Fix exactOptionalPropertyTypes not enforced through spread-with-terna…#63252
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GokhanKabar wants to merge 1 commit intomicrosoft:mainfrom
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Fix exactOptionalPropertyTypes not enforced through spread-with-terna…#63252GokhanKabar wants to merge 1 commit intomicrosoft:mainfrom
GokhanKabar wants to merge 1 commit intomicrosoft:mainfrom
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…ry (microsoft#63240) When spreading a conditional expression like `{ ...(cond ? { x: obj.optProp } : {}) }` where `optProp` is an optional property, the exactOptionalPropertyTypes check was silently bypassed. The value of an optional property read (e.g. `obj.optProp`) has the internal type `T | missingType`. In `getAnonymousPartialType`, calling `addOptionality` on that type is a no-op because `missingType` is already the first union member, producing a spread type identical to the target's exact optional property type and suppressing the diagnostic. Fix: when a *required* property's type contains `missingType`, normalize it to `undefinedType` before calling `addOptionality`, so the resulting type is `T | undefined | missingType` — distinguishable from the target — and the check fires.
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fixes #63240
When spreading a conditional expression like
{ ...(cond ? { x: obj.optProp } : {}) }whereoptPropis an optional property, the exactOptionalPropertyTypes check was silently bypassed.The value of an optional property read (e.g.
obj.optProp) has the internal typeT | missingType. IngetAnonymousPartialType, callingaddOptionalityon that type is a no-op becausemissingTypeis already the first union member, producing a spread type identical to the target's exact optional property type and suppressing the diagnostic.Fix: when a required property's type contains
missingType, normalize it toundefinedTypebefore callingaddOptionality, so the resulting type isT | undefined | missingTypedistinguishable from the target and the check fires.