René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"A few improvement/discussion points of the `PSMethod -\u003e Delegate` conversion work","articleBody":"This is about #5287\r\n\r\n- [x] `DelegateArgsComparator.ParameterTypesMatches` doesn't consider the Variance in delegate parameter types. A method signature `int CallMe(object input)` should be able to be converted to `Func\u003cstring, int\u003e`.\r\n- [x] `PSMethod.MatchesPSMethodProjectedType` doesn't handle the case where both `targetType` and `projectedSourceType` are the same `ByRef` type or `Pointer` type.\r\n- [x] I think the 'Unit' type name should be changed to 'VOID'. Use type `Unit` to represent `void` is not intuitive and I misread it to `uint` when first looking at the code.\r\n- [x] I don't get the point of having `ReplaceGenericTypeArgumentsWithMarkerTypes`. After making a generic method using our synthetic reference/value types, the generated `MethodInfo` signature won't match any real delegates except in one condition -- the original generic method doesn't use the generic type argument for any of its parameters or return type -- I think it's rare for this condition to be met for a generic method.\r\n- [x] I agree that we need pseudo types to represent `ByRef` type (ref/out), `Pointer` type `void` type and even `TypeReference`, but why do we need `PSEnum\u003c\u003e` to wrap enum types? Remove `PSEnum\u003c\u003e` and use the enum type directly.\r\n- [ ] Handle method signatures with `Span\u003cT\u003e` or `ReadOnlySpan\u003cT\u003e` as its parameter type or return type. They cannot be used as type argument, and therefore we cannot use them directly to construct a generic type of `Func\u003c\u003e`. In fact, this is a more general problem with all ref-like types, such as `public ref struct Foo { private Span\u003cint\u003e _pointer }`. It would be great if we can have a generic solution for all ref-like types, but at least we need to handle `Span\u003cT\u003e` and `ReadOnlySpan\u003cT\u003e` as they are getting more and more usage. See the discussion comments: https://github.com/PowerShell/PowerShell/pull/6851#discussion_r188111503","author":{"url":"https://github.com/daxian-dbw","@type":"Person","name":"daxian-dbw"},"datePublished":"2017-12-04T19:09:13.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":6},"url":"https://github.com/5618/PowerShell/issues/5618"}