ICE with Self in default generic type argument

[RustyYato]

I found this ICE when trying to generalize some of my code.

This works on the latest stable, and on playground

https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=312318cf9fff1be2c7cb8cc6d7d16898

pub struct Node<NodeRef = Box<Self>>(NodeRef);

pub struct Foo(Node);

And generates the following ICE

thread 'rustc' panicked at 'Box<Any>', src/librustc_errors/lib.rs:526:9
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
             at src/libstd/sys/unix/backtrace/tracing/gcc_s.rs:39
   1: std::sys_common::backtrace::_print
             at src/libstd/sys_common/backtrace.rs:70
   2: std::panicking::default_hook::{{closure}}
             at src/libstd/sys_common/backtrace.rs:58
             at src/libstd/panicking.rs:200
   3: std::panicking::default_hook
             at src/libstd/panicking.rs:215
   4: rustc::util::common::panic_hook
   5: std::panicking::rust_panic_with_hook
             at src/libstd/panicking.rs:482
   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<'a, 'gcx, 'tcx> as rustc::ty::fold::TypeFolder<'gcx, 'tcx>>::fold_ty
  15: <smallvec::SmallVec<A> as core::iter::traits::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<'tcx> for &'tcx rustc::ty::TyS<'tcx>>::super_fold_with
  18: <rustc::ty::subst::SubstFolder<'a, 'gcx, 'tcx> as rustc::ty::fold::TypeFolder<'gcx, 'tcx>>::fold_ty
  19: <smallvec::SmallVec<A> as core::iter::traits::FromIterator<<A as smallvec::Array>::Item>>::from_iter
  20: rustc::ty::fold::TypeFoldable::fold_with
  21: rustc::ty::structural_impls::<impl rustc::ty::fold::TypeFoldable<'tcx> for &'tcx rustc::ty::TyS<'tcx>>::super_fold_with
  22: <rustc::ty::subst::SubstFolder<'a, 'gcx, 'tcx> as rustc::ty::fold::TypeFolder<'gcx, 'tcx>>::fold_ty
  23: <(dyn rustc_typeck::astconv::AstConv<'gcx, 'tcx> + 'o)>::create_substs_for_ast_path::{{closure}}
  24: <(dyn rustc_typeck::astconv::AstConv<'gcx, 'tcx> + 'o)>::create_substs_for_ast_path
  25: rustc::hir::PathSegment::with_generic_args
  26: <(dyn rustc_typeck::astconv::AstConv<'gcx, 'tcx> + 'o)>::ast_path_substs_for_ty
  27: <(dyn rustc_typeck::astconv::AstConv<'gcx, 'tcx> + 'o)>::ast_path_to_ty
  28: <(dyn rustc_typeck::astconv::AstConv<'gcx, 'tcx> + 'o)>::def_to_ty
  29: <(dyn rustc_typeck::astconv::AstConv<'gcx, 'tcx> + 'o)>::ast_ty_to_ty
  30: rustc_typeck::collect::type_of
  31: rustc::ty::query::__query_compute::type_of
  32: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors<'tcx> for rustc::ty::query::queries::type_of<'tcx>>::compute
  33: rustc::dep_graph::graph::DepGraph::with_task_impl
  34: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::try_get_with
  35: <rustc_typeck::outlives::implicit_infer::InferVisitor<'cx, 'tcx> as rustc::hir::itemlikevisit::ItemLikeVisitor<'tcx>>::visit_item
  36: rustc_typeck::outlives::implicit_infer::infer_predicates
  37: rustc_typeck::outlives::inferred_outlives_crate
  38: rustc::ty::query::__query_compute::inferred_outlives_crate
  39: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors<'tcx> for rustc::ty::query::queries::inferred_outlives_crate<'tcx>>::compute
  40: rustc::dep_graph::graph::DepGraph::with_task_impl
  41: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::try_get_with
  42: rustc_typeck::outlives::inferred_outlives_of
  43: rustc::ty::query::__query_compute::inferred_outlives_of
  44: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors<'tcx> for rustc::ty::query::queries::inferred_outlives_of<'tcx>>::compute
  45: rustc::dep_graph::graph::DepGraph::with_task_impl
  46: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::try_get_with
  47: rustc_typeck::collect::predicates_defined_on
  48: rustc::ty::query::__query_compute::predicates_defined_on
  49: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors<'tcx> for rustc::ty::query::queries::predicates_defined_on<'tcx>>::compute
  50: rustc::dep_graph::graph::DepGraph::with_task_impl
  51: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::try_get_with
  52: rustc_typeck::collect::predicates_of
  53: rustc::ty::query::__query_compute::predicates_of
  54: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors<'tcx> for rustc::ty::query::queries::predicates_of<'tcx>>::compute
  55: rustc::dep_graph::graph::DepGraph::with_task_impl
  56: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::try_get_with
  57: <rustc_typeck::collect::CollectItemTypesVisitor<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_item
  58: rustc::hir::map::Map::visit_item_likes_in_module
  59: rustc_typeck::collect::collect_mod_item_types
  60: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors<'tcx> for rustc::ty::query::queries::collect_mod_item_types<'tcx>>::compute
  61: rustc::dep_graph::graph::DepGraph::with_task_impl
  62: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::try_get_with
  63: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::ensure_query
  64: rustc_typeck::collect::collect_item_types
  65: rustc::util::common::time
  66: rustc_typeck::check_crate
  67: <std::thread::local::LocalKey<T>>::with
  68: rustc::ty::context::TyCtxt::create_and_enter
  69: rustc_driver::driver::compile_input
  70: rustc_driver::run_compiler_with_pool
  71: <scoped_tls::ScopedKey<T>>::set
  72: rustc_driver::run_compiler
  73: <scoped_tls::ScopedKey<T>>::set
query stack during panic:
#0 [type_of] processing `Foo::0`
#1 [inferred_outlives_crate] computing the inferred outlives predicates for items in this crate
#2 [inferred_outlives_of] processing `Node`
#3 [predicates_defined_on] processing `Node`
#4 [predicates_of] processing `Node`
#5 [collect_mod_item_types] collecting item types in top-level module
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 1.33.0 (2aa4c46cf 2019-02-28) running on x86_64-unknown-linux-gnu

note: compiler flags: -C codegen-units=1 -C debuginfo=2 --crate-type lib

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

error: Could not compile `playground`.

To learn more, run the command again with --verbose.

[varkor]

Even simpler:

struct Node<A = Self>(A);
type Foo = Node;

[Alexendoo]

This was fixed by #64842, including a similar test