[tests] Add test for #4033

Author: catamorphism

src/test/run-pass/duplicate-use.rs

@@ -0,0 +1,9 @@
+// xfail-test
+extern mod std;
+
+use list = std::map::chained;
+use std::list;
+
+fn main() {
+    let _x: list::T<int, int> = list::mk();
+}