Loops try to clean up uninitialized variables

[brson]

while true {
    let x = alt true {
      true { break }  
      _ { "whatever" }
    };                                                                                                                                                                    
}

Under valgrind results in:

==18230== Thread 10:
==18230== Conditional jump or move depends on uninitialised value(s)
==18230==    at 0x8048858: glue_drop2 (in /home/banderson/Dev/rust/build/test/run-pass/while-break-ref.stage1)

[msullivan]

Oh, that's really awful. We zero out uninitialized local variables but we don't zero ones with initializers because we know that they will be initialized. However, if we break inside the initializer expression it won't get initialized or zeroed.

Argh.