Index: clang/lib/AST/Expr.cpp
===================================================================
--- clang/lib/AST/Expr.cpp
+++ clang/lib/AST/Expr.cpp
@@ -3812,6 +3812,11 @@
       return Source->isNullPointerConstant(Ctx, NPC);
   }
 
+  // If the expression has no type information, it cannot be a null pointer
+  // constant.
+  if (getType().isNull())
+    return NPCK_NotNull;
+
   // C++11 nullptr_t is always a null pointer constant.
   if (getType()->isNullPtrType())
     return NPCK_CXX11_nullptr;
Index: clang/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp
===================================================================
--- clang/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp
+++ clang/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp
@@ -2608,6 +2608,14 @@
   EXPECT_TRUE(matches("char *cp = (char *)0;", expr(nullPointerConstant())));
   EXPECT_TRUE(matches("int *ip = 0;", expr(nullPointerConstant())));
   EXPECT_TRUE(matches("int i = 0;", expr(nullPointerConstant())));
+  const char kTest[] = R"(
+    template <typename T>
+    struct MyTemplate {
+      MyTemplate() : field_(__null) {}
+      T* field_;
+    };
+  )";
+  EXPECT_TRUE(matches(kTest, expr(nullPointerConstant())));
 }
 
 TEST(HasExternalFormalLinkage, Basic) {