Regression tests for Issue rust-lang#27401.

Author: pnkfelix

src/test/run-pass/issue-27401-let-init.rs

@@ -0,0 +1,39 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// The stack-local drop flag associated with binding `let a = ...;`
+// (that occurred in a loop) were failing to (re-)initialize the drop
+// flag after it had been set to "moved" during an earlier iteration
+// of the loop.
+//
+// This is a regression test to ensure we don't let that behavior
+// creep back in.
+//
+// See also issue-27401-match-bind.rs
+
+struct A<'a>(&'a mut i32);
+
+impl<'a> Drop for A<'a> {
+    fn drop(&mut self) {
+        *self.0 += 1;
+    }
+}
+
+fn main() {
+    let mut cnt = 0;
+    for i in 0..2 {
+        let a = A(&mut cnt);
+        if i == 1 {
+            break
+        }
+        drop(a);
+    }
+    assert_eq!(cnt, 2);
+}

src/test/run-pass/issue-27401-match-bind.rs

@@ -0,0 +1,45 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// The stack-local drop flag for binding in match-arm `(_, a) => ...`
+// (that occurred in a loop) were failing to (re-)initialize the drop
+// flag after it had been set to "moved" during an earlier iteration
+// of the loop.
+//
+// This is a regression test to ensure we don't let that behavior
+// creep back in.
+//
+// See also issue-27401-let-init.rs
+
+use std::cell::Cell;
+
+struct A<'a>(&'a Cell<i32>);
+
+impl<'a> Drop for A<'a> {
+    fn drop(&mut self) {
+        let old_val = self.0.get();
+        self.0.set(old_val + 1);
+    }
+}
+
+fn main() {
+    let cnt = Cell::new(0);
+    for i in 0..2 {
+        match (A(&cnt), A(&cnt))  {
+            (_, aaah) => {
+                if i == 1 {
+                    break
+                }
+                drop(aaah);
+            }
+        }
+    }
+    assert_eq!(cnt.get(), 4);
+}