Don't approximate a type using Nothing as prefix#23531
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odersky merged 1 commit intoscala:mainfrom Jul 21, 2025
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Approximate range(Nothing, hi) to Nothing & hi instead of Nothing. This avoids
creating TypeRefs with a Nothing prefix which manifest themselves down the line
with an error like:
Cannot resolve reference to type path.type.AbsMember.
The classfile defining the type might be missing from the classpath.
val z1 = transition(di).ext(1) // error
^
Due to a MissingType thrown from TypeErasure#sigName.
This change required tweaking Type#findMember to handle WildcardTypes instead of
returning NoDenotation. This was only required for two
tests (tests/pos/i7414.scala and tests/pos/i13842.scala) where `wildApprox` ends
up creating a TermRef whose underlying type is a WildcardType, because of a type
parameter being substituted by a wildcard, which seems legitimate when we're using
`wildApprox`.
The presentation compiler also had a special case for Nothing appearing in
completion which had to be adapted.
Fixes scala#23530
odersky
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Thanks for the detailed description! LGTM
This was referenced Jul 26, 2025
smarter
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Jul 29, 2025
This generalizes scala#23531 which skipped higher-kinded types, turns out approximating them to Nothing can lead to the same issue. Fixes scala#23627.
noti0na1
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tgodzik
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Aug 8, 2025
This generalizes scala#23531 which skipped higher-kinded types, turns out approximating them to Nothing can lead to the same issue. Fixes scala#23627. [Cherry-picked 1ea24d6]
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Approximate range(Nothing, hi) to Nothing & hi instead of Nothing. This avoids
creating TypeRefs with a Nothing prefix which manifest themselves down the line
with an error like:
Due to a MissingType thrown from TypeErasure#sigName.
This change required tweaking Type#findMember to handle WildcardTypes instead of
returning NoDenotation. This was only required for two
tests (tests/pos/i7414.scala and tests/pos/i13842.scala) where
wildApproxendsup creating a TermRef whose underlying type is a WildcardType, because of a type
parameter being substituted by a wildcard, which seems legitimate when we're using
wildApprox.The presentation compiler also had a special case for Nothing appearing in
completion which had to be adapted.
Fixes #23530