avoid some more invalidations that are not necessary#49418
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Even if we have a new method that is more specific than the method it is
replacing, there still might exist an existing method that is more
specific than both which already covers their intersection.
An example of this pattern is adding
Base.IteratorSize(::Type{<:NewType})
causing invalidations on
Base.IteratorSize(::Type)
for specializations such as
Base.IteratorSize(::Type{<:AbstractString})
even though the intersection of these is fully covered already by
Base.IteratorSize(::Type{Union{}})
so our new method would never be selected there.
This won't detect ambiguities that already cover this intersection, but
that is why we are looking to move away from that pattern towards
explicit methods for detection in closer to O(n) instead of O(n^2): #49349.
Similarly, for this method, we were unnecessarily dropping it from the
MethodTable cache. This is not a significant latency problem (the cache
is cheap to rebuild), but it is also easy to avoid in the first place.
Refs #49350
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Even if we have a new method that is more specific than the method it is replacing, there still might exist an existing method that is more specific than both which already covers their intersection.
An example of this pattern is adding
Base.IteratorSize(::Type{<:NewType})
causing invalidations on
Base.IteratorSize(::Type)
for specializations such as
Base.IteratorSize(::Type{<:AbstractString})
even though the intersection of these is fully covered already by
Base.IteratorSize(::Type{Union{}})
so our new method would never be selected there.
This won't detect ambiguities that already cover this intersection, but that is why we are looking to move away from that pattern towards explicit methods for detection in closer to O(n) instead of O(n^2): #49349.
Similarly, for this method, we were unnecessarily dropping it from the MethodTable cache. This is not a significant latency problem (the cache is cheap to rebuild), but it is also easy to avoid in the first place.
Refs #49350