Index: clang/lib/Sema/SemaConcept.cpp
===================================================================
--- clang/lib/Sema/SemaConcept.cpp
+++ clang/lib/Sema/SemaConcept.cpp
@@ -1065,8 +1065,7 @@
   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(