ICE: src\librustc\ty\subst.rs:496: Region parameter out of range when substituting in region 'a #69136

steffahn · 2020-02-13T16:22:37Z

Code

#![feature(type_alias_impl_trait)]

trait SomeTrait where {}

trait WithAssoc<A> where {
	type AssocType;
}

type Return<A> // 'a is not in scope
 = impl WithAssoc<A, AssocType = impl SomeTrait + 'a>;

fn my_fun() -> Return<()> {}

fn main() {}

Error output

error[E0261]: use of undeclared lifetime name `'a`
  --> src/main.rs:11:51
   |
10 | type Return<A> // 'a is not in scope
   |             - help: consider introducing lifetime `'a` here: `'a,`
11 |  = impl WithAssoc<A, AssocType = impl SomeTrait + 'a>;
   |                                                   ^^ undeclared lifetime

error: internal compiler error: src/librustc/ty/subst.rs:496: Region parameter out of range when substituting in region 'a (root type=None) (index=0)

thread 'rustc' panicked at 'Box<Any>', <::std::macros::panic macros>:2:4
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/blob/master/CONTRIBUTING.md#bug-reports

note: rustc 1.43.0-dev running on x86_64-unknown-linux-gnu

note: compiler flags: -C debuginfo=2 -C incremental --crate-type bin

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

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0261`.

Backtrace

error[E0261]: use of undeclared lifetime name `'a`
  --> src/main.rs:11:51
   |
10 | type Return<A> // 'a is not in scope
   |             - help: consider introducing lifetime `'a` here: `'a,`
11 |  = impl WithAssoc<A, AssocType = impl SomeTrait + 'a>;
   |                                                   ^^ undeclared lifetime

error: internal compiler error: src/librustc/ty/subst.rs:496: Region parameter out of range when substituting in region 'a (root type=None) (index=0)

thread 'rustc' panicked at 'Box<Any>', <::std::macros::panic macros>:2:4
stack backtrace:
   0: <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt
   1: core::fmt::write
   2: std::io::Write::write_fmt
   3: std::sys_common::backtrace::print
   4: std::panicking::default_hook::{{closure}}
   5: std::panicking::default_hook
   6: rustc_driver::report_ice
   7: std::panicking::rust_panic_with_hook
   8: std::panicking::begin_panic
   9: rustc_errors::HandlerInner::span_bug
  10: rustc_errors::Handler::span_bug
  11: rustc::util::bug::opt_span_bug_fmt::{{closure}}
  12: rustc::ty::context::tls::with_opt::{{closure}}
  13: rustc::ty::context::tls::with_opt
  14: rustc::util::bug::opt_span_bug_fmt
  15: rustc::util::bug::span_bug_fmt
  16: <rustc::ty::subst::SubstFolder as rustc::ty::fold::TypeFolder>::fold_region
  17: rustc::ty::fold::TypeFoldable::fold_with
  18: <rustc::ty::subst::SubstFolder as rustc::ty::fold::TypeFolder>::fold_binder
  19: rustc::ty::subst::Subst::subst
  20: <core::iter::adapters::Map<I,F> as core::iter::traits::iterator::Iterator>::fold
  21: <alloc::vec::Vec<T> as alloc::vec::SpecExtend<T,I>>::spec_extend
  22: rustc::ty::GenericPredicates::instantiate_into
  23: rustc::ty::GenericPredicates::instantiate
  24: rustc::infer::opaque_types::Instantiator::fold_opaque_ty
  25: <rustc::ty::fold::BottomUpFolder<F,G,H> as rustc::ty::fold::TypeFolder>::fold_ty
  26: rustc::ty::fold::TypeFoldable::fold_with
  27: rustc::ty::structural_impls::<impl rustc::ty::fold::TypeFoldable for rustc::ty::sty::Binder<T>>::fold_with
  28: rustc::ty::fold::TypeFoldable::fold_with
  29: rustc::infer::opaque_types::Instantiator::instantiate_opaque_types_in_map
  30: rustc::infer::opaque_types::Instantiator::fold_opaque_ty
  31: <rustc::ty::fold::BottomUpFolder<F,G,H> as rustc::ty::fold::TypeFolder>::fold_ty
  32: rustc::infer::opaque_types::Instantiator::instantiate_opaque_types_in_map
  33: rustc::infer::opaque_types::<impl rustc::infer::InferCtxt>::instantiate_opaque_types
  34: rustc_typeck::check::FnCtxt::instantiate_opaque_types_from_value
  35: rustc_typeck::check::check_fn
  36: rustc::ty::context::GlobalCtxt::enter_local
  37: rustc::infer::InferCtxtBuilder::enter
  38: rustc_typeck::check::typeck_tables_of_with_fallback
  39: rustc_typeck::check::typeck_tables_of
  40: rustc::ty::query::__query_compute::typeck_tables_of
  41: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::typeck_tables_of>::compute
  42: rustc::dep_graph::graph::DepGraph::with_task_impl
  43: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  44: rustc_typeck::collect::find_opaque_ty_constraints::ConstraintLocator::check
  45: <rustc_typeck::collect::find_opaque_ty_constraints::ConstraintLocator as rustc_hir::intravisit::Visitor>::visit_item
  46: rustc_hir::intravisit::walk_crate
  47: rustc_typeck::collect::find_opaque_ty_constraints
  48: rustc_typeck::collect::type_of
  49: rustc::ty::query::__query_compute::type_of
  50: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::type_of>::compute
  51: rustc::dep_graph::graph::DepGraph::with_task_impl
  52: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  53: <rustc_typeck::collect::CollectItemTypesVisitor as rustc_hir::intravisit::Visitor>::visit_item
  54: rustc::hir::map::Map::visit_item_likes_in_module
  55: rustc_typeck::collect::collect_mod_item_types
  56: rustc::ty::query::__query_compute::collect_mod_item_types
  57: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::collect_mod_item_types>::compute
  58: rustc::dep_graph::graph::DepGraph::with_task_impl
  59: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  60: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::ensure_query
  61: rustc_session::session::Session::track_errors
  62: rustc_typeck::check_crate
  63: rustc_interface::passes::analysis
  64: rustc::ty::query::__query_compute::analysis
  65: rustc::dep_graph::graph::DepGraph::with_eval_always_task
  66: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  67: rustc::ty::context::tls::enter_global
  68: rustc_interface::interface::run_compiler_in_existing_thread_pool
  69: scoped_tls::ScopedKey<T>::set
  70: syntax::attr::with_globals
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

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

note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports

note: rustc 1.43.0-dev running on x86_64-unknown-linux-gnu

note: compiler flags: -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_tables_of] processing `my_fun`
#1 [type_of] processing `Return`
#2 [collect_mod_item_types] collecting item types in top-level module
#3 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0261`.

The text was updated successfully, but these errors were encountered:

Fixes rust-lang#69136 Previously, lifetime resolution errors would cause an error to be emitted, but would not mark the parent type as 'tainted' in any way. We usually abort compilation before this becomes an issue - however, opaque types can cause us to type-check function bodies before such an abort occurs. Ths can result in trying to instantiate opaque types that have invalid computed generics. Currently, this only causes issues for nested opaque types, but there's no reason to expect the computed generics to be sane when we had unresolved lifetimes (which can result in extra lifetime parameters getting added to the generics). This commit tracks 'unresolved lifetime' errors that occur during lifetime resolution. When we type-check an item, we bail out and return `tcx.types.err` if a lifetime error was reported for that type. This causes us to skip type-checking of types affected by the lifetime error, while still checking unrelated types. Additionally, we now check for errors in 'parent' opaque types (if such a 'parent' exists) when collecting constraints for opaque types. This reflects the fact that opaque types inherit generics from 'parent' opaque types - if an error ocurred while type-checking the parent, we don't attempt to type-check the child.

…=nikomatsakis Clean up type alias impl trait implementation - Removes special case for top-level impl trait - Removes associated opaque types - Forbid lifetime elision in let position impl trait. This is consistent with the behavior for inferred types. - Handle lifetimes in type alias impl trait more uniformly with other parameters cc rust-lang#69323 cc rust-lang#63063 Closes rust-lang#57188 Closes rust-lang#62988 Closes rust-lang#69136

…ikomatsakis Clean up type alias impl trait implementation - Removes special case for top-level impl trait - Removes associated opaque types - Forbid lifetime elision in let position impl trait. This is consistent with the behavior for inferred types. - Handle lifetimes in type alias impl trait more uniformly with other parameters cc rust-lang#69323 cc rust-lang#63063 Closes rust-lang#57188 Closes rust-lang#62988 Closes rust-lang#69136 Closes rust-lang#73061

steffahn added C-bug Category: This is a bug. I-ICE Issue: The compiler panicked, giving an Internal Compilation Error (ICE) ❄️ T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Feb 13, 2020

steffahn mentioned this issue Feb 13, 2020

error: internal compiler error: src/librustc/ty/subst.rs:611: type parameter B/#2 (B/2) out of range when substituting (root type=Some((B,))) substs=[ReEarlyBound(0, 'a)] #67844

Closed

jonas-schievink added F-type_alias_impl_trait `#[feature(type_alias_impl_trait)]` requires-nightly This issue requires a nightly compiler in some way. labels Feb 13, 2020

steffahn changed the title ~~ICE: Region parameter out of range when substituting in region 'a~~ ICE: src\librustc\ty\subst.rs:496: Region parameter out of range when substituting in region 'a Feb 14, 2020

rust-lang-glacier-bot added the glacier ICE tracked in rust-lang/glacier. label Feb 14, 2020

Aaron1011 mentioned this issue Feb 15, 2020

Propagate lifetime resolution errors into tcx.type_of #69178

Closed

matthewjasper mentioned this issue May 10, 2020

Clean up type alias impl trait implementation #72080

Merged

bors closed this as completed in ce6d3a7 Jun 15, 2020

github-actions bot mentioned this issue Jun 16, 2020

ices/69136.rs: fixed with errors rust-lang/glacier#396

Merged

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ICE: src\librustc\ty\subst.rs:496: Region parameter out of range when substituting in region 'a #69136

ICE: src\librustc\ty\subst.rs:496: Region parameter out of range when substituting in region 'a #69136

steffahn commented Feb 13, 2020 •

edited

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ICE: src\librustc\ty\subst.rs:496: Region parameter out of range when substituting in region 'a #69136

ICE: src\librustc\ty\subst.rs:496: Region parameter out of range when substituting in region 'a #69136

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steffahn commented Feb 13, 2020 • edited Loading

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steffahn commented Feb 13, 2020 •

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