
From: CreeperFace <165158232+dy-tea@users.noreply.github.com>
Date: Sun, 28 Sep 2025 19:56:28 +0100
Subject: [PATCH] cgen: fix short-circuiting of boolean expressions, when the
 right side calls array methods (fix #25398) (#25411)

---
 vlib/v/gen/c/if.v                             |  3 +-
 .../logical_and_short_circuit.must_have       | 24 ++++++++++++++
 .../c/testdata/logical_and_short_circuit.out  |  4 +++
 .../c/testdata/logical_and_short_circuit.vv   | 31 +++++++++++++++++++
 4 files changed, 61 insertions(+), 1 deletion(-)
 create mode 100644 vlib/v/gen/c/testdata/logical_and_short_circuit.must_have
 create mode 100644 vlib/v/gen/c/testdata/logical_and_short_circuit.out
 create mode 100644 vlib/v/gen/c/testdata/logical_and_short_circuit.vv

diff --git a/vlib/v/gen/c/if.v b/vlib/v/gen/c/if.v
index c5f012934..a7310f89c 100644
--- a/vlib/v/gen/c/if.v
+++ b/vlib/v/gen/c/if.v
@@ -62,7 +62,8 @@ fn (mut g Gen) need_tmp_var_in_expr(expr ast.Expr) bool {
 			if expr.is_method {
 				left_sym := g.table.sym(expr.receiver_type)
 				if left_sym.kind in [.array, .array_fixed, .map] {
-					return true
+					return expr.name !in ['contains', 'exists', 'len', 'cap', 'first', 'last',
+						'index', 'get']
 				}
 			}
 			if expr.or_block.kind != .absent {
diff --git a/vlib/v/gen/c/testdata/logical_and_short_circuit.must_have b/vlib/v/gen/c/testdata/logical_and_short_circuit.must_have
new file mode 100644
index 000000000..fa4b786ed
--- /dev/null
+++ b/vlib/v/gen/c/testdata/logical_and_short_circuit.must_have
@@ -0,0 +1,24 @@
+VV_LOC void main__main(void) {
+	Array_int list = builtin__new_array_from_c_array_noscan(3, 3, sizeof(int), _MOV((int[3]){1, 2, 3}));
+	int index = 3;
+	if (index < list.len && (*(int*)builtin__array_get(list, index)) == 3) {
+		builtin__println(_S("Index is within bounds and value is 3"));
+	} else {
+		builtin__println(_S("Index is out of bounds or value is not 3"));
+	}
+	if (index < list.len && main__print_true((*(int*)builtin__array_get(list, index)))) {
+		builtin__println(_S("Index is within bounds"));
+	} else {
+		builtin__println(_S("Index is out of bounds"));
+	}
+	if (index < list.len && Array_int_contains(_const_main__other_list, (*(int*)builtin__array_get(list, index)))) {
+		builtin__println(_S("Index is within bounds and value is in other_list"));
+	} else {
+		builtin__println(_S("Index is out of bounds or value is not in other_list"));
+	}
+	if (index < list.len && (Array_int_contains(_const_main__other_list, (*(int*)builtin__array_get(list, index))) || Array_int_contains(_const_main__other_list, (*(int*)builtin__array_get(list, index))))) {
+		builtin__println(_S("Index is within bounds and value is in other_list"));
+	} else {
+		builtin__println(_S("Index is out of bounds or value is not in other_list"));
+	}
+}
diff --git a/vlib/v/gen/c/testdata/logical_and_short_circuit.out b/vlib/v/gen/c/testdata/logical_and_short_circuit.out
new file mode 100644
index 000000000..974ec3589
--- /dev/null
+++ b/vlib/v/gen/c/testdata/logical_and_short_circuit.out
@@ -0,0 +1,4 @@
+Index is out of bounds or value is not 3
+Index is out of bounds
+Index is out of bounds or value is not in other_list
+Index is out of bounds or value is not in other_list
diff --git a/vlib/v/gen/c/testdata/logical_and_short_circuit.vv b/vlib/v/gen/c/testdata/logical_and_short_circuit.vv
new file mode 100644
index 000000000..8d0127935
--- /dev/null
+++ b/vlib/v/gen/c/testdata/logical_and_short_circuit.vv
@@ -0,0 +1,31 @@
+fn print_true(i int) bool {
+	println(i)
+	return true
+}
+
+const other_list = [3, 4]
+
+fn main() {
+	list := [1, 2, 3]
+	index := 3
+	if index < list.len && list[index] == 3 {
+		println('Index is within bounds and value is 3')
+	} else {
+		println('Index is out of bounds or value is not 3')
+	}
+	if index < list.len && print_true(list[index]) {
+		println('Index is within bounds')
+	} else {
+		println('Index is out of bounds')
+	}
+	if index < list.len && other_list.contains(list[index]) {
+		println('Index is within bounds and value is in other_list')
+	} else {
+		println('Index is out of bounds or value is not in other_list')
+	}
+	if index < list.len && (other_list.contains(list[index]) || other_list.contains(list[index])) {
+		println('Index is within bounds and value is in other_list')
+	} else {
+		println('Index is out of bounds or value is not in other_list')
+	}
+}
-- 
2.39.5