ICE with `#[derive(Default)]` on enum with repeated variant names

[jruderman]

Found with a modified fuzz-rustc

Code

#[derive(Default)]
enum E {
    #[default] A,
    #[default] A,
}

Error output

thread 'rustc' panicked at 'assertion failed: !suggestion.is_empty()', compiler/rustc_errors/src/diagnostic.rs:628

Backtrace

stack backtrace:
   0:        0x10816c2a6 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h1901ec5c10c2d477
   1:        0x1081cae2a - core::fmt::write::h453ba3b763f16dfb
   2:        0x10815e64c - std::io::Write::write_fmt::h35935f9cf41659e0
   3:        0x10816c08a - std::sys_common::backtrace::print::h48cb2ddd4d16ad05
   4:        0x10816f3d3 - std::panicking::default_hook::{{closure}}::hf85401495f021b7c
   5:        0x10816f128 - std::panicking::default_hook::hcc698ed67aaec0db
   6:        0x1130055fd - rustc_driver[c6bc39476a4ff69]::DEFAULT_HOOK::{closure#0}::{closure#0}
   7:        0x10816fbb7 - std::panicking::rust_panic_with_hook::h4686e220b4123e59
   8:        0x10816f923 - std::panicking::begin_panic_handler::{{closure}}::h159a2fe35d7f418a
   9:        0x10816c748 - std::sys_common::backtrace::__rust_end_short_backtrace::h0017da2a305ee472
  10:        0x10816f62d - _rust_begin_unwind
  11:        0x1081f73f3 - core::panicking::panic_fmt::h000b48597e446791
  12:        0x1081f74c7 - core::panicking::panic::h5888dcc54e62095c
  13:        0x115e67b7c - <rustc_errors[5974999511236221]::diagnostic::Diagnostic>::tool_only_multipart_suggestion::<&alloc[374a688e4a400e73]::string::String>
  14:        0x115e734d6 - rustc_builtin_macros[63bbcae8fe3c402e]::deriving::default::expand_deriving_default::{closure#0}
  15:        0x115f15b54 - <rustc_builtin_macros[63bbcae8fe3c402e]::deriving::generic::MethodDef>::expand_static_enum_method_body
  16:        0x115ef6213 - <core[e7c8723dd1d9fd02]::iter::adapters::map::Map<core[e7c8723dd1d9fd02]::slice::iter::Iter<rustc_builtin_macros[63bbcae8fe3c402e]::deriving::generic::MethodDef>, <rustc_builtin_macros[63bbcae8fe3c402e]::deriving::generic::TraitDef>::expand_enum_def::{closure#1}> as core[e7c8723dd1d9fd02]::iter::traits::iterator::Iterator>::fold::<(), core[e7c8723dd1d9fd02]::iter::traits::iterator::Iterator::for_each::call<rustc_ast[2482a7f97692ab8f]::ptr::P<rustc_ast[2482a7f97692ab8f]::ast::Item<rustc_ast[2482a7f97692ab8f]::ast::AssocItemKind>>, <alloc[374a688e4a400e73]::vec::Vec<rustc_ast[2482a7f97692ab8f]::ptr::P<rustc_ast[2482a7f97692ab8f]::ast::Item<rustc_ast[2482a7f97692ab8f]::ast::AssocItemKind>>>>::extend_trusted<core[e7c8723dd1d9fd02]::iter::adapters::map::Map<core[e7c8723dd1d9fd02]::slice::iter::Iter<rustc_builtin_macros[63bbcae8fe3c402e]::deriving::generic::MethodDef>, <rustc_builtin_macros[63bbcae8fe3c402e]::deriving::generic::TraitDef>::expand_enum_def::{closure#1}>>::{closure#0}>::{closure#0}>
  17:        0x115e3617c - <alloc[374a688e4a400e73]::vec::Vec<rustc_ast[2482a7f97692ab8f]::ptr::P<rustc_ast[2482a7f97692ab8f]::ast::Item<rustc_ast[2482a7f97692ab8f]::ast::AssocItemKind>>> as alloc[374a688e4a400e73]::vec::spec_from_iter::SpecFromIter<rustc_ast[2482a7f97692ab8f]::ptr::P<rustc_ast[2482a7f97692ab8f]::ast::Item<rustc_ast[2482a7f97692ab8f]::ast::AssocItemKind>>, core[e7c8723dd1d9fd02]::iter::adapters::map::Map<core[e7c8723dd1d9fd02]::slice::iter::Iter<rustc_builtin_macros[63bbcae8fe3c402e]::deriving::generic::MethodDef>, <rustc_builtin_macros[63bbcae8fe3c402e]::deriving::generic::TraitDef>::expand_enum_def::{closure#1}>>>::from_iter
  18:        0x115f1019e - <rustc_builtin_macros[63bbcae8fe3c402e]::deriving::generic::TraitDef>::expand_ext
  19:        0x115e6fff1 - rustc_builtin_macros[63bbcae8fe3c402e]::deriving::default::expand_deriving_default
  20:        0x115ec3964 - <rustc_builtin_macros[63bbcae8fe3c402e]::deriving::BuiltinDerive as rustc_expand[f485642205b044c8]::base::MultiItemModifier>::expand
  21:        0x1171491ed - <rustc_expand[f485642205b044c8]::expand::MacroExpander>::fully_expand_fragment
  22:        0x1171479a3 - <rustc_expand[f485642205b044c8]::expand::MacroExpander>::expand_crate
  23:        0x1130878aa - <rustc_session[bf9d936332845243]::session::Session>::time::<core[e7c8723dd1d9fd02]::result::Result<rustc_ast[2482a7f97692ab8f]::ast::Crate, rustc_errors[5974999511236221]::ErrorGuaranteed>, rustc_interface[6b0baa6f0acee236]::passes::configure_and_expand::{closure#1}>
  24:        0x1130ca643 - rustc_interface[6b0baa6f0acee236]::passes::configure_and_expand
  25:        0x1130d23f6 - <rustc_interface[6b0baa6f0acee236]::queries::Queries>::expansion
  26:        0x112fdda67 - <rustc_interface[6b0baa6f0acee236]::interface::Compiler>::enter::<rustc_driver[c6bc39476a4ff69]::run_compiler::{closure#1}::{closure#2}, core[e7c8723dd1d9fd02]::result::Result<core[e7c8723dd1d9fd02]::option::Option<rustc_interface[6b0baa6f0acee236]::queries::Linker>, rustc_errors[5974999511236221]::ErrorGuaranteed>>
  27:        0x112f79d5d - rustc_span[db835ecaf6c42563]::with_source_map::<core[e7c8723dd1d9fd02]::result::Result<(), rustc_errors[5974999511236221]::ErrorGuaranteed>, rustc_interface[6b0baa6f0acee236]::interface::run_compiler<core[e7c8723dd1d9fd02]::result::Result<(), rustc_errors[5974999511236221]::ErrorGuaranteed>, rustc_driver[c6bc39476a4ff69]::run_compiler::{closure#1}>::{closure#0}::{closure#0}>
  28:        0x112fd0a9d - <scoped_tls[9dceb67bf45baec5]::ScopedKey<rustc_span[db835ecaf6c42563]::SessionGlobals>>::set::<rustc_interface[6b0baa6f0acee236]::interface::run_compiler<core[e7c8723dd1d9fd02]::result::Result<(), rustc_errors[5974999511236221]::ErrorGuaranteed>, rustc_driver[c6bc39476a4ff69]::run_compiler::{closure#1}>::{closure#0}, core[e7c8723dd1d9fd02]::result::Result<(), rustc_errors[5974999511236221]::ErrorGuaranteed>>
  29:        0x112f9fffa - std[e853a6d0ec043b70]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[6b0baa6f0acee236]::util::run_in_thread_pool_with_globals<rustc_interface[6b0baa6f0acee236]::interface::run_compiler<core[e7c8723dd1d9fd02]::result::Result<(), rustc_errors[5974999511236221]::ErrorGuaranteed>, rustc_driver[c6bc39476a4ff69]::run_compiler::{closure#1}>::{closure#0}, core[e7c8723dd1d9fd02]::result::Result<(), rustc_errors[5974999511236221]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[e7c8723dd1d9fd02]::result::Result<(), rustc_errors[5974999511236221]::ErrorGuaranteed>>
  30:        0x112f802a5 - <<std[e853a6d0ec043b70]::thread::Builder>::spawn_unchecked_<rustc_interface[6b0baa6f0acee236]::util::run_in_thread_pool_with_globals<rustc_interface[6b0baa6f0acee236]::interface::run_compiler<core[e7c8723dd1d9fd02]::result::Result<(), rustc_errors[5974999511236221]::ErrorGuaranteed>, rustc_driver[c6bc39476a4ff69]::run_compiler::{closure#1}>::{closure#0}, core[e7c8723dd1d9fd02]::result::Result<(), rustc_errors[5974999511236221]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[e7c8723dd1d9fd02]::result::Result<(), rustc_errors[5974999511236221]::ErrorGuaranteed>>::{closure#1} as core[e7c8723dd1d9fd02]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  31:        0x108178e87 - std::sys::unix::thread::Thread::new::thread_start::hb253bfeab5e611e1
  32:     0x7ff8083354e1 - __pthread_start

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 1.67.0-nightly (1eb62b123 2022-11-27) running on x86_64-apple-darwin

Regression

First ICEd in nightly-2021-07-29, likely from #86735 (@jhpratt), which added #[derive(Default)] support for enums.

Version

rustc 1.67.0-nightly (1eb62b123 2022-11-27)
binary: rustc
commit-hash: 1eb62b1235fd77200e6bd967d70e83c0f2497233
commit-date: 2022-11-27
host: x86_64-apple-darwin
release: 1.67.0-nightly
LLVM version: 15.0.4

[jhpratt]

@rustbot claim

[jhpratt]

PR is up at #105106