Resolve the vtables for method calls to generic Drop impls with trait bounds.

src/test/run-pass/issue-4252.rs

@@ -8,30 +8,34 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// ignore-test
-
 trait X {
-    fn call(&self);
+    fn call<T>(&self, x: &T);
+    fn default_method<T>(&self, x: &T) {
+        println!("X::default_method {:?} {:?}", self, x);
+    }
 }
 
-struct Y;
+struct Y(int);
 
 struct Z<T> {
     x: T
 }
 
 impl X for Y {
-    fn call(&self) {
+    fn call<T>(&self, x: &T) {
+        println!("X::call {:?} {:?}", self, x);
     }
 }
 
+#[unsafe_destructor]
 impl<T: X> Drop for Z<T> {
     fn drop(&mut self) {
-        self.x.call(); // Adding this statement causes an ICE.
+        // These statements used to cause an ICE.
+        self.x.call(self);
+        self.x.default_method(self);
     }
 }
 
 pub fn main() {
-    let y = Y;
-    let _z = Z{x: y};
+    let _z = Z {x: Y(42)};
 }