Convert SAM result types to function types #17740
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odersky
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Jun 4, 2023
| case SAMType(mt @ MethodTpe(_, formals, restpe)) => | ||
| case pt1 @ SAMType(mt @ MethodTpe(_, formals, methResType)) => | ||
| val restpe = methResType match | ||
| case mt: MethodType if !mt.isParamDependent => mt.toFunctionType(isJava = pt1.classSymbol.is(JavaDefined)) |
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What happens if mt is ParamDependent? Can we still get a crash then?
Maybe we should in that case fall back to the default composition with wildcard types?
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I tried and I think if you make it param dependent it doesn't qualify as a SAM type? I guess it'll be good to have a case in, just to prove it doesn't crash the compiler - and that way you can review that I've written the test case correctly.
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I tried and I think if you make it param dependent it doesn't qualify as a SAM type?
I doubt that. Types with ParamDependent method types cannot be SAM types. But I don't see that ParamDependent result types are excluded.
In decomposeProtoFunction I wanted to reuse WithFunctionType by running toFunctionType on the whole SAM and then dropping the first parameters. But with result dependent functions that results in a refined type, which is composed of: * the function with a result that is a non-depedent approximation * the original, non-function, method type So I went back to calling toFunctionType on the method result type specifically, like it used to be. Which means I stopped using the SAMType.WithFunctionType extract, so I merged it with its remaining usage with subtype checking and called the SAMType.isSamCompatible.
smarter
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Jun 30, 2023
This reverts most of scala#17740 and instead add a check on currying in SAMType. We could consider allowing curried methods in SAM types, but this would be a language change that requires a SIP, and the implementation would need an adaptation step in erasure since the invokedynamic method needs to have a compatible signature with the abstract method in the trait.
smarter
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Jun 30, 2023
This reverts most of scala#17740 and instead add a check on currying in SAMType. We could consider allowing curried methods in SAM types, but this would be a language change that requires a SIP, and the implementation would need an adaptation step in erasure since the invokedynamic method needs to have a compatible signature with the abstract method in the trait.
smarter
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Jul 5, 2023
This reverts most of scala#17740 and instead add a check on currying in SAMType. We could consider allowing curried methods in SAM types, but this would be a language change that requires a SIP, and the implementation would need an adaptation step in erasure since the invokedynamic method needs to have a compatible signature with the abstract method in the trait.
smarter
added a commit
to dotty-staging/dotty
that referenced
this pull request
Jul 5, 2023
This reverts most of scala#17740 and instead add a check on currying in SAMType. We could consider allowing curried methods in SAM types, but this would be a language change that requires a SIP, and the implementation would need an adaptation step in erasure since the invokedynamic method needs to have a compatible signature with the abstract method in the trait.
smarter
added a commit
that referenced
this pull request
Jul 5, 2023
This reverts most of #17740 and instead add a check on currying in SAMType. We could consider allowing curried methods in SAM types, but this would be a language change that requires a SIP, and the implementation would need an adaptation step in erasure since the invokedynamic method needs to have a compatible signature with the abstract method in the trait.
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