fixes#25123; fixes#11862
follow up https://github.com/nim-lang/Nim/pull/24442
ref https://github.com/nim-lang/Nim/pull/24441
> To fix this, fields from inactive branches are now detected in
semmacrosanity.annotateType (called in fixupTypeAfterEval) and marked to
prevent the codegen of their assignments. In
https://github.com/nim-lang/Nim/pull/24441 these fields were excluded
from the resulting node, but this causes issues when the node is
directly supposed to go back into the VM, for example as const values. I
don't know if this is the only case where this happens, so I wasn't sure
about how to keep that implementation working.
Object variants fields coming from inactive branches from VM are now
flagged `nfPreventCg`. We can ignore them, as done by the C backends.
fixes#24021
The field checking for case object branches at some point generates a
negated set `contains` check for the object discriminator. For enum
types, this tries to generate a complement set and convert to a
`contains` check in that instead. It obtains this type from the type of
the element node in the `contains` check.
`buildProperFieldCheck` creates the element node by changing a field
access expression like `foo.z` into `foo.kind`. In order to do this, it
copies the node `foo.z` and sets the field name in the node to the
symbol `kind`. But when copying the node, the type of the original
`foo.z` is retained. This means that the complement is performed on the
type of the accessed field rather than the type of the discriminator,
which causes problems when the accessed field is also an enum.
To fix this, we properly set the type of the copied node to the type of
the kind field. An alternative is just to make a new node instead.
A lot of text for a single line change, I know, but this part of the
codebase could use more explanation.
