Give InitListChecker a verification-only mode, where it neither emits diagnostics nor

builds a semantic (structured) initializer list, just reports on whether it can match
the given list to the target type.
Use this mode for doing init list checking in the initial step of initialization, which
will eventually allow us to do overload resolution based on the outcome.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@140457 91177308-0d34-0410-b5e6-96231b3b80d8

6 files changed, 369 insertions, 245 deletions

diff --git a/include/clang/Sema/Initialization.h b/include/clang/Sema/Initialization.h
index 958183c3ef..ef592d2ab9 100644
--- a/include/clang/Sema/Initialization.h
+++ b/include/clang/Sema/Initialization.h
@@ -810,7 +810,7 @@ public:
   void AddConversionSequenceStep(const ImplicitConversionSequence &ICS,
                                  QualType T);
 
-  /// \brief Add a list-initialiation step  
+  /// \brief Add a list-initialiation step.
   void AddListInitializationStep(QualType T);
 
   /// \brief Add a constructor-initialization step.
diff --git a/include/clang/Sema/Overload.h b/include/clang/Sema/Overload.h
index 214f8c0eb2..e4f923703b 100644
--- a/include/clang/Sema/Overload.h
+++ b/include/clang/Sema/Overload.h
@@ -464,6 +464,7 @@ namespace clang {
     bool isEllipsis() const { return getKind() == EllipsisConversion; }
     bool isAmbiguous() const { return getKind() == AmbiguousConversion; }
     bool isUserDefined() const { return getKind() == UserDefinedConversion; }
+    bool isFailure() const { return isBad() || isAmbiguous(); }
 
     /// Determines whether this conversion sequence has been
     /// initialized.  Most operations should never need to query
diff --git a/include/clang/Sema/Sema.h b/include/clang/Sema/Sema.h
index a1887c2245..a7a0c2f7ae 100644
--- a/include/clang/Sema/Sema.h
+++ b/include/clang/Sema/Sema.h
@@ -1383,7 +1383,7 @@ public:
                                              QualType ResultType,
                                              Expr *Value,
                                              bool AllowNRVO = true);
-  
+
   bool CanPerformCopyInitialization(const InitializedEntity &Entity,
                                     ExprResult Init);
   ExprResult PerformCopyInitialization(const InitializedEntity &Entity,
@@ -2217,8 +2217,9 @@ public:
   //===--------------------------------------------------------------------===//
   // Expression Parsing Callbacks: SemaExpr.cpp.
 
-  bool DiagnoseUseOfDecl(NamedDecl *D, SourceLocation Loc, 
-                         const ObjCInterfaceDecl *UnknownObjCClass=0);
+  bool CanUseDecl(NamedDecl *D);
+  bool DiagnoseUseOfDecl(NamedDecl *D, SourceLocation Loc,
+                         const ObjCInterfaceDecl *UnknownObjCClass = 0);
   std::string getDeletedOrUnavailableSuffix(const FunctionDecl *FD);
   bool DiagnosePropertyAccessorMismatch(ObjCPropertyDecl *PD,
                                         ObjCMethodDecl *Getter,
@@ -5580,7 +5581,8 @@ public:
   // CheckAssignmentOperands, and ActOnReturnStmt. Prior to type checking,
   // this routine performs the default function/array converions.
   AssignConvertType CheckSingleAssignmentConstraints(QualType LHSType,
-                                                     ExprResult &RHS);
+                                                     ExprResult &RHS,
+                                                     bool Diagnose = true);
 
   // \brief If the lhs type is a transparent union, check whether we
   // can initialize the transparent union with the given expression.
@@ -5593,11 +5595,13 @@ public:
 
   ExprResult PerformImplicitConversion(Expr *From, QualType ToType,
                                        AssignmentAction Action,
-                                       bool AllowExplicit = false);
+                                       bool AllowExplicit = false,
+                                       bool Diagnose = true);
   ExprResult PerformImplicitConversion(Expr *From, QualType ToType,
                                        AssignmentAction Action,
                                        bool AllowExplicit,
-                                       ImplicitConversionSequence& ICS);
+                                       ImplicitConversionSequence& ICS,
+                                       bool Diagnose = true);
   ExprResult PerformImplicitConversion(Expr *From, QualType ToType,
                                        const ImplicitConversionSequence& ICS,
                                        AssignmentAction Action,
diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index c06f5a7b83..209afe330d 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -41,6 +41,20 @@
 using namespace clang;
 using namespace sema;
 
+/// \brief Determine whether the use of this declaration is valid, without
+/// emitting diagnostics.
+bool Sema::CanUseDecl(NamedDecl *D) {
+  // See if this is an auto-typed variable whose initializer we are parsing.
+  if (ParsingInitForAutoVars.count(D))
+    return false;
+
+  // See if this is a deleted function.
+  if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
+    if (FD->isDeleted())
+      return false;
+  }
+  return true;
+}
 
 /// \brief Determine whether the use of this declaration is valid, and
 /// emit any corresponding diagnostics.
@@ -51,9 +65,6 @@ using namespace sema;
 /// used, or produce an error (and return true) if a C++0x deleted
 /// function is being used.
 ///
-/// If IgnoreDeprecated is set to true, this should not warn about deprecated
-/// decls.
-///
 /// \returns true if there was an error (this declaration cannot be
 /// referenced), false otherwise.
 ///
@@ -5659,7 +5670,8 @@ Sema::CheckTransparentUnionArgumentConstraints(QualType ArgType,
 }
 
 Sema::AssignConvertType
-Sema::CheckSingleAssignmentConstraints(QualType LHSType, ExprResult &RHS) {
+Sema::CheckSingleAssignmentConstraints(QualType LHSType, ExprResult &RHS,
+                                       bool Diagnose) {
   if (getLangOptions().CPlusPlus) {
     if (!LHSType->isRecordType()) {
       // C++ 5.17p3: If the left operand is not of class type, the
@@ -5667,7 +5679,7 @@ Sema::CheckSingleAssignmentConstraints(QualType LHSType, ExprResult &RHS) {
       // cv-unqualified type of the left operand.
       ExprResult Res = PerformImplicitConversion(RHS.get(),
                                                  LHSType.getUnqualifiedType(),
-                                                 AA_Assigning);
+                                                 AA_Assigning, Diagnose);
       if (Res.isInvalid())
         return Incompatible;
       Sema::AssignConvertType result = Compatible;
@@ -5681,7 +5693,7 @@ Sema::CheckSingleAssignmentConstraints(QualType LHSType, ExprResult &RHS) {
 
     // FIXME: Currently, we fall through and treat C++ classes like C
     // structures.
-  }  
+  }
 
   // C99 6.5.16.1p1: the left operand is a pointer and the right is
   // a null pointer constant.
diff --git a/lib/Sema/SemaInit.cpp b/lib/Sema/SemaInit.cpp
index 15bcb451e5..7c27e6fbae 100644
--- a/lib/Sema/SemaInit.cpp
+++ b/lib/Sema/SemaInit.cpp
@@ -169,6 +169,7 @@ namespace {
 class InitListChecker {
   Sema &SemaRef;
   bool hadError;
+  bool VerifyOnly; // no diagnostics, no structure building
   std::map<InitListExpr *, InitListExpr *> SyntacticToSemantic;
   InitListExpr *FullyStructuredList;
 
@@ -257,7 +258,7 @@ class InitListChecker {
                               bool TopLevelObject);
 public:
   InitListChecker(Sema &S, const InitializedEntity &Entity,
-                  InitListExpr *IL, QualType &T);
+                  InitListExpr *IL, QualType &T, bool VerifyOnly);
   bool HadError() { return hadError; }
 
   // @brief Retrieves the fully-structured initializer list used for
@@ -450,8 +451,9 @@ InitListChecker::FillInValueInitializations(const InitializedEntity &Entity,
 
 
 InitListChecker::InitListChecker(Sema &S, const InitializedEntity &Entity,
-                                 InitListExpr *IL, QualType &T)
-  : SemaRef(S) {
+                                 InitListExpr *IL, QualType &T,
+                                 bool VerifyOnly)
+  : SemaRef(S), VerifyOnly(VerifyOnly) {
   hadError = false;
 
   unsigned newIndex = 0;
@@ -462,7 +464,7 @@ InitListChecker::InitListChecker(Sema &S, const InitializedEntity &Entity,
                         FullyStructuredList, newStructuredIndex,
                         /*TopLevelObject=*/true);
 
-  if (!hadError) {
+  if (!hadError && !VerifyOnly) {
     bool RequiresSecondPass = false;
     FillInValueInitializations(Entity, FullyStructuredList, RequiresSecondPass);
     if (RequiresSecondPass && !hadError)
@@ -513,8 +515,9 @@ void InitListChecker::CheckImplicitInitList(const InitializedEntity &Entity,
     llvm_unreachable("CheckImplicitInitList(): Illegal type");
 
   if (maxElements == 0) {
-    SemaRef.Diag(ParentIList->getInit(Index)->getLocStart(),
-                  diag::err_implicit_empty_initializer);
+    if (!VerifyOnly)
+      SemaRef.Diag(ParentIList->getInit(Index)->getLocStart(),
+                   diag::err_implicit_empty_initializer);
     ++Index;
     hadError = true;
     return;
@@ -535,26 +538,29 @@ void InitListChecker::CheckImplicitInitList(const InitializedEntity &Entity,
                         StructuredSubobjectInitList,
                         StructuredSubobjectInitIndex);
   unsigned EndIndex = (Index == StartIndex? StartIndex : Index - 1);
-  StructuredSubobjectInitList->setType(T);
-
-  // Update the structured sub-object initializer so that it's ending
-  // range corresponds with the end of the last initializer it used.
-  if (EndIndex < ParentIList->getNumInits()) {
-    SourceLocation EndLoc
-      = ParentIList->getInit(EndIndex)->getSourceRange().getEnd();
-    StructuredSubobjectInitList->setRBraceLoc(EndLoc);
-  }
-
-  // Warn about missing braces.
-  if (T->isArrayType() || T->isRecordType()) {
-    SemaRef.Diag(StructuredSubobjectInitList->getLocStart(),
-                 diag::warn_missing_braces)
-    << StructuredSubobjectInitList->getSourceRange()
-    << FixItHint::CreateInsertion(StructuredSubobjectInitList->getLocStart(),
-                                  "{")
-    << FixItHint::CreateInsertion(SemaRef.PP.getLocForEndOfToken(
+  if (!VerifyOnly) {
+    StructuredSubobjectInitList->setType(T);
+
+    // Update the structured sub-object initializer so that it's ending
+    // range corresponds with the end of the last initializer it used.
+    if (EndIndex < ParentIList->getNumInits()) {
+      SourceLocation EndLoc
+        = ParentIList->getInit(EndIndex)->getSourceRange().getEnd();
+      StructuredSubobjectInitList->setRBraceLoc(EndLoc);
+    }
+
+    // Warn about missing braces.
+    if (T->isArrayType() || T->isRecordType()) {
+      SemaRef.Diag(StructuredSubobjectInitList->getLocStart(),
+                   diag::warn_missing_braces)
+        << StructuredSubobjectInitList->getSourceRange()
+        << FixItHint::CreateInsertion(
+              StructuredSubobjectInitList->getLocStart(), "{")
+        << FixItHint::CreateInsertion(
+              SemaRef.PP.getLocForEndOfToken(
                                       StructuredSubobjectInitList->getLocEnd()),
-                                  "}");
+              "}");
+    }
   }
 }
 
@@ -565,18 +571,31 @@ void InitListChecker::CheckExplicitInitList(const InitializedEntity &Entity,
                                             unsigned &StructuredIndex,
                                             bool TopLevelObject) {
   assert(IList->isExplicit() && "Illegal Implicit InitListExpr");
-  SyntacticToSemantic[IList] = StructuredList;
-  StructuredList->setSyntacticForm(IList);
+  if (!VerifyOnly) {
+    SyntacticToSemantic[IList] = StructuredList;
+    StructuredList->setSyntacticForm(IList);
+  }
   CheckListElementTypes(Entity, IList, T, /*SubobjectIsDesignatorContext=*/true,
                         Index, StructuredList, StructuredIndex, TopLevelObject);
-  QualType ExprTy = T.getNonLValueExprType(SemaRef.Context);
-  IList->setType(ExprTy);
-  StructuredList->setType(ExprTy);
+  if (!VerifyOnly) {
+    QualType ExprTy = T.getNonLValueExprType(SemaRef.Context);
+    IList->setType(ExprTy);
+    StructuredList->setType(ExprTy);
+  }
   if (hadError)
     return;
 
   if (Index < IList->getNumInits()) {
     // We have leftover initializers
+    if (VerifyOnly) {
+      if (SemaRef.getLangOptions().CPlusPlus ||
+          (SemaRef.getLangOptions().OpenCL &&
+           IList->getType()->isVectorType())) {
+        hadError = true;
+      }
+      return;
+    }
+
     if (StructuredIndex == 1 &&
         IsStringInit(StructuredList->getInit(0), T, SemaRef.Context)) {
       unsigned DK = diag::warn_excess_initializers_in_char_array_initializer;
@@ -613,7 +632,8 @@ void InitListChecker::CheckExplicitInitList(const InitializedEntity &Entity,
     }
   }
 
-  if (T->isScalarType() && IList->getNumInits() == 1 && !TopLevelObject)
+  if (!VerifyOnly && T->isScalarType() && IList->getNumInits() == 1 &&
+      !TopLevelObject)
     SemaRef.Diag(IList->getLocStart(), diag::warn_braces_around_scalar_init)
       << IList->getSourceRange()
       << FixItHint::CreateRemoval(IList->getLocStart())
@@ -658,8 +678,9 @@ void InitListChecker::CheckListElementTypes(const InitializedEntity &Entity,
   } else if (DeclType->isVoidType() || DeclType->isFunctionType()) {
     // This type is invalid, issue a diagnostic.
     ++Index;
-    SemaRef.Diag(IList->getLocStart(), diag::err_illegal_initializer_type)
-      << DeclType;
+    if (!VerifyOnly)
+      SemaRef.Diag(IList->getLocStart(), diag::err_illegal_initializer_type)
+        << DeclType;
     hadError = true;
   } else if (DeclType->isRecordType()) {
     // C++ [dcl.init]p14:
@@ -670,19 +691,22 @@ void InitListChecker::CheckListElementTypes(const InitializedEntity &Entity,
     // we have an initializer list and a destination type that is not
     // an aggregate.
     // FIXME: In C++0x, this is yet another form of initialization.
-    SemaRef.Diag(IList->getLocStart(), diag::err_init_non_aggr_init_list)
-      << DeclType << IList->getSourceRange();
+    if (!VerifyOnly)
+      SemaRef.Diag(IList->getLocStart(), diag::err_init_non_aggr_init_list)
+        << DeclType << IList->getSourceRange();
     hadError = true;
   } else if (DeclType->isReferenceType()) {
     CheckReferenceType(Entity, IList, DeclType, Index,
                        StructuredList, StructuredIndex);
   } else if (DeclType->isObjCObjectType()) {
-    SemaRef.Diag(IList->getLocStart(), diag::err_init_objc_class)
-      << DeclType;
+    if (!VerifyOnly)
+      SemaRef.Diag(IList->getLocStart(), diag::err_init_objc_class)
+        << DeclType;
     hadError = true;
   } else {
-    SemaRef.Diag(IList->getLocStart(), diag::err_illegal_initializer_type)
-      << DeclType;
+    if (!VerifyOnly)
+      SemaRef.Diag(IList->getLocStart(), diag::err_illegal_initializer_type)
+        << DeclType;
     hadError = true;
   }
 }
@@ -741,13 +765,15 @@ void InitListChecker::CheckSubElementType(const InitializedEntity &Entity,
     InitializationSequence Seq(SemaRef, Entity, Kind, &expr, 1);
 
     if (Seq) {
-      ExprResult Result =
-        Seq.Perform(SemaRef, Entity, Kind, MultiExprArg(&expr, 1));
-      if (Result.isInvalid())
-        hadError = true;
-
-      UpdateStructuredListElement(StructuredList, StructuredIndex,
-                                  Result.takeAs<Expr>());
+      if (!VerifyOnly) {
+        ExprResult Result =
+          Seq.Perform(SemaRef, Entity, Kind, MultiExprArg(&expr, 1));
+        if (Result.isInvalid())
+          hadError = true;
+
+        UpdateStructuredListElement(StructuredList, StructuredIndex,
+                                    Result.takeAs<Expr>());
+      }
       ++Index;
       return;
     }
@@ -764,7 +790,8 @@ void InitListChecker::CheckSubElementType(const InitializedEntity &Entity,
     //   that of the expression.
     ExprResult ExprRes = SemaRef.Owned(expr);
     if ((ElemType->isRecordType() || ElemType->isVectorType()) &&
-        SemaRef.CheckSingleAssignmentConstraints(ElemType, ExprRes)
+        SemaRef.CheckSingleAssignmentConstraints(ElemType, ExprRes,
+                                                 !VerifyOnly)
           == Sema::Compatible) {
       if (ExprRes.isInvalid())
         hadError = true;
@@ -794,11 +821,13 @@ void InitListChecker::CheckSubElementType(const InitializedEntity &Entity,
                           StructuredIndex);
     ++StructuredIndex;
   } else {
-    // We cannot initialize this element, so let
-    // PerformCopyInitialization produce the appropriate diagnostic.
-    SemaRef.PerformCopyInitialization(Entity, SourceLocation(),
-                                      SemaRef.Owned(expr),
-                                      /*TopLevelOfInitList=*/true);
+    if (!VerifyOnly) {
+      // We cannot initialize this element, so let
+      // PerformCopyInitialization produce the appropriate diagnostic.
+      SemaRef.PerformCopyInitialization(Entity, SourceLocation(),
+                                        SemaRef.Owned(expr),
+                                        /*TopLevelOfInitList=*/true);
+    }
     hadError = true;
     ++Index;
     ++StructuredIndex;
@@ -825,7 +854,7 @@ void InitListChecker::CheckComplexType(const InitializedEntity &Entity,
 
   // This is an extension in C.  (The builtin _Complex type does not exist
   // in the C++ standard.)
-  if (!SemaRef.getLangOptions().CPlusPlus)
+  if (!SemaRef.getLangOptions().CPlusPlus && !VerifyOnly)
     SemaRef.Diag(IList->getLocStart(), diag::ext_complex_component_init)
       << IList->getSourceRange();
 
@@ -848,8 +877,10 @@ void InitListChecker::CheckScalarType(const InitializedEntity &Entity,
                                       InitListExpr *StructuredList,
                                       unsigned &StructuredIndex) {
   if (Index >= IList->getNumInits()) {
-    SemaRef.Diag(IList->getLocStart(), diag::err_empty_scalar_initializer)
-      << IList->getSourceRange();
+    // FIXME: Allowed in C++11.
+    if (!VerifyOnly)
+      SemaRef.Diag(IList->getLocStart(), diag::err_empty_scalar_initializer)
+        << IList->getSourceRange();
     hadError = true;
     ++Index;
     ++StructuredIndex;
@@ -858,23 +889,32 @@ void InitListChecker::CheckScalarType(const InitializedEntity &Entity,
 
   Expr *expr = IList->getInit(Index);
   if (InitListExpr *SubIList = dyn_cast<InitListExpr>(expr)) {
-    SemaRef.Diag(SubIList->getLocStart(),
-                 diag::warn_many_braces_around_scalar_init)
-      << SubIList->getSourceRange();
+    if (!VerifyOnly)
+      SemaRef.Diag(SubIList->getLocStart(),
+                   diag::warn_many_braces_around_scalar_init)
+        << SubIList->getSourceRange();
 
     CheckScalarType(Entity, SubIList, DeclType, Index, StructuredList,
                     StructuredIndex);
     return;
   } else if (isa<DesignatedInitExpr>(expr)) {
-    SemaRef.Diag(expr->getSourceRange().getBegin(),
-                 diag::err_designator_for_scalar_init)
-      << DeclType << expr->getSourceRange();
+    if (!VerifyOnly)
+      SemaRef.Diag(expr->getSourceRange().getBegin(),
+                   diag::err_designator_for_scalar_init)
+        << DeclType << expr->getSourceRange();
     hadError = true;
     ++Index;
     ++StructuredIndex;
     return;
   }
 
+  if (VerifyOnly) {
+    if (!SemaRef.CanPerformCopyInitialization(Entity, SemaRef.Owned(expr)))
+      hadError = true;
+    ++Index;
+    return;
+  }
+
   ExprResult Result =
     SemaRef.PerformCopyInitialization(Entity, expr->getLocStart(),
                                       SemaRef.Owned(expr),
@@ -904,47 +944,57 @@ void InitListChecker::CheckReferenceType(const InitializedEntity &Entity,
                                          unsigned &Index,
                                          InitListExpr *StructuredList,
                                          unsigned &StructuredIndex) {
-  if (Index < IList->getNumInits()) {
-    Expr *expr = IList->getInit(Index);
-    if (isa<InitListExpr>(expr)) {
-      SemaRef.Diag(IList->getLocStart(), diag::err_init_non_aggr_init_list)
-        << DeclType << IList->getSourceRange();
-      hadError = true;
-      ++Index;
-      ++StructuredIndex;
-      return;
-    }
-
-    ExprResult Result =
-      SemaRef.PerformCopyInitialization(Entity, expr->getLocStart(),
-                                        SemaRef.Owned(expr),
-                                        /*TopLevelOfInitList=*/true);
-
-    if (Result.isInvalid())
-      hadError = true;
-
-    expr = Result.takeAs<Expr>();
-    IList->setInit(Index, expr);
-
-    if (hadError)
-      ++StructuredIndex;
-    else
-      UpdateStructuredListElement(StructuredList, StructuredIndex, expr);
-    ++Index;
-  } else {
+  if (Index >= IList->getNumInits()) {
     // FIXME: It would be wonderful if we could point at the actual member. In
     // general, it would be useful to pass location information down the stack,
     // so that we know the location (or decl) of the "current object" being
     // initialized.
-    SemaRef.Diag(IList->getLocStart(),
-                  diag::err_init_reference_member_uninitialized)
-      << DeclType
-      << IList->getSourceRange();
+    if (!VerifyOnly)
+      SemaRef.Diag(IList->getLocStart(),
+                    diag::err_init_reference_member_uninitialized)
+        << DeclType
+        << IList->getSourceRange();
     hadError = true;
     ++Index;
     ++StructuredIndex;
     return;
   }
+
+  Expr *expr = IList->getInit(Index);
+  if (isa<InitListExpr>(expr)) {
+    // FIXME: Allowed in C++11.
+    if (!VerifyOnly)
+      SemaRef.Diag(IList->getLocStart(), diag::err_init_non_aggr_init_list)
+        << DeclType << IList->getSourceRange();
+    hadError = true;
+    ++Index;
+    ++StructuredIndex;
+    return;
+  }
+
+  if (VerifyOnly) {
+    if (!SemaRef.CanPerformCopyInitialization(Entity, SemaRef.Owned(expr)))
+      hadError = true;
+    ++Index;
+    return;
+  }
+
+  ExprResult Result =
+    SemaRef.PerformCopyInitialization(Entity, expr->getLocStart(),
+                                      SemaRef.Owned(expr),
+                                      /*TopLevelOfInitList=*/true);
+
+  if (Result.isInvalid())
+    hadError = true;
+
+  expr = Result.takeAs<Expr>();
+  IList->setInit(Index, expr);
+
+  if (hadError)
+    ++StructuredIndex;
+  else
+    UpdateStructuredListElement(StructuredList, StructuredIndex, expr);
+  ++Index;
 }
 
 void InitListChecker::CheckVectorType(const InitializedEntity &Entity,
@@ -965,6 +1015,13 @@ void InitListChecker::CheckVectorType(const InitializedEntity &Entity,
     // instead of breaking it apart (which is doomed to failure anyway).
     Expr *Init = IList->getInit(Index);
     if (!isa<InitListExpr>(Init) && Init->getType()->isVectorType()) {
+      if (VerifyOnly) {
+        if (!SemaRef.CanPerformCopyInitialization(Entity, SemaRef.Owned(Init)))
+          hadError = true;
+        ++Index;
+        return;
+      }
+
       ExprResult Result =
         SemaRef.PerformCopyInitialization(Entity, Init->getLocStart(),
                                           SemaRef.Owned(Init),
@@ -984,7 +1041,8 @@ void InitListChecker::CheckVectorType(const InitializedEntity &Entity,
       if (hadError)
         ++StructuredIndex;
       else
-        UpdateStructuredListElement(StructuredList, StructuredIndex, ResultExpr);
+        UpdateStructuredListElement(StructuredList, StructuredIndex,
+                                    ResultExpr);
       ++Index;
       return;
     }
@@ -1037,11 +1095,11 @@ void InitListChecker::CheckVectorType(const InitializedEntity &Entity,
   }
 
   // OpenCL requires all elements to be initialized.
-  if (numEltsInit != maxElements)
-    if (SemaRef.getLangOptions().OpenCL)
-      SemaRef.Diag(IList->getSourceRange().getBegin(),
-                   diag::err_vector_incorrect_num_initializers)
-        << (numEltsInit < maxElements) << maxElements << numEltsInit;
+  // FIXME: Shouldn't this set hadError to true then?
+  if (numEltsInit != maxElements && !VerifyOnly)
+    SemaRef.Diag(IList->getSourceRange().getBegin(),
+                 diag::err_vector_incorrect_num_initializers)
+      << (numEltsInit < maxElements) << maxElements << numEltsInit;
 }
 
 void InitListChecker::CheckArrayType(const InitializedEntity &Entity,
@@ -1063,8 +1121,10 @@ void InitListChecker::CheckArrayType(const InitializedEntity &Entity,
       // of the structured initializer list doesn't match exactly,
       // because doing so would involve allocating one character
       // constant for each string.
-      UpdateStructuredListElement(StructuredList, StructuredIndex, Str);
-      StructuredList->resizeInits(SemaRef.Context, StructuredIndex);
+      if (!VerifyOnly) {
+        UpdateStructuredListElement(StructuredList, StructuredIndex, Str);
+        StructuredList->resizeInits(SemaRef.Context, StructuredIndex);
+      }
       ++Index;
       return;
     }
@@ -1073,9 +1133,10 @@ void InitListChecker::CheckArrayType(const InitializedEntity &Entity,
     // Check for VLAs; in standard C it would be possible to check this
     // earlier, but I don't know where clang accepts VLAs (gcc accepts
     // them in all sorts of strange places).
-    SemaRef.Diag(VAT->getSizeExpr()->getLocStart(),
-                  diag::err_variable_object_no_init)
-      << VAT->getSizeExpr()->getSourceRange();
+    if (!VerifyOnly)
+      SemaRef.Diag(VAT->getSizeExpr()->getLocStart(),
+                    diag::err_variable_object_no_init)
+        << VAT->getSizeExpr()->getSourceRange();
     hadError = true;
     ++Index;
     ++StructuredIndex;
@@ -1145,7 +1206,7 @@ void InitListChecker::CheckArrayType(const InitializedEntity &Entity,
     if (!maxElementsKnown && elementIndex > maxElements)
       maxElements = elementIndex;
   }
-  if (!hadError && DeclType->isIncompleteArrayType()) {
+  if (!hadError && DeclType->isIncompleteArrayType() && !VerifyOnly) {
     // If this is an incomplete array type, the actual type needs to
     // be calculated here.
     llvm::APSInt Zero(maxElements.getBitWidth(), maxElements.isUnsigned());
@@ -1188,12 +1249,14 @@ bool InitListChecker::CheckFlexibleArrayInit(const InitializedEntity &Entity,
     // Allow other cases.
     FlexArrayDiag = diag::ext_flexible_array_init;
   }
-  
-  SemaRef.Diag(InitExpr->getSourceRange().getBegin(),
-               FlexArrayDiag)
-    << InitExpr->getSourceRange().getBegin();
-  SemaRef.Diag(Field->getLocation(), diag::note_flexible_array_member)
-    << Field;
+
+  if (!VerifyOnly) {
+    SemaRef.Diag(InitExpr->getSourceRange().getBegin(),
+                 FlexArrayDiag)
+      << InitExpr->getSourceRange().getBegin();
+    SemaRef.Diag(Field->getLocation(), diag::note_flexible_array_member)
+      << Field;
+  }
 
   return FlexArrayDiag != diag::ext_flexible_array_init;
 }
@@ -1217,13 +1280,15 @@ void InitListChecker::CheckStructUnionTypes(const InitializedEntity &Entity,
   }
 
   if (DeclType->isUnionType() && IList->getNumInits() == 0) {
-    // Value-initialize the first named member of the union.
-    RecordDecl *RD = DeclType->getAs<RecordType>()->getDecl();
-    for (RecordDecl::field_iterator FieldEnd = RD->field_end();
-         Field != FieldEnd; ++Field) {
-      if (Field->getDeclName()) {
-        StructuredList->setInitializedFieldInUnion(*Field);
-        break;
+    if (!VerifyOnly) {
+      // Value-initialize the first named member of the union.
+      RecordDecl *RD = DeclType->getAs<RecordType>()->getDecl();
+      for (RecordDecl::field_iterator FieldEnd = RD->field_end();
+           Field != FieldEnd; ++Field) {
+        if (Field->getDeclName()) {
+          StructuredList->setInitializedFieldInUnion(*Field);
+          break;
+        }
       }
     }
     return;
@@ -1283,13 +1348,18 @@ void InitListChecker::CheckStructUnionTypes(const InitializedEntity &Entity,
     }
 
     // Make sure we can use this declaration.
-    if (SemaRef.DiagnoseUseOfDecl(*Field, 
-                                  IList->getInit(Index)->getLocStart())) {
+    bool InvalidUse;
+    if (VerifyOnly)
+      InvalidUse = !SemaRef.CanUseDecl(*Field);
+    else
+      InvalidUse = SemaRef.DiagnoseUseOfDecl(*Field,
+                                          IList->getInit(Index)->getLocStart());
+    if (InvalidUse) {
       ++Index;
       ++Field;
       hadError = true;
       continue;
-    }        
+    }
 
     InitializedEntity MemberEntity =
       InitializedEntity::InitializeMember(*Field, &Entity);
@@ -1297,7 +1367,7 @@ void InitListChecker::CheckStructUnionTypes(const InitializedEntity &Entity,
                         StructuredList, StructuredIndex);
     InitializedSomething = true;
 
-    if (DeclType->isUnionType()) {
+    if (DeclType->isUnionType() && !VerifyOnly) {
       // Initialize the first field within the union.
       StructuredList->setInitializedFieldInUnion(*Field);
     }
@@ -1306,8 +1376,9 @@ void InitListChecker::CheckStructUnionTypes(const InitializedEntity &Entity,
   }
 
   // Emit warnings for missing struct field initializers.
-  if (InitializedSomething && CheckForMissingFields && Field != FieldEnd &&
-      !Field->getType()->isIncompleteArrayType() && !DeclType->isUnionType()) {
+  if (!VerifyOnly && InitializedSomething && CheckForMissingFields &&
+      Field != FieldEnd && !Field->getType()->isIncompleteArrayType() &&
+      !DeclType->isUnionType()) {
     // It is possible we have one or more unnamed bitfields remaining.
     // Find first (if any) named field and emit warning.
     for (RecordDecl::field_iterator it = Field, end = RD->field_end();
@@ -1388,6 +1459,18 @@ static IndirectFieldDecl *FindIndirectFieldDesignator(FieldDecl *AnonField,
   return 0;
 }
 
+static DesignatedInitExpr *CloneDesignatedInitExpr(Sema &SemaRef,
+                                                   DesignatedInitExpr *DIE) {
+  unsigned NumIndexExprs = DIE->getNumSubExprs() - 1;
+  SmallVector<Expr*, 4> IndexExprs(NumIndexExprs);
+  for (unsigned I = 0; I < NumIndexExprs; ++I)
+    IndexExprs[I] = DIE->getSubExpr(I + 1);
+  return DesignatedInitExpr::Create(SemaRef.Context, DIE->designators_begin(),
+                                    DIE->size(), IndexExprs.data(),
+                                    NumIndexExprs, DIE->getEqualOrColonLoc(),
+                                    DIE->usesGNUSyntax(), DIE->getInit());
+}
+
 /// @brief Check the well-formedness of a C99 designated initializer.
 ///
 /// Determines whether the designated initializer @p DIE, which
@@ -1426,14 +1509,14 @@ static IndirectFieldDecl *FindIndirectFieldDesignator(FieldDecl *AnonField,
 bool
 InitListChecker::CheckDesignatedInitializer(const InitializedEntity &Entity,
                                             InitListExpr *IList,
-                                      DesignatedInitExpr *DIE,
-                                      unsigned DesigIdx,
-                                      QualType &CurrentObjectType,
-                                      RecordDecl::field_iterator *NextField,
-                                      llvm::APSInt *NextElementIndex,
-                                      unsigned &Index,
-                                      InitListExpr *StructuredList,
-                                      unsigned &StructuredIndex,
+                                            DesignatedInitExpr *DIE,
+                                            unsigned DesigIdx,
+                                            QualType &CurrentObjectType,
+                                          RecordDecl::field_iterator *NextField,
+                                            llvm::APSInt *NextElementIndex,
+                                            unsigned &Index,
+                                            InitListExpr *StructuredList,
+                                            unsigned &StructuredIndex,
                                             bool FinishSubobjectInit,
                                             bool TopLevelObject) {
   if (DesigIdx == DIE->size()) {
@@ -1458,19 +1541,21 @@ InitListChecker::CheckDesignatedInitializer(const InitializedEntity &Entity,
     return hadError && !prevHadError;
   }
 
-  bool IsFirstDesignator = (DesigIdx == 0);
-  assert((IsFirstDesignator || StructuredList) &&
-         "Need a non-designated initializer list to start from");
-
   DesignatedInitExpr::Designator *D = DIE->getDesignator(DesigIdx);
-  // Determine the structural initializer list that corresponds to the
-  // current subobject.
-  StructuredList = IsFirstDesignator? SyntacticToSemantic[IList]
-    : getStructuredSubobjectInit(IList, Index, CurrentObjectType,
-                                 StructuredList, StructuredIndex,
-                                 SourceRange(D->getStartLocation(),
-                                             DIE->getSourceRange().getEnd()));
-  assert(StructuredList && "Expected a structured initializer list");
+  bool IsFirstDesignator = (DesigIdx == 0);
+  if (!VerifyOnly) {
+    assert((IsFirstDesignator || StructuredList) &&
+           "Need a non-designated initializer list to start from");
+
+    // Determine the structural initializer list that corresponds to the
+    // current subobject.
+    StructuredList = IsFirstDesignator? SyntacticToSemantic[IList]
+      : getStructuredSubobjectInit(IList, Index, CurrentObjectType,
+                                   StructuredList, StructuredIndex,
+                                   SourceRange(D->getStartLocation(),
+                                               DIE->getSourceRange().getEnd()));
+    assert(StructuredList && "Expected a structured initializer list");
+  }
 
   if (D->isFieldDesignator()) {
     // C99 6.7.8p7:
@@ -1487,8 +1572,9 @@ InitListChecker::CheckDesignatedInitializer(const InitializedEntity &Entity,
       SourceLocation Loc = D->getDotLoc();
       if (Loc.isInvalid())
         Loc = D->getFieldLoc();
-      SemaRef.Diag(Loc, diag::err_field_designator_non_aggr)
-        << SemaRef.getLangOptions().CPlusPlus << CurrentObjectType;
+      if (!VerifyOnly)
+        SemaRef.Diag(Loc, diag::err_field_designator_non_aggr)
+          << SemaRef.getLangOptions().CPlusPlus << CurrentObjectType;
       ++Index;
       return true;
     }
@@ -1511,6 +1597,9 @@ InitListChecker::CheckDesignatedInitializer(const InitializedEntity &Entity,
       if (!KnownField && Field->isAnonymousStructOrUnion()) {
         if (IndirectFieldDecl *IF =
             FindIndirectFieldDesignator(*Field, FieldName)) {
+          // In verify mode, don't modify the original.
+          if (VerifyOnly)
+            DIE = CloneDesignatedInitExpr(SemaRef, DIE);
           ExpandAnonymousFieldDesignator(SemaRef, DIE, DesigIdx, IF);
           D = DIE->getDesignator(DesigIdx);
           break;
@@ -1525,6 +1614,9 @@ InitListChecker::CheckDesignatedInitializer(const InitializedEntity &Entity,
     }
 
     if (Field == FieldEnd) {
+      if (VerifyOnly)
+        return true; // No typo correction when just trying this out.
+
       // There was no normal field in the struct with the designated
       // name. Perform another lookup for this name, which may find
       // something that we can't designate (e.g., a member function),
@@ -1594,22 +1686,30 @@ InitListChecker::CheckDesignatedInitializer(const InitializedEntity &Entity,
     // the initializer list.
     if (RT->getDecl()->isUnion()) {
       FieldIndex = 0;
-      StructuredList->setInitializedFieldInUnion(*Field);
+      if (!VerifyOnly)
+        StructuredList->setInitializedFieldInUnion(*Field);
     }
 
     // Make sure we can use this declaration.
-    if (SemaRef.DiagnoseUseOfDecl(*Field, D->getFieldLoc())) {
+    bool InvalidUse;
+    if (VerifyOnly)
+      InvalidUse = !SemaRef.CanUseDecl(*Field);
+    else
+      InvalidUse = SemaRef.DiagnoseUseOfDecl(*Field, D->getFieldLoc());
+    if (InvalidUse) {
       ++Index;
       return true;
-    }        
+    }
 
-    // Update the designator with the field declaration.
-    D->setField(*Field);
+    if (!VerifyOnly) {
+      // Update the designator with the field declaration.
+      D->setField(*Field);
 
-    // Make sure that our non-designated initializer list has space
-    // for a subobject corresponding to this field.
-    if (FieldIndex >= StructuredList->getNumInits())
-      StructuredList->resizeInits(SemaRef.Context, FieldIndex + 1);
+      // Make sure that our non-designated initializer list has space
+      // for a subobject corresponding to this field.
+      if (FieldIndex >= Str