Update `str` utils to prevent ICEs and FNs
This PR reworks some string handling for lints regarding enum naming. I hope the refactoring will prevent future ICEs and help with new bug free implementations.
It might be better to review this PR by going through the commits, as `clippy_utils::camel_case` was renamed to `clippy_utils::str_utils` and then changed further. GH sadly doesn't really make the changes that obvious 🙃
Not too much more to say. Have a nice day 🌞
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Fixes: rust-lang/rust-clippy#7869
changelog: ICE Fix: [`enum_variant_names`] #7869
make test module detection more strict
I started with some small improvements to clippy_utils/src/lib.rs, but then found that our "test" module detection would also catch words containing "test" like e.g. "attestation". So I made this a bit more strict (splitting by `'_'` and checking for `test` or `tests`), adding a test case as I went.
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*Please write a short comment explaining your change (or "none" for internal only changes)*
changelog: none
Coerce const FnDefs to implement const Fn traits
You can now pass a FnDef to a function expecting `F` where `F: ~const FnTrait`.
r? ``@oli-obk``
``@rustbot`` label T-compiler F-const_trait_impl
Introduce `Rvalue::ShallowInitBox`
Polished version of #88700.
Implements MCP rust-lang/compiler-team#460, and should allow #43596 to go forward.
In short, creating an empty box is split from a nullary-op `NullOp::Box` into two steps, first a call to `exchange_malloc`, then a `Rvalue::ShallowInitBox` which transmutes `*mut u8` to a shallow-initialized `Box<T>`. This allows the `exchange_malloc` call to unwind. Details can be found in the MCP.
`NullOp::Box` is not yet removed, purely to make reverting easier in case anything goes wrong as the result of this PR. If revert is needed a reversion of "Use Rvalue::ShallowInitBox for box expression" commit followed by a test bless should be sufficient.
Experiments in #88700 showed a very slight compile-time perf regression due to (supposedly) slightly more time spent in LLVM. We could omit unwind edge generation (in non-`oom=panic` case) in box expression MIR construction to restore perf; but I don't think it's necessary since runtime perf isn't affected and perf difference is rather small.
This allows the format_args! macro to keep the pre-expansion code out of
the unsafe block without doing gymnastics with nested `match`
expressions. This reduces codegen.
