ICE: `assertion failed: !value.has_infer()` in `rustc_hir_typeck/src/writeback.rs`

[cushionbadak]

Code

(hand-reduced)

#![feature(type_alias_impl_trait)]
type Bar = impl std::fmt::Display;

async fn test<const N: crate::Bar>() {}

fn main () {}

(original)

//@ check-pass

#![feature(type_alias_impl_trait)]
#![allow(dead_code)]

// test that the type alias impl trait defining use is in a submodule

fn main() {}

type Foo = impl std::fmt::Display;
type Bar = impl std::fmt::Display;

mod foo {
    pub(crate) fn foo() -> super::Foo {
        "foo"
    }

    pub(crate) mod bar {
        pub(crate) fn bar() -> crate::Bar {
            1
        }
    }
}


//@ check-pass

trait Database: for<'r> HasValueRef<'r, Database = Self> {}

trait HasValueRef<'r> {
    type Database: Database;
}

struct Any;

impl Database for Any {}

impl<'r> HasValueRef<'r> for Any {
    // Make sure we don't have issues when the GAT assumption
    // `<Any as HasValue<'r>>::Database = Any` isn't universally
    // parameterized over `'r`.
    type Database = Any;
}

fn main() {}


async fn main() {
    // Adding an .await here avoids the ICE
    test()?;
}

// Removing the const generic parameter here avoids the ICE
async fn test<const N: crate::Bar>() {
}

Meta

rustc --version --verbose:

rustc 1.80.0-nightly (debd22da6 2024-05-29)
binary: rustc
commit-hash: debd22da66cfa97c74040ebf68e420672ac8560e
commit-date: 2024-05-29
host: x86_64-apple-darwin
release: 1.80.0-nightly
LLVM version: 18.1.6

Error output

Command: rustc --edition=2018

• --edition option is added to avoid async fn error message

error[E0283]: type annotations needed
 --> r_writeback_C9DEFA.rs:4:1
  |
4 | async fn test<const N: crate::Bar>() {}
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer type
  |
  = note: cannot satisfy `_: std::fmt::Display`

(there exists another error at the end of the backtrace)

Backtrace

thread 'rustc' panicked at compiler/rustc_hir_typeck/src/writeback.rs:749:9:
assertion failed: !value.has_infer()
stack backtrace:
   0: _rust_begin_unwind
   1: core::panicking::panic_fmt
   2: core::panicking::panic
   3: <rustc_hir_typeck::fn_ctxt::FnCtxt>::resolve_type_vars_in_body
   4: rustc_hir_typeck::typeck
      [... omitted 1 frame ...]
   5: rustc_middle::query::plumbing::query_get_at::<rustc_query_system::query::caches::VecCache<rustc_span::def_id::LocalDefId, rustc_middle::query::erase::Erased<[u8; 8]>>>
   6: <rustc_hir_analysis::collect::type_of::opaque::TaitConstraintLocator>::check
   7: rustc_hir_analysis::collect::type_of::type_of_opaque
      [... omitted 1 frame ...]
   8: rustc_middle::query::plumbing::query_get_at::<rustc_query_system::query::caches::DefIdCache<rustc_middle::query::erase::Erased<[u8; 8]>>>
   9: rustc_hir_analysis::collect::type_of::type_of
      [... omitted 1 frame ...]
  10: rustc_middle::query::plumbing::query_get_at::<rustc_query_system::query::caches::DefIdCache<rustc_middle::query::erase::Erased<[u8; 8]>>>
  11: rustc_hir_analysis::check::check::check_item_type
  12: rustc_hir_analysis::check::wfcheck::check_well_formed
      [... omitted 1 frame ...]
  13: rustc_middle::query::plumbing::query_ensure_error_guaranteed::<rustc_query_system::query::caches::VecCache<rustc_hir::hir_id::OwnerId, rustc_middle::query::erase::Erased<[u8; 1]>>, ()>
  14: rustc_hir_analysis::check::wfcheck::check_mod_type_wf
      [... omitted 1 frame ...]
  15: rustc_hir_analysis::check_crate
  16: rustc_interface::passes::run_required_analyses
  17: rustc_interface::passes::analysis
      [... omitted 1 frame ...]
  18: <rustc_interface::queries::QueryResult<&rustc_middle::ty::context::GlobalCtxt>>::enter::<core::result::Result<(), rustc_span::ErrorGuaranteed>, rustc_driver_impl::run_compiler::{closure#0}::{closure#1}::{closure#3}>
  19: rustc_interface::interface::run_compiler::<core::result::Result<(), rustc_span::ErrorGuaranteed>, rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

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

note: please attach the file at `/Volumes/T7/workspace/240529_100chaos_tree_combine_typ/icefiles/rustc-ice-2024-05-30T07_50_14-17949.txt` to your bug report

query stack during panic:
#0 [typeck] type-checking `test`
#1 [type_of_opaque] computing type of opaque `Bar::{opaque#0}`
#2 [type_of] computing type of `Bar::{opaque#0}`
#3 [check_well_formed] checking that `Bar::{opaque#0}` is well-formed
#4 [check_mod_type_wf] checking that types are well-formed in top-level module
#5 [analysis] running analysis passes on this crate
end of query stack
error: `Bar` is forbidden as the type of a const generic parameter
 --> r_writeback_C9DEFA.rs:4:24
  |
4 | async fn test<const N: crate::Bar>() {}
  |                        ^^^^^^^^^^
  |
  = note: the only supported types are integers, `bool` and `char`

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0283`.

Note

• ICE location: rustc_hir_typeck/src/writeback.rs L749
  

  rust/compiler/rustc_hir_typeck/src/writeback.rs

  Lines 743 to 749 in debd22d

  	fn resolve<T>(&mut self, value: T, span: &dyn Locatable) -> T
  	where
  	T: TypeFoldable<TyCtxt<'tcx>>,
  	{
  	let value = self.fcx.resolve_vars_if_possible(value);
  	let value = value.fold_with(&mut Resolver::new(self.fcx, span, self.body));
  	assert!(!value.has_infer());

• Might be related to unsolved ICE Issue-115806 (issue fixed by adding test-case), where the issue points to rustc_trait_selection/src/solve/canonicalize.rs L72
  

  rust/compiler/rustc_trait_selection/src/solve/canonicalize.rs

  Lines 71 to 72 in e5fedce

  	let value = value.fold_with(&mut canonicalizer);
  	assert!(!value.has_infer());