ICE when declaring static char inside a function

[chris-morgan]

Minimal test case:

fn main() {
    static A: &'static char = &'A';
}

Also tried a couple of other types; crashes with a u8, doesn't crash with a str.

$ RUST_LOG=rustc=1,::rt::backtrace rustc bad.rs
rust: task failed at 'No enclosing scope for id 7', /home/chris/vc/rust/src/librustc/middle/region.rs:121
/home/chris/opt/rust/bin/../lib/librustrt.so(_ZN9rust_task13begin_failureEPKcS1_m+0x4b)[0x7fa7f8d9076b]
/home/chris/opt/rust/bin/../lib/librustrt.so(+0x2c0c9)[0x7fa7f8da20c9]
/home/chris/opt/rust/bin/../lib/librustrt.so(upcall_fail+0x1a8)[0x7fa7f8d927b8]
/home/chris/opt/rust/bin/../lib/libstd-6c65cf4b443341b1-0.8-pre.so(_ZN3sys13begin_unwind_16_89e154cd091567114_0$x2e8$x2dpreE+0x59b)[0x7fa7fa8e22db]
/home/chris/opt/rust/bin/../lib/libstd-6c65cf4b443341b1-0.8-pre.so(+0x11dd32)[0x7fa7fa8e1d32]
/home/chris/opt/rust/bin/../lib/libstd-6c65cf4b443341b1-0.8-pre.so(+0x11dc61)[0x7fa7fa8e1c61]
/home/chris/opt/rust/bin/../lib/libstd-6c65cf4b443341b1-0.8-pre.so(+0x11dcec)[0x7fa7fa8e1cec]
/home/chris/opt/rust/bin/../lib/libstd-6c65cf4b443341b1-0.8-pre.so(+0x11dc61)[0x7fa7fa8e1c61]
/home/chris/opt/rust/bin/../lib/libstd-6c65cf4b443341b1-0.8-pre.so(_ZN3sys14__extensions__10meth_109519fail_with17_d96679812a86c36714_0$x2e8$x2dpreE+0x7b)[0x7fa7fa838fbb]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6middle6region14__extensions__10meth_7153210encl_scope16_07d3310c43b907714_0$x2e8$x2dpreE+0xcf)[0x7fa7f95c08af]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(+0x6314eb)[0x7fa7f95f84eb]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6middle18mem_categorization14__extensions__10meth_7377119cat_expr_unadjusted17_683e145e9333e52a14_0$x2e8$x2dpreE+0xb6c)[0x7fa7f95f702c]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6middle18mem_categorization14__extensions__10meth_737698cat_expr17_683e145e9333e52a14_0$x2e8$x2dpreE+0x16b)[0x7fa7f95f639b]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6middle18mem_categorization8cat_expr17_8bc74df1a33e285114_0$x2e8$x2dpreE+0x5b)[0x7fa7f95ef9fb]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6middle8borrowck14__extensions__10meth_713678cat_expr17_683e145e9333e52a14_0$x2e8$x2dpreE+0x47)[0x7fa7f95baeb7]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6middle8borrowck12gather_loans20gather_loans_in_expr17_9ac743166529fa5c14_0$x2e8$x2dpreE+0x1d07)[0x7fa7f95b7bf7]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(+0x1c9819)[0x7fa7f9190819]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(+0x1c958a)[0x7fa7f919058a]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(+0x1cd5c6)[0x7fa7f91945c6]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(+0x1cbc50)[0x7fa7f9192c50]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6middle8borrowck12gather_loans15add_stmt_to_map16_e77dfbedc63106514_0$x2e8$x2dpreE+0x12a)[0x7fa7f95b9bba]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(+0x1bdfed)[0x7fa7f9184fed]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6middle8borrowck12gather_loans21gather_loans_in_block17_b194266daf4fe94614_0$x2e8$x2dpreE+0xf5)[0x7fa7f95b93f5]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6middle8borrowck12gather_loans12gather_loans17_d9b64e693c94523614_0$x2e8$x2dpreE+0x4ee)[0x7fa7f95b1afe]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6middle8borrowck11borrowck_fn17_a5de7b93bc5f209c14_0$x2e8$x2dpreE+0x178)[0x7fa7f95e3388]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(+0x1c9970)[0x7fa7f9190970]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(+0x1c958a)[0x7fa7f919058a]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(+0x1c8865)[0x7fa7f918f865]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(+0x1c85f5)[0x7fa7f918f5f5]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(+0x5b23d4)[0x7fa7f95793d4]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6middle8borrowck11check_crate17_23db9f9f8380cf2d14_0$x2e8$x2dpreE+0x4da)[0x7fa7f95df58a]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(+0x815ad1)[0x7fa7f97dcad1]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6driver6driver12compile_rest16_a7f24595f9c1d7f14_0$x2e8$x2dpreE+0x1e1b)[0x7fa7f97d9c0b]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(+0x84e3b4)[0x7fa7f98153b4]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6driver6driver12compile_upto17_ac70fe6818e1c68914_0$x2e8$x2dpreE+0x13c)[0x7fa7f97dd0bc]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6driver6driver13compile_input16_a54eace447e7c4014_0$x2e8$x2dpreE+0xd5)[0x7fa7f97dd455]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN12run_compiler17_e4c098586c60ab4f14_0$x2e8$x2dpreE+0x18e9)[0x7fa7f97fd1a9]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(+0x84e0de)[0x7fa7f98150de]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(+0x84ace1)[0x7fa7f9811ce1]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(+0x84044b)[0x7fa7f980744b]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(+0x84e3b4)[0x7fa7f98153b4]
/home/chris/opt/rust/bin/../lib/libstd-6c65cf4b443341b1-0.8-pre.so(+0xebbb9)[0x7fa7fa8afbb9]
/home/chris/opt/rust/bin/../lib/libstd-6c65cf4b443341b1-0.8-pre.so(+0x18ea8c)[0x7fa7fa952a8c]
/home/chris/opt/rust/bin/../lib/librustrt.so(_Z18task_start_wrapperP10spawn_args+0x2b)[0x7fa7f8d910fb]
error: internal compiler error: unexpected failure
note: the compiler hit an unexpected failure path. this is a bug
note: try running with RUST_LOG=rustc=1,::rt::backtrace to get further details and report the results to github.com/mozilla/rust/issues
rust: task failed at 'explicit failure', /home/chris/vc/rust/src/librustc/rustc.rs:355
/home/chris/opt/rust/bin/../lib/librustrt.so(_ZN9rust_task13begin_failureEPKcS1_m+0x4b)[0x7fa7f8d9076b]
/home/chris/opt/rust/bin/../lib/librustrt.so(+0x2c0c9)[0x7fa7f8da20c9]
/home/chris/opt/rust/bin/../lib/librustrt.so(upcall_fail+0x1a8)[0x7fa7f8d927b8]
/home/chris/opt/rust/bin/../lib/libstd-6c65cf4b443341b1-0.8-pre.so(_ZN3sys13begin_unwind_16_89e154cd091567114_0$x2e8$x2dpreE+0x59b)[0x7fa7fa8e22db]
/home/chris/opt/rust/bin/../lib/libstd-6c65cf4b443341b1-0.8-pre.so(+0x11e422)[0x7fa7fa8e2422]
/home/chris/opt/rust/bin/../lib/libstd-6c65cf4b443341b1-0.8-pre.so(+0x11dc61)[0x7fa7fa8e1c61]
/home/chris/opt/rust/bin/../lib/libstd-6c65cf4b443341b1-0.8-pre.so(+0x11e3dc)[0x7fa7fa8e23dc]
/home/chris/opt/rust/bin/../lib/libstd-6c65cf4b443341b1-0.8-pre.so(+0x11dc61)[0x7fa7fa8e1c61]
/home/chris/opt/rust/bin/../lib/libstd-6c65cf4b443341b1-0.8-pre.so(+0x8ba84)[0x7fa7fa84fa84]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN7monitor17_1ce38b927b935cbd14_0$x2e8$x2dpreE+0x2af5)[0x7fa7f9800825]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(+0x84e3b4)[0x7fa7f98153b4]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN4main15_f3d16eaf7d573814_0$x2e8$x2dpreE+0x69)[0x7fa7f9815009]
/home/chris/opt/rust/bin/../lib/librustrt.so(_Z18task_start_wrapperP10spawn_args+0x2b)[0x7fa7f8d910fb]
rust: domain main @0x160fd70 root task failed

[pnkfelix]

visiting for bug triage, 2013-09-02.

I know some labels to add here. And I'll poke at it a bit too, see if I can dissect a little about the caller (mem_categorization.rs) and why it isn't doing whatever it usually does to deal with the static lifetime.

[pnkfelix]

By the way, here is one way to work-around this:

pub fn f() {
    static A_backing: char = 'A';   // <---- this is the important thing.
    static A: &'static char = &A_backing;
}

fn main() {
    f();
}

So, next steps for the bug itself:

1. Obviously we need to deal with the ICE
2. But also, we need to decide whether the original program is legal. It is conceptually taking the address of the result of evaluating const-expr. That doesn't seem like any big intellectual hurdle, at least for a non-mut static borrow. (I do wonder whether there is any overlap between this and our need to define what const-exprs actually are in the first place.)