Index: clang/lib/Format/QualifierAlignmentFixer.cpp
===================================================================
--- clang/lib/Format/QualifierAlignmentFixer.cpp
+++ clang/lib/Format/QualifierAlignmentFixer.cpp
@@ -334,7 +334,8 @@
         Next->Previous->startsSequence(tok::identifier, TT_TemplateOpener)) {
       // Read from to the end of the TemplateOpener to
       // TemplateCloser const ArrayRef<int> a; const ArrayRef<int> &a;
-      assert(Next->MatchingParen && "Missing template closer");
+      if (!Next->MatchingParen)
+        return Next;
       Next = Next->MatchingParen->Next;
 
       // Move to the end of any template class members e.g.
Index: clang/unittests/Format/QualifierFixerTest.cpp
===================================================================
--- clang/unittests/Format/QualifierFixerTest.cpp
+++ clang/unittests/Format/QualifierFixerTest.cpp
@@ -818,5 +818,18 @@
   EXPECT_EQ(ReplacementCount, 0);
 }
 
+TEST_F(QualifierFixerTest, QualifierTemplates) {
+
+  FormatStyle Style = getLLVMStyle();
+  Style.QualifierAlignment = FormatStyle::QAS_Custom;
+  Style.QualifierOrder = {"static", "const", "type"};
+
+  ReplacementCount = 0;
+  EXPECT_EQ(ReplacementCount, 0);
+  verifyFormat("template <class Id> using A = quantity /**/<kind<Id>, 1>;",
+               Style);
+  EXPECT_EQ(ReplacementCount, 0);
+}
+
 } // namespace format
 } // namespace clang