Propagate 'undefined' instead of the optional type marker at an optional chain boundary #34588
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…nal chain boundary
# Conflicts: # src/compiler/utilities.ts
| @@ -45,9 +45,9 @@ const n4: number | undefined = a?.m?.({x: absorb()}); // likewise | |||
| >a?.m : (<T>(obj: { x: T; }) => T) | undefined | |||
| >a : { m?<T>(obj: { x: T; }): T; } | undefined | |||
| >m : (<T>(obj: { x: T; }) => T) | undefined | |||
| >{x: absorb()} : { x: number | undefined; } | |||
| >x : number | undefined | |||
| >absorb() : number | undefined | |||
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Interesting change to inference - I assume this is because previously this undefined was the optional chain type, and so managed to skip out on the "cleave matching types" logic in inference?
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That's correct. The resulting type now aligns with other examples in the file.
Co-Authored-By: Nathan Shively-Sanders <[email protected]>
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@RyanCavanaugh should we cherry-pick this into release-3.7? |
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The issue this PR resolves (#34579) was added to the 3.7.2 milestone https://github.com/microsoft/TypeScript/milestone/106, so I think this should be cherry-picked to 3.7 |
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@typescript-bot port this to release-3.7 |
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@typescript-bot cherry-pick this to release-3.7 bot reference for reference |
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Me bad at bot |
Component commits: 99328e9 Propagate 'undefined' instead of the optional type marker at an optional chain boundary 7aa6eee Merge branch 'master' into fix34579 # Conflicts: # src/compiler/utilities.ts 61e6765 Update src/compiler/types.ts Co-Authored-By: Nathan Shively-Sanders <[email protected]>
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Hey @weswigham, I've opened #34988 for you. |
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Thanks for the quick response 👍 |
Component commits: 99328e9 Propagate 'undefined' instead of the optional type marker at an optional chain boundary 7aa6eee Merge branch 'master' into fix34579 # Conflicts: # src/compiler/utilities.ts 61e6765 Update src/compiler/types.ts Co-Authored-By: Nathan Shively-Sanders <[email protected]>
This ensures that the
optionalTypemarker type does not escape the boundary of an optional chain. This causes unintended side effects even thoughoptionalTypeis essentially the same asundefinedType.Fixes #34579