Merge pull request swiftlang#60076 from DougGregor/existential-var-opening

Author: DougGregor

lib/Sema/CSApply.cpp

@@ -5935,7 +5935,8 @@ ArgumentList *ExprRewriter::coerceCallArguments(
 
  // If the argument is an existential type that has been opened, perform
  // the open operation.
- if (argType->getInOutObjectType()->isAnyExistentialType() &&
+ if (argType->getRValueType()->getInOutObjectType()
+ ->isAnyExistentialType() &&
  paramType->hasOpenedExistential()) {
  // FIXME: Look for an opened existential and use it. We need to
  // know how far out we need to go to close the existentials. Huh.

lib/Sema/CSSimplify.cpp

@@ -1468,6 +1468,7 @@ namespace {
  enum class OpenedExistentialAdjustmentFlags {
  /// The argument should be made inout after opening.
  InOut = 0x01,
+ LValue = 0x02,
  };
 
  using OpenedExistentialAdjustments =
@@ -1541,6 +1542,12 @@ shouldOpenExistentialCallArgument(
 
  OpenedExistentialAdjustments adjustments;
 
+ // The argument may be a "var" instead of a "let".
+ if (auto lv = argTy->getAs<LValueType>()) {
+ argTy = lv->getObjectType();
+ adjustments |= OpenedExistentialAdjustmentFlags::LValue;
+ }
+
  // If the argument is inout, strip it off and we can add it back.
  if (auto inOutArg = argTy->getAs<InOutType>()) {
  argTy = inOutArg->getObjectType();
@@ -1944,6 +1951,9 @@ static ConstraintSystem::TypeMatchResult matchCallArguments(
  std::tie(argTy, opened) = cs.openExistentialType(
  existentialType, cs.getConstraintLocator(loc));
 
+ if (adjustments.contains(OpenedExistentialAdjustmentFlags::LValue))
+ argTy = LValueType::get(argTy);
+
  if (adjustments.contains(OpenedExistentialAdjustmentFlags::InOut))
  argTy = InOutType::get(argTy);
 

test/Constraints/opened_existentials.swift

@@ -25,6 +25,10 @@ func testSimpleExistentialOpening(p: any P, pq: any P & Q, c: any Collection) {
  let pa = acceptGeneric(p)
  let _: Int = pa // expected-error{{cannot convert value of type '(any Q)?' to specified type 'Int'}}
 
+ var vp = p
+ let vpa = acceptGeneric(vp)
+ let _: Int = vpa // expected-error{{cannot convert value of type '(any Q)?' to specified type 'Int'}}
+
  let pqa = acceptGeneric(pq)
  let _: Int = pqa // expected-error{{cannot convert value of type '(any Q)?' to specified type 'Int'}}