From 29a052d2d807dcb9f1d45878a3083af7a993263d Mon Sep 17 00:00:00 2001
From: Jeffrey Seyfried <jeffrey.seyfried@gmail.com>
Date: Sat, 25 Mar 2017 04:04:13 +0000
Subject: [PATCH] Fix ICE with nested macros in certain situations.

---
 src/libsyntax/ext/placeholders.rs |  2 +-
 src/test/run-pass/issue-40770.rs  | 19 +++++++++++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)
 create mode 100644 src/test/run-pass/issue-40770.rs

diff --git a/src/libsyntax/ext/placeholders.rs b/src/libsyntax/ext/placeholders.rs
index f0e328a551d5f..2d0994a7b78fb 100644
--- a/src/libsyntax/ext/placeholders.rs
+++ b/src/libsyntax/ext/placeholders.rs
@@ -106,8 +106,8 @@ impl<'a, 'b> PlaceholderExpander<'a, 'b> {
 impl<'a, 'b> Folder for PlaceholderExpander<'a, 'b> {
     fn fold_item(&mut self, item: P<ast::Item>) -> SmallVector<P<ast::Item>> {
         match item.node {
-            ast::ItemKind::Mac(ref mac) if !mac.node.path.segments.is_empty() => {}
             ast::ItemKind::Mac(_) => return self.remove(item.id).make_items(),
+            ast::ItemKind::MacroDef(_) => return SmallVector::one(item),
             _ => {}
         }
 
diff --git a/src/test/run-pass/issue-40770.rs b/src/test/run-pass/issue-40770.rs
new file mode 100644
index 0000000000000..599d0b273e3f1
--- /dev/null
+++ b/src/test/run-pass/issue-40770.rs
@@ -0,0 +1,19 @@
+// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+macro_rules! m {
+    ($e:expr) => {
+        macro_rules! n { () => { $e } }
+    }
+}
+
+fn main() {
+    m!(foo!());
+}