diff --git a/include/clang/AST/CanonicalType.h b/include/clang/AST/CanonicalType.h
index 9460757..9c699b7 100644
--- a/include/clang/AST/CanonicalType.h
+++ b/include/clang/AST/CanonicalType.h
@@ -81,7 +81,7 @@
   operator QualType() const { return Stored; }
 
   /// \brief Implicit conversion to bool.
-  operator bool() const { return !isNull(); }
+  LLVM_EXPLICIT operator bool() const { return !isNull(); }
   
   bool isNull() const {
     return Stored.isNull();
diff --git a/include/clang/AST/DeclFriend.h b/include/clang/AST/DeclFriend.h
index 3a12878..589178e 100644
--- a/include/clang/AST/DeclFriend.h
+++ b/include/clang/AST/DeclFriend.h
@@ -228,7 +228,7 @@
 }
 
 inline void CXXRecordDecl::pushFriendDecl(FriendDecl *FD) {
-  assert(FD->NextFriend == 0 && "friend already has next friend?");
+  assert(!FD->NextFriend && "friend already has next friend?");
   FD->NextFriend = data().FirstFriend;
   data().FirstFriend = FD;
 }
diff --git a/include/clang/AST/DeclObjC.h b/include/clang/AST/DeclObjC.h
index 40de013..0028240 100644
--- a/include/clang/AST/DeclObjC.h
+++ b/include/clang/AST/DeclObjC.h
@@ -452,7 +452,7 @@
   }
 
   /// \brief Determine whether this method has a body.
-  virtual bool hasBody() const { return Body; }
+  virtual bool hasBody() const { return Body.isValid(); }
 
   /// \brief Retrieve the body of this method, if it has one.
   virtual Stmt *getBody() const;
@@ -463,7 +463,7 @@
   void setBody(Stmt *B) { Body = B; }
 
   /// \brief Returns whether this specific method is a definition.
-  bool isThisDeclarationADefinition() const { return Body; }
+  bool isThisDeclarationADefinition() const { return hasBody(); }
 
   // Implement isa/cast/dyncast/etc.
   static bool classof(const Decl *D) { return classofKind(D->getKind()); }
diff --git a/include/clang/AST/DeclarationName.h b/include/clang/AST/DeclarationName.h
index e01b80f..00766c2 100644
--- a/include/clang/AST/DeclarationName.h
+++ b/include/clang/AST/DeclarationName.h
@@ -182,11 +182,16 @@
 
   // operator bool() - Evaluates true when this declaration name is
   // non-empty.
-  operator bool() const {
+  LLVM_EXPLICIT operator bool() const {
     return ((Ptr & PtrMask) != 0) ||
            (reinterpret_cast<IdentifierInfo *>(Ptr & ~PtrMask));
   }
 
+  /// \brief Evaluates true when this declaration name is empty.
+  bool isEmpty() const {
+    return !*this;
+  }
+
   /// Predicate functions for querying what type of name this is.
   bool isIdentifier() const { return getStoredNameKind() == StoredIdentifier; }
   bool isObjCZeroArgSelector() const {
diff --git a/include/clang/AST/ExprCXX.h b/include/clang/AST/ExprCXX.h
index 91e5b21..a4f296c 100644
--- a/include/clang/AST/ExprCXX.h
+++ b/include/clang/AST/ExprCXX.h
@@ -1935,7 +1935,7 @@
   /// \brief Determines whether this member expression actually had
   /// a C++ nested-name-specifier prior to the name of the member, e.g.,
   /// x->Base::foo.
-  bool hasQualifier() const { return QualifierLoc; }
+  bool hasQualifier() const { return QualifierLoc.hasQualifier(); }
 
   /// \brief Retrieves the nested-name-specifier that qualifies the type name,
   /// with source-location information.
diff --git a/include/clang/AST/ExternalASTSource.h b/include/clang/AST/ExternalASTSource.h
index 81fcf24..b077426 100644
--- a/include/clang/AST/ExternalASTSource.h
+++ b/include/clang/AST/ExternalASTSource.h
@@ -329,7 +329,12 @@
   /// \brief Whether this pointer is non-NULL.
   ///
   /// This operation does not require the AST node to be deserialized.
-  operator bool() const { return Ptr != 0; }
+  LLVM_EXPLICIT operator bool() const { return Ptr != 0; }
+
+  /// \brief Whether this pointer is non-NULL.
+  ///
+  /// This operation does not require the AST node to be deserialized.
+  bool isValid() const { return Ptr != 0; }
 
   /// \brief Whether this pointer is currently stored as an offset.
   bool isOffset() const { return Ptr & 0x01; }
diff --git a/include/clang/AST/NestedNameSpecifier.h b/include/clang/AST/NestedNameSpecifier.h
index 58f3986..b332b15 100644
--- a/include/clang/AST/NestedNameSpecifier.h
+++ b/include/clang/AST/NestedNameSpecifier.h
@@ -231,7 +231,11 @@
 
   /// \brief Evalutes true when this nested-name-specifier location is
   /// non-empty.
-  operator bool() const { return Qualifier; }
+  LLVM_EXPLICIT operator bool() const { return Qualifier; }
+
+  /// \brief Evalutes true when this nested-name-specifier location is
+  /// empty.
+  bool hasQualifier() const { return Qualifier; }
 
   /// \brief Retrieve the nested-name-specifier to which this instance
   /// refers.
diff --git a/include/clang/AST/StmtIterator.h b/include/clang/AST/StmtIterator.h
index b933ed0..fc25fa9 100644
--- a/include/clang/AST/StmtIterator.h
+++ b/include/clang/AST/StmtIterator.h
@@ -15,6 +15,7 @@
 #define LLVM_CLANG_AST_STMT_ITR_H
 
 #include "llvm/Support/DataTypes.h"
+#include "llvm/Support/Compiler.h"
 #include <cassert>
 #include <cstddef>
 #include <iterator>
@@ -156,7 +157,7 @@
     : std::pair<StmtIterator,StmtIterator>(begin, end) {}
 
   bool empty() const { return first == second; }
-  operator bool() const { return !empty(); }
+  LLVM_EXPLICIT operator bool() const { return !empty(); }
 
   Stmt *operator->() const { return first.operator->(); }
   Stmt *&operator*() const { return first.operator*(); }
@@ -199,7 +200,7 @@
     : std::pair<ConstStmtIterator,ConstStmtIterator>(begin, end) {}
 
   bool empty() const { return first == second; }
-  operator bool() const { return !empty(); }
+  LLVM_EXPLICIT operator bool() const { return !empty(); }
 
   const Stmt *operator->() const { return first.operator->(); }
   const Stmt *operator*() const { return first.operator*(); }
diff --git a/include/clang/AST/Type.h b/include/clang/AST/Type.h
index 39f10d3..93c287f 100644
--- a/include/clang/AST/Type.h
+++ b/include/clang/AST/Type.h
@@ -441,7 +441,7 @@
   bool operator==(Qualifiers Other) const { return Mask == Other.Mask; }
   bool operator!=(Qualifiers Other) const { return Mask != Other.Mask; }
 
-  operator bool() const { return hasQualifiers(); }
+  LLVM_EXPLICIT operator bool() const { return hasQualifiers(); }
 
   Qualifiers &operator+=(Qualifiers R) {
     addQualifiers(R);
diff --git a/include/clang/AST/TypeLoc.h b/include/clang/AST/TypeLoc.h
index 11cad9b..9e2d3bf 100644
--- a/include/clang/AST/TypeLoc.h
+++ b/include/clang/AST/TypeLoc.h
@@ -90,7 +90,7 @@
   }
 
   bool isNull() const { return !Ty; }
-  operator bool() const { return Ty; }
+  LLVM_EXPLICIT operator bool() const { return Ty; }
 
   /// \brief Returns the size of type source info data block for the given type.
   static unsigned getFullDataSizeForType(QualType Ty);
diff --git a/include/clang/Analysis/Analyses/FormatString.h b/include/clang/Analysis/Analyses/FormatString.h
index 4bd989c..6ad89ae 100644
--- a/include/clang/Analysis/Analyses/FormatString.h
+++ b/include/clang/Analysis/Analyses/FormatString.h
@@ -49,7 +49,7 @@
   const char *toString() const { return representation; }
 
   // Overloaded operators for bool like qualities
-  operator bool() const { return flag; }
+  LLVM_EXPLICIT operator bool() const { return flag; }
   OptionalFlag& operator=(const bool &rhs) {
     flag = rhs;
     return *this;  // Return a reference to myself.
diff --git a/include/clang/Analysis/CFG.h b/include/clang/Analysis/CFG.h
index ee0be73..01480ed 100644
--- a/include/clang/Analysis/CFG.h
+++ b/include/clang/Analysis/CFG.h
@@ -269,7 +269,7 @@
   Stmt &operator*() { return *getStmt(); }
   const Stmt &operator*() const { return *getStmt(); }
 
-  operator bool() const { return getStmt(); }
+  LLVM_EXPLICIT operator bool() const { return getStmt(); }
 };
 
 /// CFGBlock - Represents a single basic block in a source-level CFG.
diff --git a/include/clang/Basic/Diagnostic.h b/include/clang/Basic/Diagnostic.h
index 3e12594..1354120 100644
--- a/include/clang/Basic/Diagnostic.h
+++ b/include/clang/Basic/Diagnostic.h
@@ -1212,7 +1212,7 @@
   ~StoredDiagnostic();
 
   /// \brief Evaluates true when this object stores a diagnostic.
-  operator bool() const { return Message.size() > 0; }
+  LLVM_EXPLICIT operator bool() const { return Message.size() > 0; }
 
   unsigned getID() const { return ID; }
   DiagnosticsEngine::Level getLevel() const { return Level; }
diff --git a/include/clang/Frontend/ASTUnit.h b/include/clang/Frontend/ASTUnit.h
index 9bd0ef3..1fc56ce 100644
--- a/include/clang/Frontend/ASTUnit.h
+++ b/include/clang/Frontend/ASTUnit.h
@@ -456,7 +456,7 @@
   void setASTContext(ASTContext *ctx) { Ctx = ctx; }
   void setPreprocessor(Preprocessor *pp);
 
-  bool hasSema() const { return TheSema; }
+  bool hasSema() const { return TheSema.isValid(); }
   Sema &getSema() const { 
     assert(TheSema && "ASTUnit does not have a Sema object!");
     return *TheSema; 
diff --git a/include/clang/Frontend/CompilerInstance.h b/include/clang/Frontend/CompilerInstance.h
index dbd7606..ee48505 100644
--- a/include/clang/Frontend/CompilerInstance.h
+++ b/include/clang/Frontend/CompilerInstance.h
@@ -395,7 +395,7 @@
   /// @name ASTConsumer
   /// {
 
-  bool hasASTConsumer() const { return Consumer != 0; }
+  bool hasASTConsumer() const { return Consumer.isValid(); }
 
   ASTConsumer &getASTConsumer() const {
     assert(Consumer && "Compiler instance has no AST consumer!");
@@ -413,7 +413,7 @@
   /// }
   /// @name Semantic analysis
   /// {
-  bool hasSema() const { return TheSema != 0; }
+  bool hasSema() const { return TheSema.isValid(); }
   
   Sema &getSema() const { 
     assert(TheSema && "Compiler instance has no Sema object!");
@@ -433,7 +433,9 @@
   /// @name Code Completion
   /// {
 
-  bool hasCodeCompletionConsumer() const { return CompletionConsumer != 0; }
+  bool hasCodeCompletionConsumer() const {
+    return CompletionConsumer.isValid();
+  }
 
   CodeCompleteConsumer &getCodeCompletionConsumer() const {
     assert(CompletionConsumer &&
@@ -455,7 +457,7 @@
   /// @name Frontend timer
   /// {
 
-  bool hasFrontendTimer() const { return FrontendTimer != 0; }
+  bool hasFrontendTimer() const { return FrontendTimer.isValid(); }
 
   llvm::Timer &getFrontendTimer() const {
     assert(FrontendTimer && "Compiler instance has no frontend timer!");
diff --git a/include/clang/Frontend/FrontendAction.h b/include/clang/Frontend/FrontendAction.h
index c67be92..fee8d95 100644
--- a/include/clang/Frontend/FrontendAction.h
+++ b/include/clang/Frontend/FrontendAction.h
@@ -116,7 +116,7 @@
 
   bool isCurrentFileAST() const {
     assert(!CurrentInput.isEmpty() && "No current file!");
-    return CurrentASTUnit != 0;
+    return CurrentASTUnit.isValid();
   }
 
   const FrontendInputFile &getCurrentInput() const {
diff --git a/include/clang/Lex/HeaderSearch.h b/include/clang/Lex/HeaderSearch.h
index c46c8ce..498de09 100644
--- a/include/clang/Lex/HeaderSearch.h
+++ b/include/clang/Lex/HeaderSearch.h
@@ -264,7 +264,7 @@
 
   /// \brief Checks whether the map exists or not.
   bool HasIncludeAliasMap() const {
-    return IncludeAliases;
+    return IncludeAliases.isValid();
   }
 
   /// \brief Map the source include name to the dest include name.
diff --git a/include/clang/Lex/MacroInfo.h b/include/clang/Lex/MacroInfo.h
index 64323b7..b4ce4db 100644
--- a/include/clang/Lex/MacroInfo.h
+++ b/include/clang/Lex/MacroInfo.h
@@ -421,7 +421,7 @@
     bool isValid() const { return DefDirective != 0; }
     bool isInvalid() const { return !isValid(); }
 
-    operator bool() const { return isValid(); }
+    LLVM_EXPLICIT operator bool() const { return isValid(); }
 
     inline DefInfo getPreviousDefinition(bool AllowHidden = false);
     const DefInfo getPreviousDefinition(bool AllowHidden = false) const {
diff --git a/include/clang/Lex/ModuleMap.h b/include/clang/Lex/ModuleMap.h
index 9fe97d0..bd57ce4 100644
--- a/include/clang/Lex/ModuleMap.h
+++ b/include/clang/Lex/ModuleMap.h
@@ -80,7 +80,7 @@
 
     // \brief Whether this known header is valid (i.e., it has an
     // associated module).
-    operator bool() const { return Storage.getPointer() != 0; }
+    LLVM_EXPLICIT operator bool() const { return Storage.getPointer() != 0; }
   };
 
   typedef llvm::DenseMap<const FileEntry *, KnownHeader> HeadersMap;
diff --git a/include/clang/Lex/Preprocessor.h b/include/clang/Lex/Preprocessor.h
index c598177..89cb696 100644
--- a/include/clang/Lex/Preprocessor.h
+++ b/include/clang/Lex/Preprocessor.h
@@ -1400,7 +1400,7 @@
   bool InCachingLexMode() const {
     // If the Lexer pointers are 0 and IncludeMacroStack is empty, it means
     // that we are past EOF, not that we are in CachingLex mode.
-    return CurPPLexer == 0 && CurTokenLexer == 0 && CurPTHLexer == 0 &&
+    return !CurPPLexer && !CurTokenLexer && !CurPTHLexer &&
            !IncludeMacroStack.empty();
   }
   void EnterCachingLexMode();
diff --git a/include/clang/Sema/Initialization.h b/include/clang/Sema/Initialization.h
index 58781ac..3f70672 100644
--- a/include/clang/Sema/Initialization.h
+++ b/include/clang/Sema/Initialization.h
@@ -841,7 +841,7 @@
   void setSequenceKind(enum SequenceKind SK) { SequenceKind = SK; }
   
   /// \brief Determine whether the initialization sequence is valid.
-  operator bool() const { return !Failed(); }
+  LLVM_EXPLICIT operator bool() const { return !Failed(); }
 
   /// \brief Determine whether the initialization sequence is invalid.
   bool Failed() const { return SequenceKind == FailedSequence; }
diff --git a/include/clang/Sema/Ownership.h b/include/clang/Sema/Ownership.h
index c3d1f4e..92c486d 100644
--- a/include/clang/Sema/Ownership.h
+++ b/include/clang/Sema/Ownership.h
@@ -65,7 +65,7 @@
       Ptr = Traits::getAsVoidPointer(P);
     }
 
-    operator bool() const { return Ptr != 0; }
+    LLVM_EXPLICIT operator bool() const { return Ptr != 0; }
 
     void *getAsOpaquePtr() const { return Ptr; }
     static OpaquePtr getFromOpaquePtr(void *P) { return OpaquePtr(P); }
diff --git a/include/clang/Sema/Sema.h b/include/clang/Sema/Sema.h
index c2300e9..61b91c5 100644
--- a/include/clang/Sema/Sema.h
+++ b/include/clang/Sema/Sema.h
@@ -5994,7 +5994,7 @@
 
     /// \brief Determines whether we have exceeded the maximum
     /// recursive template instantiations.
-    operator bool() const { return Invalid; }
+    LLVM_EXPLICIT operator bool() const { return Invalid; }
 
   private:
     Sema &SemaRef;
diff --git a/include/clang/Sema/TypoCorrection.h b/include/clang/Sema/TypoCorrection.h
index 5fbfba2..59f3417 100644
--- a/include/clang/Sema/TypoCorrection.h
+++ b/include/clang/Sema/TypoCorrection.h
@@ -140,7 +140,7 @@
   }
 
   /// \brief Returns whether this TypoCorrection has a non-empty DeclarationName
-  operator bool() const { return bool(CorrectionName); }
+  LLVM_EXPLICIT operator bool() const { return bool(CorrectionName); }
 
   /// \brief Mark this TypoCorrection as being a keyword.
   /// Since addCorrectionDeclsand setCorrectionDecl don't allow NULL to be
diff --git a/include/clang/Serialization/ASTReader.h b/include/clang/Serialization/ASTReader.h
index bb59784..073baf5 100644
--- a/include/clang/Serialization/ASTReader.h
+++ b/include/clang/Serialization/ASTReader.h
@@ -1232,7 +1232,7 @@
   void setDeserializationListener(ASTDeserializationListener *Listener);
 
   /// \brief Determine whether this AST reader has a global index.
-  bool hasGlobalIndex() const { return GlobalIndex; }
+  bool hasGlobalIndex() const { return GlobalIndex.isValid(); }
 
   /// \brief Attempts to load the global index.
   ///
diff --git a/include/clang/StaticAnalyzer/Core/BugReporter/PathDiagnostic.h b/include/clang/StaticAnalyzer/Core/BugReporter/PathDiagnostic.h
index a80b5a7..09ee005 100644
--- a/include/clang/StaticAnalyzer/Core/BugReporter/PathDiagnostic.h
+++ b/include/clang/StaticAnalyzer/Core/BugReporter/PathDiagnostic.h
@@ -504,7 +504,7 @@
   }
   
   bool hasCallStackHint() {
-    return (CallStackHint != 0);
+    return CallStackHint.isValid();
   }
 
   /// Produce the hint for the given node. The node contains 
diff --git a/include/clang/StaticAnalyzer/Core/Checker.h b/include/clang/StaticAnalyzer/Core/Checker.h
index 0dbaab0..d56f8e9 100644
--- a/include/clang/StaticAnalyzer/Core/Checker.h
+++ b/include/clang/StaticAnalyzer/Core/Checker.h
@@ -505,7 +505,7 @@
 struct DefaultBool {
   bool val;
   DefaultBool() : val(false) {}
-  operator bool() const { return val; }
+  LLVM_EXPLICIT operator bool() const { return val; }
   DefaultBool &operator=(bool b) { val = b; return *this; }
 };
 
diff --git a/include/clang/StaticAnalyzer/Core/PathSensitive/Store.h b/include/clang/StaticAnalyzer/Core/PathSensitive/Store.h
index b219495..230ce1e 100644
--- a/include/clang/StaticAnalyzer/Core/PathSensitive/Store.h
+++ b/include/clang/StaticAnalyzer/Core/PathSensitive/Store.h
@@ -231,7 +231,7 @@
 
     bool HandleBinding(StoreManager& SMgr, Store store, const MemRegion* R,
                        SVal val);
-    operator bool() { return First && Binding; }
+    LLVM_EXPLICIT operator bool() { return First && Binding; }
     const MemRegion *getRegion() { return Binding; }
   };
 
diff --git a/lib/AST/ASTDumper.cpp b/lib/AST/ASTDumper.cpp
index 790538f..cd974f0 100644
--- a/lib/AST/ASTDumper.cpp
+++ b/lib/AST/ASTDumper.cpp
@@ -1329,7 +1329,7 @@
     return;
   }
 
-  setMoreChildren(S->children());
+  setMoreChildren(!S->children().empty());
   ConstStmtVisitor<ASTDumper>::Visit(S);
   setMoreChildren(false);
   for (Stmt::const_child_range CI = S->children(); CI; ++CI) {
diff --git a/lib/AST/ASTImporter.cpp b/lib/AST/ASTImporter.cpp
index 740b4ff..204b9d0 100644
--- a/lib/AST/ASTImporter.cpp
+++ b/lib/AST/ASTImporter.cpp
@@ -2878,7 +2878,7 @@
 
       if (Importer.IsStructurallyEquivalent(D->getType(), 
                                             FoundField->getType(),
-                                            Name)) {
+                                            !Name.isEmpty())) {
         Importer.Imported(D, FoundField);
         return FoundField;
       }
diff --git a/lib/AST/Decl.cpp b/lib/AST/Decl.cpp
index 3e4c2cb..b8f4787 100644
--- a/lib/AST/Decl.cpp
+++ b/lib/AST/Decl.cpp
@@ -2319,7 +2319,7 @@
     const FunctionDecl *Prev = this;
     bool FoundBody = false;
     while ((Prev = Prev->getPreviousDecl())) {
-      FoundBody |= Prev->Body;
+      FoundBody |= Prev->Body.isValid();
 
       if (Prev->Body) {
         // If it's not the case that both 'inline' and 'extern' are
@@ -2347,7 +2347,7 @@
   const FunctionDecl *Prev = this;
   bool FoundBody = false;
   while ((Prev = Prev->getPreviousDecl())) {
-    FoundBody |= Prev->Body;
+    FoundBody |= Prev->Body.isValid();
     if (RedeclForcesDefC99(Prev))
       return false;
   }
diff --git a/lib/AST/Expr.cpp b/lib/AST/Expr.cpp
index 15cf5ac..f587dfa 100644
--- a/lib/AST/Expr.cpp
+++ b/lib/AST/Expr.cpp
@@ -423,7 +423,7 @@
     FoundD = 0;
 
   std::size_t Size = sizeof(DeclRefExpr);
-  if (QualifierLoc != 0)
+  if (QualifierLoc)
     Size += sizeof(NestedNameSpecifierLoc);
   if (FoundD)
     Size += sizeof(NamedDecl *);
diff --git a/lib/AST/ExprConstant.cpp b/lib/AST/ExprConstant.cpp
index 2a3efb2..3741bf1 100644
--- a/lib/AST/ExprConstant.cpp
+++ b/lib/AST/ExprConstant.cpp
@@ -1809,7 +1809,7 @@
     assert(Value && "missing value for complete object");
   }
 
-  operator bool() const { return Value; }
+  LLVM_EXPLICIT operator bool() const { return Value; }
 };
 
 /// Find the designated sub-object of an rvalue.
diff --git a/lib/Analysis/CFG.cpp b/lib/Analysis/CFG.cpp
index 096c7a0..6eb84ce 100644
--- a/lib/Analysis/CFG.cpp
+++ b/lib/Analysis/CFG.cpp
@@ -155,7 +155,7 @@
       return !(*this == rhs);
     }
 
-    operator bool() const {
+    LLVM_EXPLICIT operator bool() const {
       return *this != const_iterator();
     }
 
diff --git a/lib/CodeGen/CodeGenFunction.h b/lib/CodeGen/CodeGenFunction.h
index 6caf168..5a7c305 100644
--- a/lib/CodeGen/CodeGenFunction.h
+++ b/lib/CodeGen/CodeGenFunction.h
@@ -2422,7 +2422,7 @@
       return ConstantEmission(C, false);
     }
 
-    operator bool() const { return ValueAndIsReference.getOpaqueValue() != 0; }
+    LLVM_EXPLICIT operator bool() const { return ValueAndIsReference.getOpaqueValue() != 0; }
 
     bool isReference() const { return ValueAndIsReference.getInt(); }
     LValue getReferenceLValue(CodeGenFunction &CGF, Expr *refExpr) const {
diff --git a/lib/Lex/HeaderMap.cpp b/lib/Lex/HeaderMap.cpp
index dcf1f0c..478462c 100644
--- a/lib/Lex/HeaderMap.cpp
+++ b/lib/Lex/HeaderMap.cpp
@@ -82,7 +82,7 @@
   if (FileSize <= sizeof(HMapHeader)) return 0;
 
   OwningPtr<const llvm::MemoryBuffer> FileBuffer(FM.getBufferForFile(FE));
-  if (FileBuffer == 0) return 0;  // Unreadable file?
+  if (!FileBuffer) return 0;  // Unreadable file?
   const char *FileStart = FileBuffer->getBufferStart();
 
   // We know the file is at least as big as the header, check it now.
diff --git a/lib/Lex/PPDirectives.cpp b/lib/Lex/PPDirectives.cpp
index 50a0cb5..ba3291a 100644
--- a/lib/Lex/PPDirectives.cpp
+++ b/lib/Lex/PPDirectives.cpp
@@ -241,7 +241,7 @@
                                                 bool FoundElse,
                                                 SourceLocation ElseLoc) {
   ++NumSkipped;
-  assert(CurTokenLexer == 0 && CurPPLexer && "Lexing a macro, not a file?");
+  assert(!CurTokenLexer && CurPPLexer && "Lexing a macro, not a file?");
 
   CurPPLexer->pushConditionalLevel(IfTokenLoc, /*isSkipping*/false,
                                  FoundNonSkipPortion, FoundElse);
diff --git a/lib/Lex/PPLexerChange.cpp b/lib/Lex/PPLexerChange.cpp
index be4defe..a22d67a6e 100644
--- a/lib/Lex/PPLexerChange.cpp
+++ b/lib/Lex/PPLexerChange.cpp
@@ -70,7 +70,7 @@
 /// start lexing tokens from it instead of the current buffer.
 void Preprocessor::EnterSourceFile(FileID FID, const DirectoryLookup *CurDir,
                                    SourceLocation Loc) {
-  assert(CurTokenLexer == 0 && "Cannot #include a file inside a macro!");
+  assert(!CurTokenLexer && "Cannot #include a file inside a macro!");
   ++NumEnteredSourceFiles;
 
   if (MaxIncludeStackDepth < IncludeMacroStack.size())
diff --git a/lib/Parse/ParseDecl.cpp b/lib/Parse/ParseDecl.cpp
index 6a87b78..8ad0281 100644
--- a/lib/Parse/ParseDecl.cpp
+++ b/lib/Parse/ParseDecl.cpp
@@ -2524,7 +2524,7 @@
       // erroneous: We already checked about that it has no type specifier, and
       // C++ doesn't have implicit int.  Diagnose it as a typo w.r.t. to the
       // typename.
-      if (TypeRep == 0) {
+      if (!TypeRep) {
         ConsumeToken();   // Eat the scope spec so the identifier is current.
         ParsedAttributesWithRange Attrs(AttrFactory);
         if (ParseImplicitInt(DS, &SS, TemplateInfo, AS, DSContext, Attrs)) {
diff --git a/lib/Rewrite/Core/Rewriter.cpp b/lib/Rewrite/Core/Rewriter.cpp
index c1c6595..540e8b2 100644
--- a/lib/Rewrite/Core/Rewriter.cpp
+++ b/lib/Rewrite/Core/Rewriter.cpp
@@ -463,7 +463,7 @@
     }
   }
 
-  bool ok() { return FileStream; }
+  bool ok() { return FileStream.isValid(); }
   raw_ostream &getStream() { return *FileStream; }
 
 private:
diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index e5e4389..437a9da 100644
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -9307,7 +9307,7 @@
   ParmVarDecl *Other = MoveAssignOperator->getParamDecl(0);
   QualType OtherRefType = Other->getType()->
       getAs<RValueReferenceType>()->getPointeeType();
-  assert(OtherRefType.getQualifiers() == 0 &&
+  assert(!OtherRefType.getQualifiers() &&
          "Bad argument type of defaulted move assignment");
 
   // Our location for everything implicitly-generated.
diff --git a/lib/Sema/SemaDeclObjC.cpp b/lib/Sema/SemaDeclObjC.cpp
index 0761058..3265ab0 100644
--- a/lib/Sema/SemaDeclObjC.cpp
+++ b/lib/Sema/SemaDeclObjC.cpp
@@ -2945,7 +2945,7 @@
     QualType ArgType;
     TypeSourceInfo *DI;
 
-    if (ArgInfo[i].Type == 0) {
+    if (!ArgInfo[i].Type) {
       ArgType = Context.getObjCIdType();
       DI = 0;
     } else {
diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index 2595f2d..fa2bfd2 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -4468,7 +4468,7 @@
 ExprResult
 Sema::ActOnCompoundLiteral(SourceLocation LParenLoc, ParsedType Ty,
                            SourceLocation RParenLoc, Expr *InitExpr) {
-  assert((Ty != 0) && "ActOnCompoundLiteral(): missing type");
+  assert(Ty && "ActOnCompoundLiteral(): missing type");
   // FIXME: put back this assert when initializers are worked out.
   //assert((InitExpr != 0) && "ActOnCompoundLiteral(): missing expression");
 
diff --git a/test/SemaCXX/constant-expression-cxx1y.cpp b/test/SemaCXX/constant-expression-cxx1y.cpp
index 59a972a..ea0c9e6 100644
--- a/test/SemaCXX/constant-expression-cxx1y.cpp
+++ b/test/SemaCXX/constant-expression-cxx1y.cpp
@@ -250,11 +250,12 @@
 }
 
 namespace const_modify {
-  constexpr int modify(int &n) { return n = 1; } // expected-note {{modification of object of const-qualified type 'const int'}}
+  constexpr int modify(int &n) { return n = 1; } // expected-note 2 {{modification of object of const-qualified type 'const int'}}
   constexpr int test1() { int k = 0; return modify(k); }
-  constexpr int test2() { const int k = 0; return modify(const_cast<int&>(k)); } // expected-note {{in call}}
+  constexpr int test2() { const int k = 0; return modify(const_cast<int&>(k)); } // expected-note 2 {{in call}}
   static_assert(test1() == 1, "");
   static_assert(test2() == 1, ""); // expected-error {{constant expression}} expected-note {{in call}}
+  constexpr int i = test2(); // expected-error {{constant expression}} expected-note {{in call}}
 }
 
 namespace null {
diff --git a/unittests/Tooling/CompilationDatabaseTest.cpp b/unittests/Tooling/CompilationDatabaseTest.cpp
index c453b05..defde91 100644
--- a/unittests/Tooling/CompilationDatabaseTest.cpp
+++ b/unittests/Tooling/CompilationDatabaseTest.cpp
@@ -453,7 +453,7 @@
   const char *Argv[] = { "1", "2", "--\0no-constant-folding", "3", "4" };
   OwningPtr<FixedCompilationDatabase> Database(
       FixedCompilationDatabase::loadFromCommandLine(Argc, Argv));
-  ASSERT_TRUE(Database);
+  ASSERT_TRUE(Database.isValid());
   std::vector<CompileCommand> Result =
     Database->getCompileCommands("source");
   ASSERT_EQ(1ul, Result.size());
@@ -472,7 +472,7 @@
   const char *Argv[] = { "1", "2", "--\0no-constant-folding" };
   OwningPtr<FixedCompilationDatabase> Database(
       FixedCompilationDatabase::loadFromCommandLine(Argc, Argv));
-  ASSERT_TRUE(Database);
+  ASSERT_TRUE(Database.isValid());
   std::vector<CompileCommand> Result =
     Database->getCompileCommands("source");
   ASSERT_EQ(1ul, Result.size());