b365e657d4
* Add unmeasurable variance kind for marking types whose variance result is unreliable
* Remove now-unneeded nongeneric checks
* Add rule allowing `Readonly<any>` to be `any` instead of `{readonly [index: string]: any}`
* All Unmeasurable variances to still shortcut structural comparisons in some cases
* Separate unmeasurable from unreliable to reduce the impact of this change, for now
* Fix lint
* Remove Readonly<any> -> any callout
* Add fix for circularity error triggered by deep signature return type comparisons with `this` types
40 lines
1.1 KiB
TypeScript
40 lines
1.1 KiB
TypeScript
// TODO: FIXME: All the below cases labeled `no error` _should be an error_, and are only prevented from so being
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// by incorrect variance-based relationships
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// Ref: https://github.com/Microsoft/TypeScript/issues/29698
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type Record2<K extends keyof any, T> = {
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[P in K]: T;
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};
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function defaultRecord(x: Record<'a', string>, y: Record<string, string>) {
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x = y; // no error, but error expected.
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}
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function customRecord(x: Record2<'a', string>, y: Record2<string, string>) {
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x = y; // no error, but error expected.
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}
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function mixed1(x: Record2<'a', string>, y: Record<string, string>) {
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x = y; // error
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}
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function mixed2(x: Record<'a', string>, y: Record2<string, string>) {
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x = y; // error
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}
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function defaultRecord2<T>(x: Record<'a', T>, y: Record<string, T>) {
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x = y; // no error, but error expected.
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}
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function customRecord2<T>(x: Record2<'a', T>, y: Record2<string, T>) {
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x = y; // no error, but error expected.
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}
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function mixed3<T>(x: Record2<'a', T>, y: Record<string, T>) {
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x = y; // error
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}
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function mixed4<T>(x: Record<'a', T>, y: Record2<string, T>) {
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x = y; // error
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}
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