From a712ea333b9ddb140331c159d23d16ef6ed4ef14 Mon Sep 17 00:00:00 2001
From: LemonBoy <thatlemon@gmail.com>
Date: Sat, 4 Jan 2020 11:49:43 +0100
Subject: [PATCH] Fix translation of for loop init

Closes #4067
---
 src-self-hosted/translate_c.zig | 10 ++++++----
 test/translate_c.zig            | 15 +++++++++++++++
 2 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/src-self-hosted/translate_c.zig b/src-self-hosted/translate_c.zig
index 7f98ff2686..57e67d4dd5 100644
--- a/src-self-hosted/translate_c.zig
+++ b/src-self-hosted/translate_c.zig
@@ -2119,14 +2119,16 @@ fn transForLoop(
         .parent = scope,
         .id = .Loop,
     };
-    var block = false;
+
     var block_scope: ?*Scope.Block = null;
     if (ZigClangForStmt_getInit(stmt)) |init| {
         block_scope = try Scope.Block.init(rp.c, scope, null);
-        block_scope.?.block_node = try transCreateNodeBlock(rp.c, null);
+        const block = try transCreateNodeBlock(rp.c, null);
+        block_scope.?.block_node = block;
         loop_scope.parent = &block_scope.?.base;
-        const init_stmt = try transStmt(rp, &loop_scope, init, .unused, .r_value);
-        try block_scope.?.block_node.statements.push(init_stmt);
+        const result = try transStmt(rp, &block_scope.?.base, init, .unused, .r_value);
+        if (result != &block.base)
+            try block.statements.push(result);
     }
     var cond_scope = Scope{
         .parent = scope,
diff --git a/test/translate_c.zig b/test/translate_c.zig
index 98cf3df996..42b72e7cb9 100644
--- a/test/translate_c.zig
+++ b/test/translate_c.zig
@@ -696,6 +696,21 @@ pub fn addCases(cases: *tests.TranslateCContext) void {
         \\}
     });
 
+    cases.add("for loop with simple init expression",
+        \\void foo(void) {
+        \\    int i;
+        \\    for (i = 3; i; i--) { }
+        \\}
+    , &[_][]const u8{
+        \\pub export fn foo() void {
+        \\    var i: c_int = undefined;
+        \\    {
+        \\        i = 3;
+        \\        while (i != 0) : (i -= 1) {}
+        \\    }
+        \\}
+    });
+
     cases.add("break statement",
         \\void foo(void) {
         \\    for (;;) {