From a3455b8433934b19ce60ac69eeed1404441671ee Mon Sep 17 00:00:00 2001
From: zakuro <z@kuro.red>
Date: Tue, 30 Mar 2021 16:35:19 +0900
Subject: [PATCH] cgen: execute defer stmts in LIFO order (#9528)

---
 vlib/v/gen/c/cgen.v       |  3 ++-
 vlib/v/tests/defer_test.v | 16 ++++++++++++++++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/vlib/v/gen/c/cgen.v b/vlib/v/gen/c/cgen.v
index ddfd066e65..2c5fe7e02c 100644
--- a/vlib/v/gen/c/cgen.v
+++ b/vlib/v/gen/c/cgen.v
@@ -1243,7 +1243,8 @@ fn (mut g Gen) stmt(node ast.Stmt) {
 }
 
 fn (mut g Gen) write_defer_stmts() {
-	for defer_stmt in g.defer_stmts {
+	for i := g.defer_stmts.len - 1; i >= 0; i-- {
+		defer_stmt := g.defer_stmts[i]
 		g.writeln('// Defer begin')
 		g.writeln('if (${g.defer_flag_var(defer_stmt)} == true) {')
 		g.indent++
diff --git a/vlib/v/tests/defer_test.v b/vlib/v/tests/defer_test.v
index d01e6b7b39..8cdc73db84 100644
--- a/vlib/v/tests/defer_test.v
+++ b/vlib/v/tests/defer_test.v
@@ -101,3 +101,19 @@ fn test_defer_with_if() {
 	set_num_if(mut n, 20, false)
 	assert n.val == 10
 }
+
+fn test_defer_order() {
+	mut i := 0
+	defer {
+		i++
+		assert i == 3
+	}
+	defer {
+		i++
+		assert i == 2
+	}
+	defer {
+		i++
+		assert i == 1
+	}
+}