optimize imports: don't collapse into on-demand when result in ambiguity

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

@@ -47,6 +47,7 @@ import com.intellij.util.ArrayUtil;
 import com.intellij.util.IncorrectOperationException;
 import com.intellij.util.ObjectUtils;
 import com.intellij.util.containers.ContainerUtil;
+import com.intellij.util.containers.MultiMap;
 import gnu.trove.THashMap;
 import gnu.trove.THashSet;
 import gnu.trove.TObjectIntHashMap;
@@ -81,13 +82,29 @@ public class ImportHelper{
     List<PsiElement> nonImports = new ArrayList<>();
     // Note: this array may contain "<packageOrClassName>.*" for unresolved imports!
     List<Pair<String, Boolean>> names = new ArrayList<>(collectNamesToImport(file, nonImports));
-    Collections.sort(names, (o1, o2) -> o1.getFirst().compareTo(o2.getFirst()));
+    Collections.sort(names, Comparator.comparing(o -> o.getFirst()));
 
     List<Pair<String, Boolean>> resultList = sortItemsAccordingToSettings(names, mySettings);
 
     final Map<String, Boolean> classesOrPackagesToImportOnDemand = new THashMap<>();
     collectOnDemandImports(resultList, mySettings, classesOrPackagesToImportOnDemand);
 
+    MultiMap<String, String> conflictingMemberNames = new MultiMap<>();
+    for (Pair<String, Boolean> pair : resultList) {
+      if (pair.second) {
+        conflictingMemberNames.putValue(StringUtil.getShortName(pair.first), StringUtil.getPackageName(pair.first));
+      }
+    }
+
+    for (String methodName : conflictingMemberNames.keySet()) {
+      Collection<String> collection = conflictingMemberNames.get(methodName);
+      if (!classesOrPackagesToImportOnDemand.keySet().containsAll(collection)) {
+        for (String name : collection) {
+          classesOrPackagesToImportOnDemand.remove(name);
+        }
+      }
+    }
+
     Set<String> classesToUseSingle = findSingleImports(file, resultList, classesOrPackagesToImportOnDemand.keySet());
     Set<String> toReimport = new THashSet<>();
     calcClassesConflictingViaOnDemandImports(file, classesOrPackagesToImportOnDemand, file.getResolveScope(), toReimport);

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

@@ -0,0 +1,16 @@
+import java.util.ArrayList;
+
+import static java.util.Arrays.asList;
+import static java.util.Arrays.deepHashCode;
+import static java.util.Arrays.sort;
+import static java.util.Collections.sort;
+
+class OnDemand {
+  {
+    sort(new Integer[0]);
+    asList(new Integer[0]);
+    deepHashCode(new Integer[0]);
+
+    sort(new ArrayList<String>());
+  }
+}

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

@@ -0,0 +1,16 @@
+import java.util.ArrayList;
+
+import static java.util.Arrays.asList;
+import static java.util.Arrays.deepHashCode;
+import static java.util.Arrays.sort;
+import static java.util.Collections.sort;
+
+class OnDemand {
+  {
+    sort(new Integer[0]);
+    asList(new Integer[0]);
+    deepHashCode(new Integer[0]);
+
+    sort(new ArrayList<String>());
+  }
+}

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2013 JetBrains s.r.o.
+ * Copyright 2000-2016 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -38,6 +38,8 @@ public class OptimizeImportsTest extends OptimizeImportsTestCase {
   public void testNewImportListIsEmptyAndCommentPreserved() throws Exception { doTest(); }
   public void testNewImportListIsEmptyAndJavaDocWithInvalidCodePreserved() throws Exception { doTest(); }
 
+  public void testDontCollapseToOnDemandImport() throws Exception { doTest(); }
+
   private void doTest() throws Exception {
     doTest(".java");
   }