remove unused variable to fix test

Signed-off-by: Justin Stitt <[email protected]>

Author: JustinStitt

clang/lib/Sema/SemaExpr.cpp

@@ -9994,10 +9994,9 @@ AssignConvertType Sema::CheckSingleAssignmentConstraints(QualType LHSType,
 
       // Check if OBT is being discarded during assignment
       // The RHS may have propagated OBT, but if LHS doesn't have it, warn
-      if (const auto *RHSOBT = RHSType->getAs<OverflowBehaviorType>()) {
-        if (!LHSType->isOverflowBehaviorType()) {
-          result = AssignConvertType::CompatibleOBTDiscards;
-        }
+      if (RHSType->isOverflowBehaviorType() &&
+          !LHSType->isOverflowBehaviorType()) {
+        result = AssignConvertType::CompatibleOBTDiscards;
       }
 
       return result;