ICE in match expression

[nrc]

The following match expression ICEs with

Basic Block in function '_ZN6middle6typeck9coherence13get_base_type20h0f2d8662897539e9xUv11v0.11.0.preE' does not have terminator!
label %match_case10
LLVM ERROR: Broken function found, compilation aborted!
make: *** [x86_64-unknown-linux-gnu/stage0/lib/rustlib/x86_64-unknown-linux-gnu/lib/stamp.rustc] Error 1

I'm afraid I haven't been able to identify exactly what causes the error, but replacing the _ with ty_uniq(_) | ty_rptr(_, _) | ty_trait(..) fixes the problem, so the error is there somewhere. The offending match is in coherance.rs.

match get(resolved_type).sty {
        ty_enum(..) | ty_struct(..) => {
            debug!("(getting base type) found base type");
            Some(resolved_type)
        }
        _ if ty::type_is_trait(resolved_type) => {
            debug!("(getting base type) found base type (trait)");
            Some(resolved_type)
        }

        ty_nil | ty_bot | ty_bool | ty_char | ty_int(..) | ty_uint(..) | ty_float(..) |
        ty_str(..) | ty_vec(..) | ty_bare_fn(..) | ty_closure(..) | ty_tup(..) |
        ty_infer(..) | ty_param(..) | ty_self(..) | ty_err |
        ty_box(_) | ty_uniq(_) | ty_ptr(_) | ty_rptr(_, _) => {
            debug!("(getting base type) no base type; found {:?}",
                   get(original_type).sty);
            None
        }
        ty_trait(..) => fail!("should have been caught")
    }

[ghost]

Minimal test case:

enum X {
    Foo(uint),
    Bar(bool)
}

fn main() {
    match Foo(42) {
        Foo(..) => (),
        _ if true => (),
        Bar(..) => fail!("Oh dear")
    }
}

[nikomatsakis]

cc @edwardw, sounds related to the trans match code that you were looking at recently

[edwardw]

Indeed. And it seems to be very subtle. The following compiles:

enum X {
    Foo(uint),
    Bar(bool)
}

fn main() {
    match Foo(42) {
        _ if true => (),
        Foo(..) => (),
        Bar(..) => fail!("Oh dear")
    }
}

Although logically two piece of code are different, they should be of little difference as far as codegen is concerned. Yet, one compiles and the other doesn't. I'm investigating it.