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-rw-r--r--src/dotty/tools/dotc/core/Contexts.scala10
-rw-r--r--src/dotty/tools/dotc/core/Flags.scala5
-rw-r--r--src/dotty/tools/dotc/core/Symbols.scala25
-rw-r--r--src/dotty/tools/dotc/core/TypeComparer.scala22
-rw-r--r--src/dotty/tools/dotc/typer/Typer.scala30
-rw-r--r--tests/pos/i0268.scala15
6 files changed, 62 insertions, 45 deletions
diff --git a/src/dotty/tools/dotc/core/Contexts.scala b/src/dotty/tools/dotc/core/Contexts.scala
index 805b7660c..2477fd4a4 100644
--- a/src/dotty/tools/dotc/core/Contexts.scala
+++ b/src/dotty/tools/dotc/core/Contexts.scala
@@ -146,6 +146,11 @@ object Contexts {
protected def diagnostics_=(diagnostics: Option[StringBuilder]) = _diagnostics = diagnostics
def diagnostics: Option[StringBuilder] = _diagnostics
+ /** The current bounds in force for type parameters appearing in a GADT */
+ private var _gadt: GADTMap = _
+ protected def gadt_=(gadt: GADTMap) = _gadt = gadt
+ def gadt: GADTMap = _gadt
+
/** A map in which more contextual properties can be stored */
private var _moreProperties: Map[String, Any] = _
protected def moreProperties_=(moreProperties: Map[String, Any]) = _moreProperties = moreProperties
@@ -418,6 +423,8 @@ object Contexts {
def setSetting[T](setting: Setting[T], value: T): this.type =
setSettings(setting.updateIn(sstate, value))
+ def setFreshGADTBounds: this.type = { this.gadt = new GADTMap(gadt.bounds); this }
+
def setDebug = setSetting(base.settings.debug, true)
}
@@ -439,6 +446,7 @@ object Contexts {
moreProperties = Map.empty
typeComparer = new TypeComparer(this)
searchHistory = new SearchHistory(0, Map())
+ gadt = new GADTMap(SimpleMap.Empty)
}
object NoContext extends Context {
@@ -593,6 +601,8 @@ object Contexts {
implicit val ctx: Context = initctx
}
+ class GADTMap(var bounds: SimpleMap[Symbol, TypeBounds])
+
/** Initial size of superId table */
private final val InitialSuperIdsSize = 4096
diff --git a/src/dotty/tools/dotc/core/Flags.scala b/src/dotty/tools/dotc/core/Flags.scala
index 0e86a2936..53beae838 100644
--- a/src/dotty/tools/dotc/core/Flags.scala
+++ b/src/dotty/tools/dotc/core/Flags.scala
@@ -301,9 +301,6 @@ object Flags {
/** Method is assumed to be stable */
final val Stable = termFlag(24, "<stable>")
- /** Info can be refined during GADT pattern match */
- final val GADTFlexType = typeFlag(24, "<gadt-flex-type>")
-
/** A case parameter accessor */
final val CaseAccessor = termFlag(25, "<caseaccessor>")
@@ -553,7 +550,7 @@ object Flags {
/** A Java interface, potentially with default methods */
final val JavaTrait = allOf(JavaDefined, Trait, NoInits)
-
+
/** A Java interface */
final val JavaInterface = allOf(JavaDefined, Trait)
diff --git a/src/dotty/tools/dotc/core/Symbols.scala b/src/dotty/tools/dotc/core/Symbols.scala
index 9be75c11a..2be97691f 100644
--- a/src/dotty/tools/dotc/core/Symbols.scala
+++ b/src/dotty/tools/dotc/core/Symbols.scala
@@ -450,31 +450,6 @@ object Symbols {
*/
def pos: Position = if (coord.isPosition) coord.toPosition else NoPosition
-// -------- GADT handling -----------------------------------------------
-
- /** Perform given operation `op` where this symbol allows tightening of
- * its type bounds.
- */
- private[dotc] def withGADTFlexType[T](op: () => T)(implicit ctx: Context): () => T = { () =>
- assert((denot is TypeParam) && denot.owner.isTerm)
- val saved = denot
- denot = denot.copySymDenotation(initFlags = denot.flags | GADTFlexType)
- try op()
- finally denot = saved
- }
-
- /** Disallow tightening of type bounds for this symbol from now on */
- private[dotc] def resetGADTFlexType()(implicit ctx: Context): Unit = {
- assert(denot is GADTFlexType)
- denot = denot.copySymDenotation(initFlags = denot.flags &~ GADTFlexType)
- }
-
- /** Change info of this symbol to new, tightened type bounds */
- private[core] def changeGADTInfo(bounds: TypeBounds)(implicit ctx: Context): Unit = {
- assert(denot is GADTFlexType)
- denot = denot.copySymDenotation(info = bounds)
- }
-
// -------- Printing --------------------------------------------------------
/** The prefix string to be used when displaying this symbol without denotation */
diff --git a/src/dotty/tools/dotc/core/TypeComparer.scala b/src/dotty/tools/dotc/core/TypeComparer.scala
index 42af31553..5cb384361 100644
--- a/src/dotty/tools/dotc/core/TypeComparer.scala
+++ b/src/dotty/tools/dotc/core/TypeComparer.scala
@@ -617,9 +617,12 @@ class TypeComparer(initctx: Context) extends DotClass {
secondTry(OrType.make(derivedRef(tp11), derivedRef(tp12)), tp2)
*/
case TypeBounds(lo1, hi1) =>
- if ((ctx.mode is Mode.GADTflexible) && (tp1.symbol is GADTFlexType) &&
- !isSubTypeWhenFrozen(hi1, tp2))
- trySetType(tp1, TypeBounds(lo1, hi1 & tp2))
+ val gbounds1 = ctx.gadt.bounds(tp1.symbol)
+ if (gbounds1 != null)
+ isSubTypeWhenFrozen(gbounds1.hi, tp2) ||
+ (ctx.mode is Mode.GADTflexible) &&
+ narrowGADTBounds(tp1, TypeBounds(gbounds1.lo, gbounds1.hi & tp2)) ||
+ tryRebase2nd
else if (lo1 eq hi1) isSubType(hi1, tp2)
else tryRebase2nd
case _ =>
@@ -636,9 +639,12 @@ class TypeComparer(initctx: Context) extends DotClass {
}
def compareNamed: Boolean = tp2.info match {
case TypeBounds(lo2, hi2) =>
- if ((ctx.mode is Mode.GADTflexible) && (tp2.symbol is GADTFlexType) &&
- !isSubTypeWhenFrozen(tp1, lo2))
- trySetType(tp2, TypeBounds(lo2 | tp1, hi2))
+ val gbounds2 = ctx.gadt.bounds(tp2.symbol)
+ if (gbounds2 != null)
+ isSubTypeWhenFrozen(tp1, gbounds2.lo) ||
+ (ctx.mode is Mode.GADTflexible) &&
+ narrowGADTBounds(tp2, TypeBounds(gbounds2.lo | tp1, gbounds2.hi)) ||
+ tryRebase3rd
else
((frozenConstraint || !isCappable(tp1)) && isSubType(tp1, lo2)
|| tryRebase3rd)
@@ -911,9 +917,9 @@ class TypeComparer(initctx: Context) extends DotClass {
tp.exists && !tp.isLambda
}
- def trySetType(tr: NamedType, bounds: TypeBounds): Boolean =
+ def narrowGADTBounds(tr: NamedType, bounds: TypeBounds): Boolean =
isSubType(bounds.lo, bounds.hi) &&
- { tr.symbol.changeGADTInfo(bounds); true }
+ { ctx.gadt.bounds = ctx.gadt.bounds.updated(tr.symbol, bounds); true }
// Tests around `matches`
diff --git a/src/dotty/tools/dotc/typer/Typer.scala b/src/dotty/tools/dotc/typer/Typer.scala
index f6027165b..624a86c1c 100644
--- a/src/dotty/tools/dotc/typer/Typer.scala
+++ b/src/dotty/tools/dotc/typer/Typer.scala
@@ -628,10 +628,10 @@ class Typer extends Namer with TypeAssigner with Applications with Implicits wit
def typedCases(cases: List[untpd.CaseDef], selType: Type, pt: Type)(implicit ctx: Context) = {
/** gadtSyms = "all type parameters of enclosing methods that appear
- * non-variantly in the selector type" todo: should typevars
- * which appear with variances +1 and -1 (in different
- * places) be considered as well?
- */
+ * non-variantly in the selector type" todo: should typevars
+ * which appear with variances +1 and -1 (in different
+ * places) be considered as well?
+ */
val gadtSyms: Set[Symbol] = ctx.traceIndented(i"GADT syms of $selType", gadts) {
val accu = new TypeAccumulator[Set[Symbol]] {
def apply(tsyms: Set[Symbol], t: Type): Set[Symbol] = {
@@ -650,9 +650,13 @@ class Typer extends Namer with TypeAssigner with Applications with Implicits wit
cases mapconserve (typedCase(_, pt, selType, gadtSyms))
}
+ /** Type a case. Overridden in ReTyper, that's why it's separate from
+ * typedCases.
+ */
def typedCase(tree: untpd.CaseDef, pt: Type, selType: Type, gadtSyms: Set[Symbol])(implicit ctx: Context): CaseDef = track("typedCase") {
+ val originalCtx = ctx
+
def caseRest(pat: Tree)(implicit ctx: Context) = {
- gadtSyms foreach (_.resetGADTFlexType)
pat foreachSubTree {
case b: Bind =>
if (ctx.scope.lookup(b.name) == NoSymbol) ctx.enter(b.symbol)
@@ -661,11 +665,21 @@ class Typer extends Namer with TypeAssigner with Applications with Implicits wit
}
val guard1 = typedExpr(tree.guard, defn.BooleanType)
val body1 = typedExpr(tree.body, pt)
+ .ensureConforms(pt)(originalCtx) // insert a cast if body does not conform to expected type if we disregard gadt bounds
assignType(cpy.CaseDef(tree)(pat, guard1, body1), body1)
}
- val doCase: () => CaseDef =
- () => caseRest(typedPattern(tree.pat, selType))(ctx.fresh.setNewScope)
- (doCase /: gadtSyms)((op, tsym) => tsym.withGADTFlexType(op))()
+
+ val gadtCtx =
+ if (gadtSyms.isEmpty) ctx
+ else {
+ val c = ctx.fresh.setFreshGADTBounds
+ for (sym <- gadtSyms)
+ if (!c.gadt.bounds.contains(sym))
+ c.gadt.bounds = c.gadt.bounds.updated(sym, TypeBounds.empty)
+ c
+ }
+ val pat1 = typedPattern(tree.pat, selType)(gadtCtx)
+ caseRest(pat1)(gadtCtx.fresh.setNewScope)
}
def typedReturn(tree: untpd.Return)(implicit ctx: Context): Return = track("typedReturn") {
diff --git a/tests/pos/i0268.scala b/tests/pos/i0268.scala
new file mode 100644
index 000000000..6ac0c5c90
--- /dev/null
+++ b/tests/pos/i0268.scala
@@ -0,0 +1,15 @@
+package typespatmat
+
+sealed trait Box2[T]
+final case class Int2(x: Int) extends Box2[Int]
+final case class Str2(x: String)
+ extends Box2[String]
+final case class Gen[T](x: T) extends Box2[T]
+
+object Box2 {
+ def double2[T](x: Box2[T]): T = x match {
+ case Int2(i) => i * 2
+ case Str2(s) => s + s
+ case Gen(x) => x
+ }
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-02 00:15:31 +0000