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Add sealed option to mayHaveCommonChild #17194

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Add sealed option to mayHaveCommonChild #17194

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2 changes: 1 addition & 1 deletion compiler/src/dotty/tools/dotc/core/SymDenotations.scala
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Expand Up @@ -1995,7 +1995,7 @@ object SymDenotations {
* @return The result may contain false positives, but never false negatives.
*/
final def mayHaveCommonChild(that: ClassSymbol)(using Context): Boolean =
!this.is(Final) && !that.is(Final) && (this.is(Trait) || that.is(Trait)) ||
!this.isOneOf(FinalOrSealed) && !that.isOneOf(FinalOrSealed) && (this.is(Trait) || that.is(Trait)) ||
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That's not valid, because the following hierarchy is allowed:

sealed trait A
sealed trait B
class C extends A with B

this.derivesFrom(that) || that.derivesFrom(this.symbol)

final override def typeParamCreationFlags: FlagSet = ClassTypeParamCreationFlags
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