SOE in case of mutually recursive inheritance

java/java-impl/src/com/intellij/psi/impl/search/MethodDeepestSuperSearcher.java

@@ -6,6 +6,7 @@ package com.intellij.psi.impl.search;
 import com.intellij.psi.PsiMethod;
 import com.intellij.util.Processor;
 import com.intellij.util.QueryExecutor;
+import gnu.trove.THashSet;
 import org.jetbrains.annotations.NotNull;
 
 import java.util.LinkedHashSet;
@@ -15,10 +16,9 @@ import java.util.Set;
  * @author peter
  */
 public class MethodDeepestSuperSearcher implements QueryExecutor<PsiMethod, PsiMethod> {
-
   public boolean execute(@NotNull final PsiMethod method, @NotNull final Processor<PsiMethod> consumer) {
     final Set<PsiMethod> methods = new LinkedHashSet<PsiMethod>();
-    findDeepestSuperOrSelfSignature(method, methods);
+    findDeepestSuperOrSelfSignature(method, methods, null);
     for (final PsiMethod psiMethod : methods) {
       if (psiMethod != method && !consumer.process(psiMethod)) {
         return false;
@@ -27,17 +27,18 @@ public class MethodDeepestSuperSearcher implements QueryExecutor<PsiMethod, PsiM
     return true;
   }
 
-  private static void findDeepestSuperOrSelfSignature(PsiMethod method, final Set<PsiMethod> set) {
+  private static void findDeepestSuperOrSelfSignature(PsiMethod method, final Set<PsiMethod> set, Set<PsiMethod> guard) {
+    if (guard != null && !guard.add(method)) return;
     PsiMethod[] supers = method.findSuperMethods();
 
     if (supers.length == 0) {
       set.add(method);
-      return;
     }
-
-    for (PsiMethod superMethod : supers) {
-      findDeepestSuperOrSelfSignature(superMethod, set);
+    else {
+      for (PsiMethod superMethod : supers) {
+        if (guard == null) guard = new THashSet<PsiMethod>();
+        findDeepestSuperOrSelfSignature(superMethod, set, guard);
+      }
     }
   }
-
 }

java/java-tests/testSrc/com/intellij/codeInsight/daemon/LightAdvHighlightingTest.java

@@ -302,4 +302,10 @@ public class LightAdvHighlightingTest extends LightDaemonAnalyzerTestCase {
 
     field.getInitializer().getType(); // SOE
   }
+
+  public void testSOEForCyclicInheritance() throws IOException {
+    configureFromFileText("a.java", "class A extends B { String s = \"\"; void f() {}} class B extends A { void f() {} } ");
+
+    doHighlighting();
+  }
 }

java/openapi/src/com/intellij/codeInsight/ClassUtil.java

@@ -89,10 +89,11 @@ public class ClassUtil {
 
   private static boolean add(PsiMethod method, Set<PsiMethod> alreadyImplemented) {
     boolean already = alreadyImplemented.add(method);
+    if (!already) return already;
 
     for (PsiMethod superSig : method.findSuperMethods()) {
       already &= add(superSig, alreadyImplemented);
     }
     return already;
   }
-}
+}