Compiler allows tail calls to functions with aliased arguments

[catamorphism]

It seems to me that the following code:

 fn bar(&int i) -> bool {
   ret (i == 37);
  }

  fn foo(int i) -> bool {
    be bar(i);
  }

  fn main() {
    check(foo(37));
  }

should be rejected by the compiler, because foo makes a tail call to bar, whose argument is aliased. The check in the main function fails when I run this program, because bar gets garbage as its argument. The check succeeds if I change "be" to "ret" (reassuringly).

This is all with rustboot.

[marijnh]

Fixed in 9b5ebe7