Fix bytecode generation for Single Abstract Method lambdas #11839
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Partially based on scala/scala#6087 Fixes scala#10068 Fixes scala#11676
| val methodName = samMethod.javaSimpleName | ||
| val samMethodType = asmMethodType(samMethod).toASMType | ||
| val needsGenericBridge = samMethodType != instantiatedMethodType | ||
| val bridgeMethods = atPhase(erasurePhase.prev){ |
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This can actually be run at erasurePhase because when running at a certain phase we see the types as they are before the phase denotation transformer is run.
| val bridgeMethods = atPhase(erasurePhase.prev){ | |
| val bridgeMethods = atPhase(erasurePhase) { |
| @@ -927,8 +927,10 @@ object Types { | |||
| */ | |||
| final def possibleSamMethods(using Context): Seq[SingleDenotation] = { | |||
| record("possibleSamMethods") | |||
| abstractTermMembers.toList.filterConserve(m => | |||
| !m.symbol.matchingMember(defn.ObjectType).exists && !m.symbol.isSuperAccessor) | |||
| atPhaseNoLater(erasurePhase.prev) { | |||
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Same here:
| atPhaseNoLater(erasurePhase.prev) { | |
| atPhaseNoLater(erasurePhase) { |
| val Seq(unerasedSam) = lambdaType.possibleSamMethods | ||
| // We're now in erasure so the alternatives will have erased types | ||
| val Seq(erasedSam: MethodType) = unerasedSam.symbol.alternatives.map(_.info) |
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To avoid this complication I suggest changing possibleSamMethods to do .map(_.current) at the end so the denotations always correspond to the current phase.
| mt.toASMType | ||
| val methodName = samMethod.javaSimpleName | ||
| val samMethodType = asmMethodType(samMethod).toASMType | ||
| val needsGenericBridge = samMethodType != instantiatedMethodType |
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I suggest adding the same comment than in Scala 2 for context:
| val needsGenericBridge = samMethodType != instantiatedMethodType | |
| // scala/bug#10334: make sure that a lambda object for `T => U` has a method `apply(T)U`, not only the `(Object)Object` | |
| // version. Using the lambda a structural type `{def apply(t: T): U}` causes a reflective lookup for this method. | |
| val needsGenericBridge = samMethodType != instantiatedMethodType |
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@smarter reworks done |
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https://github.com/lampepfl/dotty/runs/2185729042?check_suite_focus=true |
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Looks like it was stuck in zio, maybe it would benefit from a larger heap? Restarting for now. |
Partially based on scala/scala#6087
Fixes #10068
Fixes #11676