Backport "Patmat: Use less type variables in prefix inference" #17440
Conversation
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
In code like:
class Outer:
sealed trait Foo
case class Bar() extends Foo
def mat(foo: Foo) = foo match
case Bar() =>
When in the course of decomposing the scrutinee's type, which is
`Outer.this.Foo`, we're trying to instantiate subclass `Outer.this.Bar`,
the `Outer.this` is fixed - it needn't be inferred, via type variables
and type bounds. Cutting down on type variables, particularly when GADT
symbols are also present, can really speed up the operation, including
making code that used to hang forever compile speedily.
Kordyjan
approved these changes
May 9, 2023
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in 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Outdated suggestions cannot be applied.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.
Backports #16827
Solves #17368