Suggestion Backlog Slog, 8/6/2018

[RyanCavanaugh]

• 5453 Variadic kinds - what use cases remain here?

• 26234 Disallow truthy checks of void

• 5203 Disallow OOB access on tuples

• 5863 Static polymorphic this

• 23005 T[K] should be never when K is never

• 22892 string enum object should be indexable type

• 22851 esModuleInterop should work when target = esnext

• 22815 Abstract classes that implement interfaces shouldn't require method signatures

• 22806 Partial<T> should be a weak type

• 22769 Allow unshadowed parameter initializer references in ES6+

• 22759 Let JSX children be subject to tupleness

• 22709 Allow references to literal-ish-initialized enums in type positions

• 22669 Add a new overload to Function#bind

• 22665 Add a mode to make TS act like JS

• 22649 Combine tsconfig with file list

• 22610 Keep infer variable in scope in false arm of conditional type

• 22609 Do some type guards based on overload when a good discriminant is present

• 22605 Provide a back-compat mechanism for bundled .d.ts files in package.json

• 22598 Allow speculative union type property access in typeof (expression) operands

• 22509 Something something mapped types

• 22311 Error on out-of-scope literal assigned to enum

• 22230 Allow implicit undefined->0 coercion under strictNullChecks for bitwise ops

• 22208 Prefer .d.ts over .ts if it's in files array

• 26136 Arg union type inference for overloads

• 26129 Forbid illogical generic declarations

[RyanCavanaugh]

• 5453 Variadic kinds

  • Currently we allow you to capture tuples in variadic rest positions
  • But the tuples themselves cannot contain rests
  • This would allow deconstruction of tuples
  • What functions would be typable with this that currently aren't?
  • Promisify
  • Should we close holes that allow people to write trivial turing machines in the type system?
  • ??

• 26234 Disallow testing void exprs

  • Breaking change
  • All goodness
  • Found bugs in us and VS Code
  • Found "type errors" in a couple other projects

• 5203 OOB on tuples should be errors

  • :+1:

• 5863 Polymorphic this

  • Static inheritance in signatures is plainly unsound
  • So calls to the polymorphic this are right out
  • Isn't what people want just the non-signature side?
  • Do people want instance-this or static-this ?
  • Representation vs checking
  • Discuss soundness

• 23005 T[K] should be never

  • :+1:

• 22892 String enums should be indexed types

  • Our dot behavior makes this a bad idea

• 22815 Interface members in abstract classes

  • Should we copy them automatically?
  • It's presumably what you want
  • What happens to optional members?
  • They become... abstract optional? What is that even?
    • How do you not-implement an optional abstract member?
  • Need to avoid hop-skip-jump problem
  • Post some questions on this

• 22806 Partial<T> should be weak?

  • It is
  • Weak checking applies to assignability, not comparability
  • WIA

• 22769 Parameter initializers

  • Allow in ES6, error in downlevel only

• 22759 Allow tuples in JSX children

  • :+1:

• 22709 Enum literals

  • There are actually many kinds of enums under the hood
  • Union enums only get created when only bare literals (or nothing) are initializers
  • These kinds of enums behave differently
  • You might want one or the other and this is how you choose
  • WIA; would be a BC

• 22311 Out-of-range enum assignment

  • Back compat problem
  • Not really a trap
  • Problem for e.g. mod flags
  • Maybe disallow in strict

• 22230 undefined/null in & / |

  • :-1:

• 26136 Inference of unions from argument lists

  • Would this imply filtering if you weren't capturing the whole argument list?
  • No (spreading back would be a nightmare)

[jcalz]

WIA

Wounded in action?

EDIT: It suddenly occurs to me that this is probably "Works As Intended" as acronymized by Yoda. nmv...

[RyanCavanaugh]

Well, it's accepted Wondering if actionable We're imitating ActionScript