Skip to content

improvement: Simplify match types when possible #23146

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
May 13, 2025
Merged

improvement: Simplify match types when possible #23146

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
4 changes: 3 additions & 1 deletion presentation-compiler/src/main/dotty/tools/pc/printer/ShortenedTypePrinter.scala
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -351,7 +351,9 @@ class ShortenedTypePrinter(
val paramLabelss = label(methodParams)
val extLabelss = label(extParams)

val returnType = tpe(gtpe.finalResultType)
val retType = gtpe.finalResultType
val simplified = if (retType.typeSymbol.isAliasType) retType else retType.deepDealiasAndSimplify
val returnType = tpe(simplified)
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Won't simplified negatively impact union types?

def f(): Int | String = ???

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Added a test, it seems to work. I don't think it will simplify something it's unable to simplify more. Do you have another example that might highlight the issue?

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

It's fine then, I think it works as we'd like it to. 😄 I saw it does lub on OrType but it seems to still return an unchanged OrType, maybe it only collapses same cases.

def extensionSignatureString =
val extensionSignature = paramssString(extLabelss, extParams)
if extParams.nonEmpty then
Expand Down
4 changes: 2 additions & 2 deletions presentation-compiler/src/main/dotty/tools/pc/utils/InteractiveEnrichments.scala
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -407,13 +407,13 @@ object InteractiveEnrichments extends CommonMtagsEnrichments:
case app @ AppliedType(tycon, params) =>
AppliedType(tycon, params.map(_.deepDealiasAndSimplify))
case aliasingBounds: AliasingBounds =>
aliasingBounds.derivedAlias(aliasingBounds.alias.dealias)
aliasingBounds.derivedAlias(aliasingBounds.alias.deepDealiasAndSimplify)
case TypeBounds(lo, hi) =>
TypeBounds(lo.dealias, hi.dealias)
case RefinedType(parent, name, refinedInfo) =>
RefinedType(parent.dealias, name, refinedInfo.deepDealiasAndSimplify)
case dealised => dealised
if tpe.isNamedTupleType then dealiased.simplified else dealiased
dealiased.simplified

extension[T] (list: List[T])
def get(n: Int): Option[T] = if 0 <= n && n < list.size then Some(list(n)) else None
Expand Down
18 changes: 9 additions & 9 deletions presentation-compiler/test/dotty/tools/pc/tests/completion/CompletionSuite.scala
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -94,18 +94,18 @@ class CompletionSuite extends BaseCompletionSuite:
|newBuilder[A]: Builder[A, List[A]]
|apply[A](elems: A*): List[A]
|concat[A](xss: Iterable[A]*): List[A]
|fill[A](n1: Int, n2: Int)(elem: => A): List[List[A] @uncheckedVariance]
|fill[A](n1: Int, n2: Int, n3: Int)(elem: => A): List[List[List[A]] @uncheckedVariance]
|fill[A](n1: Int, n2: Int, n3: Int, n4: Int)(elem: => A): List[List[List[List[A]]] @uncheckedVariance]
|fill[A](n1: Int, n2: Int, n3: Int, n4: Int, n5: Int)(elem: => A): List[List[List[List[List[A]]]] @uncheckedVariance]
|fill[A](n1: Int, n2: Int)(elem: => A): List[List[A]]
|fill[A](n1: Int, n2: Int, n3: Int)(elem: => A): List[List[List[A]]]
|fill[A](n1: Int, n2: Int, n3: Int, n4: Int)(elem: => A): List[List[List[List[A]]]]
|fill[A](n1: Int, n2: Int, n3: Int, n4: Int, n5: Int)(elem: => A): List[List[List[List[List[A]]]]]
|fill[A](n: Int)(elem: => A): List[A]
|iterate[A](start: A, len: Int)(f: A => A): List[A]
|range[A: Integral](start: A, end: A): List[A]
|range[A: Integral](start: A, end: A, step: A): List[A]
|tabulate[A](n1: Int, n2: Int)(f: (Int, Int) => A): List[List[A] @uncheckedVariance]
|tabulate[A](n1: Int, n2: Int, n3: Int)(f: (Int, Int, Int) => A): List[List[List[A]] @uncheckedVariance]
|tabulate[A](n1: Int, n2: Int, n3: Int, n4: Int)(f: (Int, Int, Int, Int) => A): List[List[List[List[A]]] @uncheckedVariance]
|tabulate[A](n1: Int, n2: Int, n3: Int, n4: Int, n5: Int)(f: (Int, Int, Int, Int, Int) => A): List[List[List[List[List[A]]]] @uncheckedVariance]
|tabulate[A](n1: Int, n2: Int)(f: (Int, Int) => A): List[List[A]]
|tabulate[A](n1: Int, n2: Int, n3: Int)(f: (Int, Int, Int) => A): List[List[List[A]]]
|tabulate[A](n1: Int, n2: Int, n3: Int, n4: Int)(f: (Int, Int, Int, Int) => A): List[List[List[List[A]]]]
|tabulate[A](n1: Int, n2: Int, n3: Int, n4: Int, n5: Int)(f: (Int, Int, Int, Int, Int) => A): List[List[List[List[List[A]]]]]
|tabulate[A](n: Int)(f: Int => A): List[A]
|unapplySeq[A](x: List[A] @uncheckedVariance): UnapplySeqWrapper[A]
|unfold[A, S](init: S)(f: S => Option[(A, S)]): List[A]
Expand All @@ -116,7 +116,7 @@ class CompletionSuite extends BaseCompletionSuite:
|ensuring(cond: List.type => Boolean, msg: => Any): List.type
|fromSpecific(from: Any)(it: IterableOnce[Nothing]): List[Nothing]
|fromSpecific(it: IterableOnce[Nothing]): List[Nothing]
|nn: List.type & List.type
|nn: List.type
|runtimeChecked scala.collection.immutable
|toFactory(from: Any): Factory[Nothing, List[Nothing]]
|formatted(fmtstr: String): String
Expand Down
30 changes: 30 additions & 0 deletions presentation-compiler/test/dotty/tools/pc/tests/completion/CompletionTypeSuite.scala
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -21,3 +21,33 @@ class CompletionTypeSuite extends BaseCompletionSuite:
s"""|method[T <: FS](a: T): Nothing
|""".stripMargin
)

@Test def `long-types-match` =
check(
s"""|@main
|def run =
| (1, 2).to@@
|""".stripMargin,
s"""|toString(): String
|toArray: Array[Object]
|toIArray: IArray[Object]
|toList: List[Int]
Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

PReviously this was shown as a full match type

|productIterator: Iterator[Any]
|asInstanceOf[X0]: X0
|isInstanceOf[X0]: Boolean
|""".stripMargin
)

@Test def `union-types` =
check(
s"""|
|def itsAUnionType(): Int | String = ???
|
|def hello =
| its@@
|
|
|""".stripMargin,
s"""|itsAUnionType(): Int | String
|""".stripMargin
)
Loading