---

yaml
---
r: 135300
b: refs/heads/snap-stage3
c: 36b8502
h: refs/heads/master
v: v3

Author: ftxqxd

[refs]

@@ -1,7 +1,7 @@
 ---
 refs/heads/master: 74090504219e4e37c1a6d9fdd8600f44b51c7b04
 refs/heads/snap-stage1: e33de59e47c5076a89eadeb38f4934f58a3618a6
-refs/heads/snap-stage3: a8577be6f4e2d92b4f397aa8191e4ac48e2b4c6d
+refs/heads/snap-stage3: 36b85025df8a8045428e2f9917c75e0639a210a6
 refs/heads/try: 14378ea357c06c23607ca61ade44f60a7a64a1c7
 refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/heads/ndm: f3868061cd7988080c30d6d5bf352a5a5fe2460b

branches/snap-stage3/src/librustc/middle/borrowck/mod.rs

@@ -602,6 +602,7 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> {
                                          span: Span,
                                          kind: AliasableViolationKind,
                                          cause: mc::AliasableReason) {
+        let mut is_closure = false;
         let prefix = match kind {
             MutabilityViolation => {
                 "cannot assign to data"
@@ -625,6 +626,7 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> {
             }
 
             BorrowViolation(euv::ClosureInvocation) => {
+                is_closure = true;
                 "closure invocation"
             }
 
@@ -649,14 +651,20 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> {
             mc::AliasableManaged => {
                 self.tcx.sess.span_err(
                     span,
-                    format!("{} in a `@` pointer", prefix).as_slice());
+                    format!("{} in a `Gc` pointer", prefix).as_slice());
             }
             mc::AliasableBorrowed => {
                 self.tcx.sess.span_err(
                     span,
                     format!("{} in a `&` reference", prefix).as_slice());
             }
         }
+
+        if is_closure {
+            self.tcx.sess.span_note(
+                span,
+                "closures behind references must be called via `&mut`");
+        }
     }
 
     pub fn note_and_explain_bckerr(&self, err: BckError) {