Fix issue 22865 - __traits(compiles) affects inferrence of attributes

[dkorpel]

DMD is full of variations of:

if (sc.func && !sc.intypeof && !(sc.flags & SCOPE.debug_) && sc.func.setUnsafe(...))

Sometimes intypeof is included, sometimes not. Sometimes SCOPE.debug_ is included, sometimes not.
This fix refactors them to into a single sc.setUnsafe(...), which calls setUnsafe on sc.func. This Scope* version of setUnsafe then does all the checks consistently, including the new sc.flags & SCOPE.compile check for __traits(compiles).

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Bugzilla references

Auto-close	Bugzilla	Severity	Description
✓	22865	normal	__traits(compiles) affects inferrence of attributes

Testing this PR locally

If you don't have a local development environment setup, you can use Digger to test this PR:

dub run digger -- build "master + dmd#14144"

[kinke]

Oh wow, no Buildkite breakage. 👍 - Have you checked all FuncDeclaration.setUnsafe() usages? And will we need something for setImpure() (edit: and setGC()) too?

[dkorpel]

Oh wow, no Buildkite breakage.

On the first run, this broke:

https://github.com/atilaneves/automem/blob/7e0aa929c4413679c96adf5f68dc9e4e13b83387/tests/ut/vector.d#L233

Because error() was not called when doing something unsafe in __traits(compiles). Then I added the
if (sc.func.isSafeBypassingInference()) branch that calls error, which fixed it. It's still iffy what is supposed to happen when you do __traits(compiles, unsafe()) in an inferred function: it will now return true, but maybe when you actually insert that code to make it @system, the project as a whole generates an error because it assumes the function is inferred @safe. It's really hard to account for that.

Have you checked all FuncDeclaration.setUnsafe() usages?

Yes

And will we need something for setImpure() (edit: and setGC()) too?

Probably, I haven't looked at it yet.