[ConstraintSystem] Add a new locator element to identify pack expansion types

Author: xedin

include/swift/Sema/ConstraintLocatorPathElts.def

@@ -202,6 +202,9 @@ CUSTOM_LOCATOR_PATH_ELT(PackElement)
 /// The shape of a parameter pack.
 SIMPLE_LOCATOR_PATH_ELT(PackShape)
 
+/// The type of pack expansion
+SIMPLE_LOCATOR_PATH_ELT(PackExpansionType)
+
 /// The pattern  of a pack expansion.
 SIMPLE_LOCATOR_PATH_ELT(PackExpansionPattern)
 

lib/Sema/ConstraintLocator.cpp

@@ -106,6 +106,7 @@ unsigned LocatorPathElt::getNewSummaryFlags() const {
   case ConstraintLocator::AnyPatternDecl:
   case ConstraintLocator::GlobalActorType:
   case ConstraintLocator::CoercionOperand:
+  case ConstraintLocator::PackExpansionType:
     return 0;
 
   case ConstraintLocator::FunctionArgument:
@@ -501,6 +502,10 @@ void LocatorPathElt::dump(raw_ostream &out) const {
   case ConstraintLocator::CoercionOperand: {
     out << "coercion operand";
     break;
+
+  case ConstraintLocator::PackExpansionType:
+    out << "pack expansion type";
+    break;
   }
   }
 }

lib/Sema/ConstraintSystem.cpp

@@ -5751,6 +5751,7 @@ void constraints::simplifyLocator(ASTNode &anchor,
 
     case ConstraintLocator::PackElement:
     case ConstraintLocator::PackShape:
+    case ConstraintLocator::PackExpansionType:
       break;
 
     case ConstraintLocator::PackExpansionPattern: {