Index: clang-tools-extra/trunk/clang-tidy/readability/IdentifierNamingCheck.cpp
===================================================================
--- clang-tools-extra/trunk/clang-tidy/readability/IdentifierNamingCheck.cpp
+++ clang-tools-extra/trunk/clang-tidy/readability/IdentifierNamingCheck.cpp
@@ -800,10 +800,11 @@
 
     // Fix type aliases in value declarations
     if (const auto *Value = Result.Nodes.getNodeAs<ValueDecl>("decl")) {
-      if (const auto *Typedef =
-              Value->getType().getTypePtr()->getAs<TypedefType>()) {
-        addUsage(NamingCheckFailures, Typedef->getDecl(),
-                 Value->getSourceRange());
+      if (const auto *TypePtr = Value->getType().getTypePtrOrNull()) {
+        if (const auto *Typedef = TypePtr->getAs<TypedefType>()) {
+          addUsage(NamingCheckFailures, Typedef->getDecl(),
+                   Value->getSourceRange());
+        }
       }
     }
 
Index: clang-tools-extra/trunk/test/clang-tidy/readability-identifier-naming-bugfix.cpp
===================================================================
--- clang-tools-extra/trunk/test/clang-tidy/readability-identifier-naming-bugfix.cpp
+++ clang-tools-extra/trunk/test/clang-tidy/readability-identifier-naming-bugfix.cpp
@@ -0,0 +1,5 @@
+// RUN: %check_clang_tidy -expect-clang-tidy-error %s readability-identifier-naming %t
+
+// This used to cause a null pointer dereference.
+auto [left] = right;
+// CHECK-MESSAGES: :[[@LINE-1]]:15: error: use of undeclared identifier 'right'