fix object subtype-relation between generic instances #847
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Summary
Fix a bug with the subtype-of-generic-object logic that caused generic
instances of object-like types to be treated as unrelated when one of
their in-between types is a
ref
/ptr
type while the formal type isnot (or vice versa). Refer to the added test for an example of where
this issue surfaced.
Details
The mistake was considering the skipped ptr/ref at each inheritance
step, while it must only be considered once for the formal and original
actual type. This properly considers
ref
andptr
types being usedas object base types.
In addition to the fix, the documentation of and inside
isSubtypeOfGenericInstance
is slightly improved.