ICE: assertion failed: !self.substitutions.is_empty()

[klensy]

Code

use std::result::Result;
pub fn foo(v: Option<Vec<u32>>)->Result<Vec<u32>,Err>{
    v.unwrap()
}

Meta

rustc --version --verbose:

rustc 1.52.0-nightly (a15f484b9 2021-02-22)
binary: rustc
commit-hash: a15f484b918a4533ad633ea903ccce82910af342
commit-date: 2021-02-22
host: x86_64-pc-windows-msvc
release: 1.52.0-nightly
LLVM version: 11.0.1

Error output

error[E0573]: expected type, found variant `Err`
 --> ice.rs:2:50
  |
2 | pub fn foo(v: Option<Vec<u32>>)->Result<Vec<u32>,Err>{
  |                                                  ^^^ not a type
  |
thread 'rustc' panicked at 'assertion failed: !self.substitutions.is_empty()', compiler\rustc_errors\src\lib.rs:189:9
stack backtrace:
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

error: internal compiler error: unexpected panic

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 1.52.0-nightly (a15f484b9 2021-02-22) running on x86_64-pc-windows-msvc

Backtrace

stack backtrace:
   0:      0x7fee486889e - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h160322fcc0f12a19
   1:      0x7fee48946eb - core::fmt::write::ha3ea633b18d2da75
   2:      0x7fee485ba38 - <std::io::IoSlice as core::fmt::Debug>::fmt::h0a7d0dda807c93f1
   3:      0x7fee486ca6d - std::panicking::take_hook::h7c389d310fc84231
   4:      0x7fee486c539 - std::panicking::take_hook::h7c389d310fc84231
   5:      0x7feba280b57 - rustc_driver::report_ice::h1a74db21cb8754b8
   6:      0x7fee486d4d2 - std::panicking::rust_panic_with_hook::h13af0da83034d6f3
   7:      0x7fee486cf93 - rust_begin_unwind
   8:      0x7fee486922f - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h160322fcc0f12a19
   9:      0x7fee486cf19 - rust_begin_unwind
  10:      0x7fee4890770 - core::panicking::panic_fmt::h45da916c710b88f7
  11:      0x7fee48906bc - core::panicking::panic::h3a7a516f2be28c18
  12:      0x7febe33121e - <rustc_errors::emitter::EmitterWriter as rustc_errors::emitter::Emitter>::emit_diagnostic::h3d02e1f0f59cd00e
  13:      0x7febe31b98c - rustc_errors::HandlerInner::emit_diagnostic::h49c6c3d27e650aba
  14:      0x7febe31ea40 - rustc_errors::diagnostic_builder::DiagnosticBuilder::emit::ha446fe548eb9045f
  15:      0x7febca3a296 - rustc_resolve::Resolver::traits_in_scope::h19f4a2dd68abd28b
  16:      0x7febc9acf64 - <rustc_resolve::def_collector::DefCollector as rustc_ast::visit::Visitor>::visit_struct_field::hbfddfba92fa8545b
  17:      0x7febca31962 - rustc_resolve::Resolver::resolve_crate::hd6b49611d4838c89
  18:      0x7feba3e0f9e - rustc_interface::passes::BoxedResolver::to_resolver_outputs::h07a0552f8efe1194
  19:      0x7feba47efe9 - rustc_interface::interface::try_print_query_stack::h7f59c59e34a51d59
  20:      0x7feba471536 - <rustc_interface::proc_macro_decls::Finder as rustc_hir::itemlikevisit::ItemLikeVisitor>::visit_item::h3d2eb92653f206c2
  21:      0x7feba3df547 - <rls_span::compiler::_::<impl serde::de::Deserialize for rls_span::compiler::DiagnosticSpanMacroExpansion>::deserialize::__Visitor as serde::de::Visitor>::expecting::heaaadf72ddcc941f
  22:      0x7feba3f7623 - rustc_interface::queries::Queries::expansion::hfb52f37ff02463b0
  23:      0x7feba298dc2 - <rustc_mir::transform::generator::PinArgVisitor as rustc_middle::mir::visit::MutVisitor>::tcx::h19961d02f3ef44a2
  24:      0x7feba2f7cbc - <tracing_subscriber::util::TryInitError as core::fmt::Display>::fmt::hed7ff0c137659fdb
  25:      0x7feba29a799 - <rustc_mir::transform::generator::PinArgVisitor as rustc_middle::mir::visit::MutVisitor>::tcx::h19961d02f3ef44a2
  26:      0x7feba292824 - chalk_engine::table::AnswerIndex::increment::ha0e3e0cdbbf984d6
  27:      0x7feba2942ae - rustc_query_impl::query_callbacks::mir_promoted::force_from_dep_node::h528046bbd86b3faa
  28:      0x7feba2bb74d - rustc_driver::pretty::print_after_hir_lowering::h2b3710020259b375
  29:      0x7fee487caba - std::sys::windows::thread::Thread::new::hd38a560d738a063d
  30:         0x7702556d - BaseThreadInitThunk
  31:         0x7718372d - RtlUserThreadStart

[klensy]

Slightly minimized:

use std::result::Result;
pub fn foo(v: u32)->Result<u32,Err>{
    v
}

[jonas-schievink]

duplicate of #78651