Auto merge of #22182 - nikomatsakis:cycles-in-collect, r=nikomatsakis

This resolves a number of bugs that trigger stack overflows or other cyclic errors.

r? @nick29581 (it is based on work that you started)
f? @jroesch (also based on your branch)

1 files changed, 8 insertions, 0 deletions

diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index 5979d339e17..d6778be553e 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -366,6 +366,14 @@ pub struct DefId {
     pub node: NodeId,
 }
 
+impl DefId {
+    /// Read the node id, asserting that this def-id is krate-local.
+    pub fn local_id(&self) -> NodeId {
+        assert_eq!(self.krate, LOCAL_CRATE);
+        self.node
+    }
+}
+
 /// Item definitions in the currently-compiled crate would have the CrateNum
 /// LOCAL_CRATE in their DefId.
 pub const LOCAL_CRATE: CrateNum = 0;