From cb1290ee3c80115cd1774d2d9e5bce1bf25a33bc Mon Sep 17 00:00:00 2001
From: Isaiah Norton <isaiah.norton@gmail.com>
Date: Mon, 29 Dec 2014 22:26:19 -0500
Subject: [PATCH] Handle undef refs in jl_copy_ast, fixes #9475

[ci skip] checked on branch fix9475
passed osx
passed linux except for some network issue cloning package.
---
 src/ast.c    | 5 ++++-
 test/core.jl | 6 ++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/ast.c b/src/ast.c
index e1ae91e7e0a68..767d9bd71151e 100644
--- a/src/ast.c
+++ b/src/ast.c
@@ -769,7 +769,10 @@ static jl_value_t *copy_ast(jl_value_t *expr, jl_tuple_t *sp, int do_sp)
 
 DLLEXPORT jl_value_t *jl_copy_ast(jl_value_t *expr)
 {
-    if (jl_is_expr(expr)) {
+    if (expr == NULL) {
+        return NULL;
+    }
+    else if (jl_is_expr(expr)) {
         jl_expr_t *e = (jl_expr_t*)expr;
         size_t i, l = jl_array_len(e->args);
         jl_expr_t *ne = NULL;
diff --git a/test/core.jl b/test/core.jl
index 9350e0d2635ba..e2a1aca0cf2dd 100644
--- a/test/core.jl
+++ b/test/core.jl
@@ -1976,3 +1976,9 @@ function f9134()
     end
 end
 @test_throws UndefVarError f9134()
+
+# issue #9475
+module I9475
+    arr = Array(Any, 1)
+    @eval @eval $arr[1] = 1
+end