[NFC] Replace a few calls to TypeBase::isParameterPack() with isRootParameterPack().

Author: hborla

lib/AST/ASTMangler.cpp

@@ -653,8 +653,7 @@ std::string ASTMangler::mangleAutoDiffGeneratedDeclaration(
 static Type getTypeForDWARFMangling(Type t) {
   return t.subst(
     [](SubstitutableType *t) -> Type {
-      if (isa<GenericTypeParamType>(t) &&
-          cast<GenericTypeParamType>(t)->isParameterPack()) {
+      if (t->isRootParameterPack()) {
         return PackType::getSingletonPackExpansion(t->getCanonicalType());
       }
       return t->getCanonicalType();

lib/AST/ASTVerifier.cpp

@@ -614,8 +614,7 @@ class Verifier : public ASTWalker {
         auto countType = expansion->getCountType();
         if (!(countType->is<PackType>() ||
               countType->is<PackArchetypeType>() ||
-              (countType->is<GenericTypeParamType>() &&
-               countType->castTo<GenericTypeParamType>()->isParameterPack()))) {
+              countType->isRootParameterPack())) {
           Out << "non-pack shape type" << countType->getString() << "\n";
           abort();
         }

lib/AST/GenericSignature.cpp

@@ -875,7 +875,7 @@ void GenericSignature::verify(ArrayRef<Requirement> reqts) const {
         abort();
       }
 
-      if (!reqt.getFirstType()->castTo<GenericTypeParamType>()->isParameterPack()) {
+      if (!reqt.getFirstType()->isRootParameterPack()) {
         llvm::errs() << "Left hand side is not a parameter pack: ";
         reqt.dump(llvm::errs());
         llvm::errs() << "\n";
@@ -889,7 +889,7 @@ void GenericSignature::verify(ArrayRef<Requirement> reqts) const {
         abort();
       }
 
-      if (!reqt.getSecondType()->castTo<GenericTypeParamType>()->isParameterPack()) {
+      if (!reqt.getSecondType()->isRootParameterPack()) {
         llvm::errs() << "Right hand side is not a parameter pack: ";
         reqt.dump(llvm::errs());
         llvm::errs() << "\n";

lib/AST/ParameterPack.cpp

@@ -66,8 +66,7 @@ static Type transformTypeParameterPacksRec(
     if (auto *paramType = dyn_cast<SubstitutableType>(t)) {
       if (expansionLevel == 0 &&
           (isa<PackArchetypeType>(paramType) ||
-           (isa<GenericTypeParamType>(paramType) &&
-            cast<GenericTypeParamType>(paramType)->isParameterPack()))) {
+           paramType->isRootParameterPack())) {
         return fn(paramType);
       }
 

lib/AST/TypeSubstitution.cpp

@@ -56,9 +56,7 @@ QueryTypeSubstitutionMapOrIdentity::operator()(SubstitutableType *type) const {
   if (known != substitutions.end() && known->second)
     return known->second;
 
-  if (isa<PackArchetypeType>(type) ||
-      (isa<GenericTypeParamType>(type) &&
-       cast<GenericTypeParamType>(type)->isParameterPack())) {
+  if (isa<PackArchetypeType>(type) || type->isRootParameterPack()) {
     return PackType::getSingletonPackExpansion(type);
   }