Fixes non-null assertion applied to type narrowed to never not issuing an error.#35863
Merged
Conversation
sandersn
requested review from
ahejlsberg,
sandersn and
weswigham
and removed request for
sandersn
dragomirtitian
force-pushed
the
GH-35431
branch
2 times, most recently
from
1de0ae1 to
07698d7
Compare
weswigham
requested changes
Feb 12, 2021
… return the declared type if the type was already narrowed to never. This was caused by the fact that getTypeWithFacts(resultType, TypeFacts.NEUndefinedOrNull) will return never both if resultType was already never and if resultType does not contain undefined or null. In the latter case returning the declaring type is correct, in the former case this causes something narrowed to never to still be typed as the original declared type.
dragomirtitian
force-pushed
the
GH-35431
branch
from
07698d7 to
6bd3424
Compare
weswigham
approved these changes
Feb 16, 2021
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to subscribe to this conversation on GitHub.
Already have an account?
Sign in.
4 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Fixed issue where non null assertion caused
getFlowTypeOfReferenceto return the declared type if the type was already narrowed to never.This was caused by the fact that
getTypeWithFacts(resultType, TypeFacts.NEUndefinedOrNull)will return never both ifresultTypewas alreadyneverand ifresultTypedoes not containundefinedornull. In the latter case returning the declaring type is correct, in the former case this causes something narrowed toneverto still be typed as the original declared type.Fixes #35431