---

yaml
---
r: 58331
b: refs/heads/auto
c: d43d3e5
h: refs/heads/master
i:
  58329: ebcc812
  58327: 62bf04d
v: v3

Author: bors

[refs]

@@ -14,6 +14,6 @@ refs/heads/try3: 9387340aab40a73e8424c48fd42f0c521a4875c0
 refs/tags/release-0.3.1: 495bae036dfe5ec6ceafd3312b4dca48741e845b
 refs/tags/release-0.4: e828ea2080499553b97dfe33b3f4d472b4562ad7
 refs/tags/release-0.5: 7e3bcfbf21278251ee936ad53e92e9b719702d73
-refs/heads/auto: 842e304ab505f6c0d8f6b29ec3c0dfa8dc9e1aac
+refs/heads/auto: d43d3e538c42798db0706983ba7696b44f6764eb
 refs/heads/servo: af82457af293e2a842ba6b7759b70288da276167
 refs/tags/release-0.6: b4ebcfa1812664df5e142f0134a5faea3918544c

branches/auto/src/test/run-fail/borrowck-wg-autoderef-and-autoborrowvec-combined-fail-issue-6272.rs

@@ -0,0 +1,21 @@
+// error-pattern:borrowed
+
+// Issue #6272. Tests that freezing correctly accounts for all the
+// implicit derefs that can occur and freezes the innermost box. See
+// the companion test
+//
+//     run-pass/borrowck-wg-autoderef-and-autoborrowvec-combined-issue-6272.rs
+//
+// for a detailed explanation of what is going on here.
+
+fn main() {
+    let a = @mut [3i];
+    let b = @mut [a];
+    let c = @mut b;
+
+    // this should freeze `a` only
+    let x: &mut [int] = c[0];
+
+    // hence this should fail
+    a[0] = a[0];
+}

branches/auto/src/test/run-pass/borrowck-wg-autoderef-and-autoborrowvec-combined-issue-6272.rs

@@ -0,0 +1,41 @@
+// Issue #6272. Tests that freezing correctly accounts for all the
+// implicit derefs that can occur.
+//
+// In this particular case, the expression:
+//
+//    let x: &mut [int] = c[0];
+//
+// is seen by borrowck as this sequence of derefs
+// and pointer offsets:
+//
+//    &*((**c)[0])
+//
+// or, written using `x.*` for `*x` (so that everything
+// is a postfix operation):
+//
+//    &c.*.*.[0].*
+//       ^    ^
+//       |    |
+//       b    a
+//
+// Here I also indicated where the evaluation yields the boxes `a` and
+// `b`. It is important then that we only freeze the innermost box
+// (`a`), and not the other ones (`b`, `c`).
+//
+// Also see the companion test:
+//
+// run-fail/borrowck-wg-autoderef-and-autoborrowvec-combined-fail-issue-6272.rs
+
+
+fn main() {
+    let a = @mut [3i];
+    let b = @mut [a];
+    let c = @mut b;
+
+    // this should freeze `a` only
+    let _x: &mut [int] = c[0];
+
+    // hence these writes should not fail:
+    b[0] = b[0];
+    c[0] = c[0];
+}