impl Into<{D,Subd}iagMessage>
The internal diagnostic lint currently only allows one, because that was all that occurred in practice. But rust-lang/rust-clippy/pull/12453 wants to introduce functions with more than one, and this limitation is getting in the way.
ui_test
//@
SubdiagnosticMessage
SubdiagMessage
IntoDiagnosticArg
IntoDiagArg
ParseSess
psess