optimize imports with on-demand conflicts (IDEA-164133)

explicit import for a class in the same package/file is redundant as it's implicitly imported is preferred to on-demand imported classes

java/java-impl/src/com/intellij/psi/impl/source/codeStyle/ImportHelper.java

@@ -40,6 +40,7 @@ import com.intellij.psi.search.LocalSearchScope;
 import com.intellij.psi.search.searches.ReferencesSearch;
 import com.intellij.psi.tree.IElementType;
 import com.intellij.psi.util.ClassUtil;
+import com.intellij.psi.util.PsiTreeUtil;
 import com.intellij.util.ArrayUtil;
 import com.intellij.util.IncorrectOperationException;
 import com.intellij.util.ObjectUtils;
@@ -339,6 +340,7 @@ public class ImportHelper{
       }
     }
     if (!conflicts.isEmpty() && !(file instanceof PsiCompiledElement)) {
+      String packageName = file.getPackageName();
       file.accept(new JavaRecursiveElementVisitor() {
         @Override
         public void visitReferenceElement(PsiJavaCodeReferenceElement reference) {
@@ -346,7 +348,11 @@ public class ImportHelper{
           PsiElement element = reference.resolve();
           if (element instanceof PsiClass && conflicts.contains(((PsiClass)element).getName())) {
             String fqn = ((PsiClass)element).getQualifiedName();
-            outNamesToUseSingle.add(fqn);
+            if (fqn != null && 
+                !PsiTreeUtil.isAncestor(file, element, true) && 
+                !packageName.equals(StringUtil.getPackageName(fqn))) {
+              outNamesToUseSingle.add(fqn);
+            }
           }
         }
       });

java/java-tests/testData/psi/optimizeImports/ConflictingOnDemandImports.java

@@ -0,0 +1,40 @@
+package foo;
+
+import static foo.C.*;
+import static foo.D.*;
+
+import foo.B.A;
+
+class C {
+  public static class A {}
+  public static class C1 {}
+  public static class C2 {}
+  public static class C3 {}
+  public static class C4 {}
+  public static class C5 {}
+}
+
+class D {
+  public static class A {}
+  public static class D1 {}
+  public static class D2 {}
+  public static class D3 {}
+  public static class D4 {}
+  public static class D5 {}
+}
+
+class B {
+  public static class A { }
+  
+  A aField;
+  C1 c;
+  C2 c1;
+  C3 c2;
+  C4 c3;
+  C5 c4;
+  D1 d;
+  D2 d1;
+  D3 d2;
+  D4 d3;
+  D5 d4;
+}

java/java-tests/testData/psi/optimizeImports/ConflictingOnDemandImports_after.java

@@ -0,0 +1,38 @@
+package foo;
+
+import static foo.C.*;
+import static foo.D.*;
+
+class C {
+  public static class A {}
+  public static class C1 {}
+  public static class C2 {}
+  public static class C3 {}
+  public static class C4 {}
+  public static class C5 {}
+}
+
+class D {
+  public static class A {}
+  public static class D1 {}
+  public static class D2 {}
+  public static class D3 {}
+  public static class D4 {}
+  public static class D5 {}
+}
+
+class B {
+  public static class A { }
+  
+  A aField;
+  C1 c;
+  C2 c1;
+  C3 c2;
+  C4 c3;
+  C5 c4;
+  D1 d;
+  D2 d1;
+  D3 d2;
+  D4 d3;
+  D5 d4;
+}

java/java-tests/testSrc/com/intellij/java/psi/OptimizeImportsTest.java

@@ -53,6 +53,10 @@ public class OptimizeImportsTest extends OptimizeImportsTestCase {
     doTest();
   }
 
+  public void testConflictingOnDemandImports() {
+    doTest();
+  }
+
   public void testExcludeNonStaticElementsFromStaticConflictingMembers() {
     doTest();
   }