Index: clang/lib/Sema/SemaConcept.cpp
===================================================================
--- clang/lib/Sema/SemaConcept.cpp
+++ clang/lib/Sema/SemaConcept.cpp
@@ -1062,11 +1062,8 @@
   assert(TPL->size() == 1);
   const TypeConstraint *TC =
       cast<TemplateTypeParmDecl>(TPL->getParam(0))->getTypeConstraint();
-  assert(TC &&
-         "TPL must have a template type parameter with a type constraint");
   auto *Constraint =
-      cast_or_null<ConceptSpecializationExpr>(
-          TC->getImmediatelyDeclaredConstraint());
+      cast<ConceptSpecializationExpr>(TC->getImmediatelyDeclaredConstraint());
   bool Dependent =
       Constraint->getTemplateArgsAsWritten() &&
       TemplateSpecializationType::anyInstantiationDependentTemplateArguments(