Index: clang-tidy/readability/IdentifierNamingCheck.cpp
===================================================================
--- clang-tidy/readability/IdentifierNamingCheck.cpp
+++ clang-tidy/readability/IdentifierNamingCheck.cpp
@@ -663,8 +663,9 @@
 
     if (const auto &Ref =
             Loc->getAs<DependentTemplateSpecializationTypeLoc>()) {
-      addUsage(NamingCheckFailures, Ref.getTypePtr()->getAsTagDecl(),
-               Loc->getSourceRange());
+      if (const auto *Decl = Ref.getTypePtr()->getAsTagDecl()) {
+        addUsage(NamingCheckFailures, Decl, Loc->getSourceRange());
+      }
       return;
     }
   }
Index: test/clang-tidy/readability-identifier-naming.cpp
===================================================================
--- test/clang-tidy/readability-identifier-naming.cpp
+++ test/clang-tidy/readability-identifier-naming.cpp
@@ -344,3 +344,7 @@
 // CHECK-FIXES: {{^}}void MY_TEST_MACRO(function) {}
 }
 }
+
+template <typename t_t> struct a {
+  typename t_t::template b<> c;
+};