diff --git a/RegExpSupport/src/org/intellij/lang/regexp/validation/RegExpAnnotator.java b/RegExpSupport/src/org/intellij/lang/regexp/validation/RegExpAnnotator.java
index b55984cde60d..b71544545bd8 100644
--- a/RegExpSupport/src/org/intellij/lang/regexp/validation/RegExpAnnotator.java
+++ b/RegExpSupport/src/org/intellij/lang/regexp/validation/RegExpAnnotator.java
@@ -30,7 +30,6 @@ import com.intellij.psi.PsiElement;
 import com.intellij.psi.StringEscapesTokenTypes;
 import com.intellij.psi.tree.IElementType;
 import com.intellij.psi.util.PsiTreeUtil;
-import com.intellij.util.ObjectUtils;
 import com.intellij.util.containers.ContainerUtil;
 import org.intellij.lang.regexp.*;
 import org.intellij.lang.regexp.psi.*;
@@ -124,7 +123,7 @@ public final class RegExpAnnotator extends RegExpElementVisitor implements Annot
   }
 
   @Override
-  public void visitRegExpChar(final RegExpChar ch) {
+  public void visitRegExpChar(RegExpChar ch) {
     final PsiElement child = ch.getFirstChild();
     final IElementType type = child.getNode().getElementType();
     if (type == RegExpTT.CHARACTER) {
@@ -184,15 +183,15 @@ public final class RegExpAnnotator extends RegExpElementVisitor implements Annot
     final String propertyName = category.getText();
     final ASTNode next = category.getTreeNext();
     if (next == null || next.getElementType() != RegExpTT.EQ) {
-      if(!myLanguageHosts.isValidCategory(category.getPsi(), propertyName)) {
+      if (!myLanguageHosts.isValidCategory(property, propertyName)) {
         myHolder.newAnnotation(HighlightSeverity.ERROR, RegExpBundle.message("error.unknown.character.category")).range(category)
-        .highlightType(ProblemHighlightType.LIKE_UNKNOWN_SYMBOL).create();
+          .highlightType(ProblemHighlightType.LIKE_UNKNOWN_SYMBOL).create();
       }
     }
     else {
-      if(!myLanguageHosts.isValidPropertyName(category.getPsi(), propertyName)) {
+      if (!myLanguageHosts.isValidPropertyName(category.getPsi(), propertyName)) {
         myHolder.newAnnotation(HighlightSeverity.ERROR, RegExpBundle.message("error.unknown.property.name")).range(category)
-        .highlightType(ProblemHighlightType.LIKE_UNKNOWN_SYMBOL).create();
+          .highlightType(ProblemHighlightType.LIKE_UNKNOWN_SYMBOL).create();
         return;
       }
       final ASTNode valueNode = property.getValueNode();
@@ -219,7 +218,7 @@ public final class RegExpAnnotator extends RegExpElementVisitor implements Annot
   }
 
   @Override
-  public void visitRegExpBackref(final RegExpBackref backref) {
+  public void visitRegExpBackref(RegExpBackref backref) {
     final RegExpGroup group = backref.resolve();
     if (group == null) {
       myHolder.newAnnotation(HighlightSeverity.ERROR, RegExpBundle.message("error.unresolved.back.reference"))
@@ -236,14 +235,11 @@ public final class RegExpAnnotator extends RegExpElementVisitor implements Annot
   @Override
   public void visitRegExpGroup(RegExpGroup group) {
     if (RegExpGroupImpl.isPcreConditionalGroup(group.getNode())) {
-      if (RegExpGroupImpl.isPcreDefine(group.getNode())) {
-        RegExpConditional conditional = ObjectUtils.tryCast(group.getParent(), RegExpConditional.class);
-        if (conditional != null) {
-          RegExpBranch[] branches = PsiTreeUtil.getChildrenOfType(conditional, RegExpBranch.class);
-          if (branches != null && branches.length > 1) {
-            myHolder.newAnnotation(HighlightSeverity.ERROR,
-                                   RegExpBundle.message("error.define.subpattern.contains.more.than.one.branch")).create();
-          }
+      if (RegExpGroupImpl.isPcreDefine(group.getNode()) && group.getParent() instanceof RegExpConditional conditional) {
+        final RegExpBranch[] branches = PsiTreeUtil.getChildrenOfType(conditional, RegExpBranch.class);
+        if (branches != null && branches.length > 1) {
+          myHolder.newAnnotation(HighlightSeverity.ERROR,
+                                 RegExpBundle.message("error.define.subpattern.contains.more.than.one.branch")).create();
         }
       }
       return;
@@ -256,10 +252,9 @@ public final class RegExpAnnotator extends RegExpElementVisitor implements Annot
     }
     else if (branches.length == 1) {
       final RegExpAtom[] atoms = branches[0].getAtoms();
-      if (atoms.length == 1 && atoms[0] instanceof RegExpGroup) {
+      if (atoms.length == 1 && atoms[0] instanceof RegExpGroup innerGroup) {
         final RegExpGroup.Type type = group.getType();
         if (type == RegExpGroup.Type.CAPTURING_GROUP || type == RegExpGroup.Type.ATOMIC || type == RegExpGroup.Type.NON_CAPTURING) {
-          final RegExpGroup innerGroup = (RegExpGroup)atoms[0];
           if (group.isCapturing() == innerGroup.isCapturing()) {
             myHolder.newAnnotation(HighlightSeverity.WARNING, RegExpBundle.message("error.redundant.group.nesting")).create();
           }