Closed
Description
I tried compiling this code:
struct Matrix<const ROWS: usize, const COLS: usize> {
elements: [f64; ROWS * COLS]
}
I expected to see this happen:
error[E0658]: const generics are unstable
--> src/matrix.rs:2:21
|
2 | struct Matrix<const ROWS: usize, const COLS: usize> {
| ^^^^
|
= note: see issue #44580 <https://github.com/rust-lang/rust/issues/44580> for more information
= help: add `#![feature(const_generics)]` to the crate attributes to enable
error[E0658]: const generics are unstable
--> src/matrix.rs:2:40
|
2 | struct Matrix<const ROWS: usize, const COLS: usize> {
| ^^^^
|
= note: see issue #44580 <https://github.com/rust-lang/rust/issues/44580> for more information
= help: add `#![feature(const_generics)]` to the crate attributes to enable
Instead, rustc also panicked:
error[E0658]: const generics are unstable
--> src/matrix.rs:2:21
|
2 | struct Matrix<const ROWS: usize, const COLS: usize> {
| ^^^^
|
= note: see issue #44580 <https://github.com/rust-lang/rust/issues/44580> for more information
= help: add `#![feature(const_generics)]` to the crate attributes to enable
error[E0658]: const generics are unstable
--> src/matrix.rs:2:40
|
2 | struct Matrix<const ROWS: usize, const COLS: usize> {
| ^^^^
|
= note: see issue #44580 <https://github.com/rust-lang/rust/issues/44580> for more information
= help: add `#![feature(const_generics)]` to the crate attributes to enable
error: internal compiler error: src/librustc_middle/ty/subst.rs:594:17: const parameter `ROWS/#0` (Const { ty: usize, val: Param(ROWS/#0) }/0) out of range when substituting substs=[]
thread 'rustc' panicked at 'Box<Any>', /rustc/346aec9b02f3c74f3fce97fd6bda24709d220e49/src/libstd/macros.rs:13:23
note: run with `RUST_BACKTRACE=1` environment variable to display a 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 1.46.0-nightly (346aec9b0 2020-07-11) running on x86_64-unknown-linux-gnu
note: compiler flags: -C embed-bitcode=no -C debuginfo=2 -C incremental --crate-type lib
note: some of the compiler flags provided by cargo are hidden
error: aborting due to 3 previous errors
Note: rustc doesn't panic if I add
#![feature(const_generics)]
to the top of the crate root.
Meta
rustc --version --verbose:
rustc 1.46.0-nightly (346aec9b0 2020-07-11)
binary: rustc
commit-hash: 346aec9b02f3c74f3fce97fd6bda24709d220e49
commit-date: 2020-07-11
host: x86_64-unknown-linux-gnu
release: 1.46.0-nightly
LLVM version: 10.0
Backtrace
stack backtrace:
0: backtrace::backtrace::libunwind::trace
at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.46/src/backtrace/libunwind.rs:86
1: backtrace::backtrace::trace_unsynchronized
at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.46/src/backtrace/mod.rs:66
2: std::sys_common::backtrace::_print_fmt
at src/libstd/sys_common/backtrace.rs:78
3: <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt
at src/libstd/sys_common/backtrace.rs:59
4: core::fmt::write
at src/libcore/fmt/mod.rs:1076
5: std::io::Write::write_fmt
at src/libstd/io/mod.rs:1537
6: std::sys_common::backtrace::_print
at src/libstd/sys_common/backtrace.rs:62
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:198
9: std::panicking::default_hook
at src/libstd/panicking.rs:217
10: rustc_driver::report_ice
11: std::panicking::rust_panic_with_hook
at src/libstd/panicking.rs:530
12: std::panicking::begin_panic
13: rustc_errors::HandlerInner::span_bug
14: rustc_errors::Handler::span_bug
15: rustc_middle::util::bug::opt_span_bug_fmt::{{closure}}
16: rustc_middle::ty::context::tls::with_opt::{{closure}}
17: rustc_middle::ty::context::tls::with_opt
18: rustc_middle::util::bug::opt_span_bug_fmt
19: rustc_middle::util::bug::span_bug_fmt
20: <rustc_middle::ty::subst::SubstFolder as rustc_middle::ty::fold::TypeFolder>::fold_const
21: rustc_middle::ty::normalize_erasing_regions::<impl rustc_middle::ty::context::TyCtxt>::subst_and_normalize_erasing_regions
22: rustc_mir::interpret::operand::<impl rustc_mir::interpret::eval_context::InterpCx<M>>::eval_operand
23: rustc_mir::interpret::step::<impl rustc_mir::interpret::eval_context::InterpCx<M>>::eval_rvalue_into_place
24: rustc_mir::interpret::step::<impl rustc_mir::interpret::eval_context::InterpCx<M>>::run
25: rustc_mir::const_eval::eval_queries::const_eval_raw_provider
26: rustc_middle::ty::query::<impl rustc_query_system::query::config::QueryAccessors<rustc_middle::ty::context::TyCtxt> for rustc_middle::ty::query::queries::const_eval_raw>::compute
27: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps
28: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
29: rustc_data_structures::stack::ensure_sufficient_stack
30: rustc_query_system::query::plumbing::get_query_impl
31: rustc_mir::const_eval::eval_queries::const_eval_validated_provider
32: rustc_middle::ty::query::<impl rustc_query_system::query::config::QueryAccessors<rustc_middle::ty::context::TyCtxt> for rustc_middle::ty::query::queries::const_eval_validated>::compute
33: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps
34: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
35: rustc_data_structures::stack::ensure_sufficient_stack
36: rustc_query_system::query::plumbing::get_query_impl
37: rustc_mir::const_eval::eval_queries::const_eval_validated_provider
38: rustc_middle::ty::query::<impl rustc_query_system::query::config::QueryAccessors<rustc_middle::ty::context::TyCtxt> for rustc_middle::ty::query::queries::const_eval_validated>::compute
39: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps
40: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
41: rustc_data_structures::stack::ensure_sufficient_stack
42: rustc_query_system::query::plumbing::get_query_impl
43: rustc_middle::mir::interpret::queries::<impl rustc_middle::ty::context::TyCtxt>::const_eval_global_id
44: rustc_middle::mir::interpret::queries::<impl rustc_middle::ty::context::TyCtxt>::const_eval_resolve
45: <rustc_trait_selection::traits::project::AssocTypeNormalizer as rustc_middle::ty::fold::TypeFolder>::fold_const
46: <rustc_trait_selection::traits::project::AssocTypeNormalizer as rustc_middle::ty::fold::TypeFolder>::fold_ty
47: rustc_data_structures::stack::ensure_sufficient_stack
48: rustc_trait_selection::traits::project::normalize
49: <rustc_infer::infer::InferCtxt as rustc_trait_selection::infer::InferCtxtExt>::partially_normalize_associated_types_in
50: rustc_typeck::check::FnCtxt::normalize_associated_types_in
51: rustc_typeck::check::wfcheck::<impl rustc_typeck::check::FnCtxt>::non_enum_variant::{{closure}}
52: <core::iter::adapters::Map<I,F> as core::iter::traits::iterator::Iterator>::fold
53: rustc_infer::infer::InferCtxtBuilder::enter
54: rustc_typeck::check::wfcheck::check_item_well_formed
55: rustc_middle::ty::query::<impl rustc_query_system::query::config::QueryAccessors<rustc_middle::ty::context::TyCtxt> for rustc_middle::ty::query::queries::check_item_well_formed>::compute
56: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps
57: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
58: rustc_data_structures::stack::ensure_sufficient_stack
59: rustc_query_system::query::plumbing::get_query_impl
60: rustc_query_system::query::plumbing::ensure_query_impl
61: <rustc_typeck::check::wfcheck::CheckTypeWellFormedVisitor as rustc_hir::itemlikevisit::ParItemLikeVisitor>::visit_item
62: rustc_data_structures::sync::par_for_each_in
63: rustc_hir::hir::Crate::par_visit_all_item_likes
64: rustc_session::session::Session::track_errors
65: rustc_typeck::check_crate
66: rustc_interface::passes::analysis
67: rustc_middle::ty::query::<impl rustc_query_system::query::config::QueryAccessors<rustc_middle::ty::context::TyCtxt> for rustc_middle::ty::query::queries::analysis>::compute
68: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps
69: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
70: rustc_query_system::query::plumbing::get_query_impl
71: rustc_middle::ty::context::tls::enter_global
72: rustc_interface::queries::<impl rustc_interface::interface::Compiler>::enter
73: rustc_span::with_source_map
74: rustc_interface::interface::create_compiler_and_run
75: scoped_tls::ScopedKey<T>::set
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 1.46.0-nightly (346aec9b0 2020-07-11) running on x86_64-unknown-linux-gnu
note: compiler flags: -C embed-bitcode=no -C debuginfo=2 -C incremental --crate-type lib
note: some of the compiler flags provided by cargo are hidden
query stack during panic:
#0 [const_eval_raw] const-evaluating `matrix::Matrix::elements::{{constant}}#0`
#1 [const_eval_validated] const-evaluating + checking `matrix::Matrix::elements::{{constant}}#0`
#2 [const_eval_validated] const-evaluating + checking `matrix::Matrix::elements::{{constant}}#0`
#3 [check_item_well_formed] checking that `matrix::Matrix` is well-formed
#4 [analysis] running analysis passes on this crate
end of query stack