Currently it's used for two dynamic checks:
- When a diagnostic is emitted, has it been emitted before?
- When a diagnostic is dropped, has it been emitted/cancelled?
The first check is no longer need, because `emit` is consuming, so it's
impossible to emit a `DiagnosticBuilder` twice. The second check is
still needed.
This commit replaces `DiagnosticBuilderState` with a simpler
`Option<Box<Diagnostic>>`, which is enough for the second check:
functions like `emit` and `cancel` can take the `Diagnostic` and then
`drop` can check that the `Diagnostic` was taken.
The `DiagCtxt` reference from `DiagnosticBuilderState` is now stored as
its own field, removing the need for the `dcx` method.
As well as making the code shorter and simpler, the commit removes:
- One (deprecated) `ErrorGuaranteed::unchecked_claim_error_was_emitted`
call.
- Two `FIXME(eddyb)` comments that are no longer relevant.
- The use of a dummy `Diagnostic` in `into_diagnostic`.
Nice!
`Diagnostic` has 40 methods that return `&mut Self` and could be
considered setters. Four of them have a `set_` prefix. This doesn't seem
necessary for a type that implements the builder pattern. This commit
removes the `set_` prefixes on those four methods.
And make all hand-written `IntoDiagnostic` impls generic, by using
`DiagnosticBuilder::new(dcx, level, ...)` instead of e.g.
`dcx.struct_err(...)`.
This means the `create_*` functions are the source of the error level.
This change will let us remove `struct_diagnostic`.
Note: `#[rustc_lint_diagnostics]` is added to `DiagnosticBuilder::new`,
it's necessary to pass diagnostics tests now that it's used in
`into_diagnostic` functions.
It's necessary for `derive(Diagnostic)`, but is best avoided elsewhere
because there are clearer alternatives.
This required adding `Handler::struct_almost_fatal`.
These impls are all needed for just a single `IntoDiagnostic` type, not
a family of them.
Note that `ErrorGuaranteed` is the default type parameter for
`IntoDiagnostic`.
Add MVP suggestion for `unsafe_op_in_unsafe_fn`
Rebase of https://github.com/rust-lang/rust/pull/99827
cc tracking issue https://github.com/rust-lang/rust/issues/71668
No real changes since the original PR, just migrated the new suggestion to use fluent messages and added a couple more testcases, AFAICT from the discussion there were no outstanding changes requested.
