fix prod build

vlib/v/gen/cgen.v

@@ -552,7 +552,7 @@ fn (g mut Gen) gen_fn_decl(it ast.FnDecl) {
 	// ////////////
 	if g.autofree && false {
 		scope := g.file.scope.innermost(it.pos.pos - 1)
-		for i, var in scope.vars {
+		for _, var in scope.vars {
 			sym := g.table.get_type_symbol(var.typ)
 			if sym.kind == .array && !table.type_is_optional(var.typ) {
 				g.writeln('array_free($var.name); // autofree')
@@ -1837,8 +1837,8 @@ fn (g mut Gen) call_expr(it ast.CallExpr) {
 		name = name[3..]
 	}
 	// Generate tmp vars for values that have to be freed.
-	mut tmps := []string
 	/*
+	mut tmps := []string
 	for arg in it.args {
 		if arg.typ == table.string_type_idx || is_print {
 			tmp := g.new_tmp_var()

vlib/v/tests/valgrind/1.vv

@@ -0,0 +1,18 @@
+import os
+
+fn return_array(array_arg []string) []int {
+        s := [1, 2, 3] // escaping array must not be freed
+        return s
+}
+
+fn foo() {
+        nums := [1, 2, 3] // local array must be freed
+        println(nums)
+}
+
+fn main() {
+        println('start')
+        foo()
+        println('end')
+}
+

vlib/v/tests/valgrind/valgrind_test.v

@@ -0,0 +1,15 @@
+import os
+import term
+
+fn test_all() {
+	$if !linux {
+		println('Valgrind tests can only be run on Linux.')
+		exit(1)
+	}
+	exe := os.executable()
+	dir := os.dir(exe)
+	files := os.ls('$dir/vlib/v/tests/valgrind/') or {
+		panic(err)
+	}
+	println(files)
+}