ICE: generic_const_exprs on 1.85.0-nightly

Summary:

• This is when adding const generics to an existing project (the original author is someone else). So I can't minimize it at the moment, and I most likely have some errors. But:
• nightly/stable - both are (to be) implemented.
  • stable uses a type alias (in src/trait_flags.rs: pub type TraitFlags = u8;) instead of a custom struct. stable runs all tests fine.
  • nightly (hopes to) use generic_const_exprs. It's behind unstable_generic_const_own_type feature - see the following.

Surprisingly, even though it mentions ICE, the problem shows up

• only when RUNNING tests cargo +nightly test --features unstable_generic_const_own_type
• but NOT when running a check on tests with cargo +nightly check --tests --features unstable_generic_const_own_type.

To replicate:

git clone https://github.com/peter-lyons-kehl/phantom-newtype-rs
cd phantom-newtype-rs
git checkout aaf428c25ef3f7fb1de5aa290b38e9908390fad3
cargo +nightly test --features unstable_generic_const_own_type

Code

See above.

Meta

# on current Manjaro x64
uname -a
Linux spectre 6.12.1-4-MANJARO #1 SMP PREEMPT_DYNAMIC Mon, 25 Nov 2024 05:36:03 +0000 x86_64 GNU/Linux

Rustup installed as a Manjaro (Arch) package. Both nightly and stable installed with rustup and current:

rustc --version --verbose:

rustc 1.85.0-nightly (9c707a8b7 2024-12-07)
binary: rustc
commit-hash: 9c707a8b769523bb6768bf58e74fa2c39cc24844
commit-date: 2024-12-07
host: x86_64-unknown-linux-gnu
release: 1.85.0-nightly
LLVM version: 19.1.5

Error output

See also attached ICE TXT files.

<output>
(SKIPPED WARNINGS)

running 2 tests
test instant::tests::test_complex_instant_arithmetics ... ok
test trait_flag::test_flags::all ... ok

test result: ok. 2 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s

   Doc-tests phantom_newtype

running 32 tests
test src/amount.rs - amount::Amount (line 138) ... FAILED
test src/amount.rs - amount::Amount (line 126) ... FAILED
test src/amount.rs - amount::Amount (line 31) - compile fail ... ok
test src/amount.rs - amount::Amount (line 108) ... ok
test src/amount.rs - amount::Amount (line 47) ... FAILED
test src/amount.rs - amount::Amount (line 65) ... FAILED
test src/amount.rs - amount::Amount (line 82) ... FAILED
test src/amount.rs - amount::Amount (line 96) ... FAILED
test src/amount.rs - amount::Amount<TF,Unit,Repr>::get (line 157) ... FAILED
test src/amount.rs - amount::Amount<TF,Unit,Repr>::display (line 206) ... FAILED
test src/amount.rs - amount::Amount<TF,Unit,Repr>::unit (line 185) ... FAILED
test src/id.rs - id::Id (line 48) - compile fail ... ok
test src/id.rs - id::Id (line 127) ... ok
test src/id.rs - id::Id (line 30) ... ok
test src/id.rs - id::Id (line 113) ... ok
test src/id.rs - id::Id (line 62) ... ok
test src/id.rs - id::Id (line 76) ... ok
test src/id.rs - id::Id<Entity,Repr>::get (line 145) ... ok
test src/id.rs - id::Id<Entity,Repr>::display (line 182) ... ok
test src/id.rs - id::Id<Entity,Repr>::new (line 161) ... ok
test src/id.rs - id::Id (line 95) ... ok
test src/instant.rs - instant::Instant (line 100) ... ok
test src/instant.rs - instant::Instant (line 132) ... FAILED
test src/instant.rs - instant::Instant (line 120) ... FAILED
test src/instant.rs - instant::Instant (line 53) ... FAILED
test src/instant.rs - instant::Instant (line 33) ... FAILED
test src/instant.rs - instant::Instant<TF,Unit,Repr>::display (line 200) ... FAILED
test src/instant.rs - instant::Instant (line 73) ... FAILED
test src/instant.rs - instant::Instant (line 88) ... FAILED
test src/to.rs - to::As (line 25) ... ignored
test src/instant.rs - instant::Instant<TF,Unit,Repr>::get (line 153) ... FAILED
test src/instant.rs - instant::Instant<TF,Unit,Repr>::unit (line 179) ... FAILED

failures:

---- src/amount.rs - amount::Amount (line 138) stdout ----
note: no errors encountered even though delayed bugs were created

note: those delayed bugs will now be shown as internal compiler errors

error: internal compiler error: Encountered anon const with inference variable args but no error reported
  |
  = note: delayed at compiler/rustc_trait_selection/src/traits/mod.rs:605:27 - disabled backtrace

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: please make sure that you have updated to the latest nightly

note: please attach the file at `/share/pkehl/GIT/phantom-newtype-rs/rustc-ice-2024-12-08T20_05_46-2074664.txt` to your bug report

query stack during panic:
end of query stack
Couldn't compile the test.
---- src/amount.rs - amount::Amount (line 126) stdout ----
note: no errors encountered even though delayed bugs were created

note: those delayed bugs will now be shown as internal compiler errors

error: internal compiler error: Encountered anon const with inference variable args but no error reported
  |
  = note: delayed at compiler/rustc_trait_selection/src/traits/mod.rs:605:27 - disabled backtrace

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: please make sure that you have updated to the latest nightly

note: please attach the file at `/share/pkehl/GIT/phantom-newtype-rs/rustc-ice-2024-12-08T20_05_46-2074666.txt` to your bug report

query stack during panic:
end of query stack
Couldn't compile the test.
---- src/amount.rs - amount::Amount (line 47) stdout ----
note: no errors encountered even though delayed bugs were created

note: those delayed bugs will now be shown as internal compiler errors

error: internal compiler error: Encountered anon const with inference variable args but no error reported
  |
  = note: delayed at compiler/rustc_trait_selection/src/traits/mod.rs:605:27 - disabled backtrace

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: please make sure that you have updated to the latest nightly

note: please attach the file at `/share/pkehl/GIT/phantom-newtype-rs/rustc-ice-2024-12-08T20_05_46-2074683.txt` to your bug report

query stack during panic:
end of query stack
Couldn't compile the test.
---- src/amount.rs - amount::Amount (line 65) stdout ----
note: no errors encountered even though delayed bugs were created

note: those delayed bugs will now be shown as internal compiler errors

error: internal compiler error: Encountered anon const with inference variable args but no error reported
  |
  = note: delayed at compiler/rustc_trait_selection/src/traits/mod.rs:605:27 - disabled backtrace

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: please make sure that you have updated to the latest nightly

note: please attach the file at `/share/pkehl/GIT/phantom-newtype-rs/rustc-ice-2024-12-08T20_05_46-2074687.txt` to your bug report

query stack during panic:
end of query stack
Couldn't compile the test.
---- src/amount.rs - amount::Amount (line 82) stdout ----
note: no errors encountered even though delayed bugs were created

note: those delayed bugs will now be shown as internal compiler errors

error: internal compiler error: Encountered anon const with inference variable args but no error reported
  |
  = note: delayed at compiler/rustc_trait_selection/src/traits/mod.rs:605:27 - disabled backtrace

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: please make sure that you have updated to the latest nightly

note: please attach the file at `/share/pkehl/GIT/phantom-newtype-rs/rustc-ice-2024-12-08T20_05_46-2074695.txt` to your bug report

query stack during panic:
end of query stack
Couldn't compile the test.
---- src/amount.rs - amount::Amount (line 96) stdout ----
note: no errors encountered even though delayed bugs were created

note: those delayed bugs will now be shown as internal compiler errors

error: internal compiler error: Encountered anon const with inference variable args but no error reported
  |
  = note: delayed at compiler/rustc_trait_selection/src/traits/mod.rs:605:27 - disabled backtrace

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: please make sure that you have updated to the latest nightly

note: please attach the file at `/share/pkehl/GIT/phantom-newtype-rs/rustc-ice-2024-12-08T20_05_46-2074703.txt` to your bug report

query stack during panic:
end of query stack
Couldn't compile the test.
---- src/amount.rs - amount::Amount<TF,Unit,Repr>::get (line 157) stdout ----
note: no errors encountered even though delayed bugs were created

note: those delayed bugs will now be shown as internal compiler errors

error: internal compiler error: Encountered anon const with inference variable args but no error reported
  |
  = note: delayed at compiler/rustc_trait_selection/src/traits/mod.rs:605:27 - disabled backtrace

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: please make sure that you have updated to the latest nightly

note: please attach the file at `/share/pkehl/GIT/phantom-newtype-rs/rustc-ice-2024-12-08T20_05_47-2074712.txt` to your bug report

query stack during panic:
end of query stack
Couldn't compile the test.
---- src/amount.rs - amount::Amount<TF,Unit,Repr>::display (line 206) stdout ----
note: no errors encountered even though delayed bugs were created

note: those delayed bugs will now be shown as internal compiler errors

error: internal compiler error: Encountered anon const with inference variable args but no error reported
  |
  = note: delayed at compiler/rustc_trait_selection/src/traits/mod.rs:605:27 - disabled backtrace

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: please make sure that you have updated to the latest nightly

note: please attach the file at `/share/pkehl/GIT/phantom-newtype-rs/rustc-ice-2024-12-08T20_05_47-2074709.txt` to your bug report

query stack during panic:
end of query stack
Couldn't compile the test.
---- src/amount.rs - amount::Amount<TF,Unit,Repr>::unit (line 185) stdout ----
note: no errors encountered even though delayed bugs were created

note: those delayed bugs will now be shown as internal compiler errors

error: internal compiler error: Encountered anon const with inference variable args but no error reported
  |
  = note: delayed at compiler/rustc_trait_selection/src/traits/mod.rs:605:27 - disabled backtrace

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: please make sure that you have updated to the latest nightly

note: please attach the file at `/share/pkehl/GIT/phantom-newtype-rs/rustc-ice-2024-12-08T20_05_47-2074714.txt` to your bug report

query stack during panic:
end of query stack
Couldn't compile the test.
---- src/instant.rs - instant::Instant (line 132) stdout ----
note: no errors encountered even though delayed bugs were created

note: those delayed bugs will now be shown as internal compiler errors

error: internal compiler error: Encountered anon const with inference variable args but no error reported
  |
  = note: delayed at compiler/rustc_trait_selection/src/traits/mod.rs:605:27 - disabled backtrace

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: please make sure that you have updated to the latest nightly

note: please attach the file at `/share/pkehl/GIT/phantom-newtype-rs/rustc-ice-2024-12-08T20_05_48-2074907.txt` to your bug report

query stack during panic:
end of query stack
Couldn't compile the test.
---- src/instant.rs - instant::Instant (line 120) stdout ----
note: no errors encountered even though delayed bugs were created

note: those delayed bugs will now be shown as internal compiler errors

error: internal compiler error: Encountered anon const with inference variable args but no error reported
  |
  = note: delayed at compiler/rustc_trait_selection/src/traits/mod.rs:605:27 - disabled backtrace

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: please make sure that you have updated to the latest nightly

note: please attach the file at `/share/pkehl/GIT/phantom-newtype-rs/rustc-ice-2024-12-08T20_05_48-2074892.txt` to your bug report

query stack during panic:
end of query stack
Couldn't compile the test.
---- src/instant.rs - instant::Instant (line 53) stdout ----
note: no errors encountered even though delayed bugs were created

note: those delayed bugs will now be shown as internal compiler errors

error: internal compiler error: Encountered anon const with inference variable args but no error reported
  |
  = note: delayed at compiler/rustc_trait_selection/src/traits/mod.rs:605:27 - disabled backtrace

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: please make sure that you have updated to the latest nightly

note: please attach the file at `/share/pkehl/GIT/phantom-newtype-rs/rustc-ice-2024-12-08T20_05_48-2074915.txt` to your bug report

query stack during panic:
end of query stack
Couldn't compile the test.
---- src/instant.rs - instant::Instant (line 33) stdout ----
note: no errors encountered even though delayed bugs were created

note: those delayed bugs will now be shown as internal compiler errors

error: internal compiler error: Encountered anon const with inference variable args but no error reported
  |
  = note: delayed at compiler/rustc_trait_selection/src/traits/mod.rs:605:27 - disabled backtrace

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: please make sure that you have updated to the latest nightly

note: please attach the file at `/share/pkehl/GIT/phantom-newtype-rs/rustc-ice-2024-12-08T20_05_48-2074913.txt` to your bug report

query stack during panic:
end of query stack
Couldn't compile the test.
---- src/instant.rs - instant::Instant<TF,Unit,Repr>::display (line 200) stdout ----
note: no errors encountered even though delayed bugs were created

note: those delayed bugs will now be shown as internal compiler errors

error: internal compiler error: Encountered anon const with inference variable args but no error reported
  |
  = note: delayed at compiler/rustc_trait_selection/src/traits/mod.rs:605:27 - disabled backtrace

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: please make sure that you have updated to the latest nightly

note: please attach the file at `/share/pkehl/GIT/phantom-newtype-rs/rustc-ice-2024-12-08T20_05_48-2074927.txt` to your bug report

query stack during panic:
end of query stack
Couldn't compile the test.
---- src/instant.rs - instant::Instant (line 73) stdout ----
note: no errors encountered even though delayed bugs were created

note: those delayed bugs will now be shown as internal compiler errors

error: internal compiler error: Encountered anon const with inference variable args but no error reported
  |
  = note: delayed at compiler/rustc_trait_selection/src/traits/mod.rs:605:27 - disabled backtrace

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: please make sure that you have updated to the latest nightly

note: please attach the file at `/share/pkehl/GIT/phantom-newtype-rs/rustc-ice-2024-12-08T20_05_48-2074921.txt` to your bug report

query stack during panic:
end of query stack
Couldn't compile the test.
---- src/instant.rs - instant::Instant (line 88) stdout ----
note: no errors encountered even though delayed bugs were created

note: those delayed bugs will now be shown as internal compiler errors

error: internal compiler error: Encountered anon const with inference variable args but no error reported
  |
  = note: delayed at compiler/rustc_trait_selection/src/traits/mod.rs:605:27 - disabled backtrace

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: please make sure that you have updated to the latest nightly

note: please attach the file at `/share/pkehl/GIT/phantom-newtype-rs/rustc-ice-2024-12-08T20_05_48-2074923.txt` to your bug report

query stack during panic:
end of query stack
Couldn't compile the test.
---- src/instant.rs - instant::Instant<TF,Unit,Repr>::get (line 153) stdout ----
note: no errors encountered even though delayed bugs were created

note: those delayed bugs will now be shown as internal compiler errors

error: internal compiler error: Encountered anon const with inference variable args but no error reported
  |
  = note: delayed at compiler/rustc_trait_selection/src/traits/mod.rs:605:27 - disabled backtrace

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: please make sure that you have updated to the latest nightly

note: please attach the file at `/share/pkehl/GIT/phantom-newtype-rs/rustc-ice-2024-12-08T20_05_48-2074934.txt` to your bug report

query stack during panic:
end of query stack
Couldn't compile the test.
---- src/instant.rs - instant::Instant<TF,Unit,Repr>::unit (line 179) stdout ----
note: no errors encountered even though delayed bugs were created

note: those delayed bugs will now be shown as internal compiler errors

error: internal compiler error: Encountered anon const with inference variable args but no error reported
  |
  = note: delayed at compiler/rustc_trait_selection/src/traits/mod.rs:605:27 - disabled backtrace

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: please make sure that you have updated to the latest nightly

note: please attach the file at `/share/pkehl/GIT/phantom-newtype-rs/rustc-ice-2024-12-08T20_05_48-2074938.txt` to your bug report

query stack during panic:
end of query stack
Couldn't compile the test.

failures:
    src/amount.rs - amount::Amount (line 126)
    src/amount.rs - amount::Amount (line 138)
    src/amount.rs - amount::Amount (line 47)
    src/amount.rs - amount::Amount (line 65)
    src/amount.rs - amount::Amount (line 82)
    src/amount.rs - amount::Amount (line 96)
    src/amount.rs - amount::Amount<TF,Unit,Repr>::display (line 206)
    src/amount.rs - amount::Amount<TF,Unit,Repr>::get (line 157)
    src/amount.rs - amount::Amount<TF,Unit,Repr>::unit (line 185)
    src/instant.rs - instant::Instant (line 120)
    src/instant.rs - instant::Instant (line 132)
    src/instant.rs - instant::Instant (line 33)
    src/instant.rs - instant::Instant (line 53)
    src/instant.rs - instant::Instant (line 73)
    src/instant.rs - instant::Instant (line 88)
    src/instant.rs - instant::Instant<TF,Unit,Repr>::display (line 200)
    src/instant.rs - instant::Instant<TF,Unit,Repr>::get (line 153)
    src/instant.rs - instant::Instant<TF,Unit,Repr>::unit (line 179)

test result: FAILED. 13 passed; 18 failed; 1 ignored; 0 measured; 0 filtered out; finished in 2.50s

error: doctest failed, to rerun pass `--doc`

rustc-ice-2024-12-08T20_05_48-2074938.txt
rustc-ice-2024-12-08T20_05_48-2074934.txt
rustc-ice-2024-12-08T20_05_48-2074923.txt
rustc-ice-2024-12-08T20_05_48-2074927.txt
rustc-ice-2024-12-08T20_05_48-2074921.txt
rustc-ice-2024-12-08T20_05_48-2074913.txt
rustc-ice-2024-12-08T20_05_48-2074915.txt
rustc-ice-2024-12-08T20_05_48-2074907.txt
rustc-ice-2024-12-08T20_05_48-2074892.txt
rustc-ice-2024-12-08T20_05_47-2074709.txt
rustc-ice-2024-12-08T20_05_47-2074714.txt
rustc-ice-2024-12-08T20_05_47-2074712.txt
rustc-ice-2024-12-08T20_05_46-2074703.txt
rustc-ice-2024-12-08T20_05_46-2074683.txt
rustc-ice-2024-12-08T20_05_46-2074687.txt
rustc-ice-2024-12-08T20_05_46-2074695.txt
rustc-ice-2024-12-08T20_05_46-2074666.txt
rustc-ice-2024-12-08T20_05_46-2074664.txt

Clone phantom-newtype-rs at commit aaf428c25ef3f7fb1de5aa290b38e9908390fad3 and run cargo +nightly test --features unstable_generic_const_own_type, comparing it with cargo +nightly check --tests using the pinned nightly version. Read the ICE location reported at rustc_trait_selection/src/traits/mod.rs:605:27 and inspect the attached ICE output. Done means the doc tests no longer trigger the reported internal compiler error.