rustc: Prevent destructors from being run twice with the repeated vector syntax

Author: pcwalton

src/rustc/middle/kind.rs

@@ -307,6 +307,15 @@ fn check_expr(e: @expr, cx: ctx, v: visit::vt<ctx>) {
             }
         }
       }
+      expr_repeat(element, count_expr, _) => {
+        let count = ty::eval_repeat_count(cx.tcx, count_expr, e.span);
+        if count == 1 {
+            maybe_copy(cx, element);
+        } else {
+            let element_ty = ty::expr_ty(cx.tcx, element);
+            check_copy(cx, element.id, element_ty, element.span, true);
+        }
+      }
       _ => { }
     }
     visit::visit_expr(e, cx, v);

src/test/compile-fail/repeat-to-run-dtor-twice.rs

@@ -0,0 +1,16 @@
+// Tests that one can't run a destructor twice with the repeated vector
+// literal syntax.
+
+struct Foo {
+    x: int;
+
+    drop {
+        io::println("Goodbye!");
+    }
+}
+
+fn main() {
+    let a = Foo { x: 3 };
+    let b = [ a, ..5 ];     //~ ERROR copying a noncopyable value
+}
+