LLVM abort from deref of 0 in a const expression initializing a static

[pnkfelix]

(imported from improperly closed bug #17452)

static X: usize = unsafe { *(0 as *const usize) };

fn main() {
    println!("X: {}", X);
}

playpen

This causes LLVM to abort, causing a core dump from rustc. :(

(I suspect we should be more careful, somehow, about handling such things in our const expression evaluator. Not 100% sure how best to resolve this though.)

[pnkfelix]

(i don't want to tag this as ICE -- that implies to me that we are actually catching this and issuing the ICE message...)

[pnkfelix]

(I suppose I could tag it as both I-ICE and I-crash, though that seems like it does more harm than good w.r.t. the labeling system.)

[ghost]

I think this issue is a dupe of #13973 so I'm going to close it. @pnkfelix, feel free to reopen if you disagree.

[pnkfelix]

well I'd say that one could probably argue that #13973 should actually compile successfully (and bind BLOCK_UNSAFE_SAFE_PTR to a value that points to the address that corresponds to the number 0xdeadbeef), while this code does not seem like it should compile successfully...

In other words, solving both of these problems may involve a more general solution than solving either independently...