ICE when build with const_evaluatable_checked and incremental

[moelife-coder]

Code

#![feature(const_generics)]
#![feature(const_evaluatable_checked)]
use std::mem::{size_of, transmute_copy};

fn main() {
    unsafe {
        let c: &str = convert_from_slice([0; 16]);
    }
}
unsafe fn convert_from_slice<T>(source: [u8; size_of::<T>()]) -> T where [u8; size_of::<T>()]: Sized {
    let target: T = transmute_copy(&source);
    target
}

Meta

rustc --version --verbose:

rustc 1.53.0-nightly (9d9c2c92b 2021-04-19)
binary: rustc
commit-hash: 9d9c2c92b834c430f102ea96f65119e37320776e
commit-date: 2021-04-19
host: x86_64-unknown-linux-gnu
release: 1.53.0-nightly
LLVM version: 12.0.0

Error output

error: internal compiler error: compiler/rustc_middle/src/ich/impls_ty.rs:94:17: StableHasher: unexpected region '_#1r

thread 'rustc' panicked at 'Box<Any>', /rustc/9d9c2c92b834c430f102ea96f65119e37320776e/library/std/src/panic.rs:59:5
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

note: the compiler unexpectedly panicked. this is a bug.

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 1.53.0-nightly (9d9c2c92b 2021-04-19) running on x86_64-unknown-linux-gnu

note: compiler flags: -C embed-bitcode=no -C debuginfo=2 -C incremental --crate-type bin

note: some of the compiler flags provided by cargo are hidden

query stack during panic:
#0 [typeck] type-checking `main`
#1 [typeck_item_bodies] type-checking all item bodies
end of query stack

Backtrace

thread 'rustc' panicked at 'Box<Any>', /rustc/9d9c2c92b834c430f102ea96f65119e37320776e/library/std/src/panic.rs:59:5
stack backtrace:
   0: std::panicking::begin_panic
   1: std::panic::panic_any
   2: rustc_errors::HandlerInner::bug
   3: rustc_errors::Handler::bug
   4: rustc_middle::ty::context::tls::with_opt
   5: rustc_middle::util::bug::opt_span_bug_fmt
   6: rustc_middle::util::bug::bug_fmt
   7: rustc_middle::ich::impls_ty::<impl rustc_data_structures::stable_hasher::HashStable<rustc_middle::ich::hcx::StableHashingContext> for rustc_middle::ty::sty::RegionKind>::hash_stable
   8: <rustc_middle::ty::TyS as rustc_data_structures::stable_hasher::HashStable<rustc_middle::ich::hcx::StableHashingContext>>::hash_stable
   9: std::thread::local::LocalKey<T>::with
  10: <T as rustc_query_system::dep_graph::dep_node::DepNodeParams<Ctxt>>::to_fingerprint
  11: rustc_query_system::dep_graph::dep_node::DepNode<K>::construct
  12: rustc_query_system::query::plumbing::get_query_impl
  13: rustc_query_system::query::plumbing::get_query
  14: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::try_unify_abstract_consts
  15: rustc_trait_selection::traits::fulfill::FulfillProcessor::progress_changed_obligations
  16: rustc_data_structures::obligation_forest::ObligationForest<O>::process_obligations
  17: <rustc_trait_selection::traits::fulfill::FulfillmentContext as rustc_infer::traits::engine::TraitEngine>::select_where_possible
  18: rustc_typeck::check::fn_ctxt::checks::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_argument_types
  19: rustc_typeck::check::callee::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::confirm_builtin_call
  20: rustc_typeck::check::callee::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_call
  21: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_kind
  22: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_with_expectation
  23: rustc_typeck::check::fn_ctxt::checks::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_decl_initializer
  24: rustc_typeck::check::fn_ctxt::checks::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_decl_local
  25: rustc_typeck::check::fn_ctxt::checks::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_stmt
  26: rustc_typeck::check::fn_ctxt::checks::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_block_with_expected
  27: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_with_expectation
  28: rustc_typeck::check::fn_ctxt::checks::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_block_with_expected
  29: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_with_expectation
  30: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_return_expr
  31: rustc_typeck::check::check::check_fn
  32: rustc_infer::infer::InferCtxtBuilder::enter
  33: rustc_typeck::check::typeck
  34: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps
  35: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  36: rustc_data_structures::stack::ensure_sufficient_stack
  37: rustc_query_system::query::plumbing::force_query_with_job
  38: rustc_query_system::query::plumbing::get_query_impl
  39: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::typeck
  40: rustc_middle::ty::<impl rustc_middle::ty::context::TyCtxt>::par_body_owners
  41: rustc_typeck::check::typeck_item_bodies
  42: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps
  43: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  44: rustc_data_structures::stack::ensure_sufficient_stack
  45: rustc_query_system::query::plumbing::force_query_with_job
  46: rustc_query_system::query::plumbing::get_query_impl
  47: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::typeck_item_bodies
  48: rustc_session::utils::<impl rustc_session::session::Session>::time
  49: rustc_typeck::check_crate
  50: rustc_interface::passes::analysis
  51: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps
  52: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  53: rustc_data_structures::stack::ensure_sufficient_stack
  54: rustc_query_system::query::plumbing::force_query_with_job
  55: rustc_query_system::query::plumbing::get_query_impl
  56: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::analysis
  57: rustc_interface::passes::QueryContext::enter
  58: rustc_interface::queries::<impl rustc_interface::interface::Compiler>::enter
  59: rustc_span::with_source_map
  60: rustc_interface::interface::create_compiler_and_run
  61: scoped_tls::ScopedKey<T>::set
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

[moelife-coder]

The code does work on rust playground (for now), which is running rustc 1.53.0-nightly (2021-04-18 5a4ab26459a1ccf17ef5). Not sure if it's a regression or something similar.

[hellow554]

Can't reproduce the error with your rust version :/

Have you changed something beforehand?

If it still occurs to you, please

1. do a backup of your target folder (into a .zip file for example)
2. cargo clean or rm -rf target
3. cargo check (or whatever you've done to build your code)

If it still panics, please report, else please upload the target folder and link it here

[moelife-coder]

I can still reproduce the bug after cargo clean; rm -rf ~/.config/cargo/target. I also tried to update to latest rustc (rustc 1.53.0-nightly (b84932674 2021-04-21)), but it's still not working.

I do have a custom global cargo.toml, but it should be irrelevant as it only contains a proxy and a target folder configuration (for better connection and global cache).

Global cargo.toml:

[http]
proxy = "127.0.0.1:1081"         # HTTP proxy in libcurl format
[build]
target-dir = "cargo/target"

No changes are made for the crate-level configuration file.

target.tar.gz

[moelife-coder]

I tried several times and I realized that I can actually build it successfully when appending --release argument for cargo. After some attempts, I pinned the problem down to -C incremental rustc option. No matter what path I specified as incremental folder, it will always break the compiler. I believe this issue can now be reproduced using shell code:

mkdir incremental_tmp; rustc main.rs -C incremental incremental_tmp; rm -r incremental_tmp

I tried the following command in docker rustlang/rust:nightly and the issue successfully reproduced.

[moelife-coder]

Although rust playground can build the code under default modes (build or run), it will fail when using test mode.

[hellow554]

Okay, I got it now... cargo check will also fail... I think I missed the incremental option in rustc, trying to reduce and bisect

[moelife-coder]

I realized that it's a duplicate for #77708 . I'll close this issue in favor of that one.

[Johannesd3]

Are you sure this is a duplicate? The query stack and backtrace are different to #77708.

But it looks very similar to #85031 which I opened today.

[moelife-coder]

Are you sure this is a duplicate? The query stack and backtrace are different to #77708.

But it looks very similar to #85031 which I opened today.

Sorry for the late response, but I think you are correct. The query stack is similar to your issue than #77708 .