ICE while generating debug symbols for default trait method

[chris-morgan]

Here is a minimal test case where compilation fails with rustc -Z debug-info:

#[allow(default_methods)];

pub trait TraitWithDefaultMethod {
    pub fn method(self) {
        ()
    }
}

struct MyStruct;

impl TraitWithDefaultMethod for MyStruct { }

fn main() {
    MyStruct.method();
}

(To the best of my knowledge, nothing can be removed from this example without the ICE melting, including that method cannot be empty, hence the ().)

I believe this to be what is causing #7603.

$ RUST_LOG=::rt::backtrace rustc -Z debug-info debug-info.rs
error: internal compiler error: create_function: unexpected sort of node
rust: task failed at 'explicit failure', /home/chris/vc/rust/src/libsyntax/diagnostic.rs:95
/home/chris/opt/rust/bin/../lib/librustrt.so(_ZN9rust_task13begin_failureEPKcS1_m+0x4b)[0x7f20cc97319b]
/home/chris/opt/rust/bin/../lib/librustrt.so(+0x2b899)[0x7f20cc984899]
/home/chris/opt/rust/bin/../lib/librustrt.so(upcall_fail+0x1a8)[0x7f20cc9751e8]
/home/chris/opt/rust/bin/../lib/libstd-6c65cf4b443341b1-0.8-pre.so(_ZN3sys13begin_unwind_16_89e154cd091567114_0$x2e8$x2dpreE+0x3ce)[0x7f20ce49291e]
/home/chris/opt/rust/bin/../lib/libstd-6c65cf4b443341b1-0.8-pre.so(+0x10ba22)[0x7f20ce492a22]
/home/chris/opt/rust/bin/../lib/libstd-6c65cf4b443341b1-0.8-pre.so(+0x10b471)[0x7f20ce492471]
/home/chris/opt/rust/bin/../lib/libstd-6c65cf4b443341b1-0.8-pre.so(+0x10b9dc)[0x7f20ce4929dc]
/home/chris/opt/rust/bin/../lib/libstd-6c65cf4b443341b1-0.8-pre.so(+0x10b471)[0x7f20ce492471]
/home/chris/opt/rust/bin/../lib/libstd-6c65cf4b443341b1-0.8-pre.so(+0x81c24)[0x7f20ce408c24]
/home/chris/opt/rust/bin/../lib/libsyntax-64629f7f0c6a9bc-0.8-pre.so(_ZN10diagnostic14__extensions__10meth_100605fatal17_e0de3d9f29108f6414_0$x2e8$x2dpreE+0x104)[0x7f20cd9289b4]
/home/chris/opt/rust/bin/../lib/libsyntax-64629f7f0c6a9bc-0.8-pre.so(_ZN10diagnostic14__extensions__10meth_101113bug17_e0de3d9f29108f6414_0$x2e8$x2dpreE+0xbc)[0x7f20cd92939c]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6driver7session14__extensions__10meth_225843bug16_e3e78dc632d928214_0$x2e8$x2dpreE+0x7e)[0x7f20cccd85ee]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6middle5trans9debuginfo15create_function17_fd8a269c7ed18de514_0$x2e8$x2dpreE+0x3d3)[0x7f20cce22443]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6middle5trans9debuginfo12create_block16_32d3b40cf56155214_0$x2e8$x2dpreE+0x5b9)[0x7f20cce87949]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6middle5trans9debuginfo17update_source_pos17_bf3a8dc7724bb7e414_0$x2e8$x2dpreE+0x4f7)[0x7f20ccd1a3c7]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6middle5trans11controlflow11trans_block17_ee7f10de21ab6c9114_0$x2e8$x2dpreE+0x1e3)[0x7f20ccd19133]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6middle5trans4base13trans_closure15_eb8c317d92aa4114_0$x2e8$x2dpreE+0x6f7)[0x7f20cce21597]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6middle5trans4base8trans_fn16_e7ca69dba5ead9314_0$x2e8$x2dpreE+0x46c)[0x7f20cccde86c]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6middle5trans4meth12trans_method15_4b2179042862d714_0$x2e8$x2dpreE+0x23a)[0x7f20ccd12aca]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6middle5trans12monomorphize14monomorphic_fn17_6e46edc17bf7cc1d14_0$x2e8$x2dpreE+0x2853)[0x7f20ccce1633]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6middle5trans6callee25trans_fn_ref_with_vtables17_966bf88471d939ae14_0$x2e8$x2dpreE+0x1c1b)[0x7f20ccd5cf5b]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6middle5trans6callee12trans_fn_ref15_6201f3a45fe54c14_0$x2e8$x2dpreE+0x63e)[0x7f20ccd56dfe]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6middle5trans4meth19trans_method_callee16_8c271f56084e55e14_0$x2e8$x2dpreE+0xa4f)[0x7f20ccd6569f]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(+0x1ba0f5)[0x7f20ccd640f5]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(+0x1cf877)[0x7f20ccd79877]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6middle5trans4base17with_scope_result17_b34fe6984565501914_0$x2e8$x2dpreE+0x19b)[0x7f20ccd262db]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6middle5trans6callee16trans_call_inner17_4e2d672a1713c67c14_0$x2e8$x2dpreE+0x100)[0x7f20ccd62bf0]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6middle5trans6callee17trans_method_call16_244e1becaccf29b14_0$x2e8$x2dpreE+0x6bb)[0x7f20ccd633bb]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6middle5trans4expr27trans_rvalue_dps_unadjusted17_a9cdd97d7831daaa14_0$x2e8$x2dpreE+0x6cd)[0x7f20ccd8983d]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6middle5trans4expr10trans_into17_a9cdd97d7831daaa14_0$x2e8$x2dpreE+0xad0)[0x7f20ccd1be50]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6middle5trans4base10trans_stmt17_a1207e2fc3dfb78f14_0$x2e8$x2dpreE+0x517)[0x7f20ccd1abd7]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6middle5trans11controlflow11trans_block17_ee7f10de21ab6c9114_0$x2e8$x2dpreE+0x110)[0x7f20ccd19060]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6middle5trans4base13trans_closure15_eb8c317d92aa4114_0$x2e8$x2dpreE+0x6f7)[0x7f20cce21597]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6middle5trans4base8trans_fn16_e7ca69dba5ead9314_0$x2e8$x2dpreE+0x46c)[0x7f20cccde86c]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6middle5trans4base10trans_item16_b0be10e6c143dbd14_0$x2e8$x2dpreE+0xc7b)[0x7f20cccd785b]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6middle5trans4base9trans_mod17_9439df66548551c914_0$x2e8$x2dpreE+0x8d)[0x7f20cce26dcd]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6middle5trans4base11trans_crate17_52eafc89c87e94d314_0$x2e8$x2dpreE+0x46e)[0x7f20cce3638e]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(+0x8187ac)[0x7f20cd3c27ac]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6driver6driver12compile_rest17_c3b419a0238ad86d14_0$x2e8$x2dpreE+0x2832)[0x7f20cd3c0042]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(+0x84bf34)[0x7f20cd3f5f34]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6driver6driver12compile_upto17_2aa9cc5bfaa1e08e14_0$x2e8$x2dpreE+0x13c)[0x7f20cd3c2adc]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN6driver6driver13compile_input15_7651cceb76d69d14_0$x2e8$x2dpreE+0xd5)[0x7f20cd3c2e75]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN12run_compiler16_5ecbadc50d5136214_0$x2e8$x2dpreE+0x192a)[0x7f20cd3e2c6a]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(+0x84bc5e)[0x7f20cd3f5c5e]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(+0x849707)[0x7f20cd3f3707]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(+0x8402fb)[0x7f20cd3ea2fb]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(+0x84bf34)[0x7f20cd3f5f34]
/home/chris/opt/rust/bin/../lib/libstd-6c65cf4b443341b1-0.8-pre.so(+0xdaa49)[0x7f20ce461a49]
/home/chris/opt/rust/bin/../lib/libstd-6c65cf4b443341b1-0.8-pre.so(+0x1599fc)[0x7f20ce4e09fc]
/home/chris/opt/rust/bin/../lib/librustrt.so(_Z18task_start_wrapperP10spawn_args+0x2b)[0x7f20cc973b2b]
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)[0x7f20cc97319b]
/home/chris/opt/rust/bin/../lib/librustrt.so(+0x2b899)[0x7f20cc984899]
/home/chris/opt/rust/bin/../lib/librustrt.so(upcall_fail+0x1a8)[0x7f20cc9751e8]
/home/chris/opt/rust/bin/../lib/libstd-6c65cf4b443341b1-0.8-pre.so(_ZN3sys13begin_unwind_16_89e154cd091567114_0$x2e8$x2dpreE+0x3ce)[0x7f20ce49291e]
/home/chris/opt/rust/bin/../lib/libstd-6c65cf4b443341b1-0.8-pre.so(+0x10ba22)[0x7f20ce492a22]
/home/chris/opt/rust/bin/../lib/libstd-6c65cf4b443341b1-0.8-pre.so(+0x10b471)[0x7f20ce492471]
/home/chris/opt/rust/bin/../lib/libstd-6c65cf4b443341b1-0.8-pre.so(+0x10b9dc)[0x7f20ce4929dc]
/home/chris/opt/rust/bin/../lib/libstd-6c65cf4b443341b1-0.8-pre.so(+0x10b471)[0x7f20ce492471]
/home/chris/opt/rust/bin/../lib/libstd-6c65cf4b443341b1-0.8-pre.so(+0x81c24)[0x7f20ce408c24]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN7monitor16_a04770b32d08dc114_0$x2e8$x2dpreE+0x29b5)[0x7f20cd3e61a5]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(+0x84bf34)[0x7f20cd3f5f34]
/home/chris/opt/rust/bin/../lib/librustc-d3cb8c2ccd84a7a7-0.8-pre.so(_ZN4main15_f3d16eaf7d573814_0$x2e8$x2dpreE+0x69)[0x7f20cd3f5b89]
/home/chris/opt/rust/bin/../lib/librustrt.so(_Z18task_start_wrapperP10spawn_args+0x2b)[0x7f20cc973b2b]
rust: domain main @0x181ad90 root task failed
leaked memory in rust main loop (1 objects)
rustc: /home/chris/vc/rust/src/rt/memory_region.cpp:192: memory_region::~memory_region(): Assertion `false' failed.
[1]    29254 abort (core dumped)  RUST_LOG=::rt::backtrace rustc -Z debug-info debug-info.rs

[michaelwoerister]

I may have a fix for this issue here: michaelwoerister@21920ac

At least the above example does not crash any more. I'll take another look at it tomorrow and clean it up.