destruct expected type as (type-)functions with more rationale

compiler/src/dotty/tools/dotc/cc/CheckCaptures.scala

@@ -616,13 +616,11 @@ class CheckCaptures extends Recheck, SymTransformer:
  curEnv = Env(curEnv.owner, nestedInOwner = true, CaptureSet.Var(), isBoxed = false, if boxed then null else curEnv)
 
  try
- val (eargs, eres) = expected.dealias match
+ val (eargs, eres) = expected.dealias.stripCapturing match
  case defn.FunctionOf(eargs, eres, _, _) => (eargs, eres)
- case expected => expected.stripped match
- case expected: MethodType => (expected.paramInfos, expected.resType)
- case expected @ RefinedType(_, _, rinfo: MethodType) if defn.isFunctionType(expected) => (rinfo.paramInfos, rinfo.resType)
- case _ =>
- (aargs.map(_ => WildcardType), WildcardType)
+ case expected: MethodType => (expected.paramInfos, expected.resType)
+ case expected @ RefinedType(_, _, rinfo: MethodType) if defn.isFunctionType(expected) => (rinfo.paramInfos, rinfo.resType)
+ case _ => (aargs.map(_ => WildcardType), WildcardType)
  val aargs1 = aargs.zipWithConserve(eargs) { (aarg, earg) => adapt(aarg, earg, !covariant) }
  val ares1 = adapt(ares, eres, covariant)
 
@@ -647,6 +645,7 @@ class CheckCaptures extends Recheck, SymTransformer:
  try
  val eres = expected.dealias.stripCapturing match
  case RefinedType(_, _, rinfo: PolyType) => rinfo.resType
+ case expected: PolyType => expected.resType
  case _ => WildcardType
 
  val ares1 = adapt(ares, eres, covariant)