diff --git a/java/java-impl/src/com/intellij/codeEditor/JavaEditorFileSwapper.java b/java/java-impl/src/com/intellij/codeEditor/JavaEditorFileSwapper.java
index 0847c5412e54..89d8201e8bf8 100644
--- a/java/java-impl/src/com/intellij/codeEditor/JavaEditorFileSwapper.java
+++ b/java/java-impl/src/com/intellij/codeEditor/JavaEditorFileSwapper.java
@@ -88,7 +88,7 @@ public class JavaEditorFileSwapper extends EditorFileSwapper {
     if (!(clsClass instanceof ClsClassImpl)) return null;
 
     PsiClass sourceClass = ((ClsClassImpl)clsClass).getSourceMirrorClass();
-    if (sourceClass == null || sourceClass == clsClass) return null;
+    if (sourceClass == null) return null;
 
     VirtualFile result = sourceClass.getContainingFile().getVirtualFile();
     assert result != null;
diff --git a/java/java-psi-api/src/com/intellij/psi/util/MethodSignatureUtil.java b/java/java-psi-api/src/com/intellij/psi/util/MethodSignatureUtil.java
index 986956ccbc97..8c692900f997 100644
--- a/java/java-psi-api/src/com/intellij/psi/util/MethodSignatureUtil.java
+++ b/java/java-psi-api/src/com/intellij/psi/util/MethodSignatureUtil.java
@@ -271,6 +271,7 @@ public class MethodSignatureUtil {
   }
 
   public static boolean areParametersErasureEqual(PsiMethod method1, PsiMethod method2) {
+    if (method1.getParameterList().getParametersCount() != method2.getParameterList().getParametersCount()) return false;
     return areSignaturesErasureEqual(method1.getSignature(PsiSubstitutor.EMPTY), method2.getSignature(PsiSubstitutor.EMPTY));
   }
 
diff --git a/java/java-psi-impl/src/com/intellij/psi/impl/compiled/ClsClassImpl.java b/java/java-psi-impl/src/com/intellij/psi/impl/compiled/ClsClassImpl.java
index 69512eb5d2bd..9b87f97bf064 100644
--- a/java/java-psi-impl/src/com/intellij/psi/impl/compiled/ClsClassImpl.java
+++ b/java/java-psi-impl/src/com/intellij/psi/impl/compiled/ClsClassImpl.java
@@ -571,6 +571,8 @@ public class ClsClassImpl extends ClsRepositoryPsiElement<PsiClassStub<?>> imple
       if (!(parent instanceof PsiClassOwner)) return null;
 
       PsiClassOwner fileNavigationElement = (PsiClassOwner)parent.getNavigationElement();
+      if (fileNavigationElement == parent) return null;
+
       for (PsiClass aClass : fileNavigationElement.getClasses()) {
         if (name.equals(aClass.getName())) return aClass;
       }
@@ -602,19 +604,19 @@ public class ClsClassImpl extends ClsRepositoryPsiElement<PsiClassStub<?>> imple
     }
 
     PsiClass aClass = getSourceMirrorClass();
-    return aClass != null && aClass != this ? aClass.getNavigationElement() : this;
+    return aClass != null ? aClass.getNavigationElement() : this;
   }
 
   @Override
   public ItemPresentation getPresentation() {
     PsiClass aClass = getSourceMirrorClass();
-    return aClass != null && aClass != this ? aClass.getPresentation() : ItemPresentationProviders.getItemPresentation(this);
+    return aClass != null ? aClass.getPresentation() : ItemPresentationProviders.getItemPresentation(this);
   }
 
   @Override
   public Icon getElementIcon(final int flags) {
     PsiClass aClass = getSourceMirrorClass();
-    return aClass != null && aClass != this ? aClass.getIcon(flags) : PsiClassImplUtil.getClassIcon(flags, this);
+    return aClass != null ? aClass.getIcon(flags) : PsiClassImplUtil.getClassIcon(flags, this);
   }
 
   @Override
diff --git a/java/java-psi-impl/src/com/intellij/psi/impl/compiled/ClsFieldImpl.java b/java/java-psi-impl/src/com/intellij/psi/impl/compiled/ClsFieldImpl.java
index a472439236a3..6aa5ef371d19 100644
--- a/java/java-psi-impl/src/com/intellij/psi/impl/compiled/ClsFieldImpl.java
+++ b/java/java-psi-impl/src/com/intellij/psi/impl/compiled/ClsFieldImpl.java
@@ -257,7 +257,7 @@ public class ClsFieldImpl extends ClsRepositoryPsiElement<PsiFieldStub> implemen
 
     PsiClass sourceClassMirror = ((ClsClassImpl)getParent()).getSourceMirrorClass();
     PsiElement sourceFieldMirror = sourceClassMirror != null ? sourceClassMirror.findFieldByName(getName(), false) : null;
-    return sourceFieldMirror != null && sourceFieldMirror != this ? sourceFieldMirror.getNavigationElement() : this;
+    return sourceFieldMirror != null ? sourceFieldMirror.getNavigationElement() : this;
   }
 
   @Override
diff --git a/java/java-psi-impl/src/com/intellij/psi/impl/compiled/ClsMethodImpl.java b/java/java-psi-impl/src/com/intellij/psi/impl/compiled/ClsMethodImpl.java
index 0491d84c1789..729ff5860fa5 100644
--- a/java/java-psi-impl/src/com/intellij/psi/impl/compiled/ClsMethodImpl.java
+++ b/java/java-psi-impl/src/com/intellij/psi/impl/compiled/ClsMethodImpl.java
@@ -42,6 +42,7 @@ import com.intellij.util.IncorrectOperationException;
 import com.intellij.util.PlatformIcons;
 import org.jetbrains.annotations.NonNls;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import javax.swing.*;
 import java.util.List;
@@ -363,16 +364,16 @@ public class ClsMethodImpl extends ClsRepositoryPsiElement<PsiMethodStub> implem
     return true;
   }
 
-  @NotNull
+  @Nullable
   public PsiMethod getSourceMirrorMethod() {
     PsiClass sourceClassMirror = ((ClsClassImpl)getParent()).getSourceMirrorClass();
-    if (sourceClassMirror == null) return this;
+    if (sourceClassMirror == null) return null;
     for (PsiMethod sourceMethod : sourceClassMirror.findMethodsByName(getName(), false)) {
       if (MethodSignatureUtil.areParametersErasureEqual(this, sourceMethod)) {
         return sourceMethod;
       }
     }
-    return this;
+    return null;
   }
 
   @Override
@@ -386,7 +387,7 @@ public class ClsMethodImpl extends ClsRepositoryPsiElement<PsiMethodStub> implem
     }
 
     final PsiMethod method = getSourceMirrorMethod();
-    return method != this ? method.getNavigationElement() : this;
+    return method != null ? method.getNavigationElement() : this;
   }
 
   @Override
diff --git a/java/java-psi-impl/src/com/intellij/psi/impl/compiled/ClsParameterImpl.java b/java/java-psi-impl/src/com/intellij/psi/impl/compiled/ClsParameterImpl.java
index 6e2856937e46..96d6e794a481 100644
--- a/java/java-psi-impl/src/com/intellij/psi/impl/compiled/ClsParameterImpl.java
+++ b/java/java-psi-impl/src/com/intellij/psi/impl/compiled/ClsParameterImpl.java
@@ -66,13 +66,14 @@ public class ClsParameterImpl extends ClsRepositoryPsiElement<PsiParameterStub>
 
       ClsMethodImpl method = (ClsMethodImpl)getDeclarationScope();
       PsiMethod sourceMethod = method.getSourceMirrorMethod();
-      if (sourceMethod == method) {
+      if (sourceMethod == null) {
         final PsiParameterStubImpl parameterStub = (PsiParameterStubImpl) getStub();
         if (!parameterStub.isAutoGeneratedName()) {
           return parameterStub.getName();
         }
         return null;
       }
+      assert sourceMethod != method;
       myName = sourceMethod.getParameterList().getParameters()[getIndex()].getName();
     }
     return myName;