---

yaml
---
r: 21229
b: refs/heads/snap-stage3
c: c321cdb
h: refs/heads/master
i:
  21227: 9255af5
v: v3

Author: bblum

[refs]

@@ -1,7 +1,7 @@
 ---
 refs/heads/master: e430a699f2c60890d9b86069fd0c68a70ece7120
 refs/heads/snap-stage1: e33de59e47c5076a89eadeb38f4934f58a3618a6
-refs/heads/snap-stage3: 849d5649ef0c113d75bf9f9b1c3ddcd9a2508e49
+refs/heads/snap-stage3: c321cdbac6c4ddd9fedb89e1cc8bce1569347c5a
 refs/heads/try: ffbe0e0e00374358b789b0037bcb3a577cd218be
 refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/heads/ndm: f3868061cd7988080c30d6d5bf352a5a5fe2460b

branches/snap-stage3/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/snap-stage3/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);
+}