On Tue, 7 Feb 2023 15:47:25 GMT, Maurizio Cimadamore <mcimadam...@openjdk.org> wrote:
>> Class `Signature` (aka `JavaTypeSignature`), all subclasses, >> `MethodSignature` and `ClassSignature` are designed according to [JVMS >> 4.7.9.1 >> Signatures](https://docs.oracle.com/javase/specs/jvms/se19/html/jvms-4.html#jvms-4.7.9.1) > >> Class `Signature` (aka `JavaTypeSignature`), all subclasses, >> `MethodSignature` and `ClassSignature` are designed according to [JVMS >> 4.7.9.1 >> Signatures](https://docs.oracle.com/javase/specs/jvms/se19/html/jvms-4.html#jvms-4.7.9.1) > > The production is the same as the one I quoted, but thanks for pointing me at > the correct one. So: > > > JavaTypeSignature: > ReferenceTypeSignature > BaseType > > > and > > > ReferenceTypeSignature: > ClassTypeSignature > TypeVariableSignature > ArrayTypeSignature > > > So, while I can expect that `ArrayTypeSignature` *is a* `Signature` (or > `JavaTypeSignature`), I cannot explain why `ThrowsSignature` extends > `Signature`. That doesn't seem to follow from the production. That is, if a > client obtains a `Signature` and wanted to pattern match, what are the cases > it should worry about? I believe the cases are the ones listed above. > > One thing I missed is that e.g. `TypeParam` is *not* a signature (which is > the only case among the nested classes in `Signature`). But > `ThrowsSignature`, `TypeArg` and `TypeParam` are signatures even though that > doesn't seem to be the case when looking at the production in the JVMS. If we > want to keep these fine, but I don't think they should extend `Signature`, > either directly or indirectly. That is, `Signature` should be a sealed type > with 4 leaves (base-type/array/type var/class-type). **Specification:** MethodSignature: [TypeParameters] ( {JavaTypeSignature} ) Result {ThrowsSignature} Result: JavaTypeSignature VoidDescriptor ThrowsSignature: ^ ClassTypeSignature ^ TypeVariableSignature **Reflect in API mapping:** public sealed interface ClassTypeSig extends RefTypeSig, ThrowableSig and public sealed interface TypeVarSig extends RefTypeSig, ThrowableSig and /** * @return method signature * @param typeParameters signatures for the type parameters * @param exceptions sigantures for the exceptions * @param result signature for the return type * @param arguments signatures for the method arguments */ public static MethodSignature of(List<Signature.TypeParam> typeParameters, List<Signature.ThrowableSig> exceptions, Signature result, Signature... arguments) { `Signature.ThrowableSig` is a `Signature` and it is a common super of `ClassTypeSig` and `ClassTypeSig`. ------------- PR: https://git.openjdk.org/jdk/pull/10982
