borrowck: no entry for key (only panic for some types)

[EqualMa]

Code

trait FnOnceForGenericRef<T>: FnOnce(&T) -> Self::FnOutput {
    type FnOutput;
}

impl<T, R, F: FnOnce(&T) -> R> FnOnceForGenericRef<T> for F {
    type FnOutput = R;
}

struct Data<T, D: FnOnceForGenericRef<T>> {
    value: Option<T>,
    output: Option<D::FnOutput>,
}

impl<T, D: FnOnceForGenericRef<T>> Data<T, D> {
    fn new(value: T, f: D) -> Self {
        let output = f(&value);
        Self {
            value: Some(value),
            output: Some(output),
        }
    }
}

fn test() {
    Data::new(String::new(), |_| {});

    // It is very weird that the following code doesn't panic but
    // emit error as expected: "implementation of `FnOnce` is not general enough"
    // Data::new(1, |_| {});
}

Here is the playground: https://play.rust-lang.org/?version=nightly&mode=debug&edition=2021&gist=aba30e89981874a854cb8252c652b7f2

This might be related to #99665 and #102800 .

Meta

rustc --version --verbose:

rustc 1.64.0 (a55dd71d5 2022-09-19)
binary: rustc
commit-hash: a55dd71d5fb0ec5a6a3a9e8c27b2127ba491ce52
commit-date: 2022-09-19
host: aarch64-unknown-linux-gnu
release: 1.64.0
LLVM version: 14.0.6

The bug also exists for rustc 1.66.0-nightly (bf15a9e52 2022-10-14)

Error output

thread 'rustc' panicked at 'no entry found for key', compiler/rustc_borrowck/src/region_infer/mod.rs:2237:9

Backtrace

thread 'rustc' panicked at 'no entry found for key', compiler/rustc_borrowck/src/region_infer/mod.rs:2237:9
stack backtrace:
   0:     0x7f9c41ebf510 - std::backtrace_rs::backtrace::libunwind::trace::hc83d2ca9877ed15f
                               at /rustc/bf15a9e5263fcea065a7ae9c179b2d24c2deb670/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   1:     0x7f9c41ebf510 - std::backtrace_rs::backtrace::trace_unsynchronized::h761490c78a8d3c90
                               at /rustc/bf15a9e5263fcea065a7ae9c179b2d24c2deb670/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7f9c41ebf510 - std::sys_common::backtrace::_print_fmt::h74c2d9c05b36a5cb
                               at /rustc/bf15a9e5263fcea065a7ae9c179b2d24c2deb670/library/std/src/sys_common/backtrace.rs:66:5
   3:     0x7f9c41ebf510 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::hb42a8b90000bb024
                               at /rustc/bf15a9e5263fcea065a7ae9c179b2d24c2deb670/library/std/src/sys_common/backtrace.rs:45:22
   4:     0x7f9c41f1b52e - core::fmt::write::h5ee7341ed55b8805
                               at /rustc/bf15a9e5263fcea065a7ae9c179b2d24c2deb670/library/core/src/fmt/mod.rs:1209:17
   5:     0x7f9c41eaf7d5 - std::io::Write::write_fmt::hacce97c59cf194e4
                               at /rustc/bf15a9e5263fcea065a7ae9c179b2d24c2deb670/library/std/src/io/mod.rs:1680:15
   6:     0x7f9c41ec2143 - std::sys_common::backtrace::_print::h6884fdd5ab3f424d
                               at /rustc/bf15a9e5263fcea065a7ae9c179b2d24c2deb670/library/std/src/sys_common/backtrace.rs:48:5
   7:     0x7f9c41ec2143 - std::sys_common::backtrace::print::hb66e100356b39aaa
                               at /rustc/bf15a9e5263fcea065a7ae9c179b2d24c2deb670/library/std/src/sys_common/backtrace.rs:35:9
   8:     0x7f9c41ec2143 - std::panicking::default_hook::{{closure}}::h437804d1a6836d5e
                               at /rustc/bf15a9e5263fcea065a7ae9c179b2d24c2deb670/library/std/src/panicking.rs:267:22
   9:     0x7f9c41ec1e1a - std::panicking::default_hook::h65e830729b214390
                               at /rustc/bf15a9e5263fcea065a7ae9c179b2d24c2deb670/library/std/src/panicking.rs:286:9
  10:     0x7f9c448083c4 - rustc_driver[f331bf04a31a4474]::DEFAULT_HOOK::{closure#0}::{closure#0}
  11:     0x7f9c41ec2a79 - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::hef73fb3e3355d020
                               at /rustc/bf15a9e5263fcea065a7ae9c179b2d24c2deb670/library/alloc/src/boxed.rs:1952:9
  12:     0x7f9c41ec2a79 - std::panicking::rust_panic_with_hook::hcab2853c64105b40
                               at /rustc/bf15a9e5263fcea065a7ae9c179b2d24c2deb670/library/std/src/panicking.rs:692:13
  13:     0x7f9c41ec27f7 - std::panicking::begin_panic_handler::{{closure}}::hd9c5ea26691d8270
                               at /rustc/bf15a9e5263fcea065a7ae9c179b2d24c2deb670/library/std/src/panicking.rs:579:13
  14:     0x7f9c41ebf9bc - std::sys_common::backtrace::__rust_end_short_backtrace::hd8a22d71267b4b61
                               at /rustc/bf15a9e5263fcea065a7ae9c179b2d24c2deb670/library/std/src/sys_common/backtrace.rs:138:18
  15:     0x7f9c41ec2512 - rust_begin_unwind
                               at /rustc/bf15a9e5263fcea065a7ae9c179b2d24c2deb670/library/std/src/panicking.rs:575:5
  16:     0x7f9c41f17f13 - core::panicking::panic_fmt::h4c6b07d94019a3f0
                               at /rustc/bf15a9e5263fcea065a7ae9c179b2d24c2deb670/library/core/src/panicking.rs:65:14
  17:     0x7f9c41f18061 - core::panicking::panic_display::hafe927c06584f593
                               at /rustc/bf15a9e5263fcea065a7ae9c179b2d24c2deb670/library/core/src/panicking.rs:139:5
  18:     0x7f9c41f1800b - core::panicking::panic_str::hab929c599078f017
                               at /rustc/bf15a9e5263fcea065a7ae9c179b2d24c2deb670/library/core/src/panicking.rs:123:5
  19:     0x7f9c41f17c86 - core::option::expect_failed::ha0bacc385d0a2f07
                               at /rustc/bf15a9e5263fcea065a7ae9c179b2d24c2deb670/library/core/src/option.rs:1876:5
  20:     0x7f9c44e9bebe - <rustc_borrowck[8ef346bc23d797c8]::region_infer::RegionInferenceContext>::universe_info
  21:     0x7f9c43681b7e - rustc_borrowck[8ef346bc23d797c8]::do_mir_borrowck
  22:     0x7f9c4367c9d0 - rustc_borrowck[8ef346bc23d797c8]::mir_borrowck
  23:     0x7f9c4367c361 - <rustc_borrowck[8ef346bc23d797c8]::provide::{closure#0} as core[2c5081d8f0108272]::ops::function::FnOnce<(rustc_middle[3d73d7ef627e8bf]::ty::context::TyCtxt, rustc_span[c16ea33475d6785f]::def_id::LocalDefId)>>::call_once
  24:     0x7f9c43dfcd75 - rustc_query_system[5f73ab021976280c]::query::plumbing::try_execute_query::<rustc_query_impl[84f7ded2d44823f6]::plumbing::QueryCtxt, rustc_query_system[5f73ab021976280c]::query::caches::DefaultCache<rustc_span[c16ea33475d6785f]::def_id::LocalDefId, &rustc_middle[3d73d7ef627e8bf]::mir::query::BorrowCheckResult>>
  25:     0x7f9c4470db8e - <rustc_query_impl[84f7ded2d44823f6]::Queries as rustc_middle[3d73d7ef627e8bf]::ty::query::QueryEngine>::mir_borrowck
  26:     0x7f9c441f72d3 - rustc_data_structures[5f783117a6880793]::sync::par_for_each_in::<&[rustc_span[c16ea33475d6785f]::def_id::LocalDefId], <rustc_middle[3d73d7ef627e8bf]::hir::map::Map>::par_body_owners<rustc_interface[24040f739c3f95dc]::passes::analysis::{closure#2}::{closure#0}>::{closure#0}>
  27:     0x7f9c441f7033 - <rustc_session[665a57f624cd1b0d]::session::Session>::time::<(), rustc_interface[24040f739c3f95dc]::passes::analysis::{closure#2}>
  28:     0x7f9c441f62a5 - rustc_interface[24040f739c3f95dc]::passes::analysis
  29:     0x7f9c4459a284 - rustc_query_system[5f73ab021976280c]::query::plumbing::try_execute_query::<rustc_query_impl[84f7ded2d44823f6]::plumbing::QueryCtxt, rustc_query_system[5f73ab021976280c]::query::caches::DefaultCache<(), core[2c5081d8f0108272]::result::Result<(), rustc_errors[3e7e0c00279b1c89]::ErrorGuaranteed>>>
  30:     0x7f9c44599fb7 - rustc_query_system[5f73ab021976280c]::query::plumbing::get_query::<rustc_query_impl[84f7ded2d44823f6]::queries::analysis, rustc_query_impl[84f7ded2d44823f6]::plumbing::QueryCtxt>
  31:     0x7f9c434c0f93 - <rustc_interface[24040f739c3f95dc]::passes::QueryContext>::enter::<rustc_driver[f331bf04a31a4474]::run_compiler::{closure#1}::{closure#2}::{closure#3}, core[2c5081d8f0108272]::result::Result<(), rustc_errors[3e7e0c00279b1c89]::ErrorGuaranteed>>
  32:     0x7f9c434b9db8 - rustc_interface[24040f739c3f95dc]::interface::create_compiler_and_run::<core[2c5081d8f0108272]::result::Result<(), rustc_errors[3e7e0c00279b1c89]::ErrorGuaranteed>, rustc_driver[f331bf04a31a4474]::run_compiler::{closure#1}>
  33:     0x7f9c434b8be2 - <scoped_tls[fdb5e1dcf3b8ea2]::ScopedKey<rustc_span[c16ea33475d6785f]::SessionGlobals>>::set::<rustc_interface[24040f739c3f95dc]::interface::run_compiler<core[2c5081d8f0108272]::result::Result<(), rustc_errors[3e7e0c00279b1c89]::ErrorGuaranteed>, rustc_driver[f331bf04a31a4474]::run_compiler::{closure#1}>::{closure#0}, core[2c5081d8f0108272]::result::Result<(), rustc_errors[3e7e0c00279b1c89]::ErrorGuaranteed>>
  34:     0x7f9c434b80bf - std[eb0ada501a1276bc]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[24040f739c3f95dc]::util::run_in_thread_pool_with_globals<rustc_interface[24040f739c3f95dc]::interface::run_compiler<core[2c5081d8f0108272]::result::Result<(), rustc_errors[3e7e0c00279b1c89]::ErrorGuaranteed>, rustc_driver[f331bf04a31a4474]::run_compiler::{closure#1}>::{closure#0}, core[2c5081d8f0108272]::result::Result<(), rustc_errors[3e7e0c00279b1c89]::ErrorGuaranteed>>::{closure#0}, core[2c5081d8f0108272]::result::Result<(), rustc_errors[3e7e0c00279b1c89]::ErrorGuaranteed>>
  35:     0x7f9c4462582f - <<std[eb0ada501a1276bc]::thread::Builder>::spawn_unchecked_<rustc_interface[24040f739c3f95dc]::util::run_in_thread_pool_with_globals<rustc_interface[24040f739c3f95dc]::interface::run_compiler<core[2c5081d8f0108272]::result::Result<(), rustc_errors[3e7e0c00279b1c89]::ErrorGuaranteed>, rustc_driver[f331bf04a31a4474]::run_compiler::{closure#1}>::{closure#0}, core[2c5081d8f0108272]::result::Result<(), rustc_errors[3e7e0c00279b1c89]::ErrorGuaranteed>>::{closure#0}, core[2c5081d8f0108272]::result::Result<(), rustc_errors[3e7e0c00279b1c89]::ErrorGuaranteed>>::{closure#1} as core[2c5081d8f0108272]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  36:     0x7f9c41ecc593 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::hb87d6f0b287ef99f
                               at /rustc/bf15a9e5263fcea065a7ae9c179b2d24c2deb670/library/alloc/src/boxed.rs:1938:9
  37:     0x7f9c41ecc593 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h57e28d10de971273
                               at /rustc/bf15a9e5263fcea065a7ae9c179b2d24c2deb670/library/alloc/src/boxed.rs:1938:9
  38:     0x7f9c41ecc593 - std::sys::unix::thread::Thread::new::thread_start::h4ee249ae8a0419de
                               at /rustc/bf15a9e5263fcea065a7ae9c179b2d24c2deb670/library/std/src/sys/unix/thread.rs:108:17
  39:     0x7f9c41d9e609 - start_thread
  40:     0x7f9c41cc1133 - clone
  41:                0x0 - <unknown>

error: internal compiler error: unexpected panic