Closed
Description
EDIT: Generalized the error.
A clean rust project with just this code:
#![feature(const_generics)]
fn f<T, const N: usize>(v: &mut [T; N]) -> &mut [T; N] { v }
/* note that everything works fine if `&mut` is replaced with just `&` */
fn main() {}Produces this error:
Checking rust4 v0.1.0 (/home/carado/tmp/rust4)
warning: the feature `const_generics` is incomplete and may cause the compiler to crash
--> src/main.rs:1:12
|
1 | #![feature(const_generics)]
| ^^^^^^^^^^^^^^
error: internal compiler error: src/librustc/ty/sty.rs:2311: expected constant usize, got Const {
ty: usize,
val: Param(
N/#1,
),
}
thread 'rustc' panicked at 'Box<Any>', src/librustc_errors/lib.rs:637:9
stack backtrace:
0: backtrace::backtrace::libunwind::trace
at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.25/src/backtrace/libunwind.rs:97
1: backtrace::backtrace::trace_unsynchronized
at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.25/src/backtrace/mod.rs:66
2: std::sys_common::backtrace::_print
at src/libstd/sys_common/backtrace.rs:47
3: std::sys_common::backtrace::print
at src/libstd/sys_common/backtrace.rs:36
4: std::panicking::default_hook::{{closure}}
at src/libstd/panicking.rs:197
5: std::panicking::default_hook
at src/libstd/panicking.rs:211
6: rustc::util::common::panic_hook
7: std::panicking::rust_panic_with_hook
at src/libstd/panicking.rs:478
8: std::panicking::begin_panic
9: rustc_errors::Handler::bug
10: rustc::util::bug::opt_span_bug_fmt::{{closure}}
11: rustc::ty::context::tls::with_opt::{{closure}}
12: rustc::ty::context::tls::with_context_opt
13: rustc::ty::context::tls::with_opt
14: rustc::util::bug::opt_span_bug_fmt
15: rustc::util::bug::bug_fmt
16: rustc::ty::sty::Const::unwrap_usize::{{closure}}
17: <rustc_mir::transform::qualify_consts::HasMutInterior as rustc_mir::transform::qualify_consts::Qualif>::in_rvalue
18: rustc_mir::transform::qualify_consts::Checker::assign
19: <rustc_mir::transform::qualify_consts::QualifyAndPromoteConstants as rustc_mir::transform::MirPass>::run_pass
20: rustc_mir::transform::run_passes::{{closure}}
21: rustc_mir::transform::run_passes
22: rustc_mir::transform::mir_validated
23: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::mir_validated>::compute
24: rustc::dep_graph::graph::DepGraph::with_task_impl
25: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::force_query
26: rustc::ty::query::plumbing::force_from_dep_node
27: rustc::dep_graph::graph::DepGraph::try_mark_previous_green
28: rustc::dep_graph::graph::DepGraph::try_mark_green
29: rustc::dep_graph::graph::DepGraph::try_mark_green_and_read
30: rustc::ty::<impl rustc::ty::context::TyCtxt>::par_body_owners
31: rustc::util::common::time
32: rustc_interface::passes::analysis
33: rustc::ty::query::__query_compute::analysis
34: rustc::dep_graph::graph::DepGraph::with_task_impl
35: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
36: rustc::ty::context::tls::enter_global
37: rustc_interface::passes::BoxedGlobalCtxt::access::{{closure}}
38: rustc_interface::passes::create_global_ctxt::{{closure}}
39: rustc_interface::interface::run_compiler_in_existing_thread_pool
40: std::thread::local::LocalKey<T>::with
41: scoped_tls::ScopedKey<T>::set
42: syntax::with_globals
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
query stack during panic:
#0 [mir_validated] processing `f`
#1 [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 1.37.0-nightly (37d001e4d 2019-05-29) running on x86_64-unknown-linux-gnu
note: compiler flags: -C debuginfo=2 -C incremental --crate-type bin
note: some of the compiler flags provided by cargo are hidden
error: Could not compile `rust4`.
To learn more, run the command again with --verbose.