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Ensure all capture variables carry the attachment #23162

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merged 1 commit into from
May 14, 2025
+10 −3
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Ensure all capture variables carry the attachment #23162

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13 changes: 10 additions & 3 deletions compiler/src/dotty/tools/dotc/typer/Typer.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -3053,18 +3053,25 @@ class Typer(@constructorOnly nestingLevel: Int = 0) extends Namer
if sym.isOpaqueAlias then
checkFullyAppliedType(rhs1, "Opaque type alias must be fully applied, but ")
checkNoContextFunctionType(rhs1)
var attachCap = false
if Feature.ccEnabled then
val isCap = tdef.hasAttachment(CaptureVar)
rhs1 match
case TypeBoundsTree(lo, hi, _) =>
if !isCap && (lo.tpe.derivesFrom(defn.Caps_CapSet) ^ hi.tpe.derivesFrom(defn.Caps_CapSet)) then
val loIsCap = lo.tpe.derivesFrom(defn.Caps_CapSet)
val hiIsCap = hi.tpe.derivesFrom(defn.Caps_CapSet)
if !isCap && (loIsCap ^ hiIsCap) then
report.error(em"Illegal type bounds: >: $lo <: $hi. Capture-set bounds cannot be mixed with type bounds of other kinds", rhs.srcPos)
if isCap && !(lo.tpe.derivesFrom(defn.Caps_CapSet) && hi.tpe.derivesFrom(defn.Caps_CapSet)) then
if isCap && !(loIsCap && hiIsCap) then
report.error(em"Illegal type bounds: >: $lo <: $hi. $name^ can only have capture sets as bounds", rhs.srcPos)
attachCap = !isCap && loIsCap && hiIsCap
case LambdaTypeTree(_, _) if isCap =>
report.error(em"`$name` cannot have type parameters, because it ranges over capture sets", rhs.srcPos)
case _ =>
assignType(cpy.TypeDef(tdef)(name, rhs1), sym)
val res = assignType(cpy.TypeDef(tdef)(name, rhs1), sym)
if Feature.ccEnabled && attachCap then
res.putAttachment(CaptureVar, ())
res
}

def typedClassDef(cdef: untpd.TypeDef, cls: ClassSymbol)(using Context): Tree = ctx.profiler.onTypedDef(cls) {
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