Fix a crash in diagnostic printing when a template class type is diff'ed

against itself. PR14489.

llvm-svn: 170474

1 files changed, 6 insertions, 1 deletions

diff --git a/clang/lib/AST/ASTDiagnostic.cpp b/clang/lib/AST/ASTDiagnostic.cpp
index 31c1fbf1b78..a61abf7e34c 100644
--- a/clang/lib/AST/ASTDiagnostic.cpp
+++ b/clang/lib/AST/ASTDiagnostic.cpp
@@ -1125,7 +1125,12 @@ class TemplateDiff {
     TemplateDecl *FromTD, *ToTD;
     Tree.GetNode(FromTD, ToTD);
 
-    assert(Tree.HasChildren() && "Template difference not found in diff tree.");
+    if (!Tree.HasChildren()) {
+      // If we're dealing with a template specialization with zero
+      // arguments, there are no children; special-case this.
+      OS << FromTD->getNameAsString() << "<>";
+      return;
+    }
 
     Qualifiers FromQual, ToQual;
     Tree.GetNode(FromQual, ToQual);