initialiser. But this is only correct when the initialiser is for a
parameter. For example:
```ts
declare let x: { s: string } | undefined;
const { s } = x;
```
This PR removes undefined from the type of a binding pattern only when
the binding pattern's parent is a parameter. This fixes the regression
from 3.8. However, it's still not the ideal fix; we should be able to
use control flow to solve this problem. Consider:
```ts
const { s }: { s: string } | undefined = { s: 'hi' }
declare function f({ s }: { s: string } | undefined = { s: 'hi' }): void
```
Neither line should have an error, but the first does in 3.8 and after
this change.
* Remove superCallShouldBeFirst error
It seems redundant since TS gives an error on any use of `this` before
super, and non-`this` uses before `super` should be fine.
Fixes#37371
* Revert "Remove superCallShouldBeFirst error"
This reverts commit 3c09153c8a.
* error except for target:"esnext" && useDefineForClassFields
* Fix use-before-def with methods on esnext+useDefineForClassFields
It was incorrectly flagging methods as used before their definition, but
this is allowed under any emit.
* Add instance function test case
* Propagate nonInferrableType in &&, || and ?? operators
* Add regression test
* Simpler solution: getTypeFacts(neverType) should return TypeFacts.None
* Add fastpath to isRelatedTo for type references
* Do not check intersections or unions to ignore propegating reference flags, properly set comparing jsx flag
* Re-remove unneeded check
* Just check for TypeFlags.Object
* Remove else clause
* Error on missing BigInt in ES2020 too.
Previously it was only on ESNext, but bigint ships in ES 2020.
There are no tests for this; passing `false` doesn't cause any tests to
fail at least.
* add tests
* Avoid circular reference in this-property assignments
To do this, don't check this-property assigments that have the
this-property of the lhs appearing somewhere on the rhs:
```js
class C {
m() {
this.x = 12
this.x = this.x + this.y
}
}
```
I tried suppressing the circularity error, but because we cache the
first type discovered for a property, this still results in an implicit
any for `x` in the previous example. It just doesn't have an error.
Fixes#35099
* Add test case + rename function
* Use isMatchingReference
Get the `declaration` container just once instead of in three places.
(Minor change: one place used to start looking from
`declaration.parent`, but that shouldn't make any difference.) Also,
don't pass it to the helper functions since they're local anyway.
This only applies in JS, where `@template` tags can apply to
initialisers of variable declarations:
```js
/**
* @template T
* @returns {(b: T) => T}
*/
const seq = a => b => b
```
Fixes#36201
* Consolidated extra property check with intersections
* Fix comment
* Add tests
* Properly propagate intersectionState
* Route property check through recursive type tracking logic
* Accept new baselines
* Skip check when apparent type of source is never
* Accept new baselines
* Only check when apparent type of source is a structured type
* Fix serialisation of static class members in JS
Previously static class members would be treated the same way as expando
namespace assignments to a class:
```ts
class C {
static get x() { return 1 }
}
C.y = 12
```
This PR adds a syntactic check to the static/namespace filter that
treats symbols whose valueDeclaration.parent is a class as statics.
Fixes#37289
* fix messed-up indent
* Extract function
