Comments (11)
The actual behavior here matches the spec. It appears to be by design.
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Another interesting example where we don't error, but probably should:
var v: { [s: string]: string} = {
p: 3, // Expect an error here
q: null
}
This is a result of best common type losing information, and the nontransitivity of assignability.
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What's the action here? If we're aligned to spec, shouldn't this just be closed as by design?
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As I recall from discussion, the spec needs to be updated to align with the current behavior. Specifically, I think section 3.8.1 needs to not pull in call/construct/index signatures for the augmented types.
And it is a breaking change.
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I'm confused. You mention earlier that the "actual behavior here matches the spec. It appears to be by design." If so, is there a spec change?
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Yeah my previous comments were wrong because I misunderstood what was going on. Ignore those. It needs a spec change per my recent comment.
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Before we make this change, please confirm that the change does not impact real world code before we make the spec change.
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Reopening this because the validation on real world code was not done yet.
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Doesn't break any real world code we know of.
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Is this fixed, or by design?
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Fixed, in that it is a change from the old compiler. Spec has been updated to reflect behavior of the new compiler.
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Related Issues (20)
- Allow type annotations in .js files in preparation for Type Annotations proposal
- Refactor: move to new file does not work HOT 4
- Variables (extracted from a discriminated union object) lose narrowed types after being exported HOT 2
- Number.prototype.toFixed, Number.prototype.toExponential,Number.prototype.toPrecision comments error HOT 3
- Newly introduced type narrowing via discriminators on .filter does not work in this case HOT 9
- Long running encodedSemanticClassifications-full request HOT 3
- 5.6.0 regression: Incorrect param type inference for type with all optional props HOT 6
- Make type narrowing for destructured discriminated unions work for more types HOT 1
- Design Meeting Notes, 8/16/2024 HOT 3
- Inheriting from 21 combined mixins causes "type instantiation is excessively deep and possibly infinite" HOT 5
- `void` is treated as covariant with everything when overriding a method from a base class HOT 2
- Type Instantiation is Excessively Deep Regression In #56004
- Signatures with less parameters aren't assignable to compatible targets with more when their rest param is an instantiated `NoInfer` HOT 1
- Enable JSX.Element to be checked based on the element type HOT 3
- [NewErrors] 5.6.0-dev.20240818 vs 5.5.4 HOT 73
- Add `--strictObjectIterables` (bikeshed): exclude primitive (`string`) from `Iterable` types HOT 3
- [ServerErrors][JavaScript] 5.6.0-dev.20240818 vs 5.5.4 HOT 7
- [ServerErrors][TypeScript] 5.6.0-dev.20240818 vs 5.5.4 HOT 15
- `getTextOfJSDocComment` introduces a space in JSDoc comments HOT 1
- [tsserver] Make "configure excludes" warning more debuggable HOT 1
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