diff --git a/RegExpSupport/src/org/intellij/lang/regexp/inspection/UnnecessaryNonCapturingGroupInspection.java b/RegExpSupport/src/org/intellij/lang/regexp/inspection/UnnecessaryNonCapturingGroupInspection.java
index dbbb1b79385c..250d7b195373 100644
--- a/RegExpSupport/src/org/intellij/lang/regexp/inspection/UnnecessaryNonCapturingGroupInspection.java
+++ b/RegExpSupport/src/org/intellij/lang/regexp/inspection/UnnecessaryNonCapturingGroupInspection.java
@@ -1,4 +1,4 @@
-// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package org.intellij.lang.regexp.inspection;
 
 import com.intellij.codeInspection.LocalInspectionTool;
@@ -10,10 +10,7 @@ import com.intellij.openapi.project.Project;
 import com.intellij.psi.PsiElement;
 import com.intellij.psi.PsiElementVisitor;
 import org.intellij.lang.regexp.RegExpBundle;
-import org.intellij.lang.regexp.psi.RegExpBranch;
-import org.intellij.lang.regexp.psi.RegExpElementVisitor;
-import org.intellij.lang.regexp.psi.RegExpGroup;
-import org.intellij.lang.regexp.psi.RegExpPattern;
+import org.intellij.lang.regexp.psi.*;
 import org.jetbrains.annotations.NotNull;
 
 /**
@@ -41,20 +38,23 @@ public class UnnecessaryNonCapturingGroupInspection extends LocalInspectionTool
         return;
       }
       final PsiElement parent = group.getParent();
-      if (parent instanceof RegExpBranch) {
+      final RegExpAtom atom = getSingleAtom(group.getPattern());
+      if (atom != null) {
+        if (!(parent instanceof RegExpClosure) || !(atom instanceof RegExpClosure)) {
+          registerProblem(group);
+        }
+      }
+      else if (parent instanceof RegExpBranch) {
         if (hasOneBranch(group.getPattern())) {
           registerProblem(group);
         }
         else {
           final PsiElement grandParent = parent.getParent();
-          if (grandParent instanceof RegExpPattern && hasSingleAtom((RegExpPattern)grandParent)) {
+          if (grandParent instanceof RegExpPattern && getSingleAtom((RegExpPattern)grandParent) != null) {
             registerProblem(group);
           }
         }
       }
-      else if (hasSingleAtom(group.getPattern())) {
-        registerProblem(group);
-      }
     }
 
     void registerProblem(RegExpGroup group) {
@@ -68,12 +68,12 @@ public class UnnecessaryNonCapturingGroupInspection extends LocalInspectionTool
     return pattern != null && pattern.getBranches().length == 1;
   }
 
-  private static boolean hasSingleAtom(RegExpPattern pattern) {
-    if (pattern == null) {
-      return false;
-    }
+  private static RegExpAtom getSingleAtom(RegExpPattern pattern) {
+    if (pattern == null) return null;
     final RegExpBranch[] branches = pattern.getBranches();
-    return branches.length == 1 && branches[0].getAtoms().length == 1;
+    if (branches.length != 1) return null;
+    final RegExpAtom[] atoms = branches[0].getAtoms();
+    return atoms.length != 1 ? null : atoms[0];
   }
 
   private static class UnnecessaryNonCapturingGroupFix implements LocalQuickFix {
diff --git a/RegExpSupport/test/org/intellij/lang/regexp/inspection/UnnecessaryNonCapturingGroupInspectionTest.java b/RegExpSupport/test/org/intellij/lang/regexp/inspection/UnnecessaryNonCapturingGroupInspectionTest.java
index d52594d50bea..b5610d72bf4d 100644
--- a/RegExpSupport/test/org/intellij/lang/regexp/inspection/UnnecessaryNonCapturingGroupInspectionTest.java
+++ b/RegExpSupport/test/org/intellij/lang/regexp/inspection/UnnecessaryNonCapturingGroupInspectionTest.java
@@ -1,4 +1,4 @@
-// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package org.intellij.lang.regexp.inspection;
 
 import com.intellij.codeInspection.LocalInspectionTool;
@@ -24,6 +24,13 @@ public class UnnecessaryNonCapturingGroupInspectionTest extends RegExpInspection
     highlightTest("aa(?:bb|bbb)cccc");
   }
 
+  public void testNoWarnOnNestedClosure() {
+    highlightTest("\\d{2}(?:\\d{3})?");
+    highlightTest("\\d{2}(?:\\d{3}){2}");
+    highlightTest("\\d{2}(?:\\d{3})+");
+    highlightTest("\\d{2}(?:\\d{3})*");
+  }
+
   public void testTopLevelAlternation() {
     quickfixTest("<warning descr=\"Unnecessary non-capturing group '(?:xx|xy)'\">(?:</warning>xx|xy)", "xx|xy",
                  RegExpBundle.message("inspection.quick.fix.remove.unnecessary.non.capturing.group"));