diff --git a/clang/include/clang/Analysis/Analyses/ThreadSafetyCommon.h b/clang/include/clang/Analysis/Analyses/ThreadSafetyCommon.h
index 7bdb9052e57e74..e99c5b2466334a 100644
--- a/clang/include/clang/Analysis/Analyses/ThreadSafetyCommon.h
+++ b/clang/include/clang/Analysis/Analyses/ThreadSafetyCommon.h
@@ -330,9 +330,9 @@ class CapabilityExpr {
 
   bool shouldIgnore() const { return sexpr() == nullptr; }
 
-  bool isInvalid() const { return sexpr() && isa<til::Undefined>(sexpr()); }
+  bool isInvalid() const { return isa_and_nonnull<til::Undefined>(sexpr()); }
 
-  bool isUniversal() const { return sexpr() && isa<til::Wildcard>(sexpr()); }
+  bool isUniversal() const { return isa_and_nonnull<til::Wildcard>(sexpr()); }
 };
 
 // Translate clang::Expr to til::SExpr.
diff --git a/clang/include/clang/Lex/Preprocessor.h b/clang/include/clang/Lex/Preprocessor.h
index c0850a8fa9f7f8..9b1628d2d86f9e 100644
--- a/clang/include/clang/Lex/Preprocessor.h
+++ b/clang/include/clang/Lex/Preprocessor.h
@@ -1360,7 +1360,7 @@ class Preprocessor {
 
     MacroState &S = CurSubmoduleState->Macros[II];
     auto *MD = S.getLatest();
-    while (MD && isa<VisibilityMacroDirective>(MD))
+    while (isa_and_nonnull<VisibilityMacroDirective>(MD))
       MD = MD->getPrevious();
     return MacroDefinition(dyn_cast_or_null<DefMacroDirective>(MD),
                            S.getActiveModuleMacros(*this, II),
diff --git a/clang/include/clang/Sema/SemaObjC.h b/clang/include/clang/Sema/SemaObjC.h
index 91430797e5ed82..bb8887691ce5d3 100644
--- a/clang/include/clang/Sema/SemaObjC.h
+++ b/clang/include/clang/Sema/SemaObjC.h
@@ -383,7 +383,7 @@ class SemaObjC : public SemaBase {
   void AddAnyMethodToGlobalPool(Decl *D);
 
   void ActOnStartOfObjCMethodDef(Scope *S, Decl *D);
-  bool isObjCMethodDecl(Decl *D) { return D && isa<ObjCMethodDecl>(D); }
+  bool isObjCMethodDecl(Decl *D) { return isa_and_nonnull<ObjCMethodDecl>(D); }
 
   /// CheckImplementationIvars - This routine checks if the instance variables
   /// listed in the implelementation match those listed in the interface.
diff --git a/clang/include/clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h b/clang/include/clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h
index 151d3e57c1cb81..59805d01be5db7 100644
--- a/clang/include/clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h
+++ b/clang/include/clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h
@@ -781,7 +781,7 @@ class SymbolicRegion : public SubRegion {
       : SubRegion(sreg, SymbolicRegionKind), sym(s) {
     // Because pointer arithmetic is represented by ElementRegion layers,
     // the base symbol here should not contain any arithmetic.
-    assert(s && isa<SymbolData>(s));
+    assert(isa_and_nonnull<SymbolData>(s));
     assert(s->getType()->isAnyPointerType() ||
            s->getType()->isReferenceType() ||
            s->getType()->isBlockPointerType());
diff --git a/clang/lib/ARCMigrate/TransUnbridgedCasts.cpp b/clang/lib/ARCMigrate/TransUnbridgedCasts.cpp
index 1e6354f71e294a..7390ea17c8a4b6 100644
--- a/clang/lib/ARCMigrate/TransUnbridgedCasts.cpp
+++ b/clang/lib/ARCMigrate/TransUnbridgedCasts.cpp
@@ -371,7 +371,7 @@ class UnbridgedCastRewriter : public RecursiveASTVisitor<UnbridgedCastRewriter>{
       Stmt *parent = E;
       do {
         parent = StmtMap->getParentIgnoreParenImpCasts(parent);
-      } while (parent && isa<FullExpr>(parent));
+      } while (isa_and_nonnull<FullExpr>(parent));
 
       if (ReturnStmt *retS = dyn_cast_or_null<ReturnStmt>(parent)) {
         std::string note = "remove the cast and change return type of function "
diff --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp
index 3b9080e09b3313..02cd4ed9a6cace 100644
--- a/clang/lib/AST/ASTImporter.cpp
+++ b/clang/lib/AST/ASTImporter.cpp
@@ -1505,7 +1505,7 @@ ExpectedType ASTNodeImporter::VisitInjectedClassNameType(
   // The InjectedClassNameType is created in VisitRecordDecl when the
   // T->getDecl() is imported. Here we can return the existing type.
   const Type *Ty = (*ToDeclOrErr)->getTypeForDecl();
-  assert(Ty && isa<InjectedClassNameType>(Ty));
+  assert(isa_and_nonnull<InjectedClassNameType>(Ty));
   return QualType(Ty, 0);
 }
 
diff --git a/clang/lib/AST/DeclBase.cpp b/clang/lib/AST/DeclBase.cpp
index 7f1ed9c691e988..e64a8326e8d5dd 100644
--- a/clang/lib/AST/DeclBase.cpp
+++ b/clang/lib/AST/DeclBase.cpp
@@ -1116,7 +1116,7 @@ bool Decl::isInExportDeclContext() const {
   while (DC && !isa<ExportDecl>(DC))
     DC = DC->getLexicalParent();
 
-  return DC && isa<ExportDecl>(DC);
+  return isa_and_nonnull<ExportDecl>(DC);
 }
 
 bool Decl::isInAnotherModuleUnit() const {
diff --git a/clang/lib/AST/Expr.cpp b/clang/lib/AST/Expr.cpp
index f9d634550dc061..7e555689b64c48 100644
--- a/clang/lib/AST/Expr.cpp
+++ b/clang/lib/AST/Expr.cpp
@@ -837,7 +837,7 @@ std::string PredefinedExpr::ComputeName(PredefinedIdentKind IK,
     typedef SmallVector<const ClassTemplateSpecializationDecl *, 8> SpecsTy;
     SpecsTy Specs;
     const DeclContext *Ctx = FD->getDeclContext();
-    while (Ctx && isa<NamedDecl>(Ctx)) {
+    while (isa_and_nonnull<NamedDecl>(Ctx)) {
       const ClassTemplateSpecializationDecl *Spec
                                = dyn_cast<ClassTemplateSpecializationDecl>(Ctx);
       if (Spec && !Spec->isExplicitSpecialization())
@@ -3067,7 +3067,7 @@ Expr *Expr::IgnoreParenCasts() {
 
 Expr *Expr::IgnoreConversionOperatorSingleStep() {
   if (auto *MCE = dyn_cast<CXXMemberCallExpr>(this)) {
-    if (MCE->getMethodDecl() && isa<CXXConversionDecl>(MCE->getMethodDecl()))
+    if (isa_and_nonnull<CXXConversionDecl>(MCE->getMethodDecl()))
       return MCE->getImplicitObjectArgument();
   }
   return this;
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 86fb396fabe2d9..d5057452cec9c5 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -2130,7 +2130,7 @@ static bool IsWeakLValue(const LValue &Value) {
 
 static bool isZeroSized(const LValue &Value) {
   const ValueDecl *Decl = GetLValueBaseDecl(Value);
-  if (Decl && isa<VarDecl>(Decl)) {
+  if (isa_and_nonnull<VarDecl>(Decl)) {
     QualType Ty = Decl->getType();
     if (Ty->isArrayType())
       return Ty->isIncompleteType() ||
diff --git a/clang/lib/AST/Mangle.cpp b/clang/lib/AST/Mangle.cpp
index 30cff1ba2e6f37..4af4d7c00c5cb3 100644
--- a/clang/lib/AST/Mangle.cpp
+++ b/clang/lib/AST/Mangle.cpp
@@ -302,7 +302,7 @@ void MangleContext::mangleBlock(const DeclContext *DC, const BlockDecl *BD,
     assert((isa<NamedDecl>(DC) || isa<BlockDecl>(DC)) &&
            "expected a NamedDecl or BlockDecl");
     if (isa<BlockDecl>(DC))
-      for (; DC && isa<BlockDecl>(DC); DC = DC->getParent())
+      for (; isa_and_nonnull<BlockDecl>(DC); DC = DC->getParent())
         (void) getBlockId(cast<BlockDecl>(DC), true);
     assert((isa<TranslationUnitDecl>(DC) || isa<NamedDecl>(DC)) &&
            "expected a TranslationUnitDecl or a NamedDecl");
diff --git a/clang/lib/AST/MicrosoftMangle.cpp b/clang/lib/AST/MicrosoftMangle.cpp
index 36d611750ca48c..2f7a2763639207 100644
--- a/clang/lib/AST/MicrosoftMangle.cpp
+++ b/clang/lib/AST/MicrosoftMangle.cpp
@@ -2748,7 +2748,7 @@ void MicrosoftCXXNameMangler::mangleFunctionType(const FunctionType *T,
       return;
     }
     Out << '@';
-  } else if (IsInLambda && D && isa<CXXConversionDecl>(D)) {
+  } else if (IsInLambda && isa_and_nonnull<CXXConversionDecl>(D)) {
     // The only lambda conversion operators are to function pointers, which
     // can differ by their calling convention and are typically deduced.  So
     // we make sure that this type gets mangled properly.
diff --git a/clang/lib/AST/ParentMap.cpp b/clang/lib/AST/ParentMap.cpp
index 3d6a1cc84c7b10..e97cb5e226f5c2 100644
--- a/clang/lib/AST/ParentMap.cpp
+++ b/clang/lib/AST/ParentMap.cpp
@@ -139,7 +139,9 @@ Stmt* ParentMap::getParent(Stmt* S) const {
 }
 
 Stmt *ParentMap::getParentIgnoreParens(Stmt *S) const {
-  do { S = getParent(S); } while (S && isa<ParenExpr>(S));
+  do {
+    S = getParent(S);
+  } while (isa_and_nonnull<ParenExpr>(S));
   return S;
 }
 
@@ -155,7 +157,8 @@ Stmt *ParentMap::getParentIgnoreParenCasts(Stmt *S) const {
 Stmt *ParentMap::getParentIgnoreParenImpCasts(Stmt *S) const {
   do {
     S = getParent(S);
-  } while (S && isa<Expr>(S) && cast<Expr>(S)->IgnoreParenImpCasts() != S);
+  } while (isa_and_nonnull<Expr>(S) &&
+           cast<Expr>(S)->IgnoreParenImpCasts() != S);
 
   return S;
 }
diff --git a/clang/lib/AST/StmtPrinter.cpp b/clang/lib/AST/StmtPrinter.cpp
index 7e030e05512690..8f51d16b5db037 100644
--- a/clang/lib/AST/StmtPrinter.cpp
+++ b/clang/lib/AST/StmtPrinter.cpp
@@ -84,7 +84,7 @@ namespace {
 
     void PrintStmt(Stmt *S, int SubIndent) {
       IndentLevel += SubIndent;
-      if (S && isa<Expr>(S)) {
+      if (isa_and_nonnull<Expr>(S)) {
         // If this is an expr used in a stmt context, indent and newline it.
         Indent();
         Visit(S);
@@ -1939,7 +1939,7 @@ void StmtPrinter::VisitCXXOperatorCallExpr(CXXOperatorCallExpr *Node) {
 void StmtPrinter::VisitCXXMemberCallExpr(CXXMemberCallExpr *Node) {
   // If we have a conversion operator call only print the argument.
   CXXMethodDecl *MD = Node->getMethodDecl();
-  if (MD && isa<CXXConversionDecl>(MD)) {
+  if (isa_and_nonnull<CXXConversionDecl>(MD)) {
     PrintExpr(Node->getImplicitObjectArgument());
     return;
   }
diff --git a/clang/lib/CodeGen/CGBlocks.cpp b/clang/lib/CodeGen/CGBlocks.cpp
index bf50f2025de573..5dac1cd425bf61 100644
--- a/clang/lib/CodeGen/CGBlocks.cpp
+++ b/clang/lib/CodeGen/CGBlocks.cpp
@@ -577,7 +577,7 @@ static void computeBlockInfo(CodeGenModule &CGM, CodeGenFunction *CGF,
 
   // First, 'this'.
   if (block->capturesCXXThis()) {
-    assert(CGF && CGF->CurFuncDecl && isa<CXXMethodDecl>(CGF->CurFuncDecl) &&
+    assert(CGF && isa_and_nonnull<CXXMethodDecl>(CGF->CurFuncDecl) &&
            "Can't capture 'this' outside a method");
     QualType thisType = cast<CXXMethodDecl>(CGF->CurFuncDecl)->getThisType();
 
diff --git a/clang/lib/CodeGen/CGClass.cpp b/clang/lib/CodeGen/CGClass.cpp
index b8cb78266130c8..5a032bdbf93791 100644
--- a/clang/lib/CodeGen/CGClass.cpp
+++ b/clang/lib/CodeGen/CGClass.cpp
@@ -859,7 +859,7 @@ void CodeGenFunction::EmitConstructorBody(FunctionArgList &Args) {
 
   // Enter the function-try-block before the constructor prologue if
   // applicable.
-  bool IsTryBody = (Body && isa<CXXTryStmt>(Body));
+  bool IsTryBody = isa_and_nonnull<CXXTryStmt>(Body);
   if (IsTryBody)
     EnterCXXTryStmt(*cast<CXXTryStmt>(Body), true);
 
@@ -1475,7 +1475,7 @@ void CodeGenFunction::EmitDestructorBody(FunctionArgList &Args) {
 
   // If the body is a function-try-block, enter the try before
   // anything else.
-  bool isTryBody = (Body && isa<CXXTryStmt>(Body));
+  bool isTryBody = isa_and_nonnull<CXXTryStmt>(Body);
   if (isTryBody)
     EnterCXXTryStmt(*cast<CXXTryStmt>(Body), true);
   EmitAsanPrologueOrEpilogue(false);
diff --git a/clang/lib/CodeGen/CGExprConstant.cpp b/clang/lib/CodeGen/CGExprConstant.cpp
index 4eb65b34a89f56..0712f40fd8215a 100644
--- a/clang/lib/CodeGen/CGExprConstant.cpp
+++ b/clang/lib/CodeGen/CGExprConstant.cpp
@@ -715,7 +715,7 @@ bool ConstStructBuilder::Build(const InitListExpr *ILE, bool AllowOverwrite) {
     const Expr *Init = nullptr;
     if (ElementNo < ILE->getNumInits())
       Init = ILE->getInit(ElementNo++);
-    if (Init && isa<NoInitExpr>(Init))
+    if (isa_and_nonnull<NoInitExpr>(Init))
       continue;
 
     // Zero-sized fields are not emitted, but their initializers may still
diff --git a/clang/lib/CodeGen/CGStmtOpenMP.cpp b/clang/lib/CodeGen/CGStmtOpenMP.cpp
index 6410f9e102c907..f73d32de7c4848 100644
--- a/clang/lib/CodeGen/CGStmtOpenMP.cpp
+++ b/clang/lib/CodeGen/CGStmtOpenMP.cpp
@@ -72,7 +72,7 @@ class OMPLexicalScope : public CodeGenFunction::LexicalScope {
   static bool isCapturedVar(CodeGenFunction &CGF, const VarDecl *VD) {
     return CGF.LambdaCaptureFields.lookup(VD) ||
            (CGF.CapturedStmtInfo && CGF.CapturedStmtInfo->lookup(VD)) ||
-           (CGF.CurCodeDecl && isa<BlockDecl>(CGF.CurCodeDecl) &&
+           (isa_and_nonnull<BlockDecl>(CGF.CurCodeDecl) &&
             cast<BlockDecl>(CGF.CurCodeDecl)->capturesVariable(VD));
   }
 
@@ -227,7 +227,7 @@ class OMPSimdLexicalScope : public CodeGenFunction::LexicalScope {
   static bool isCapturedVar(CodeGenFunction &CGF, const VarDecl *VD) {
     return CGF.LambdaCaptureFields.lookup(VD) ||
            (CGF.CapturedStmtInfo && CGF.CapturedStmtInfo->lookup(VD)) ||
-           (CGF.CurCodeDecl && isa<BlockDecl>(CGF.CurCodeDecl) &&
+           (isa_and_nonnull<BlockDecl>(CGF.CurCodeDecl) &&
             cast<BlockDecl>(CGF.CurCodeDecl)->capturesVariable(VD));
   }
 
@@ -315,7 +315,7 @@ LValue CodeGenFunction::EmitOMPSharedLValue(const Expr *E) {
       bool IsCaptured =
           LambdaCaptureFields.lookup(OrigVD) ||
           (CapturedStmtInfo && CapturedStmtInfo->lookup(OrigVD)) ||
-          (CurCodeDecl && isa<BlockDecl>(CurCodeDecl));
+          (isa_and_nonnull<BlockDecl>(CurCodeDecl));
       DeclRefExpr DRE(getContext(), const_cast<VarDecl *>(OrigVD), IsCaptured,
                       OrigDRE->getType(), VK_LValue, OrigDRE->getExprLoc());
       return EmitLValue(&DRE);
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index f0345f3b191b88..f84b3b08220fd9 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -2951,7 +2951,7 @@ void CodeGenFunction::emitAlignmentAssumptionCheck(
     SourceLocation SecondaryLoc, llvm::Value *Alignment,
     llvm::Value *OffsetValue, llvm::Value *TheCheck,
     llvm::Instruction *Assumption) {
-  assert(Assumption && isa<llvm::CallInst>(Assumption) &&
+  assert(isa_and_nonnull<llvm::CallInst>(Assumption) &&
          cast<llvm::CallInst>(Assumption)->getCalledOperand() ==
              llvm::Intrinsic::getDeclaration(
                  Builder.GetInsertBlock()->getParent()->getParent(),
diff --git a/clang/lib/Index/IndexBody.cpp b/clang/lib/Index/IndexBody.cpp
index 08136baa5d408e..c18daf7faa7497 100644
--- a/clang/lib/Index/IndexBody.cpp
+++ b/clang/lib/Index/IndexBody.cpp
@@ -268,7 +268,7 @@ class BodyIndexer : public RecursiveASTVisitor<BodyIndexer> {
         }
         return true;
       };
-      bool IsPropCall = Containing && isa<PseudoObjectExpr>(Containing);
+      bool IsPropCall = isa_and_nonnull<PseudoObjectExpr>(Containing);
       // Implicit property message sends are not 'implicit'.
       if ((E->isImplicit() || IsPropCall) &&
           !(IsPropCall &&
diff --git a/clang/lib/Lex/PPMacroExpansion.cpp b/clang/lib/Lex/PPMacroExpansion.cpp
index 8af4a97d00cb82..f085b943716442 100644
--- a/clang/lib/Lex/PPMacroExpansion.cpp
+++ b/clang/lib/Lex/PPMacroExpansion.cpp
@@ -226,7 +226,7 @@ void Preprocessor::updateModuleMacroInfo(const IdentifierInfo *II,
   bool IsSystemMacro = true;
   bool IsAmbiguous = false;
   if (auto *MD = Info.MD) {
-    while (MD && isa<VisibilityMacroDirective>(MD))
+    while (isa_and_nonnull<VisibilityMacroDirective>(MD))
       MD = MD->getPrevious();
     if (auto *DMD = dyn_cast_or_null<DefMacroDirective>(MD)) {
       MI = DMD->getInfo();
diff --git a/clang/lib/Sema/AnalysisBasedWarnings.cpp b/clang/lib/Sema/AnalysisBasedWarnings.cpp
index b9d0b59ef1db73..0f604c61fa3af9 100644
--- a/clang/lib/Sema/AnalysisBasedWarnings.cpp
+++ b/clang/lib/Sema/AnalysisBasedWarnings.cpp
@@ -442,7 +442,7 @@ static ControlFlowKind CheckFallThrough(AnalysisDeclContext &AC) {
       if (!live[B->getBlockID()]) {
         if (B->pred_begin() == B->pred_end()) {
           const Stmt *Term = B->getTerminatorStmt();
-          if (Term && isa<CXXTryStmt>(Term))
+          if (isa_and_nonnull<CXXTryStmt>(Term))
             // When not adding EH edges from calls, catch clauses
             // can otherwise seem dead.  Avoid noting them as dead.
             count += reachable_code::ScanReachableFromBlock(B, live);
@@ -1100,7 +1100,7 @@ namespace {
       // issue a warn_fallthrough_attr_unreachable for them.
       for (const auto *B : *Cfg) {
         const Stmt *L = B->getLabel();
-        if (L && isa<SwitchCase>(L) && ReachableBlocks.insert(B).second)
+        if (isa_and_nonnull<SwitchCase>(L) && ReachableBlocks.insert(B).second)
           BlockQueue.push_back(B);
       }
 
@@ -1128,7 +1128,7 @@ namespace {
         if (!P) continue;
 
         const Stmt *Term = P->getTerminatorStmt();
-        if (Term && isa<SwitchStmt>(Term))
+        if (isa_and_nonnull<SwitchStmt>(Term))
           continue; // Switch statement, good.
 
         const SwitchCase *SW = dyn_cast_or_null<SwitchCase>(P->getLabel());
@@ -1327,7 +1327,7 @@ static void DiagnoseSwitchLabelsFallthrough(Sema &S, AnalysisDeclContext &AC,
         B = *B->succ_begin();
         Term = B->getTerminatorStmt();
       }
-      if (!(B->empty() && Term && isa<BreakStmt>(Term))) {
+      if (!(B->empty() && isa_and_nonnull<BreakStmt>(Term))) {
         Preprocessor &PP = S.getPreprocessor();
         StringRef AnnotationSpelling = getFallthroughAttrSpelling(PP, L);
         SmallString<64> TextToInsert(AnnotationSpelling);
diff --git a/clang/lib/Sema/SemaCXXScopeSpec.cpp b/clang/lib/Sema/SemaCXXScopeSpec.cpp
index c405fbc0aa421b..da88b6cae6e361 100644
--- a/clang/lib/Sema/SemaCXXScopeSpec.cpp
+++ b/clang/lib/Sema/SemaCXXScopeSpec.cpp
@@ -974,7 +974,7 @@ bool Sema::ActOnCXXNestedNameSpecifier(Scope *S,
       R.setBegin(SS.getRange().getBegin());
 
     Diag(CCLoc, diag::err_non_type_template_in_nested_name_specifier)
-      << (TD && isa<VarTemplateDecl>(TD)) << Template << R;
+        << isa_and_nonnull<VarTemplateDecl>(TD) << Template << R;
     NoteAllFoundTemplates(Template);
     return true;
   }
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 300af02239779f..07cd0727eb3f4a 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -3839,11 +3839,11 @@ void Sema::checkCall(NamedDecl *FDecl, const FunctionProtoType *Proto,
   if (CallType != VariadicDoesNotApply &&
       (!FD || FD->getBuiltinID() != Builtin::BI__noop)) {
     unsigned NumParams = Proto ? Proto->getNumParams()
-                       : FDecl && isa<FunctionDecl>(FDecl)
-                           ? cast<FunctionDecl>(FDecl)->getNumParams()
-                       : FDecl && isa<ObjCMethodDecl>(FDecl)
-                           ? cast<ObjCMethodDecl>(FDecl)->param_size()
-                       : 0;
+                         : isa_and_nonnull<FunctionDecl>(FDecl)
+                             ? cast<FunctionDecl>(FDecl)->getNumParams()
+                         : isa_and_nonnull<ObjCMethodDecl>(FDecl)
+                             ? cast<ObjCMethodDecl>(FDecl)->param_size()
+                             : 0;
 
     for (unsigned ArgIdx = NumParams; ArgIdx < Args.size(); ++ArgIdx) {
       // Args[ArgIdx] can be null in malformed code.
diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
index cf461a68d55263..f3af8dee6b090c 100644
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -2074,7 +2074,7 @@ ExprResult Sema::BuildCXXNew(SourceRange Range, bool UseGlobal,
   if (DirectInitRange.isValid()) {
     assert(Initializer && "Have parens but no initializer.");
     InitStyle = CXXNewInitializationStyle::Parens;
-  } else if (Initializer && isa<InitListExpr>(Initializer))
+  } else if (isa_and_nonnull<InitListExpr>(Initializer))
     InitStyle = CXXNewInitializationStyle::Braces;
   else {
     assert((!Initializer || isa<ImplicitValueInitExpr>(Initializer) ||
@@ -3823,7 +3823,7 @@ Sema::ActOnCXXDelete(SourceLocation StartLoc, bool UseGlobal,
 
         // Otherwise, the usual operator delete[] should be the
         // function we just found.
-        else if (OperatorDelete && isa<CXXMethodDecl>(OperatorDelete))
+        else if (isa_and_nonnull<CXXMethodDecl>(OperatorDelete))
           UsualArrayDeleteWantsSize =
             UsualDeallocFnInfo(*this,
                                DeclAccessPair::make(OperatorDelete, AS_public))
@@ -8595,7 +8595,7 @@ static void CheckIfAnyEnclosingLambdasMustCaptureAnyPotentialCaptures(
   assert(S.CurContext->isDependentContext());
 #ifndef NDEBUG
   DeclContext *DC = S.CurContext;
-  while (DC && isa<CapturedDecl>(DC))
+  while (isa_and_nonnull<CapturedDecl>(DC))
     DC = DC->getParent();
   assert(
       CurrentLSI->CallOperator == DC &&
@@ -9172,7 +9172,7 @@ ExprResult Sema::ActOnFinishFullExpr(Expr *FE, SourceLocation CC,
   //  - Teach the handful of places that iterate over FunctionScopes to
   //    stop at the outermost enclosing lexical scope."
   DeclContext *DC = CurContext;
-  while (DC && isa<CapturedDecl>(DC))
+  while (isa_and_nonnull<CapturedDecl>(DC))
     DC = DC->getParent();
   const bool IsInLambdaDeclContext = isLambdaCallOperator(DC);
   if (IsInLambdaDeclContext && CurrentLSI &&
diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index ed8b226a6b39f5..7244f3ef4e829e 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -2194,7 +2194,7 @@ void InitListChecker::CheckStructUnionTypes(
 
     // Designated inits always initialize fields, so if we see one, all
     // remaining base classes have no explicit initializer.
-    if (Init && isa<DesignatedInitExpr>(Init))
+    if (isa_and_nonnull<DesignatedInitExpr>(Init))
       Init = nullptr;
 
     // C++ [over.match.class.deduct]p1.6:
@@ -6350,7 +6350,7 @@ void InitializationSequence::InitializeFrom(Sema &S,
     // class member of array type from a parenthesized initializer list.
     else if (S.getLangOpts().CPlusPlus &&
              Entity.getKind() == InitializedEntity::EK_Member &&
-             Initializer && isa<InitListExpr>(Initializer)) {
+             isa_and_nonnull<InitListExpr>(Initializer)) {
       TryListInitialization(S, Entity, Kind, cast<InitListExpr>(Initializer),
                             *this, TreatUnavailableAsInvalid);
       AddParenthesizedArrayInitStep(DestType);
@@ -8793,7 +8793,7 @@ ExprResult InitializationSequence::Perform(Sema &S,
   // constant expressions here in order to perform narrowing checks =(
   EnterExpressionEvaluationContext Evaluated(
       S, EnterExpressionEvaluationContext::InitList,
-      CurInit.get() && isa<InitListExpr>(CurInit.get()));
+      isa_and_nonnull<InitListExpr>(CurInit.get()));
 
   // C++ [class.abstract]p2:
   //   no objects of an abstract class can be created except as subobjects
diff --git a/clang/lib/Sema/SemaStmt.cpp b/clang/lib/Sema/SemaStmt.cpp
index 57465d4a77ac29..411e9af26f2b7b 100644
--- a/clang/lib/Sema/SemaStmt.cpp
+++ b/clang/lib/Sema/SemaStmt.cpp
@@ -3701,7 +3701,7 @@ bool Sema::DeduceFunctionTypeFromReturnExpr(FunctionDecl *FD,
   if (isLambdaConversionOperator(FD))
     return false;
 
-  if (RetExpr && isa<InitListExpr>(RetExpr)) {
+  if (isa_and_nonnull<InitListExpr>(RetExpr)) {
     //  If the deduction is for a return statement and the initializer is
     //  a braced-init-list, the program is ill-formed.
     Diag(RetExpr->getExprLoc(),
diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
index 40a759ea330de4..a032e3ec6f6353 100644
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -1936,7 +1936,7 @@ DeclResult Sema::CheckClassTemplate(
   // We may have found the injected-class-name of a class template,
   // class template partial specialization, or class template specialization.
   // In these cases, grab the template that is being defined or specialized.
-  if (!PrevClassTemplate && PrevDecl && isa<CXXRecordDecl>(PrevDecl) &&
+  if (!PrevClassTemplate && isa_and_nonnull<CXXRecordDecl>(PrevDecl) &&
       cast<CXXRecordDecl>(PrevDecl)->isInjectedClassName()) {
     PrevDecl = cast<CXXRecordDecl>(PrevDecl->getDeclContext());
     PrevClassTemplate