RUST_CC_ZEAL crash: too much recursion in walk_uniq

[jruderman]

fn main() {
    let _x = @{a: @10, b: ~true};
}

When run with RUST_CC_ZEAL=1, this program crashes. The crash looks like it's due to too much recursion in

 shape::data<cc::irc, shape::ptr>::walk_uniq().

It's also suspicious that the cycle collector hits a stack guard rather than growing the stack, btw.

[catamorphism]

I got a different error trying to repro this:

Assertion failed: (box->ref_count >= 1), function box_body_td, file ./src/rt/rust_shape.h, line 704

which is at least better than a crash :-)

[nikomatsakis]

Hmm, for me I do not get a crash at all. Perhaps optimizations have to be enabled, though...