[refactor] Address further code-review from @reinhapa

Author: adamretter

exist-core/src/main/java/org/exist/xquery/BindingExpression.java

@@ -83,8 +83,8 @@ public void analyze(final AnalyzeContextInfo contextInfo) throws XPathException
 
     @Override
     public Sequence postEval(Sequence seq) throws XPathException {
-        if (returnExpr instanceof FLWORClause) {
-            seq = ((FLWORClause)returnExpr).postEval(seq);
+        if (returnExpr instanceof FLWORClause flworClause) {
+            seq = flworClause.postEval(seq);
         }
         return super.postEval(seq);
     }

exist-core/src/main/java/org/exist/xquery/CountClause.java

@@ -111,8 +111,8 @@ private boolean hasPreviousOrderByDescending() {
                 case ORDERBY -> {
                     return isDescending(((OrderByClause) prev).getOrderSpecs());
                 }
+                default -> prev = prev.getPreviousClause();
             }
-            prev = prev.getPreviousClause();
         }
         return true;
     }
@@ -183,8 +183,8 @@ public Sequence eval(final Sequence contextSequence, final Item contextItem) thr
 
     @Override
     public Sequence postEval(Sequence seq) throws XPathException {
-        if (returnExpr instanceof FLWORClause) {
-            seq = ((FLWORClause)returnExpr).postEval(seq);
+        if (returnExpr instanceof FLWORClause flworClause) {
+            seq = flworClause.postEval(seq);
         }
         return super.postEval(seq);
     }

exist-core/src/main/java/org/exist/xquery/GroupByClause.java

@@ -172,8 +172,8 @@ public Sequence postEval(final Sequence seq) throws XPathException {
                 context.popLocalVariables(mark, result);
             }
 
-            if (returnExpr instanceof FLWORClause) {
-                result = ((FLWORClause) returnExpr).postEval(result);
+            if (returnExpr instanceof FLWORClause flworClause) {
+                result = flworClause.postEval(result);
             }
             result = super.postEval(result);
             return result;

exist-core/src/main/java/org/exist/xquery/OrderByClause.java

@@ -95,8 +95,8 @@ public Sequence postEval(Sequence seq) throws XPathException {
         orderedResult.sort();
         Sequence result = orderedResult;
 
-        if (getReturnExpression() instanceof FLWORClause) {
-            result = ((FLWORClause) getReturnExpression()).postEval(result);
+        if (getReturnExpression() instanceof FLWORClause flworClause) {
+            result = flworClause.postEval(result);
         }
         return super.postEval(result);
     }

exist-core/src/main/java/org/exist/xquery/WhereClause.java

@@ -133,8 +133,8 @@ public Sequence eval(Sequence contextSequence, Item contextItem) throws XPathExc
     @Override
     public Sequence postEval(Sequence seq) throws XPathException {
         fastTrack = false;
-        if (returnExpr instanceof FLWORClause) {
-            seq = ((FLWORClause) returnExpr).postEval(seq);
+        if (returnExpr instanceof FLWORClause flworClause) {
+            seq = flworClause.postEval(seq);
         }
         return super.postEval(seq);
     }