Fix a crash on invalid with template handling

This is a fix for https://llvm.org/bugs/show_bug.cgi?id=25561 which was a
crash on invalid.  Change the handling of invalid decls to have a catch-all
case to prevent unexpecting decls from triggering an assertion.

llvm-svn: 265467

1 files changed, 12 insertions, 6 deletions

diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
index 18b739df7f5..fdb7d762d29 100644
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -7277,15 +7277,21 @@ Sema::ActOnExplicitInstantiation(Scope *S,
   assert(Kind != TTK_Enum &&
          "Invalid enum tag in class template explicit instantiation!");
 
-  if (isa<TypeAliasTemplateDecl>(TD)) {
-      Diag(KWLoc, diag::err_tag_reference_non_tag) << Kind;
-      Diag(TD->getTemplatedDecl()->getLocation(),
-           diag::note_previous_use);
+  ClassTemplateDecl *ClassTemplate = dyn_cast<ClassTemplateDecl>(TD);
+
+  if (!ClassTemplate) {
+    unsigned ErrorKind = 0;
+    if (isa<TypeAliasTemplateDecl>(TD)) {
+      ErrorKind = 4;
+    } else if (isa<TemplateTemplateParmDecl>(TD)) {
+      ErrorKind = 5;
+    }
+
+    Diag(TemplateNameLoc, diag::err_tag_reference_non_tag) << ErrorKind;
+    Diag(TD->getLocation(), diag::note_previous_use);
     return true;
   }
 
-  ClassTemplateDecl *ClassTemplate = cast<ClassTemplateDecl>(TD);
-
   if (!isAcceptableTagRedeclaration(ClassTemplate->getTemplatedDecl(),
                                     Kind, /*isDefinition*/false, KWLoc,
                                     ClassTemplate->getIdentifier())) {