---

yaml
---
r: 29937
b: refs/heads/incoming
c: c321cdb
h: refs/heads/master
i:
  29935: 88f7a8e
v: v3

Author: bblum

[refs]

@@ -6,7 +6,7 @@ refs/heads/try: d324a424d8f84b1eb049b12cf34182bda91b0024
 refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/heads/ndm: f3868061cd7988080c30d6d5bf352a5a5fe2460b
 refs/heads/try2: d0c6ce338884ee21843f4b40bf6bf18d222ce5df
-refs/heads/incoming: 849d5649ef0c113d75bf9f9b1c3ddcd9a2508e49
+refs/heads/incoming: c321cdbac6c4ddd9fedb89e1cc8bce1569347c5a
 refs/heads/dist-snap: 2f32a1581f522e524009138b33b1c7049ced668d
 refs/tags/release-0.2: c870d2dffb391e14efb05aa27898f1f6333a9596
 refs/tags/release-0.3: b5f0d0f648d9a6153664837026ba1be43d3e2503

branches/incoming/src/rustc/middle/typeck/check/alt.rs

@@ -270,6 +270,12 @@ fn check_pat(pcx: pat_ctxt, pat: @ast::pat, expected: ty::t) {
             }
         }
 
+        // Forbid pattern-matching structs with destructors.
+        if ty::has_dtor(tcx, class_id) {
+            tcx.sess.span_err(pat.span, ~"deconstructing struct not allowed \
+                                          in pattern (it has a destructor)");
+        }
+
         // Index the class fields.
         let field_map = std::map::box_str_hash();
         for class_fields.eachi |i, class_field| {

branches/incoming/src/test/compile-fail/disallowed-deconstructing-destructing-struct.rs

@@ -0,0 +1,17 @@
+struct X {
+    x: ~str;
+    drop {
+        error!("value: %s", self.x);
+    }
+}
+
+fn unwrap(+x: X) -> ~str {
+    let X { x: y } = x; //~ ERROR deconstructing struct not allowed in pattern
+    y
+}
+
+fn main() {
+    let x = X { x: ~"hello" };
+    let y = unwrap(x);
+    error!("contents: %s", y);
+}