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ICE with const generics with explicit lifetime argument #60814

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moxian opened this issue May 14, 2019 · 8 comments
Closed

ICE with const generics with explicit lifetime argument #60814

moxian opened this issue May 14, 2019 · 8 comments
Labels
A-const-generics Area: const generics (parameters and arguments) C-bug Category: This is a bug. F-const_generics `#![feature(const_generics)]` glacier ICE tracked in rust-lang/glacier. I-ICE Issue: The compiler panicked, giving an Internal Compilation Error (ICE) ❄️ requires-nightly This issue requires a nightly compiler in some way. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue.

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@moxian
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moxian commented May 14, 2019

This is a very slight modification of an example in #60813, but filing as a separate bug, since the error message is very different.

The following code

#![feature(const_generics)]

pub fn function_with_str<'a, const STRING: &'a str>() {
}

pub fn use_it() {
    function_with_str::<"Hello, world!">()
}

results in the following ICE:

   Compiling playground v0.0.1 (/playground)
warning: the feature `const_generics` is incomplete and may cause the compiler to crash
 --> src/lib.rs:1:12
  |
1 | #![feature(const_generics)]
  |            ^^^^^^^^^^^^^^

error: internal compiler error: src/librustc/ty/subst.rs:489: Region parameter out of range when substituting in region 'a (root type=Some(&'a str)) (index=0)

thread 'rustc' panicked at 'Box<Any>', src/librustc_errors/lib.rs:572:9
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
stack backtrace:
   0: std::sys::unix::backtrace::tracing::imp::unwind_backtrace
             at src/libstd/sys/unix/backtrace/tracing/gcc_s.rs:39
   1: std::sys_common::backtrace::_print
             at src/libstd/sys_common/backtrace.rs:71
   2: std::panicking::default_hook::{{closure}}
             at src/libstd/sys_common/backtrace.rs:59
             at src/libstd/panicking.rs:197
   3: std::panicking::default_hook
             at src/libstd/panicking.rs:211
   4: rustc::util::common::panic_hook
   5: std::panicking::rust_panic_with_hook
             at src/libstd/panicking.rs:478
   6: std::panicking::begin_panic
   7: rustc_errors::Handler::span_bug
   8: rustc::util::bug::opt_span_bug_fmt::{{closure}}
   9: rustc::ty::context::tls::with_opt::{{closure}}
  10: rustc::ty::context::tls::with_context_opt
  11: rustc::ty::context::tls::with_opt
  12: rustc::util::bug::opt_span_bug_fmt
  13: rustc::util::bug::span_bug_fmt
  14: <rustc::ty::subst::SubstFolder as rustc::ty::fold::TypeFolder>::fold_region
  15: rustc::ty::structural_impls::<impl rustc::ty::fold::TypeFoldable for &rustc::ty::TyS>::super_fold_with
  16: <rustc::ty::subst::SubstFolder as rustc::ty::fold::TypeFolder>::fold_ty
  17: rustc::ty::instance::Instance::resolve
  18: <rustc::traits::project::AssociatedTypeNormalizer as rustc::ty::fold::TypeFolder>::fold_const
  19: <smallvec::SmallVec<A> as core::iter::traits::collect::FromIterator<<A as smallvec::Array>::Item>>::from_iter
  20: rustc::ty::fold::TypeFoldable::fold_with
  21: rustc::ty::structural_impls::<impl rustc::ty::fold::TypeFoldable for &rustc::ty::TyS>::super_fold_with
  22: <rustc::traits::project::AssociatedTypeNormalizer as rustc::ty::fold::TypeFolder>::fold_ty
  23: rustc::traits::project::normalize
  24: rustc_typeck::check::FnCtxt::instantiate_value_path
  25: rustc_typeck::check::FnCtxt::check_expr_kind
  26: rustc_typeck::check::FnCtxt::check_expr_with_expectation_and_needs
  27: rustc_typeck::check::callee::<impl rustc_typeck::check::FnCtxt>::check_call
  28: rustc_typeck::check::FnCtxt::check_expr_kind
  29: rustc_typeck::check::FnCtxt::check_expr_with_expectation_and_needs
  30: rustc_typeck::check::FnCtxt::check_block_with_expected
  31: rustc_typeck::check::FnCtxt::check_expr_kind
  32: rustc_typeck::check::FnCtxt::check_expr_with_expectation_and_needs
  33: rustc_typeck::check::FnCtxt::check_return_expr
  34: rustc_typeck::check::check_fn
  35: rustc::ty::context::GlobalCtxt::enter_local
  36: rustc_typeck::check::typeck_tables_of
  37: rustc::ty::query::__query_compute::typeck_tables_of
  38: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::typeck_tables_of>::compute
  39: rustc::dep_graph::graph::DepGraph::with_task_impl
  40: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  41: rustc::ty::<impl rustc::ty::context::TyCtxt>::par_body_owners
  42: rustc_typeck::check::typeck_item_bodies
  43: rustc::ty::query::__query_compute::typeck_item_bodies
  44: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::typeck_item_bodies>::compute
  45: rustc::dep_graph::graph::DepGraph::with_task_impl
  46: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  47: rustc::util::common::time
  48: rustc_typeck::check_crate
  49: rustc_interface::passes::analysis
  50: rustc::ty::query::__query_compute::analysis
  51: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::analysis>::compute
  52: rustc::dep_graph::graph::DepGraph::with_task_impl
  53: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  54: rustc::ty::context::tls::enter_global
  55: rustc_interface::passes::BoxedGlobalCtxt::access::{{closure}}
  56: rustc_interface::passes::create_global_ctxt::{{closure}}
  57: rustc_interface::interface::run_compiler_in_existing_thread_pool
  58: std::thread::local::LocalKey<T>::with
  59: scoped_tls::ScopedKey<T>::set
  60: syntax::with_globals
query stack during panic:
#0 [typeck_tables_of] processing `use_it`
#1 [typeck_item_bodies] type-checking all item bodies
#2 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to previous error


note: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports

note: rustc 1.36.0-nightly (a9ec99f42 2019-05-13) running on x86_64-unknown-linux-gnu

note: compiler flags: -C codegen-units=1 -C debuginfo=2 --crate-type lib

note: some of the compiler flags provided by cargo are hidden

error: Could not compile `playground`.

To learn more, run the command again with --verbose.

Playground link

cc @Serentty
@hellow554
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@rustbot modify labels: I-ICE C-Bug T-compiler A-const-generics

@rustbot rustbot added A-const-generics Area: const generics (parameters and arguments) C-bug Category: This is a bug. I-ICE Issue: The compiler panicked, giving an Internal Compilation Error (ICE) ❄️ T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels May 14, 2019
@varkor
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varkor commented May 14, 2019 •
edited
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Ah, this is interesting. I don't think we intend to allow consts to be parameterised over other generic parameters just yet. Currently, you cannot parameterise a const by a type parameter, but we also should exclude lifetime parameters (for now).

Edit: it seems like the implementation of fold_const for AssociatedTypeNormalizer might be wrong.

@hellow554 hellow554 mentioned this issue May 23, 2019
Closed
@Centril Centril added requires-nightly This issue requires a nightly compiler in some way. F-const_generics `#![feature(const_generics)]` labels Aug 6, 2019
@BenLewis-Seequent
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The current ICE is:
error: internal compiler error: src/librustc_mir/borrow_check/nll/universal_regions.rs:741: cannot convert ReEarlyBound(0, 'a) to a region vid

thread 'rustc' panicked at 'Box<Any>', src/librustc_errors/lib.rs:912:9
stack backtrace:
   0: backtrace::backtrace::libunwind::trace
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.37/src/backtrace/libunwind.rs:88
   1: backtrace::backtrace::trace_unsynchronized
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.37/src/backtrace/mod.rs:66
   2: std::sys_common::backtrace::_print_fmt
             at src/libstd/sys_common/backtrace.rs:76
   3: <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt
             at src/libstd/sys_common/backtrace.rs:60
   4: core::fmt::write
             at src/libcore/fmt/mod.rs:1028
   5: std::io::Write::write_fmt
             at src/libstd/io/mod.rs:1412
   6: std::sys_common::backtrace::_print
             at src/libstd/sys_common/backtrace.rs:64
   7: std::sys_common::backtrace::print
             at src/libstd/sys_common/backtrace.rs:49
   8: std::panicking::default_hook::{{closure}}
             at src/libstd/panicking.rs:196
   9: std::panicking::default_hook
             at src/libstd/panicking.rs:210
  10: rustc_driver::report_ice
  11: std::panicking::rust_panic_with_hook
             at src/libstd/panicking.rs:477
  12: std::panicking::begin_panic
  13: rustc_errors::HandlerInner::bug
  14: rustc_errors::Handler::bug
  15: rustc::util::bug::opt_span_bug_fmt::{{closure}}
  16: rustc::ty::context::tls::with_opt::{{closure}}
  17: rustc::ty::context::tls::with_context_opt
  18: rustc::ty::context::tls::with_opt
  19: rustc::util::bug::opt_span_bug_fmt
  20: rustc::util::bug::bug_fmt
  21: rustc_mir::borrow_check::nll::universal_regions::UniversalRegionIndices::to_region_vid::{{closure}}
  22: rustc_mir::borrow_check::nll::universal_regions::UniversalRegionIndices::fold_to_region_vids::{{closure}}
  23: rustc::ty::structural_impls::<impl rustc::ty::fold::TypeFoldable for &rustc::ty::TyS>::super_fold_with
  24: rustc_mir::borrow_check::nll::universal_regions::UniversalRegions::new
  25: rustc_mir::borrow_check::nll::replace_regions_in_mir
  26: rustc_mir::borrow_check::do_mir_borrowck
  27: rustc::ty::context::GlobalCtxt::enter_local
  28: rustc_mir::borrow_check::mir_borrowck
  29: rustc::ty::query::__query_compute::mir_borrowck
  30: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::mir_borrowck>::compute
  31: rustc::dep_graph::graph::DepGraph::with_task_impl
  32: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  33: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::ensure_query
  34: rustc_mir::transform::optimized_mir
  35: rustc::ty::query::__query_compute::optimized_mir
  36: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::optimized_mir>::compute
  37: rustc::dep_graph::graph::DepGraph::with_task_impl
  38: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  39: rustc_mir::interpret::eval_context::InterpCx<M>::load_mir
  40: rustc_mir::const_eval::const_eval_raw_provider
  41: rustc::ty::query::__query_compute::const_eval_raw
  42: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::const_eval_raw>::compute
  43: rustc::dep_graph::graph::DepGraph::with_task_impl
  44: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  45: rustc_mir::const_eval::const_eval_provider
  46: rustc::ty::query::__query_compute::const_eval
  47: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::const_eval>::compute
  48: rustc::dep_graph::graph::DepGraph::with_task_impl
  49: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  50: rustc_mir::const_eval::const_eval_provider
  51: rustc::ty::query::__query_compute::const_eval
  52: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::const_eval>::compute
  53: rustc::dep_graph::graph::DepGraph::with_task_impl
  54: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  55: rustc::ty::sty::Const::eval
  56: <smallvec::SmallVec<A> as core::iter::traits::collect::FromIterator<<A as smallvec::Array>::Item>>::from_iter
  57: rustc::ty::fold::TypeFoldable::fold_with
  58: <rustc::traits::project::AssocTypeNormalizer as rustc::ty::fold::TypeFolder>::fold_ty
  59: rustc::traits::project::normalize
  60: rustc_typeck::check::FnCtxt::instantiate_value_path
  61: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_kind
  62: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_with_expectation_and_needs
  63: rustc_typeck::check::callee::<impl rustc_typeck::check::FnCtxt>::check_call
  64: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_kind
  65: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_with_expectation_and_needs
  66: rustc_typeck::check::FnCtxt::check_block_with_expected
  67: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_kind
  68: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_with_expectation_and_needs
  69: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_return_expr
  70: rustc_typeck::check::check_fn
  71: rustc::ty::context::GlobalCtxt::enter_local
  72: rustc_typeck::check::typeck_tables_of
  73: rustc::ty::query::__query_compute::typeck_tables_of
  74: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::typeck_tables_of>::compute
  75: rustc::dep_graph::graph::DepGraph::with_task_impl
  76: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  77: rustc::ty::<impl rustc::ty::context::TyCtxt>::par_body_owners
  78: rustc_typeck::check::typeck_item_bodies
  79: rustc::ty::query::__query_compute::typeck_item_bodies
  80: rustc::dep_graph::graph::DepGraph::with_task_impl
  81: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  82: rustc::util::common::time
  83: rustc_typeck::check_crate
  84: rustc_interface::passes::analysis
  85: rustc::ty::query::__query_compute::analysis
  86: rustc::dep_graph::graph::DepGraph::with_task_impl
  87: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  88: rustc::ty::context::tls::enter_global
  89: rustc_interface::passes::BoxedGlobalCtxt::access::{{closure}}
  90: rustc_interface::passes::create_global_ctxt::{{closure}}
  91: rustc_interface::interface::run_compiler_in_existing_thread_pool
  92: std::thread::local::LocalKey<T>::with
  93: syntax::with_globals
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

note: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports

note: rustc 1.40.0-nightly (084beb83e 2019-09-27) running on x86_64-unknown-linux-gnu

note: compiler flags: -C codegen-units=1 -C debuginfo=2 --crate-type lib

note: some of the compiler flags provided by cargo are hidden

query stack during panic:
thread 'rustc' panicked at 'already borrowed: BorrowMutError', src/libcore/result.rs:1165:5
stack backtrace:
   0:     0x7fee13d27af4 - backtrace::backtrace::libunwind::trace::ha5983032afb4d10c
                               at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.37/src/backtrace/libunwind.rs:88
   1:     0x7fee13d27af4 - backtrace::backtrace::trace_unsynchronized::hcde1d0d574f77864
                               at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.37/src/backtrace/mod.rs:66
   2:     0x7fee13d27af4 - std::sys_common::backtrace::_print_fmt::he5e6e380d77c46da
                               at src/libstd/sys_common/backtrace.rs:76
   3:     0x7fee13d27af4 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h2828e17b2f96be03
                               at src/libstd/sys_common/backtrace.rs:60
   4:     0x7fee13d6013c - core::fmt::write::h56881cea5b0fc863
                               at src/libcore/fmt/mod.rs:1028
   5:     0x7fee13d1bd17 - std::io::Write::write_fmt::h7e23e2336d419271
                               at src/libstd/io/mod.rs:1412
   6:     0x7fee13d2c325 - std::sys_common::backtrace::_print::h17d82b35dd2dffa0
                               at src/libstd/sys_common/backtrace.rs:64
   7:     0x7fee13d2c325 - std::sys_common::backtrace::print::h8a39b56b63e48ce4
                               at src/libstd/sys_common/backtrace.rs:49
   8:     0x7fee13d2c325 - std::panicking::default_hook::{{closure}}::h5eeec7a4ddaaba52
                               at src/libstd/panicking.rs:196
   9:     0x7fee13d2c016 - std::panicking::default_hook::h66510563f6c6226f
                               at src/libstd/panicking.rs:210
  10:     0x7fee142585b3 - rustc_driver::report_ice::h1c629111e9f307b8
  11:     0x7fee13d2cb0c - std::panicking::rust_panic_with_hook::h12ec097c8ec6e99f
                               at src/libstd/panicking.rs:477
  12:     0x7fee13d2c5c2 - std::panicking::continue_panic_fmt::h5bf5b33e69b73cec
                               at src/libstd/panicking.rs:380
  13:     0x7fee13d2c4b6 - rust_begin_unwind
                               at src/libstd/panicking.rs:307
  14:     0x7fee13d59aca - core::panicking::panic_fmt::he80091724924a82c
                               at src/libcore/panicking.rs:84
  15:     0x7fee13d59d07 - core::result::unwrap_failed::h72740bd67ffc7cd7
                               at src/libcore/result.rs:1165
  16:     0x7fee1605eea5 - rustc_errors::Handler::force_print_diagnostic::h39e643eb1cc2a78a
  17:     0x7fee15934031 - rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::try_print_query_stack::h050a2688d5964137
  18:     0x7fee142591c0 - rustc_driver::report_ice::h1c629111e9f307b8
  19:     0x7fee13d2cb0c - std::panicking::rust_panic_with_hook::h12ec097c8ec6e99f
                               at src/libstd/panicking.rs:477
  20:     0x7fee1604589d - std::panicking::begin_panic::h4199802c8e4d790b
  21:     0x7fee1605f7c3 - rustc_errors::HandlerInner::bug::h9cd50550a7a56234
  22:     0x7fee1605e48a - rustc_errors::Handler::bug::hafbfb033a9f794cc
  23:     0x7fee158f48f3 - rustc::util::bug::opt_span_bug_fmt::{{closure}}::ha31ac8110405284c
  24:     0x7fee158efbb3 - rustc::ty::context::tls::with_opt::{{closure}}::h28854b2634b6f3b7
  25:     0x7fee158efb23 - rustc::ty::context::tls::with_context_opt::h03c933b0a2d32a88
  26:     0x7fee158efb67 - rustc::ty::context::tls::with_opt::ha89131ef0a05072b
  27:     0x7fee158f4808 - rustc::util::bug::opt_span_bug_fmt::h9b3e8e6451c1aa0d
  28:     0x7fee158f4772 - rustc::util::bug::bug_fmt::h5291243634e000d6
  29:     0x7fee14d5f252 - rustc_mir::borrow_check::nll::universal_regions::UniversalRegionIndices::to_region_vid::{{closure}}::h8612057275a898c1
  30:     0x7fee14c723f8 - rustc_mir::borrow_check::nll::universal_regions::UniversalRegionIndices::fold_to_region_vids::{{closure}}::h0953af38a7078e37
  31:     0x7fee14c7c934 - rustc::ty::structural_impls::<impl rustc::ty::fold::TypeFoldable for &rustc::ty::TyS>::super_fold_with::h8b02d7fb2dcab4b0
  32:     0x7fee14d5d536 - rustc_mir::borrow_check::nll::universal_regions::UniversalRegions::new::h7fcc25cec5b78174
  33:     0x7fee14ee654c - rustc_mir::borrow_check::nll::replace_regions_in_mir::he9d731fff3d7a090
  34:     0x7fee14ca7ebf - rustc_mir::borrow_check::do_mir_borrowck::hc39a57967360e334
  35:     0x7fee14c6d871 - rustc::ty::context::GlobalCtxt::enter_local::h29949b025c5ba6d1
  36:     0x7fee14ca7b7d - rustc_mir::borrow_check::mir_borrowck::h018e7e1ada6edfeb
  37:     0x7fee14cc7412 - rustc::ty::query::__query_compute::mir_borrowck::h8dc8b1616af15f3a
  38:     0x7fee14be798c - rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::mir_borrowck>::compute::hdcb9f6976a4a08bb
  39:     0x7fee14d38eb4 - rustc::dep_graph::graph::DepGraph::with_task_impl::hde7fb5c62185a36b
  40:     0x7fee14c457e5 - rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query::hb4708141f0981130
  41:     0x7fee14be7f42 - rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::ensure_query::h7547adcea9b278af
  42:     0x7fee14bd2206 - rustc_mir::transform::optimized_mir::hf03249ac0924248a
  43:     0x7fee14cc7877 - rustc::ty::query::__query_compute::optimized_mir::h794b24a7edaf132b
  44:     0x7fee14be7a3b - rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::optimized_mir>::compute::h3f30d6f9c2410248
  45:     0x7fee14d33a7a - rustc::dep_graph::graph::DepGraph::with_task_impl::ha52cfdd56dfba685
  46:     0x7fee14c6917b - rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query::hfd16edc3b4feea06
  47:     0x7fee14d69187 - rustc_mir::interpret::eval_context::InterpCx<M>::load_mir::h2de2515521415ee7
  48:     0x7fee14bd934e - rustc_mir::const_eval::const_eval_raw_provider::h671d68a4defeaffb
  49:     0x7fee14cc7b83 - rustc::ty::query::__query_compute::const_eval_raw::hf13b2828fb4ba75b
  50:     0x7fee14be7aba - rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::const_eval_raw>::compute::hb9ed27d8ad9172ec
  51:     0x7fee14d27d9f - rustc::dep_graph::graph::DepGraph::with_task_impl::h1c6091fc643d2537
  52:     0x7fee14c3be1d - rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query::h91e0da907a6a694d
  53:     0x7fee14bd83a1 - rustc_mir::const_eval::const_eval_provider::h8e2a58add2486388
  54:     0x7fee14cc6f73 - rustc::ty::query::__query_compute::const_eval::hfd2ea6f750148679
  55:     0x7fee14be78ca - rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::const_eval>::compute::h6c2a76ec5e5ab95d
  56:     0x7fee14d360ca - rustc::dep_graph::graph::DepGraph::with_task_impl::hcb79c6e82af5d3c7
  57:     0x7fee14c2650b - rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query::h5229152ade8d4d0a
  58:     0x7fee14bd814a - rustc_mir::const_eval::const_eval_provider::h8e2a58add2486388
  59:     0x7fee157ddcea - rustc::ty::query::__query_compute::const_eval::hc34072f292851a88
  60:     0x7fee15afcf8a - rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::const_eval>::compute::h6c2a76ec5e5ab95d
  61:     0x7fee1568e596 - rustc::dep_graph::graph::DepGraph::with_task_impl::heefbde2df5b44b1a
  62:     0x7fee15a17d64 - rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query::hf11cd80153774b60
  63:     0x7fee15b5329e - rustc::ty::sty::Const::eval::h0eae12e23a55375c
  64:     0x7fee1571e5bd - <smallvec::SmallVec<A> as core::iter::traits::collect::FromIterator<<A as smallvec::Array>::Item>>::from_iter::h8d0b1b3ea78f477f
  65:     0x7fee15b40abb - rustc::ty::fold::TypeFoldable::fold_with::hb1bda0c820fbf271
  66:     0x7fee15b36de5 - <rustc::traits::project::AssocTypeNormalizer as rustc::ty::fold::TypeFolder>::fold_ty::h747449a17c0dab0b
  67:     0x7fee149c5402 - rustc::traits::project::normalize::hd2067db985d0231a
  68:     0x7fee147f1cf7 - rustc_typeck::check::FnCtxt::instantiate_value_path::h50ee1884851af0d7
  69:     0x7fee147ba5d7 - rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_kind::he47250f016a8eef2
  70:     0x7fee147b744b - rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_with_expectation_and_needs::h0c40a8d4b8ce32dc
  71:     0x7fee147d15b9 - rustc_typeck::check::callee::<impl rustc_typeck::check::FnCtxt>::check_call::hbcf8c36ff5442110
  72:     0x7fee147b806f - rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_kind::he47250f016a8eef2
  73:     0x7fee147b744b - rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_with_expectation_and_needs::h0c40a8d4b8ce32dc
  74:     0x7fee147eddd8 - rustc_typeck::check::FnCtxt::check_block_with_expected::h96f4b7ca7329cd3f
  75:     0x7fee147b808a - rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_kind::he47250f016a8eef2
  76:     0x7fee147b744b - rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_with_expectation_and_needs::h0c40a8d4b8ce32dc
  77:     0x7fee147c153b - rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_return_expr::h97fe5415cfd05f0b
  78:     0x7fee147daefd - rustc_typeck::check::check_fn::h859fc3661b72bd16
  79:     0x7fee1494b9e8 - rustc::ty::context::GlobalCtxt::enter_local::hac2f7370bf276850
  80:     0x7fee147da038 - rustc_typeck::check::typeck_tables_of::h59f8043f3f17ac24
  81:     0x7fee1482b88a - rustc::ty::query::__query_compute::typeck_tables_of::h42163918d08f8266
  82:     0x7fee148c29db - rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::typeck_tables_of>::compute::h09b0f5088548e8ae
  83:     0x7fee14852eda - rustc::dep_graph::graph::DepGraph::with_task_impl::h723db1099faa82fb
  84:     0x7fee1492ea6b - rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query::hc60a06724fc07dfe
  85:     0x7fee148bf76f - rustc::ty::<impl rustc::ty::context::TyCtxt>::par_body_owners::hcfb519f359bb6929
  86:     0x7fee147d9aad - rustc_typeck::check::typeck_item_bodies::hc913bf0ca937a1f4
  87:     0x7fee1482bcd5 - rustc::ty::query::__query_compute::typeck_item_bodies::h758eadccaa8a2c0c
  88:     0x7fee148547fe - rustc::dep_graph::graph::DepGraph::with_task_impl::h976b38fc2413d3fd
  89:     0x7fee148de27b - rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query::h27900a70a9748c27
  90:     0x7fee148305ee - rustc::util::common::time::hcd7c3e9497174d75
  91:     0x7fee14a0b1ef - rustc_typeck::check_crate::h892282f507cd6731
  92:     0x7fee143043ca - rustc_interface::passes::analysis::hd64918a47f1f7d3a
  93:     0x7fee14216c61 - rustc::ty::query::__query_compute::analysis::h0229eceff6d5a7c8
  94:     0x7fee141fa8fd - rustc::dep_graph::graph::DepGraph::with_task_impl::h8bf215e7a8cc2169
  95:     0x7fee1420cd9e - rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query::h8e7e99bf128d8deb
  96:     0x7fee1424fa05 - rustc::ty::context::tls::enter_global::h534d47119b4c622e
  97:     0x7fee1422ccc7 - rustc_interface::passes::BoxedGlobalCtxt::access::{{closure}}::hcffbc94c8465e346
  98:     0x7fee143356db - rustc_interface::passes::create_global_ctxt::{{closure}}::hca029ea5891e3746
  99:     0x7fee1422de2b - rustc_interface::interface::run_compiler_in_existing_thread_pool::h25b2e9493fee162d
 100:     0x7fee14259b52 - std::thread::local::LocalKey<T>::with::hcac2a20d00f0f99f
 101:     0x7fee142737d0 - syntax::with_globals::h7fb4835074222545
 102:     0x7fee14212e40 - std::sys_common::backtrace::__rust_begin_short_backtrace::h098e301179af4344
 103:     0x7fee13d3d25a - __rust_maybe_catch_panic
                               at src/libpanic_unwind/lib.rs:80
 104:     0x7fee14218fe9 - core::ops::function::FnOnce::call_once{{vtable.shim}}::h395db1c737913721
 105:     0x7fee13d0e1ff - <alloc::boxed::Box<F> as core::ops::function::FnOnce<A>>::call_once::hb018c40cf7dc8a37
                               at /rustc/084beb83e0e87d673d5fabc844d28e8e8ae2ab4c/src/liballoc/boxed.rs:922
 106:     0x7fee13d3bf00 - <alloc::boxed::Box<F> as core::ops::function::FnOnce<A>>::call_once::h10e62b586f634658
                               at /rustc/084beb83e0e87d673d5fabc844d28e8e8ae2ab4c/src/liballoc/boxed.rs:922
 107:     0x7fee13d3bf00 - std::sys_common::thread::start_thread::h6ada4f3bef71d083
                               at src/libstd/sys_common/thread.rs:13
 108:     0x7fee13d3bf00 - std::sys::unix::thread::Thread::new::thread_start::h65408e9b6d37b640
                               at src/libstd/sys/unix/thread.rs:79
 109:     0x7fee13aa86db - start_thread
 110:     0x7fee133c588f - __clone
 111:                0x0 - <unknown>

error: internal compiler error: unexpected panic

note: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports

note: rustc 1.40.0-nightly (084beb83e 2019-09-27) running on x86_64-unknown-linux-gnu

note: compiler flags: -C codegen-units=1 -C debuginfo=2 --crate-type lib

note: some of the compiler flags provided by cargo are hidden

query stack during panic:
thread panicked while processing panic. aborting.
error: could not compile `playground`.

@rust-lang-glacier-bot rust-lang-glacier-bot added the glacier ICE tracked in rust-lang/glacier. label Oct 15, 2019
@snf snf mentioned this issue Jan 5, 2020
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@ghost
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ghost commented Jun 14, 2020 •
edited by ghost
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Shouldn't the code actually fail to compile?
Lifetimes like that in const are not allowed, correct?
As far as I understand only 'static lifetimes are allowed in const / static variables.

For example, this code is very similar and fails to compile:

fn greet<'a>(name: &'a str) {
    const HELLO: &'a str = "Hello";

    println!("{} {}", HELLO, name);
}
error[E0261]: use of undeclared lifetime name `'a`
 --> src/main.rs:2:19
  |
2 |     const HELLO: &'a str = "Hello";
  |                   ^^ undeclared lifetime

error: aborting due to previous error

The const HELLO refers to lifetime 'a but rustc doesn't accept that.
So I think we should throw a similar error for the const generics case.

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varkor commented Jun 14, 2020

The nomenclature is a bit confusing, but const variables don't act the same way that const generic parameters do. It doesn't make sense to have a const variable with a non-static lifetime, because consts should really be thought of as global declarations. However, const parameters are local, and may well refer to non-static lifetimes.

@ghost
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ghost commented Jun 15, 2020

Ok, thanks for the answer! I will dig into this today. See what I find.

I'm curious however why there is this difference. Can I read up on that somewhere? What is a valid use case for non-static lifetimes in const generics?

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varkor commented Jun 15, 2020

The difference is just due to the word "const" being reused for different things. Const variables are essentially just inlined, whereas const parameters are values that are are guaranteed to be constant, and known at compile time. In theory, I don't see why consts couldn't have non-static lifetimes in general. I don't know of a realistic example for non-static lifetimes in const generics either, but there's no technical reason they shouldn't work, so we should fix it :)

This was referenced Jul 5, 2020
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yodaldevoid added a commit to yodaldevoid/rust that referenced this issue Jul 19, 2020
@yodaldevoid
disallow non-static lifetimes in const generics
69d5dd6 
This has been put in place to patch over an ICE caused when we encounter
a non-static lifetime in a const generic during borrow checking. This
restriction may be relaxed in the future, but we need more discussion
before then, and in the meantime we should still deal with this ICE.

Fixes issue rust-lang#60814
Manishearth added a commit to Manishearth/rust that referenced this issue Jul 20, 2020
@Manishearth
Rollup merge of rust-lang#74051 - yodaldevoid:issue_60814, r=nikomats…
991da05 
…akis

disallow non-static lifetimes in const generics

Disallow non-static lifetimes in const generics in order to to patch over an ICE caused when we encounter a non-static lifetime in a const generic during borrow checking. This restriction may be relaxed in the future, but we need more discussion before then, and in the meantime we should still deal with this ICE.

Fixes issue rust-lang#60814
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varkor commented Jul 22, 2020

Fixed by #74051.

@varkor varkor closed this as completed Jul 22, 2020
@github-actions github-actions bot mentioned this issue Jul 23, 2020
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A-const-generics Area: const generics (parameters and arguments) C-bug Category: This is a bug. F-const_generics `#![feature(const_generics)]` glacier ICE tracked in rust-lang/glacier. I-ICE Issue: The compiler panicked, giving an Internal Compilation Error (ICE) ❄️ requires-nightly This issue requires a nightly compiler in some way. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue.
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