Dont create a union type to infer conditional type branches #30010
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This also addresses a core problem we're seeing in #30029 |
ahejlsberg
approved these changes
Feb 26, 2019
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@weswigham Can you also take a look at #30049 #30047? |
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Fixes #29945
This was actually substantially simpler to fix than I initially thought. Turns out the only issue is that when we infer from a union to another union, we lop off the common members before inferring to a type parameter in that union. For conditional types, doing this to the union of both branches isn't what we'd like to have happen, so instead we just infer to each branch separately to skip the top level union inference logic.