Skip to content

Backport "Always interpret underscores inside patterns as type bounds" to LTS #15

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 1 commit into from
Dec 6, 2024
Merged

Backport "Always interpret underscores inside patterns as type bounds" to LTS #15

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
14 changes: 11 additions & 3 deletions compiler/src/dotty/tools/dotc/parsing/Parsers.scala
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -429,6 +429,14 @@ object Parsers {
finally inEnum = saved
}

private var inMatchPattern = false
private def withinMatchPattern[T](body: => T): T = {
val saved = inMatchPattern
inMatchPattern = true
try body
finally inMatchPattern = saved
}

private var staged = StageKind.None
def withinStaged[T](kind: StageKind)(op: => T): T = {
val saved = staged
Expand Down Expand Up @@ -1857,7 +1865,7 @@ object Parsers {
if isSimpleLiteral then
SingletonTypeTree(simpleLiteral())
else if in.token == USCORE then
if ctx.settings.YkindProjector.value == "underscores" then
if ctx.settings.YkindProjector.value == "underscores" && !inMatchPattern then
val start = in.skipToken()
Ident(tpnme.USCOREkw).withSpan(Span(start, in.lastOffset, start))
else
Expand Down Expand Up @@ -2883,7 +2891,7 @@ object Parsers {
def caseClause(exprOnly: Boolean = false): CaseDef = atSpan(in.offset) {
val (pat, grd) = inSepRegion(InCase) {
accept(CASE)
(pattern(), guard())
(withinMatchPattern(pattern()), guard())
}
CaseDef(pat, grd, atSpan(accept(ARROW)) {
if exprOnly then
Expand All @@ -2907,7 +2915,7 @@ object Parsers {
val start = in.skipToken()
Ident(tpnme.WILDCARD).withSpan(Span(start, in.lastOffset, start))
case _ =>
rejectWildcardType(infixType())
withinMatchPattern(rejectWildcardType(infixType()))
}
}
CaseDef(pat, EmptyTree, atSpan(accept(ARROW)) {
Expand Down
9 changes: 9 additions & 0 deletions tests/pos/14952.scala
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,9 @@
//> using options -Ykind-projector:underscores

import Tuple.*

type LiftP[F[_], T] <: Tuple =
T match {
case _ *: _ => F[Head[T]] *: LiftP[F, Tail[T]]
case _ => EmptyTuple
}
7 changes: 7 additions & 0 deletions tests/pos/21400.scala
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,7 @@
//> using options -Ykind-projector:underscores

import scala.compiletime.ops.int.S

type IndexOf[T <: Tuple, E] <: Int = T match
case E *: _ => 0
case _ *: es => 1 // S[IndexOf[es, E]]
10 changes: 10 additions & 0 deletions tests/pos/21400b.scala
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,10 @@
//> using options -Ykind-projector:underscores

import scala.quoted.Type
import scala.quoted.Quotes

def x[A](t: Type[A])(using Quotes): Boolean = t match
case '[_ *: _] =>
true
case _ =>
false
Loading