ICE error triggered by adding feature "effects" to code

[iamanonymouscs]

Adding the feature "effects" to the provided code triggers an internal compiler error (ICE) in rustc. The ICE occurs when attempting to match a variable and assign either a constant function (fn1) or a regular function (fnc1) to another variable.

Code

#![feature(effects)]
const fn fn1() {}

fn fnc1() {}

fn main() {
 let y=3;
 let x = match y {
  2 => fn1,
  _ => fnc1
 };
}

Meta

rustc --version --verbose:

rustc 1.74.0-nightly (8142a319e 2023-09-13)
binary: rustc
commit-hash: 8142a319ed5c1d1f96e5a1881a6546e463b77c8f
commit-date: 2023-09-13
host: x86_64-unknown-linux-gnu
release: 1.74.0-nightly
LLVM version: 17.0.0

Error output

error[E0282]: type annotations needed
 --> bug_9_14.rs:9:8
  |
9 |   2 => fn1,
  |        ^^^ cannot infer the value of the const parameter `host` declared on the function `fn1`
  |
help: consider specifying the generic argument
  |
9 |   2 => fn1::<_>,
  |           +++++

Backtrace

thread 'rustc' panicked at /rustc/8142a319ed5c1d1f96e5a1881a6546e463b77c8f/compiler/rustc_infer/src/infer/mod.rs:1422:9:
`Ok(FnDef(DefId(0:3 ~ bug_9_14[d365]::fn1), [Const { ty: bool, kind: ?0e }]))` is not fully resolved
stack backtrace:
   0:     0x7fa8e5eecefc - std::backtrace_rs::backtrace::libunwind::trace::h7d696a3fe83931ea
                               at /rustc/8142a319ed5c1d1f96e5a1881a6546e463b77c8f/library/std/src/../../backtrace/src/backtrace/libunwind.rs:93:5
   1:     0x7fa8e5eecefc - std::backtrace_rs::backtrace::trace_unsynchronized::h32ed3b706756d880
                               at /rustc/8142a319ed5c1d1f96e5a1881a6546e463b77c8f/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7fa8e5eecefc - std::sys_common::backtrace::_print_fmt::h234b1d6e2050b1c7
                               at /rustc/8142a319ed5c1d1f96e5a1881a6546e463b77c8f/library/std/src/sys_common/backtrace.rs:67:5
   3:     0x7fa8e5eecefc - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::hdba83e95158d24b7
                               at /rustc/8142a319ed5c1d1f96e5a1881a6546e463b77c8f/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x7fa8e5f5315c - core::fmt::rt::Argument::fmt::h56eddd6c4c48048d
                               at /rustc/8142a319ed5c1d1f96e5a1881a6546e463b77c8f/library/core/src/fmt/rt.rs:138:9
   5:     0x7fa8e5f5315c - core::fmt::write::heb62e4111c27e516
                               at /rustc/8142a319ed5c1d1f96e5a1881a6546e463b77c8f/library/core/src/fmt/mod.rs:1094:21
   6:     0x7fa8e5edfb1e - std::io::Write::write_fmt::he7699d16423b5914
                               at /rustc/8142a319ed5c1d1f96e5a1881a6546e463b77c8f/library/std/src/io/mod.rs:1714:15
   7:     0x7fa8e5eecce4 - std::sys_common::backtrace::_print::h17c88990d1e7ffc8
                               at /rustc/8142a319ed5c1d1f96e5a1881a6546e463b77c8f/library/std/src/sys_common/backtrace.rs:47:5
   8:     0x7fa8e5eecce4 - std::sys_common::backtrace::print::h18bfa712e4237a54
                               at /rustc/8142a319ed5c1d1f96e5a1881a6546e463b77c8f/library/std/src/sys_common/backtrace.rs:34:9
   9:     0x7fa8e5eefdda - std::panicking::panic_hook_with_disk_dump::{{closure}}::h29435e023d2fef53
                               at /rustc/8142a319ed5c1d1f96e5a1881a6546e463b77c8f/library/std/src/panicking.rs:280:22
  10:     0x7fa8e5eefa98 - std::panicking::panic_hook_with_disk_dump::h747314e0eb3083d0
                               at /rustc/8142a319ed5c1d1f96e5a1881a6546e463b77c8f/library/std/src/panicking.rs:307:9
  11:     0x7fa8e4cc4229 - <rustc_driver_impl[6872457824a876c8]::install_ice_hook::{closure#0} as core[468698755226bf15]::ops::function::FnOnce<(&core[468698755226bf15]::panic::panic_info::PanicInfo,)>>::call_once::{shim:vtable#0}
  12:     0x7fa8e5ef0693 - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h28a1f6f4d204892e
                               at /rustc/8142a319ed5c1d1f96e5a1881a6546e463b77c8f/library/alloc/src/boxed.rs:2021:9
  13:     0x7fa8e5ef0693 - std::panicking::rust_panic_with_hook::hcbc867ec0eddd0c3
                               at /rustc/8142a319ed5c1d1f96e5a1881a6546e463b77c8f/library/std/src/panicking.rs:757:13
  14:     0x7fa8e5ef0411 - std::panicking::begin_panic_handler::{{closure}}::h3c9eb8c1fbf3ea52
                               at /rustc/8142a319ed5c1d1f96e5a1881a6546e463b77c8f/library/std/src/panicking.rs:631:13
  15:     0x7fa8e5eed426 - std::sys_common::backtrace::__rust_end_short_backtrace::hd2324a4c2985e4f3
                               at /rustc/8142a319ed5c1d1f96e5a1881a6546e463b77c8f/library/std/src/sys_common/backtrace.rs:170:18
  16:     0x7fa8e5ef0152 - rust_begin_unwind
                               at /rustc/8142a319ed5c1d1f96e5a1881a6546e463b77c8f/library/std/src/panicking.rs:619:5
  17:     0x7fa8e5f4f505 - core::panicking::panic_fmt::h583d94a3776bd1d2
                               at /rustc/8142a319ed5c1d1f96e5a1881a6546e463b77c8f/library/core/src/panicking.rs:72:14
  18:     0x7fa8e317f798 - <rustc_hir_typeck[ee6c5a539d897b28]::writeback::WritebackCx as rustc_hir[3c4396802e23c779]::intravisit::Visitor>::visit_expr
  19:     0x7fa8e317dd7b - <rustc_hir_typeck[ee6c5a539d897b28]::writeback::WritebackCx as rustc_hir[3c4396802e23c779]::intravisit::Visitor>::visit_expr
  20:     0x7fa8e3186fc9 - <rustc_hir_typeck[ee6c5a539d897b28]::writeback::WritebackCx as rustc_hir[3c4396802e23c779]::intravisit::Visitor>::visit_local
  21:     0x7fa8e31851c5 - <rustc_hir_typeck[ee6c5a539d897b28]::writeback::WritebackCx as rustc_hir[3c4396802e23c779]::intravisit::Visitor>::visit_block
  22:     0x7fa8e317d82c - <rustc_hir_typeck[ee6c5a539d897b28]::writeback::WritebackCx as rustc_hir[3c4396802e23c779]::intravisit::Visitor>::visit_expr
  23:     0x7fa8e3d63714 - <rustc_hir_typeck[ee6c5a539d897b28]::fn_ctxt::FnCtxt>::resolve_type_vars_in_body
  24:     0x7fa8e3d527f3 - rustc_hir_typeck[ee6c5a539d897b28]::typeck
  25:     0x7fa8e2dcad2e - rustc_query_impl[faff4f3901442888]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[faff4f3901442888]::query_impl::typeck::dynamic_query::{closure#2}::{closure#0}, rustc_middle[a5aa27c2964d564a]::query::erase::Erased<[u8; 8usize]>>
  26:     0x7fa8e2dcacfe - <rustc_query_impl[faff4f3901442888]::query_impl::typeck::dynamic_query::{closure#2} as core[468698755226bf15]::ops::function::FnOnce<(rustc_middle[a5aa27c2964d564a]::ty::context::TyCtxt, rustc_span[3e6de59a27d5529]::def_id::LocalDefId)>>::call_once
  27:     0x7fa8e2ea6618 - rustc_query_system[ed0180b2c936d7a1]::query::plumbing::try_execute_query::<rustc_query_impl[faff4f3901442888]::DynamicConfig<rustc_query_system[ed0180b2c936d7a1]::query::caches::VecCache<rustc_span[3e6de59a27d5529]::def_id::LocalDefId, rustc_middle[a5aa27c2964d564a]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[faff4f3901442888]::plumbing::QueryCtxt, false>
  28:     0x7fa8e4652451 - rustc_query_impl[faff4f3901442888]::query_impl::typeck::get_query_non_incr::__rust_end_short_backtrace
  29:     0x7fa8e4051c6f - rustc_data_structures[b8028d6e438e0bab]::sync::parallel::disabled::par_for_each_in::<&[rustc_span[3e6de59a27d5529]::def_id::LocalDefId], <rustc_middle[a5aa27c2964d564a]::hir::map::Map>::par_body_owners<rustc_hir_analysis[93ddd5062bb3fb28]::check_crate::{closure#7}>::{closure#0}>
  30:     0x7fa8e4050f13 - rustc_hir_analysis[93ddd5062bb3fb28]::check_crate
  31:     0x7fa8e404a062 - rustc_interface[89ffa3a3953ed9b2]::passes::analysis
  32:     0x7fa8e410ecfa - rustc_query_impl[faff4f3901442888]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[faff4f3901442888]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[a5aa27c2964d564a]::query::erase::Erased<[u8; 1usize]>>
  33:     0x7fa8e410ece9 - <rustc_query_impl[faff4f3901442888]::query_impl::analysis::dynamic_query::{closure#2} as core[468698755226bf15]::ops::function::FnOnce<(rustc_middle[a5aa27c2964d564a]::ty::context::TyCtxt, ())>>::call_once
  34:     0x7fa8e441d1d4 - rustc_query_system[ed0180b2c936d7a1]::query::plumbing::try_execute_query::<rustc_query_impl[faff4f3901442888]::DynamicConfig<rustc_query_system[ed0180b2c936d7a1]::query::caches::SingleCache<rustc_middle[a5aa27c2964d564a]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[faff4f3901442888]::plumbing::QueryCtxt, false>
  35:     0x7fa8e441cf49 - rustc_query_impl[faff4f3901442888]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
  36:     0x7fa8e41f9e63 - <rustc_middle[a5aa27c2964d564a]::ty::context::GlobalCtxt>::enter::<rustc_driver_impl[6872457824a876c8]::run_compiler::{closure#1}::{closure#2}::{closure#6}, core[468698755226bf15]::result::Result<(), rustc_span[3e6de59a27d5529]::ErrorGuaranteed>>
  37:     0x7fa8e41f8f58 - <rustc_interface[89ffa3a3953ed9b2]::interface::Compiler>::enter::<rustc_driver_impl[6872457824a876c8]::run_compiler::{closure#1}::{closure#2}, core[468698755226bf15]::result::Result<core[468698755226bf15]::option::Option<rustc_interface[89ffa3a3953ed9b2]::queries::Linker>, rustc_span[3e6de59a27d5529]::ErrorGuaranteed>>
  38:     0x7fa8e41f21a4 - std[1d99e526d3fccd95]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[89ffa3a3953ed9b2]::util::run_in_thread_with_globals<rustc_interface[89ffa3a3953ed9b2]::interface::run_compiler<core[468698755226bf15]::result::Result<(), rustc_span[3e6de59a27d5529]::ErrorGuaranteed>, rustc_driver_impl[6872457824a876c8]::run_compiler::{closure#1}>::{closure#0}, core[468698755226bf15]::result::Result<(), rustc_span[3e6de59a27d5529]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[468698755226bf15]::result::Result<(), rustc_span[3e6de59a27d5529]::ErrorGuaranteed>>
  39:     0x7fa8e41f18fe - <<std[1d99e526d3fccd95]::thread::Builder>::spawn_unchecked_<rustc_interface[89ffa3a3953ed9b2]::util::run_in_thread_with_globals<rustc_interface[89ffa3a3953ed9b2]::interface::run_compiler<core[468698755226bf15]::result::Result<(), rustc_span[3e6de59a27d5529]::ErrorGuaranteed>, rustc_driver_impl[6872457824a876c8]::run_compiler::{closure#1}>::{closure#0}, core[468698755226bf15]::result::Result<(), rustc_span[3e6de59a27d5529]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[468698755226bf15]::result::Result<(), rustc_span[3e6de59a27d5529]::ErrorGuaranteed>>::{closure#1} as core[468698755226bf15]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  40:     0x7fa8e5efb075 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::ha4104662ef3c5bbd
                               at /rustc/8142a319ed5c1d1f96e5a1881a6546e463b77c8f/library/alloc/src/boxed.rs:2007:9
  41:     0x7fa8e5efb075 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::hb8d3ac4a3d377b23
                               at /rustc/8142a319ed5c1d1f96e5a1881a6546e463b77c8f/library/alloc/src/boxed.rs:2007:9
  42:     0x7fa8e5efb075 - std::sys::unix::thread::Thread::new::thread_start::h1cee3a3217d3e553
                               at /rustc/8142a319ed5c1d1f96e5a1881a6546e463b77c8f/library/std/src/sys/unix/thread.rs:108:17
  43:     0x7fa8e155c6db - start_thread
                               at /build/glibc-CVJwZb/glibc-2.27/nptl/pthread_create.c:463
  44:     0x7fa8e128561f - clone
                               at /build/glibc-CVJwZb/glibc-2.27/misc/../sysdeps/unix/sysv/linux/x86_64/clone.S:95
  45:                0x0 - <unknown>


rustc version: 1.74.0-nightly (8142a319e 2023-09-13)
platform: x86_64-unknown-linux-gnu

query stack during panic:
#0 [typeck] type-checking `main`
#1 [analysis] running analysis passes on this crate
end of query stack

[matthiaskrgr]

Probably duplicate of #115791

[compiler-errors]

Yeah, this is a dupe!