Fix crash if substitution fails during deduction of variable template partial specialization arguments.

llvm-svn: 290484

4 files changed, 31 insertions, 23 deletions

diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index da8f532f3a8..5f59a10c1c1 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -4145,9 +4145,9 @@ def note_explicit_template_arg_substitution_here : Note<
 def note_function_template_deduction_instantiation_here : Note<
   "while substituting deduced template arguments into function template %0 "
   "%1">;
-def note_partial_spec_deduct_instantiation_here : Note<
-  "during template argument deduction for class template partial "
-  "specialization %0 %1">;
+def note_deduced_template_arg_substitution_here : Note<
+  "during template argument deduction for %select{class|variable}0 template "
+  "partial specialization %1 %2">;
 def note_prior_template_arg_substitution : Note<
   "while substituting prior template arguments into %select{non-type|template}0"
   " template parameter%1 %2">;
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index 47a5ca621a7..512a667f690 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -6749,7 +6749,7 @@ public:
       /// We are substituting template argument determined as part of
       /// template argument deduction for either a class template
       /// partial specialization or a function template. The
-      /// Entity is either a ClassTemplatePartialSpecializationDecl or
+      /// Entity is either a {Class|Var}TemplatePartialSpecializationDecl or
       /// a FunctionTemplateDecl.
       DeducedTemplateArgumentSubstitution,
 
diff --git a/clang/lib/Sema/SemaTemplateInstantiate.cpp b/clang/lib/Sema/SemaTemplateInstantiate.cpp
index 382c23ce87f..4f2e74740df 100644
--- a/clang/lib/Sema/SemaTemplateInstantiate.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiate.cpp
@@ -484,29 +484,40 @@ void Sema::PrintInstantiationStack() {
       break;
     }
 
-    case ActiveTemplateInstantiation::DeducedTemplateArgumentSubstitution:
-      if (ClassTemplatePartialSpecializationDecl *PartialSpec =
-            dyn_cast<ClassTemplatePartialSpecializationDecl>(Active->Entity)) {
+    case ActiveTemplateInstantiation::DeducedTemplateArgumentSubstitution: {
+      if (FunctionTemplateDecl *FnTmpl =
+              dyn_cast<FunctionTemplateDecl>(Active->Entity)) {
         Diags.Report(Active->PointOfInstantiation,
-                     diag::note_partial_spec_deduct_instantiation_here)
-          << PartialSpec
-          << getTemplateArgumentBindingsText(
-                                         PartialSpec->getTemplateParameters(), 
+                     diag::note_function_template_deduction_instantiation_here)
+          << FnTmpl
+          << getTemplateArgumentBindingsText(FnTmpl->getTemplateParameters(), 
                                              Active->TemplateArgs, 
                                              Active->NumTemplateArgs)
           << Active->InstantiationRange;
       } else {
-        FunctionTemplateDecl *FnTmpl
-          = cast<FunctionTemplateDecl>(Active->Entity);
+        bool IsVar = isa<VarTemplateDecl>(Active->Entity) ||
+                     isa<VarTemplateSpecializationDecl>(Active->Entity);
+        TemplateParameterList *Params;
+        if (auto *D = dyn_cast<ClassTemplatePartialSpecializationDecl>(
+                       Active->Entity)) {
+          Params = D->getTemplateParameters();
+        } else if (auto *D = dyn_cast<VarTemplatePartialSpecializationDecl>(
+                       Active->Entity)) {
+          Params = D->getTemplateParameters();
+        } else {
+          llvm_unreachable("unexpected template kind");
+        }
+
+          //<< Context.getTypeDeclType(PartialSpec)
         Diags.Report(Active->PointOfInstantiation,
-                     diag::note_function_template_deduction_instantiation_here)
-          << FnTmpl
-          << getTemplateArgumentBindingsText(FnTmpl->getTemplateParameters(), 
-                                             Active->TemplateArgs, 
+                     diag::note_deduced_template_arg_substitution_here)
+          << IsVar << cast<NamedDecl>(Active->Entity)
+          << getTemplateArgumentBindingsText(Params, Active->TemplateArgs, 
                                              Active->NumTemplateArgs)
           << Active->InstantiationRange;
       }
       break;
+    }
 
     case ActiveTemplateInstantiation::DefaultFunctionArgumentInstantiation: {
       ParmVarDecl *Param = cast<ParmVarDecl>(Active->Entity);
diff --git a/clang/test/SemaTemplate/deduction.cpp b/clang/test/SemaTemplate/deduction.cpp
index 8cd4331755a..9471bac91c3 100644
--- a/clang/test/SemaTemplate/deduction.cpp
+++ b/clang/test/SemaTemplate/deduction.cpp
@@ -338,16 +338,13 @@ namespace member_pointer {
 }
 
 namespace deduction_substitution_failure {
-  template<typename T> struct Fail { typedef typename T::error error; }; // expected-error {{prior to '::'}}
+  template<typename T> struct Fail { typedef typename T::error error; }; // expected-error 2{{prior to '::'}}
 
   template<typename T, typename U> struct A {};
   template<typename T> struct A<T, typename Fail<T>::error> {}; // expected-note {{instantiation of}}
   A<int, int> ai; // expected-note {{during template argument deduction for class template partial specialization 'A<T, typename Fail<T>::error>' [with T = int]}}
 
-  // FIXME: This tickles an assertion.
-#if 0
   template<typename T, typename U> int B; // expected-warning 0-1 {{extension}}
-  template<typename T> int B<T, typename Fail<T>::error> {};
-  int bi = B<char, char>;
-#endif
+  template<typename T> int B<T, typename Fail<T>::error> {}; // expected-note {{instantiation of}}
+  int bi = B<char, char>; // expected-note {{during template argument deduction for variable template partial specialization 'B<T, typename Fail<T>::error>' [with T = char]}}
 }