Fix #18649: Use loBound of param types when materializing a context function. #18651
Conversation
This file contains 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
…ext function. Since the param types come from type arguments to `ContextFunctionN[...]`, nothing prevents them a priori from being wildcard type params, i.e., `TypeBounds`. However, that is not a valid type to give to a concrete term param. We can arbitrarily choose any type that conforms to the bounds, which realistically means one of the two bounds. Since type inference already chooses the lower bound when explicitly writing the context function, we align and choose the lower bound when materializing it.
sjrd
force-pushed
the
fix-wildcard-contextual-fun-param
branch
from
3ba4ce1
to
242e68f
Compare
# for free
to join this conversation on GitHub.
Already have an account?
# to comment
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Outdated suggestions cannot be applied.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.
Since the param types come from type arguments to
ContextFunctionN[...], nothing prevents them a priori from being wildcard type params, i.e.,TypeBounds. However, that is not a valid type to give to a concrete term param.We can arbitrarily choose any type that conforms to the bounds, which realistically means one of the two bounds. Since type inference already chooses the lower bound when explicitly writing the context function, we align and choose the lower bound when materializing it.
Giving this one to @nicolasstucki, since you've been playing with function types recently.