Properties on intersections should be readonly only if all declarations are #45263
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bwrrp
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src/compiler/checker.ts
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| @@ -11825,8 +11825,15 @@ namespace ts { | |||
| } | |||
| } | |||
| } | |||
| checkFlags |= (isReadonlySymbol(prop) ? CheckFlags.Readonly : 0) | | |||
| (!(modifiers & ModifierFlags.NonPublicAccessibilityModifier) ? CheckFlags.ContainsPublic : 0) | | |||
| // For unions, prop is readonly if any definition of it is readonly | |||
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these comments seem superfluous to me -- the intersection one might need a comment if it were on its own, but here it's clearly the inverse of the union case, and the union case is clear as-is
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Thanks for the review! I've removed the unnecessary comments. |
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A last-minute 4.4 PR made a change to mappedTypeRecursiveInference. =( @bwrrp can you merge from main and update the baselines one more time? |
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Fixes #45122
This changes the behavior of readonly properties in intersection types to be writable if any of the definitions of the property are writable. Before, the property would only be writable if none of its definitions were readonly (same as for unions).
I've added a new test containing the two cases from the issue, as well as a case that verifies that the property is still readonly if all of the definitions are readonly. I also had to update the baseline for two existing tests:
tests/cases/conformance/types/intersection/intersectionTypeReadonly.ts- contained a test for the mutable & readonly case, which I've updated to not expect an errortests/cases/compiler/mappedTypeRecursiveInference.ts-lib.dom.d.tsdefines the type ofdocument.defaultViewas(WindowProxy & typeof globalThis) | null. It turned out that some of the properties (such asnavigator) onWindowProxyare readonly, while the corresponding global declaration is not. This change makes those properties writable in the intersection type.It seems a little odd that properties defined as readonly on
Windoware considered writable on the global. I'm not sure if that is something that needs to be addressed here?