Don't perform template argument deduction against invalid templates;

it's likely to lead to a crash later on. Fixes PR12933 /
<rdar://problem/11525335>.

llvm-svn: 163838

clang/include/clang/Sema/Sema.h

@@ -5280,6 +5280,8 @@ public:
   enum TemplateDeductionResult {
     /// \brief Template argument deduction was successful.
     TDK_Success = 0,
+    /// \brief The declaration was invalid; do nothing.
+    TDK_Invalid,
     /// \brief Template argument deduction exceeded the maximum template
     /// instantiation depth (which has already been diagnosed).
     TDK_InstantiationDepth,

clang/lib/Sema/SemaOverload.cpp

@@ -555,6 +555,7 @@ static MakeDeductionFailureInfo(ASTContext &Context,
   Result.Data = 0;
   switch (TDK) {
   case Sema::TDK_Success:
+  case Sema::TDK_Invalid:
   case Sema::TDK_InstantiationDepth:
   case Sema::TDK_TooManyArguments:
   case Sema::TDK_TooFewArguments:
@@ -597,6 +598,7 @@ static MakeDeductionFailureInfo(ASTContext &Context,
 void OverloadCandidate::DeductionFailureInfo::Destroy() {
   switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
   case Sema::TDK_Success:
+  case Sema::TDK_Invalid:
   case Sema::TDK_InstantiationDepth:
   case Sema::TDK_Incomplete:
   case Sema::TDK_TooManyArguments:
@@ -637,6 +639,7 @@ TemplateParameter
 OverloadCandidate::DeductionFailureInfo::getTemplateParameter() {
   switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
   case Sema::TDK_Success:
+  case Sema::TDK_Invalid:
   case Sema::TDK_InstantiationDepth:
   case Sema::TDK_TooManyArguments:
   case Sema::TDK_TooFewArguments:
@@ -664,6 +667,7 @@ TemplateArgumentList *
 OverloadCandidate::DeductionFailureInfo::getTemplateArgumentList() {
   switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
     case Sema::TDK_Success:
+    case Sema::TDK_Invalid:
     case Sema::TDK_InstantiationDepth:
     case Sema::TDK_TooManyArguments:
     case Sema::TDK_TooFewArguments:
@@ -688,6 +692,7 @@ OverloadCandidate::DeductionFailureInfo::getTemplateArgumentList() {
 const TemplateArgument *OverloadCandidate::DeductionFailureInfo::getFirstArg() {
   switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
   case Sema::TDK_Success:
+  case Sema::TDK_Invalid:
   case Sema::TDK_InstantiationDepth:
   case Sema::TDK_Incomplete:
   case Sema::TDK_TooManyArguments:
@@ -713,6 +718,7 @@ const TemplateArgument *
 OverloadCandidate::DeductionFailureInfo::getSecondArg() {
   switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
   case Sema::TDK_Success:
+  case Sema::TDK_Invalid:
   case Sema::TDK_InstantiationDepth:
   case Sema::TDK_Incomplete:
   case Sema::TDK_TooManyArguments:
@@ -8555,6 +8561,7 @@ RankDeductionFailure(const OverloadCandidate::DeductionFailureInfo &DFI) {
   case Sema::TDK_Success:
     llvm_unreachable("TDK_success while diagnosing bad deduction");
 
+  case Sema::TDK_Invalid:
   case Sema::TDK_Incomplete:
     return 1;
 

clang/lib/Sema/SemaTemplateDeduction.cpp

@@ -2165,6 +2165,9 @@ Sema::TemplateDeductionResult
 Sema::DeduceTemplateArguments(ClassTemplatePartialSpecializationDecl *Partial,
                               const TemplateArgumentList &TemplateArgs,
                               TemplateDeductionInfo &Info) {
+  if (Partial->isInvalidDecl())
+    return TDK_Invalid;
+
   // C++ [temp.class.spec.match]p2:
   //   A partial specialization matches a given actual template
   //   argument list if the template arguments of the partial
@@ -3015,6 +3018,9 @@ Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate,
                               llvm::ArrayRef<Expr *> Args,
                               FunctionDecl *&Specialization,
                               TemplateDeductionInfo &Info) {
+  if (FunctionTemplate->isInvalidDecl())
+    return TDK_Invalid;
+
   FunctionDecl *Function = FunctionTemplate->getTemplatedDecl();
 
   // C++ [temp.deduct.call]p1:
@@ -3271,6 +3277,9 @@ Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate,
                               QualType ArgFunctionType,
                               FunctionDecl *&Specialization,
                               TemplateDeductionInfo &Info) {
+  if (FunctionTemplate->isInvalidDecl())
+    return TDK_Invalid;
+
   FunctionDecl *Function = FunctionTemplate->getTemplatedDecl();
   TemplateParameterList *TemplateParams
     = FunctionTemplate->getTemplateParameters();
@@ -3330,6 +3339,9 @@ Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate,
                               QualType ToType,
                               CXXConversionDecl *&Specialization,
                               TemplateDeductionInfo &Info) {
+  if (FunctionTemplate->isInvalidDecl())
+    return TDK_Invalid;
+
   CXXConversionDecl *Conv
     = cast<CXXConversionDecl>(FunctionTemplate->getTemplatedDecl());
   QualType FromType = Conv->getConversionType();

clang/test/SemaTemplate/deduction-crash.cpp

@@ -2,7 +2,7 @@
 
 // Note that the error count below doesn't matter. We just want to
 // make sure that the parser doesn't crash.
-// CHECK: 13 errors
+// CHECK: 15 errors
 
 // PR7511
 template<a>
@@ -87,3 +87,15 @@ void register_object_imp ( )
 {
 cout << endl<1>;
 }
+
+// PR12933
+namespacae PR12933 {
+  template<typename S>
+    template<typename T>
+    void function(S a, T b) {}
+
+  int main() {
+    function(0, 1);
+    return 0;
+  }
+}