[WIP] Take typed identifiers into account when optimizing matches #24972
+310
−187
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
SolalPirelli
changed the title
SolalPirelli
force-pushed
the
solal/tuple-of-literals-deconstruct
branch
2 times, most recently
from
1296cdb to
495187a
Compare
SolalPirelli
force-pushed
the
solal/tuple-of-literals-deconstruct
branch
from
c4103a3 to
39116e9
Compare
SolalPirelli
commented
Jan 16, 2026
| sel | ||
| end match | ||
|
|
||
| case class TuplePatternInfo(arity: Int, varNum: Int, wildcardNum: Int) |
Contributor
Author
There was a problem hiding this comment.
Review in split diff, this is a rewrite
SolalPirelli
commented
Jan 16, 2026
| def makeLambda(gen: GenFrom, body: Tree): Tree = gen.pat match { | ||
| case IdPattern(named, tpt) if gen.checkMode != GenCheckMode.FilterAlways => | ||
| Function(derivedValDef(gen.pat, named, tpt, EmptyTree, Modifiers(Param)) :: Nil, body) | ||
| case IdPattern(named, tpt) if named.name != nme.WILDCARD && gen.checkMode != GenCheckMode.FilterAlways => |
Contributor
Author
There was a problem hiding this comment.
I found it quite confusing that IdPattern ignored wildcards, and in my case I wanted "any (un)typed ID, even a wildcard", so I moved the check to the existing uses and removed it from IdPattern
SolalPirelli
commented
Jan 16, 2026
| case _ => Modifiers() | ||
| makePatDef(valeq, mods, defpat, rhs) | ||
| val pdefs = valeqs.lazyZip(defpats).map { case (valeq @ GenAlias(_, rhs), defpat) => | ||
| makePatDef(defpat, rhs, valeq.span, givenPatternsAllowed = true) |
Contributor
Author
There was a problem hiding this comment.
No behavior change here (hopefully), just cleaning up some rather messy maps and zips
SolalPirelli
commented
Jan 16, 2026
| case _ => Modifiers() | ||
| makePatDef(valeq, mods, defpat, rhs) | ||
| val pdefs = valeqs.map { case valeq @ GenAlias(pat, rhs) => | ||
| makePatDef(makeIdPat(pat)._1, rhs, valeq.span, givenPatternsAllowed = true) |
SolalPirelli
commented
Jan 16, 2026
| @@ -1,3 +1,3 @@ | |||
| object Foo { | |||
| val (A, B) = () // error // error | |||
| val (A, B) = () // error | |||
Contributor
Author
There was a problem hiding this comment.
Not quite sure why there were 2 errors before but I think 1 is quite enough :)
SolalPirelli
commented
Jan 16, 2026
| def test = | ||
| val (x: "x", y: "y") = (("x", "y"): ("x", "y")) | ||
| println(x) | ||
| } |
Contributor
Author
There was a problem hiding this comment.
This is the original test from the issue this PR is fixing
SolalPirelli
commented
Jan 16, 2026
|
|
||
| def test = | ||
| val (x: List[B @unchecked], y: List[C @unchecked]) = foo(): @unchecked | ||
| bar(x, y) |
Contributor
Author
There was a problem hiding this comment.
This is a simplified version of code in Typer.scala that failed to compile in my initial attempt at fixing this
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
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.
Fixes #24435
makePatDefwas quite hard to understand and also wrong in edge cases related to types and `@unchecked conversions.I rewrote it with (1) detailed comments of what the optimizations are, (2) support for more patterns such as
Typed(Tuple(_), _), and (3) aprintingtest that enshrines what we expect from these optimizations.