Cannot create binary operator with two operands of differing type!

```
fn fail_len(v: [const int]) -> uint {
    let mut i = fail;
    for v.each {|x| i += 1u; }
    ret i;
}
fn main() {}
```

Breaks rustc:

```
Assertion failed: (S1->getType() == S2->getType() && "Cannot create binary operator with two operands of differing type!"), function Create, file /Users/jruderman/code/rust/src/llvm/lib/VMCore/Instructions.cpp, line 1825.
```
