Closed
Description
I was using nightly rust extensively for its async/await and specialization feature. After a recent update (nightly-2019-05-02), a new ICE introduced with following logs:
thread 'rustc' panicked at 'called `Option::unwrap()` on a `None` value', src/libcore/option.rs:347:21
stack backtrace:
0: 0x110e581b3 - std::sys::unix::backtrace::tracing::imp::unwind_backtrace::h6365da97c1471e71
1: 0x110e50892 - std::sys_common::backtrace::_print::h16aa04d49feca3fd
2: 0x110e54756 - std::panicking::default_hook::{{closure}}::h9fc4c0be5c9ca44c
3: 0x110e544ff - std::panicking::default_hook::h9f3e4e5508e6484c
4: 0x10fd84862 - rustc::util::common::panic_hook::h4551d4322cc0be4e
5: 0x110e54fb0 - std::panicking::rust_panic_with_hook::h297147e5cbed8f24
6: 0x110e549fc - std::panicking::continue_panic_fmt::h3ae1ed03b6fbf85b
7: 0x110e548e8 - rust_begin_unwind
8: 0x110e7bda1 - core::panicking::panic_fmt::h92ee99ae8e2af121
9: 0x110e7bce6 - core::panicking::panic::hb56cbf1700d827ce
10: 0x10fb86454 - rustc::hir::lowering::LoweringContext::lower_ty_direct::h9ebc55904e648f31
11: 0x10fb701f8 - <core::iter::adapters::Map<I,F> as core::iter::traits::iterator::Iterator>::fold::h653da98ee2e15104
12: 0x10fa9a102 - <alloc::vec::Vec<T> as alloc::vec::SpecExtend<T,I>>::from_iter::h736c20ebb9808f68
13: 0x10fb8c4f5 - rustc::hir::lowering::LoweringContext::lower_fn_decl::h65e61c23b5e1db51
14: 0x10fb97896 - rustc::hir::lowering::LoweringContext::lower_method_sig::hcc9e0b8d06e43390
15: 0x10fb83948 - <rustc::hir::lowering::LoweringContext::lower_crate::ItemLowerer as syntax::visit::Visitor>::visit_impl_item::hf58ebdc514d497b2
16: 0x10fc6b431 - syntax::visit::walk_item::h07763bacbb55de9b
17: 0x10fb81e06 - <rustc::hir::lowering::LoweringContext::lower_crate::ItemLowerer as syntax::visit::Visitor>::visit_item::h0d167e58e23044e6
18: 0x10fb81aab - <rustc::hir::lowering::LoweringContext::lower_crate::ItemLowerer as syntax::visit::Visitor>::visit_mod::hd9777ed3e1d08615
19: 0x10fb80aa3 - rustc::hir::lowering::lower_crate::h0c5e238015c897e0
20: 0x10cc0a276 - rustc::util::common::time::h348b235e44461401
21: 0x10cb636e9 - rustc_interface::passes::BoxedResolver::access::{{closure}}::h5e3406b2f5a3ba63
22: 0x10cbaf2a4 - rustc_interface::passes::configure_and_expand::{{closure}}::hab3456cc016f1063
23: 0x10cb87880 - rustc_data_structures::box_region::PinnedGenerator<I,A,R>::access::h947d707adafbf1b3
24: 0x10cbf43d2 - rustc_interface::queries::Query<T>::compute::h0c12b0325a8fa361
25: 0x10cbf4f7e - rustc_interface::queries::Query<T>::compute::h419fdaafe2fe1061
26: 0x10cbdffbb - rustc_interface::queries::<impl rustc_interface::interface::Compiler>::prepare_outputs::h0b2ca183a9af9723
27: 0x10c9b1141 - rustc_interface::interface::run_compiler_in_existing_thread_pool::h6a703186bc682b69
28: 0x10ca29396 - std::thread::local::LocalKey<T>::with::h31807013e3f0179f
29: 0x10c9f7ad5 - scoped_tls::ScopedKey<T>::set::h4a42df1285ef48d6
30: 0x10ca24f42 - syntax::with_globals::h968f8ffc9c58c643
31: 0x10c995988 - std::sys_common::backtrace::__rust_begin_short_backtrace::h209394f9599ce87a
32: 0x110e645ee - __rust_maybe_catch_panic
33: 0x10c9adea6 - core::ops::function::FnOnce::call_once{{vtable.shim}}::h56573a7f40ae7fa3
34: 0x110e3688d - <alloc::boxed::Box<F> as core::ops::function::FnOnce<A>>::call_once::hc80e6bd391717f52
35: 0x110e633ad - std::sys::unix::thread::Thread::new::thread_start::hfe8c382e207f42b7
36: 0x7fff6444f304 - _pthread_body
37: 0x7fff6445226e - _pthread_start
After a quick search it seems like this is the only unwrap in direct cause lower_ty_direct (stack frame 10).
I cannot share the code or produce a minimal case because the code base is rather big.