[clang][AST][NFC] Make FieldDecl in SubobjectAdjustment const

Author: tbaederr

clang/include/clang/AST/Expr.h

@@ -82,7 +82,7 @@ struct SubobjectAdjustment {
 
   union {
     struct DTB DerivedToBase;
-    FieldDecl *Field;
+    const FieldDecl *Field;
     struct P Ptr;
   };
 
@@ -93,8 +93,7 @@ struct SubobjectAdjustment {
     DerivedToBase.DerivedClass = DerivedClass;
   }
 
-  SubobjectAdjustment(FieldDecl *Field)
-    : Kind(FieldAdjustment) {
+  SubobjectAdjustment(const FieldDecl *Field) : Kind(FieldAdjustment) {
     this->Field = Field;
   }
 

clang/lib/AST/Expr.cpp

@@ -86,12 +86,12 @@ const Expr *Expr::skipRValueSubobjectAdjustments(
   while (true) {
     E = E->IgnoreParens();
 
-    if (const CastExpr *CE = dyn_cast<CastExpr>(E)) {
+    if (const auto *CE = dyn_cast<CastExpr>(E)) {
       if ((CE->getCastKind() == CK_DerivedToBase ||
            CE->getCastKind() == CK_UncheckedDerivedToBase) &&
           E->getType()->isRecordType()) {
         E = CE->getSubExpr();
-        auto *Derived =
+        const auto *Derived =
             cast<CXXRecordDecl>(E->getType()->castAs<RecordType>()->getDecl());
         Adjustments.push_back(SubobjectAdjustment(CE, Derived));
         continue;
@@ -101,23 +101,22 @@ const Expr *Expr::skipRValueSubobjectAdjustments(
         E = CE->getSubExpr();
         continue;
       }
-    } else if (const MemberExpr *ME = dyn_cast<MemberExpr>(E)) {
+    } else if (const auto *ME = dyn_cast<MemberExpr>(E)) {
       if (!ME->isArrow()) {
         assert(ME->getBase()->getType()->isRecordType());
-        if (FieldDecl *Field = dyn_cast<FieldDecl>(ME->getMemberDecl())) {
+        if (const auto *Field = dyn_cast<FieldDecl>(ME->getMemberDecl())) {
           if (!Field->isBitField() && !Field->getType()->isReferenceType()) {
             E = ME->getBase();
             Adjustments.push_back(SubobjectAdjustment(Field));
             continue;
           }
         }
       }
-    } else if (const BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
+    } else if (const auto *BO = dyn_cast<BinaryOperator>(E)) {
       if (BO->getOpcode() == BO_PtrMemD) {
         assert(BO->getRHS()->isPRValue());
         E = BO->getLHS();
-        const MemberPointerType *MPT =
-          BO->getRHS()->getType()->getAs<MemberPointerType>();
+        const auto *MPT = BO->getRHS()->getType()->getAs<MemberPointerType>();
         Adjustments.push_back(SubobjectAdjustment(MPT, BO->getRHS()));
         continue;
       }