#2420. Add extension types exhaustiveness tests. Enums #2422
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LGTM!
I think we should have a set of similar tests where the underlying exhaustiveness of a non-extension type is trivial, because it will be very easy to see with those tests that they are testing exactly the support for a matched value type which is an extension type.
The current tests are also including a tricky case involving enumerated values which are instances of a generic enum, so they are much easier to mess up (say, if they need to be updated somehow in the future).
However, that could just as well be in a different PR, so I'll land this one.
| switch (e) { | ||
| case E.a: | ||
| case E.c: | ||
| return "ok"; |
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This seems to work, but it would be somewhat esoteric (and this has nothing to do with extension types, the situation exists after erasure).
The reason why this is a very special exception is that we (presumably) rely on the fact that this is a switch over enumerated values. This means that we can iterate over all the elements, and it is guaranteed that we won't encounter any other objects than the ones that are declared in the enum declaration itself, and they have a statically known run-time type.
Lots and lots of stuff to know!
OK, I was worried that this would be on the very edge of the capabilities of the exhaustiveness analysis, but it seems to work fine.
In any case, we should probably also have a simpler test where the enumerated type isn't generic, such that it is easy to see that we have an extension type on top of a very straightforward setup (which will be a test that is only about being an extension type, so it's very safe to assume that it will test just that).
2023-12-19 sgrekhov22@gmail.com Fixes dart-lang/co19#2441. Fix roll failures (dart-lang/co19#2443) 2023-12-18 sgrekhov22@gmail.com Fixes dart-lang/co19#2435. Fix roll failures (dart-lang/co19#2437) 2023-12-18 sgrekhov22@gmail.com dart-lang/co19#2420. Add extension types exhaustiveness tests. Variables (dart-lang/co19#2431) 2023-12-15 sgrekhov22@gmail.com Fixes dart-lang/co19#2430. Update expected errors positions for CFE (dart-lang/co19#2433) 2023-12-15 sgrekhov22@gmail.com Fixes dart-lang/co19#2432. Remove excessive expected error for CFE (dart-lang/co19#2434) 2023-12-14 sgrekhov22@gmail.com dart-lang/co19#2420. Add extension types exhaustiveness tests. Maps (dart-lang/co19#2426) 2023-12-14 sgrekhov22@gmail.com dart-lang/co19#2420. Add extension types exhaustiveness tests. Lists (dart-lang/co19#2424) 2023-12-14 sgrekhov22@gmail.com dart-lang/co19#2139. Fix wrong failure of Language/Functions/element_type_A02_t06 (dart-lang/co19#2429) 2023-12-13 sgrekhov22@gmail.com dart-lang/co19#2350. Add more factory constructors tests (dart-lang/co19#2427) 2023-12-13 sgrekhov22@gmail.com Fixes dart-lang/co19#2415. Update `StreamController.broadcast()` test according to the changed documentation (dart-lang/co19#2425) 2023-12-13 sgrekhov22@gmail.com dart-lang/co19#2350. Add/update factory constructor tests. Part 4 (dart-lang/co19#2367) 2023-12-12 sgrekhov22@gmail.com dart-lang/co19#2420. Add extension types exhaustiveness tests. Enums, trivial cases (dart-lang/co19#2423) 2023-12-11 sgrekhov22@gmail.com dart-lang/co19#2420. Add extension types exhaustiveness tests. Enums (dart-lang/co19#2422) 2023-12-11 sgrekhov22@gmail.com dart-lang/co19#2386. Rename well-bounded tests. Update descriptions (dart-lang/co19#2405) 2023-12-08 sgrekhov22@gmail.com dart-lang/co19#2415. Change expectations for Stream.asyncMap() according to the current behavior (dart-lang/co19#2421) Change-Id: I777eba4f1615c8477a5d2044f295696dfc210b1d Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/342582 Commit-Queue: Erik Ernst <eernst@google.com> Reviewed-by: Alexander Thomas <athom@google.com> Reviewed-by: Erik Ernst <eernst@google.com>
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