min_specialization
These crates all needed specialization for `newtype_index!`, which will no longer be necessary when the current nightly eventually becomes the next bootstrap compiler.
DiagCtxt
EarlyDiagCtxt
String
SubdiagnosticMessageOp
ErrorGuaranteed
Emitter::emit_diagnostic
StringPart
_ == _ || _ == _
matches!(_, _ | _)
DiagnosticArg