[NFC] ConstraintSystem: Rename openExistentialType to openAnyExistentialType

This method can open an existential metatype too, and we already use
`isAnyExistentialType` to mean "existential type or existential
metatype"

Author: AnthonyLatsis

include/swift/Sema/ConstraintSystem.h

@@ -3277,10 +3277,11 @@ class ConstraintSystem {
   ConstraintLocator *getOpenOpaqueLocator(
       ConstraintLocatorBuilder locator, OpaqueTypeDecl *opaqueDecl);
 
-  /// Open the given existential type, recording the opened type in the
-  /// constraint system and returning both it and the root opened archetype.
-  std::pair<Type, OpenedArchetypeType *> openExistentialType(
-      Type type, ConstraintLocator *locator);
+  /// Open the given existential type or existential metatype, recording the
+  /// opened archetype in the constraint system and returning both the opened
+  /// type and opened archetype.
+  std::pair<Type, OpenedArchetypeType *>
+  openAnyExistentialType(Type type, ConstraintLocator *locator);
 
   /// Update OpenedExistentials and record a change in the trail.
   void recordOpenedExistentialType(ConstraintLocator *locator,

lib/Sema/CSSimplify.cpp

@@ -1825,7 +1825,7 @@ static ConstraintSystem::TypeMatchResult matchCallArguments(
         std::tie(openedTypeVar, existentialType, adjustments) = *existentialArg;
 
         OpenedArchetypeType *opened;
-        std::tie(argTy, opened) = cs.openExistentialType(
+        std::tie(argTy, opened) = cs.openAnyExistentialType(
             existentialType, cs.getConstraintLocator(loc));
 
         if (adjustments.contains(OpenedExistentialAdjustmentFlags::LValue))
@@ -8647,7 +8647,7 @@ ConstraintSystem::SolutionKind ConstraintSystem::simplifyConformsToConstraint(
     if (type->isExistentialType()) {
       if (auto elt = loc->getLastElementAs<LocatorPathElt::ContextualType>()) {
         if (elt->getPurpose() == CTP_ForEachSequence) {
-          type = openExistentialType(type, loc).first;
+          type = openAnyExistentialType(type, loc).first;
         }
       }
     }
@@ -12430,8 +12430,8 @@ ConstraintSystem::simplifyOpenedExistentialOfConstraint(
   if (type2->isAnyExistentialType()) {
     // We have the existential side. Produce an opened archetype and bind
     // type1 to it.
-    Type openedTy = openExistentialType(type2, getConstraintLocator(locator))
-        .first;
+    Type openedTy =
+        openAnyExistentialType(type2, getConstraintLocator(locator)).first;
     return matchTypes(type1, openedTy, ConstraintKind::Bind, subflags, locator);
   }
   if (!type2->isTypeVariableOrMember())

lib/Sema/ConstraintSystem.cpp

@@ -853,8 +853,9 @@ ConstraintLocator *ConstraintSystem::getOpenOpaqueLocator(
       { LocatorPathElt::OpenedOpaqueArchetype(opaqueDecl) }, 0);
 }
 
-std::pair<Type, OpenedArchetypeType *> ConstraintSystem::openExistentialType(
-    Type type, ConstraintLocator *locator) {
+std::pair<Type, OpenedArchetypeType *>
+ConstraintSystem::openAnyExistentialType(Type type,
+                                         ConstraintLocator *locator) {
   Type result = OpenedArchetypeType::getAny(type);
   Type t = result;
   while (t->is<MetatypeType>())