ICE: parent also has host effect param?

[matthiaskrgr]

auto-reduced (treereduce-rust):

#![feature(effects)]

struct S;
trait T {}

impl const T {
    pub const fn new() -> LazyLock<T> {}
}

original:

#![allow(unused_variables)]
#![feature(
    associated_type_bounds,
    const_trait_impl,
    const_cmp,
    return_position_impl_trait_in_trait,
)]

struct S;
trait T {}

impl const S {
    fn ffi(
        #[allow(unused_mut)] a: i32,
        #[cfg(something)] b: i32,
        #[cfg_attr(something, cfg(nothing))] c: i32,
        #[forbid(unused_mut)] d: i32,
        #[deny(unused_mut)] #[warn(unused_mut)] ...
    );
}
// issue #88015

impl const T {
    pub const fn new(f: fn() -> T) -> LazyLock<T> {
        LazyLock { data: (None, f) }
    }
}
//~^ ERROR inherent impls cannot be `const`

fn main() {}

Version information

rustc 1.78.0-nightly (f8131a48a 2024-02-21)
binary: rustc
commit-hash: f8131a48a46ac3bc8a3d0fe0477055b132cffdc3
commit-date: 2024-02-21
host: x86_64-unknown-linux-gnu
release: 1.78.0-nightly
LLVM version: 18.1.0

Command:
/home/matthias/.rustup/toolchains/master/bin/rustc -Zcrate-attr=feature(effects)

Program output

error: inherent impls cannot be `const`
 --> /tmp/icemaker_global_tempdir.hviw91Tg4hl3/rustc_testrunner_tmpdir_reporting.NAMwIoI8bW6T/mvce.rs:4:12
  |
4 | impl const T {
  |      ----- ^ inherent impl for this type
  |      |
  |      `const` because of this
  |
  = note: only trait implementations may be annotated with `const`

error[E0412]: cannot find type `LazyLock` in this scope
 --> /tmp/icemaker_global_tempdir.hviw91Tg4hl3/rustc_testrunner_tmpdir_reporting.NAMwIoI8bW6T/mvce.rs:5:27
  |
5 |     pub const fn new() -> LazyLock<T> {}
  |                           ^^^^^^^^ not found in this scope
  |
help: consider importing this struct
  |
1 + use std::sync::LazyLock;
  |

error[E0658]: const trait impls are experimental
 --> /tmp/icemaker_global_tempdir.hviw91Tg4hl3/rustc_testrunner_tmpdir_reporting.NAMwIoI8bW6T/mvce.rs:4:6
  |
4 | impl const T {
  |      ^^^^^
  |
  = note: see issue #67792 <https://github.com/rust-lang/rust/issues/67792> for more information
  = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
  = note: this compiler was built on 2024-02-21; consider upgrading it if it is out of date

error[E0601]: `main` function not found in crate `mvce`
 --> /tmp/icemaker_global_tempdir.hviw91Tg4hl3/rustc_testrunner_tmpdir_reporting.NAMwIoI8bW6T/mvce.rs:6:2
  |
6 | }
  |  ^ consider adding a `main` function to `/tmp/icemaker_global_tempdir.hviw91Tg4hl3/rustc_testrunner_tmpdir_reporting.NAMwIoI8bW6T/mvce.rs`

warning: trait objects without an explicit `dyn` are deprecated
 --> /tmp/icemaker_global_tempdir.hviw91Tg4hl3/rustc_testrunner_tmpdir_reporting.NAMwIoI8bW6T/mvce.rs:4:12
  |
4 | impl const T {
  |            ^
  |
  = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
  = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
  = note: `#[warn(bare_trait_objects)]` on by default
help: if this is an object-safe trait, use `dyn`
  |
4 | impl const dyn T {
  |            +++

error: internal compiler error: parent also has host effect param? index: 0, def: DefId(0:7 ~ mvce[8c01]::{impl#0}::new)
 --> /tmp/icemaker_global_tempdir.hviw91Tg4hl3/rustc_testrunner_tmpdir_reporting.NAMwIoI8bW6T/mvce.rs:5:9
  |
5 |     pub const fn new() -> LazyLock<T> {}
  |         ^^^^^

thread 'rustc' panicked at compiler/rustc_hir_analysis/src/collect/generics_of.rs:318:31:
Box<dyn Any>
stack backtrace:
   0:     0x7fa7e2b8caf6 - std::backtrace_rs::backtrace::libunwind::trace::hbec2edc838b433e2
                               at /rustc/f8131a48a46ac3bc8a3d0fe0477055b132cffdc3/library/std/src/../../backtrace/src/backtrace/libunwind.rs:104:5
   1:     0x7fa7e2b8caf6 - std::backtrace_rs::backtrace::trace_unsynchronized::h88c30257ee0dd166
                               at /rustc/f8131a48a46ac3bc8a3d0fe0477055b132cffdc3/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7fa7e2b8caf6 - std::sys_common::backtrace::_print_fmt::h9176654d509e3088
                               at /rustc/f8131a48a46ac3bc8a3d0fe0477055b132cffdc3/library/std/src/sys_common/backtrace.rs:68:5
   3:     0x7fa7e2b8caf6 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h671feaee1776bf19
                               at /rustc/f8131a48a46ac3bc8a3d0fe0477055b132cffdc3/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x7fa7e2bdda7c - core::fmt::rt::Argument::fmt::h59605c83ae32d935
                               at /rustc/f8131a48a46ac3bc8a3d0fe0477055b132cffdc3/library/core/src/fmt/rt.rs:142:9
   5:     0x7fa7e2bdda7c - core::fmt::write::hf7af8dfcfd20db5b
                               at /rustc/f8131a48a46ac3bc8a3d0fe0477055b132cffdc3/library/core/src/fmt/mod.rs:1120:17
   6:     0x7fa7e2b814bf - std::io::Write::write_fmt::h92a5dbf489025e71
                               at /rustc/f8131a48a46ac3bc8a3d0fe0477055b132cffdc3/library/std/src/io/mod.rs:1846:15
   7:     0x7fa7e2b8c8a4 - std::sys_common::backtrace::_print::h00080302d23998ae
                               at /rustc/f8131a48a46ac3bc8a3d0fe0477055b132cffdc3/library/std/src/sys_common/backtrace.rs:47:5
   8:     0x7fa7e2b8c8a4 - std::sys_common::backtrace::print::h6b23124445400245
                               at /rustc/f8131a48a46ac3bc8a3d0fe0477055b132cffdc3/library/std/src/sys_common/backtrace.rs:34:9
   9:     0x7fa7e2b8f5eb - std::panicking::default_hook::{{closure}}::hd67b2f9d36675a28
  10:     0x7fa7e2b8f339 - std::panicking::default_hook::h10a39ef11c714e42
                               at /rustc/f8131a48a46ac3bc8a3d0fe0477055b132cffdc3/library/std/src/panicking.rs:292:9
  11:     0x7fa7e5a7a94c - std[5a8e7f94216a9138]::panicking::update_hook::<alloc[e14ab1f516d287ab]::boxed::Box<rustc_driver_impl[e279e4f1fedd9109]::install_ice_hook::{closure#0}>>::{closure#0}
  12:     0x7fa7e2b8fd50 - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h37ba37dc48823c1d
                               at /rustc/f8131a48a46ac3bc8a3d0fe0477055b132cffdc3/library/alloc/src/boxed.rs:2030:9
  13:     0x7fa7e2b8fd50 - std::panicking::rust_panic_with_hook::he3e3bc7c345bf54b
                               at /rustc/f8131a48a46ac3bc8a3d0fe0477055b132cffdc3/library/std/src/panicking.rs:786:13
  14:     0x7fa7e5aa7524 - std[5a8e7f94216a9138]::panicking::begin_panic::<rustc_errors[34364e5c712fab73]::ExplicitBug>::{closure#0}
  15:     0x7fa7e5aa4176 - std[5a8e7f94216a9138]::sys_common::backtrace::__rust_end_short_backtrace::<std[5a8e7f94216a9138]::panicking::begin_panic<rustc_errors[34364e5c712fab73]::ExplicitBug>::{closure#0}, !>
  16:     0x7fa7e5a9f936 - std[5a8e7f94216a9138]::panicking::begin_panic::<rustc_errors[34364e5c712fab73]::ExplicitBug>
  17:     0x7fa7e4417631 - <rustc_errors[34364e5c712fab73]::diagnostic::BugAbort as rustc_errors[34364e5c712fab73]::diagnostic::EmissionGuarantee>::emit_producing_guarantee
  18:     0x7fa7e727f3f0 - rustc_hir_analysis[71d4294717f7f2b7]::collect::generics_of::generics_of
  19:     0x7fa7e727cfb9 - rustc_query_impl[9d4c51777e2bb749]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[9d4c51777e2bb749]::query_impl::generics_of::dynamic_query::{closure#2}::{closure#0}, rustc_middle[446dd094ad85939e]::query::erase::Erased<[u8; 8usize]>>
  20:     0x7fa7e6e74da1 - rustc_query_system[9b2ccfe41ae3bb1b]::query::plumbing::try_execute_query::<rustc_query_impl[9d4c51777e2bb749]::DynamicConfig<rustc_query_system[9b2ccfe41ae3bb1b]::query::caches::DefIdCache<rustc_middle[446dd094ad85939e]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[9d4c51777e2bb749]::plumbing::QueryCtxt, false>
  21:     0x7fa7e6e74a1b - rustc_query_impl[9d4c51777e2bb749]::query_impl::generics_of::get_query_non_incr::__rust_end_short_backtrace
  22:     0x7fa7e72981b8 - <rustc_hir_analysis[71d4294717f7f2b7]::collect::CollectItemTypesVisitor as rustc_hir[170b9793d794ea06]::intravisit::Visitor>::visit_impl_item
  23:     0x7fa7e71f31ca - rustc_hir_analysis[71d4294717f7f2b7]::collect::collect_mod_item_types
  24:     0x7fa7e71f3109 - rustc_query_impl[9d4c51777e2bb749]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[9d4c51777e2bb749]::query_impl::collect_mod_item_types::dynamic_query::{closure#2}::{closure#0}, rustc_middle[446dd094ad85939e]::query::erase::Erased<[u8; 0usize]>>
  25:     0x7fa7e7a2b2ed - rustc_query_system[9b2ccfe41ae3bb1b]::query::plumbing::try_execute_query::<rustc_query_impl[9d4c51777e2bb749]::DynamicConfig<rustc_query_system[9b2ccfe41ae3bb1b]::query::caches::DefaultCache<rustc_span[adb133ac03280fc1]::def_id::LocalModDefId, rustc_middle[446dd094ad85939e]::query::erase::Erased<[u8; 0usize]>>, false, false, false>, rustc_query_impl[9d4c51777e2bb749]::plumbing::QueryCtxt, false>
  26:     0x7fa7e7a2ae17 - rustc_query_impl[9d4c51777e2bb749]::query_impl::collect_mod_item_types::get_query_non_incr::__rust_end_short_backtrace
  27:     0x7fa7e77ad4e8 - rustc_hir_analysis[71d4294717f7f2b7]::check_crate
  28:     0x7fa7e78a2dd3 - rustc_interface[7ca501d7f8f3a34f]::passes::analysis
  29:     0x7fa7e78a2a29 - rustc_query_impl[9d4c51777e2bb749]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[9d4c51777e2bb749]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[446dd094ad85939e]::query::erase::Erased<[u8; 1usize]>>
  30:     0x7fa7e7b3d4a5 - rustc_query_system[9b2ccfe41ae3bb1b]::query::plumbing::try_execute_query::<rustc_query_impl[9d4c51777e2bb749]::DynamicConfig<rustc_query_system[9b2ccfe41ae3bb1b]::query::caches::SingleCache<rustc_middle[446dd094ad85939e]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[9d4c51777e2bb749]::plumbing::QueryCtxt, false>
  31:     0x7fa7e7b3d209 - rustc_query_impl[9d4c51777e2bb749]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
  32:     0x7fa7e7b4c719 - rustc_interface[7ca501d7f8f3a34f]::interface::run_compiler::<core[85b4fd477ce5bb21]::result::Result<(), rustc_span[adb133ac03280fc1]::ErrorGuaranteed>, rustc_driver_impl[e279e4f1fedd9109]::run_compiler::{closure#0}>::{closure#0}
  33:     0x7fa7e7dbe705 - std[5a8e7f94216a9138]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[7ca501d7f8f3a34f]::util::run_in_thread_with_globals<rustc_interface[7ca501d7f8f3a34f]::util::run_in_thread_pool_with_globals<rustc_interface[7ca501d7f8f3a34f]::interface::run_compiler<core[85b4fd477ce5bb21]::result::Result<(), rustc_span[adb133ac03280fc1]::ErrorGuaranteed>, rustc_driver_impl[e279e4f1fedd9109]::run_compiler::{closure#0}>::{closure#0}, core[85b4fd477ce5bb21]::result::Result<(), rustc_span[adb133ac03280fc1]::ErrorGuaranteed>>::{closure#0}, core[85b4fd477ce5bb21]::result::Result<(), rustc_span[adb133ac03280fc1]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[85b4fd477ce5bb21]::result::Result<(), rustc_span[adb133ac03280fc1]::ErrorGuaranteed>>
  34:     0x7fa7e7dbe532 - <<std[5a8e7f94216a9138]::thread::Builder>::spawn_unchecked_<rustc_interface[7ca501d7f8f3a34f]::util::run_in_thread_with_globals<rustc_interface[7ca501d7f8f3a34f]::util::run_in_thread_pool_with_globals<rustc_interface[7ca501d7f8f3a34f]::interface::run_compiler<core[85b4fd477ce5bb21]::result::Result<(), rustc_span[adb133ac03280fc1]::ErrorGuaranteed>, rustc_driver_impl[e279e4f1fedd9109]::run_compiler::{closure#0}>::{closure#0}, core[85b4fd477ce5bb21]::result::Result<(), rustc_span[adb133ac03280fc1]::ErrorGuaranteed>>::{closure#0}, core[85b4fd477ce5bb21]::result::Result<(), rustc_span[adb133ac03280fc1]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[85b4fd477ce5bb21]::result::Result<(), rustc_span[adb133ac03280fc1]::ErrorGuaranteed>>::{closure#1} as core[85b4fd477ce5bb21]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  35:     0x7fa7e2b99725 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h1bff3efb61c3fa6b
                               at /rustc/f8131a48a46ac3bc8a3d0fe0477055b132cffdc3/library/alloc/src/boxed.rs:2016:9
  36:     0x7fa7e2b99725 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h83141cf549dced8a
                               at /rustc/f8131a48a46ac3bc8a3d0fe0477055b132cffdc3/library/alloc/src/boxed.rs:2016:9
  37:     0x7fa7e2b99725 - std::sys::pal::unix::thread::Thread::new::thread_start::hbe9287fdd7c325bc
                               at /rustc/f8131a48a46ac3bc8a3d0fe0477055b132cffdc3/library/std/src/sys/pal/unix/thread.rs:108:17
  38:     0x7fa7e29819eb - <unknown>
  39:     0x7fa7e2a057cc - <unknown>
  40:                0x0 - <unknown>

note: we would appreciate a bug report: https://github.com/rust-lang/rust/issues/new?labels=C-bug%2C+I-ICE%2C+T-compiler&template=ice.md

note: rustc 1.78.0-nightly (f8131a48a 2024-02-21) running on x86_64-unknown-linux-gnu

note: compiler flags: -Z crate-attr=feature(effects) -Z dump-mir-dir=dir

query stack during panic:
#0 [generics_of] computing generics of `<impl at /tmp/icemaker_global_tempdir.hviw91Tg4hl3/rustc_testrunner_tmpdir_reporting.NAMwIoI8bW6T/mvce.rs:4:1: 4:13>::new`
#1 [collect_mod_item_types] collecting item types in top-level module
#2 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to 5 previous errors; 1 warning emitted

Some errors have detailed explanations: E0412, E0601, E0658.
For more information about an error, try `rustc --explain E0412`.

[matthiaskrgr]

#121208 cc @nnethercote I'm pretty sure this was previously fixed explicitly, @fmease may know more

[nnethercote]

@lcnr and @fee1-dead were confident that this path should be unreachable...

[matthiaskrgr]

🙃

[fee1-dead]

Welp. I forgot about invalid programs like this. This will be fixed by the new desugaring though, so don't think we need to revert back to delay span bug yet

[nnethercote]

How soon will the new desugaring merge? If it's not "really soon" then I think it probably is worth reverting.

[fee1-dead]

That won't happen for a while. Feel free to revert and add this file as a test

[nnethercote]

#121208 cc @nnethercote I'm pretty sure this was previously fixed explicitly, @fmease may know more

It was converted from a bug to a span_delayed_bug in #119505, but there was no associated test case.