From 8ae4ffa49357a4939985884285fef39e86f5f705 Mon Sep 17 00:00:00 2001
From: Andrew Kelley <superjoe30@gmail.com>
Date: Mon, 29 May 2017 14:08:39 -0400
Subject: [PATCH] fix crash when unwrapping optional field of global variable

closes #379
---
 src/ir.cpp          |  5 ++---
 test/cases/null.zig | 21 +++++++++++++++++++++
 2 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/src/ir.cpp b/src/ir.cpp
index 8e1a97435..669de6e28 100644
--- a/src/ir.cpp
+++ b/src/ir.cpp
@@ -11119,10 +11119,9 @@ static TypeTableEntry *ir_analyze_instruction_unwrap_maybe(IrAnalyze *ira,
         ConstExprValue *val = ir_resolve_const(ira, value, UndefBad);
         if (!val)
             return ira->codegen->builtin_types.entry_invalid;
-        assert(val->data.x_ptr.special == ConstPtrSpecialRef);
-        ConstExprValue *maybe_val = val->data.x_ptr.data.ref.pointee;
+        ConstExprValue *maybe_val = const_ptr_pointee(ira->codegen, val);
 
-        if (maybe_val->special != ConstValSpecialRuntime) {
+        if (val->data.x_ptr.mut != ConstPtrMutRuntimeVar) {
             if (!maybe_val->data.x_maybe) {
                 ir_add_error(ira, &unwrap_maybe_instruction->base, buf_sprintf("unable to unwrap null"));
                 return ira->codegen->builtin_types.entry_invalid;
diff --git a/test/cases/null.zig b/test/cases/null.zig
index 2b3b9aa13..484e3a076 100644
--- a/test/cases/null.zig
+++ b/test/cases/null.zig
@@ -122,3 +122,24 @@ fn bar(x: ?void) -> ?void {
         return null;
     }
 }
+
+
+
+const StructWithNullable = struct {
+    field: ?i32,
+};
+
+var struct_with_nullable: StructWithNullable = undefined;
+
+test "unwrap nullable which is field of global var" {
+    struct_with_nullable.field = null;
+    if (struct_with_nullable.field) |payload| {
+        unreachable;
+    }
+    struct_with_nullable.field = 1234;
+    if (struct_with_nullable.field) |payload| {
+        assert(payload == 1234);
+    } else {
+        unreachable;
+    }
+}