ICE: `enum Foo<T=Self> { }`: type parameter `T/#0` (T/0) out of range when substituting

[ConnorGray]

The following code triggers an ICE:

enum MyVariants<T=Self> { }

struct Use(MyVariants)

Related issues: #33070, #61808, #59956

rustc version

rustc 1.36.0-nightly (d628c2e 2019-05-05)
binary: rustc
commit-hash: d628c2e
commit-date: 2019-05-05
host: x86_64-apple-darwin
release: 1.36.0-nightly
LLVM version: 8.0

Playground link

https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=7cab718ccb3318a61d01decb71e0d7ce

Backtrace

error: internal compiler error: src/librustc/ty/subst.rs:569: type parameter `T/#0` (T/0) out of range when substituting (root type=Some(MyVariants<T>)) substs=[]
 --> test.rs:3:12
  |
3 | struct Use(MyVariants);
  |            ^^^^^^^^^^

thread 'rustc' panicked at 'Box<Any>', src/librustc_errors/lib.rs:578:9
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
stack backtrace:
   0: std::sys::unix::backtrace::tracing::imp::unwind_backtrace
   1: std::sys_common::backtrace::_print
   2: std::panicking::default_hook::{{closure}}
   3: std::panicking::default_hook
   4: rustc::util::common::panic_hook
   5: std::panicking::rust_panic_with_hook
   6: std::panicking::begin_panic
   7: rustc_errors::Handler::span_bug
   8: rustc::util::bug::opt_span_bug_fmt::{{closure}}
   9: rustc::ty::context::tls::with_opt::{{closure}}
  10: rustc::ty::context::tls::with_context_opt
  11: rustc::ty::context::tls::with_opt
  12: rustc::util::bug::opt_span_bug_fmt
  13: rustc::util::bug::span_bug_fmt
  14: <rustc::ty::subst::SubstFolder as rustc::ty::fold::TypeFolder>::fold_ty
  15: <smallvec::SmallVec<A> as core::iter::traits::collect::FromIterator<<A as smallvec::Array>::Item>>::from_iter
  16: rustc::ty::fold::TypeFoldable::fold_with
  17: rustc::ty::structural_impls::<impl rustc::ty::fold::TypeFoldable for &rustc::ty::TyS>::super_fold_with
  18: <rustc::ty::subst::SubstFolder as rustc::ty::fold::TypeFolder>::fold_ty
  19: <dyn +rustc_typeck::astconv::AstConv>::create_substs_for_ast_path::{{closure}}
  20: <dyn +rustc_typeck::astconv::AstConv>::create_substs_for_ast_path
  21: rustc::hir::PathSegment::with_generic_args
  22: <dyn +rustc_typeck::astconv::AstConv>::ast_path_substs_for_ty
  23: <dyn +rustc_typeck::astconv::AstConv>::res_to_ty
  24: <dyn +rustc_typeck::astconv::AstConv>::ast_ty_to_ty
  25: rustc_typeck::collect::checked_type_of
  26: rustc_typeck::collect::type_of
  27: rustc::ty::query::__query_compute::type_of
  28: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::type_of>::compute
  29: rustc::dep_graph::graph::DepGraph::with_task_impl
  30: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  31: <rustc_typeck::outlives::implicit_infer::InferVisitor as rustc::hir::itemlikevisit::ItemLikeVisitor>::visit_item
  32: rustc::hir::Crate::visit_all_item_likes
  33: rustc_typeck::outlives::inferred_outlives_crate
  34: rustc::ty::query::__query_compute::inferred_outlives_crate
  35: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::inferred_outlives_crate>::compute
  36: rustc::dep_graph::graph::DepGraph::with_task_impl
  37: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  38: rustc_typeck::outlives::inferred_outlives_of
  39: rustc::ty::query::__query_compute::inferred_outlives_of
  40: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::inferred_outlives_of>::compute
  41: rustc::dep_graph::graph::DepGraph::with_task_impl
  42: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  43: rustc_typeck::collect::predicates_defined_on
  44: rustc::ty::query::__query_compute::predicates_defined_on
  45: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::predicates_defined_on>::compute
  46: rustc::dep_graph::graph::DepGraph::with_task_impl
  47: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  48: rustc_typeck::collect::predicates_of
  49: rustc::ty::query::__query_compute::predicates_of
  50: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::predicates_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_typeck::check_crate::{{closure}}::{{closure}}
  61: rustc::util::common::time
  62: rustc_typeck::check_crate
  63: rustc_interface::passes::analysis
  64: rustc::ty::query::__query_compute::analysis
  65: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::analysis>::compute
  66: rustc::dep_graph::graph::DepGraph::with_task_impl
  67: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  68: rustc::ty::context::tls::enter_global
  69: rustc_interface::passes::BoxedGlobalCtxt::access::{{closure}}
  70: rustc_interface::passes::create_global_ctxt::{{closure}}
  71: rustc_interface::passes::BoxedGlobalCtxt::enter
  72: rustc_interface::interface::run_compiler_in_existing_thread_pool
  73: std::thread::local::LocalKey<T>::with
  74: scoped_tls::ScopedKey<T>::set
  75: syntax::with_globals
query stack during panic:
#0 [type_of] processing `Use::0`
#1 [inferred_outlives_crate] computing the inferred outlives predicates for items in this crate
#2 [inferred_outlives_of] processing `MyVariants`
#3 [predicates_defined_on] processing `MyVariants`
#4 [predicates_of] processing `MyVariants`
#5 [collect_mod_item_types] collecting item types in top-level module
#6 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to previous error


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 1.36.0-nightly (d628c2e64 2019-05-05) running on x86_64-apple-darwin

[jonas-schievink]

Duplicate of #59956 (comment)