-Zmir-enable-passes=+SimplifyCfg doesn't enable any passes and doesn't warn

[saethlin]

We have a warning to detect trying to enable MIR optimizations that don't exist, but it doesn't seem to understand SimplifyCfg and SimplifyLocals, probably related to the way those passes are written using enums?

[ShoyuVanilla]

Should this run all of the SimplifyCfg-* group passes or just warn there's no such pass?

[saethlin]

I think warning that there is no such pass is better. It would also be nice if there was a way to dump the pass names, because the SimplifyCfg and SimplifyLocals ones are not discoverable.

[sgasho]

@rustbot claim

[sgasho]

I think warning that there is no such pass is better

I created a PR to emit warnings in such situations: #151596

It would also be nice if there was a way to dump the pass names, because the SimplifyCfg and SimplifyLocals ones are not discoverable.

I'll work on this part as another PR