Improve recovery in a wonky case where one tries to specialize a

template template parameter.

When building a template-id type, check whether the template-name
itself is dependent (even if the template arguments are not!) and
handle it as a template-id type.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@86913 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 11 insertions, 2 deletions

diff --git a/lib/Sema/SemaTemplate.cpp b/lib/Sema/SemaTemplate.cpp
index 9305d6ebb1..419347adcf 100644
--- a/lib/Sema/SemaTemplate.cpp
+++ b/lib/Sema/SemaTemplate.cpp
@@ -1188,7 +1188,9 @@ QualType Sema::CheckTemplateIdType(TemplateName Name,
 
   if (TemplateSpecializationType::anyDependentTemplateArguments(
                                                       TemplateArgs,
-                                                      NumTemplateArgs)) {
+                                                      NumTemplateArgs) ||
+      isa<TemplateTemplateParmDecl>(Template) || 
+      Template->getDeclContext()->isDependentContext()) {
     // This class template specialization is a dependent
     // type. Therefore, its canonical type is another class template
     // specialization type that contains all of the converted
@@ -2935,7 +2937,14 @@ Sema::ActOnClassTemplateSpecialization(Scope *S, unsigned TagSpec,
   // Find the class template we're specializing
   TemplateName Name = TemplateD.getAsVal<TemplateName>();
   ClassTemplateDecl *ClassTemplate
-    = cast<ClassTemplateDecl>(Name.getAsTemplateDecl());
+    = dyn_cast_or_null<ClassTemplateDecl>(Name.getAsTemplateDecl());
+
+  if (!ClassTemplate) {
+    Diag(TemplateNameLoc, diag::err_not_class_template_specialization)
+      << (Name.getAsTemplateDecl() && 
+          isa<TemplateTemplateParmDecl>(Name.getAsTemplateDecl()));
+    return true;
+  }
 
   bool isExplicitSpecialization = false;
   bool isPartialSpecialization = false;