[clang] NFC: change more places to use Type::getAsTagDecl and friends (#155313)

This changes a bunch of places which use getAs<TagType>, including
derived types, just to obtain the tag definition.

This is preparation for #155028, offloading all the changes that PR used
to introduce which don't depend on any new helpers.

1 files changed, 2 insertions, 3 deletions

diff --git a/clang/lib/CodeGen/CGObjCMac.cpp b/clang/lib/CodeGen/CGObjCMac.cpp
index eb49040..d1fb05d 100644
--- a/clang/lib/CodeGen/CGObjCMac.cpp
+++ b/clang/lib/CodeGen/CGObjCMac.cpp
@@ -3353,9 +3353,8 @@ static bool hasWeakMember(QualType type) {
     return true;
   }
 
-  if (auto recType = type->getAs<RecordType>()) {
-    for (auto *field :
-         recType->getOriginalDecl()->getDefinitionOrSelf()->fields()) {
+  if (auto *RD = type->getAsRecordDecl()) {
+    for (auto *field : RD->fields()) {
       if (hasWeakMember(field->getType()))
         return true;
     }