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Fix narrow-by-constructor logic #37698

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Merged
merged 2 commits into from
Mar 31, 2020
Merged

Fix narrow-by-constructor logic #37698

merged 2 commits into from
Mar 31, 2020

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ahejlsberg
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This PR fixes two issues in the narrow-by-constructor logic that was added in #32774:

  • Removes unnecessary resetting of control flow type to the declared type.
  • Reorganizes logic and adds a missing isMatchingReference check, the absence of which would cause constructor checks to erroneously narrow all references in the code path.

Fixes #37660.

@ahejlsberg ahejlsberg merged commit 2b0f351 into master Mar 31, 2020
@ahejlsberg ahejlsberg added this to the TypeScript 3.9.1 milestone Mar 31, 2020
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@RyanCavanaugh We should pull this fix into the next 3.9 release.

@jakebailey jakebailey deleted the fix37660 branch November 7, 2022 17:36
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@weswigham weswigham weswigham approved these changes

@RyanCavanaugh RyanCavanaugh Awaiting requested review from RyanCavanaugh

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Successfully merging this pull request may close these issues.

[3.9.0-beta] Type gets incorrectly un-narrowed after ifs
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@ahejlsberg @weswigham