IDEA-113585 Cast to Type quick fix creates code that doesn't help

java/java-analysis-api/src/com/intellij/codeInsight/intention/QuickFixFactory.java

@@ -298,7 +298,9 @@ public abstract class QuickFixFactory {
   public abstract List<IntentionAction> createAddAnnotationAttributeNameFixes(@NotNull PsiNameValuePair pair);
 
   @NotNull
-  public abstract IntentionAction createCollectionToArrayFix(@NotNull PsiExpression collectionExpression, @NotNull PsiArrayType arrayType);
+  public abstract IntentionAction createCollectionToArrayFix(@NotNull PsiExpression collectionExpression,
+                                                             @NotNull PsiExpression expressionToReplace,
+                                                             @NotNull PsiArrayType arrayType);
 
   @NotNull
   public abstract IntentionAction createInsertMethodCallFix(@NotNull PsiMethodCallExpression call, PsiMethod method);

java/java-analysis-impl/src/com/intellij/codeInsight/daemon/impl/analysis/HighlightFixUtil.java

@@ -30,6 +30,7 @@ import com.intellij.psi.*;
 import com.intellij.psi.util.*;
 import com.intellij.util.ArrayUtil;
 import com.intellij.util.IncorrectOperationException;
+import com.siyeh.ig.callMatcher.CallMatcher;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
@@ -42,6 +43,9 @@ public class HighlightFixUtil {
 
   private static final QuickFixFactory QUICK_FIX_FACTORY = QuickFixFactory.getInstance();
 
+  private static final CallMatcher COLLECTION_TO_ARRAY =
+    CallMatcher.instanceCall(CommonClassNames.JAVA_UTIL_COLLECTION, "toArray").parameterCount(0);
+
   static void registerCollectionToArrayFixAction(@Nullable HighlightInfo info,
                                                  @Nullable PsiType fromType,
                                                  @Nullable PsiType toType,
@@ -49,11 +53,25 @@ public class HighlightFixUtil {
     if (toType instanceof PsiArrayType) {
       PsiType arrayComponentType = ((PsiArrayType)toType).getComponentType();
       if (!(arrayComponentType instanceof PsiPrimitiveType) &&
-          !(PsiUtil.resolveClassInType(arrayComponentType) instanceof PsiTypeParameter) &&
-          InheritanceUtil.isInheritor(fromType, CommonClassNames.JAVA_UTIL_COLLECTION)) {
-        PsiType collectionItemType = JavaGenericsUtil.getCollectionItemType(fromType, expression.getResolveScope());
-        if (collectionItemType != null && arrayComponentType.isAssignableFrom(collectionItemType)) {
-          QuickFixAction.registerQuickFixAction(info, QUICK_FIX_FACTORY.createCollectionToArrayFix(expression, (PsiArrayType)toType));
+          !(PsiUtil.resolveClassInType(arrayComponentType) instanceof PsiTypeParameter)) {
+        PsiExpression collection = expression;
+        if (expression instanceof PsiMethodCallExpression) {
+          PsiMethodCallExpression call = (PsiMethodCallExpression)expression;
+          if (COLLECTION_TO_ARRAY.test(call)) {
+            collection = call.getMethodExpression().getQualifierExpression();
+            if (collection == null) return;
+            fromType = collection.getType();
+          }
+        }
+        if (fromType instanceof PsiClassType &&
+            (CommonClassNames.JAVA_LANG_OBJECT.equals(arrayComponentType.getCanonicalText()) ||
+             !((PsiClassType)fromType).isRaw()) &&
+            InheritanceUtil.isInheritor(fromType, CommonClassNames.JAVA_UTIL_COLLECTION)) {
+          PsiType collectionItemType = JavaGenericsUtil.getCollectionItemType(fromType, expression.getResolveScope());
+          if (collectionItemType != null && arrayComponentType.isConvertibleFrom(collectionItemType)) {
+            QuickFixAction
+              .registerQuickFixAction(info, QUICK_FIX_FACTORY.createCollectionToArrayFix(collection, expression, (PsiArrayType)toType));
+          }
         }
       }
     }

java/java-analysis-impl/src/com/intellij/codeInsight/intention/EmptyQuickFixFactory.java

@@ -677,7 +677,9 @@ public class EmptyQuickFixFactory extends QuickFixFactory {
 
   @NotNull
   @Override
-  public IntentionAction createCollectionToArrayFix(@NotNull PsiExpression collectionExpression, @NotNull PsiArrayType arrayType) {
+  public IntentionAction createCollectionToArrayFix(@NotNull PsiExpression collectionExpression,
+                                                    @NotNull PsiExpression expressionToReplace,
+                                                    @NotNull PsiArrayType arrayType) {
     return QuickFixes.EMPTY_FIX;
   }
 

java/java-impl/src/com/intellij/codeInsight/daemon/impl/quickfix/ConvertCollectionToArrayFix.java

@@ -30,10 +30,14 @@ import org.jetbrains.annotations.NotNull;
  */
 public class ConvertCollectionToArrayFix implements IntentionAction {
   private final PsiExpression myCollectionExpression;
+  private final PsiExpression myExpressionToReplace;
   private final String myNewArrayText;
 
-  public ConvertCollectionToArrayFix(@NotNull PsiExpression collectionExpression, @NotNull PsiArrayType arrayType) {
+  public ConvertCollectionToArrayFix(@NotNull PsiExpression collectionExpression,
+                                     @NotNull PsiExpression expressionToReplace,
+                                     @NotNull PsiArrayType arrayType) {
     myCollectionExpression = collectionExpression;
+    myExpressionToReplace = expressionToReplace;
 
     PsiType componentType = arrayType.getComponentType();
     myNewArrayText = componentType.equalsToText(CommonClassNames.JAVA_LANG_OBJECT) ? "" : "new " + getArrayTypeText(componentType);
@@ -55,7 +59,8 @@ public class ConvertCollectionToArrayFix implements IntentionAction {
 
   @Override
   public boolean isAvailable(@NotNull Project project, Editor editor, PsiFile file) {
-    return myCollectionExpression.isValid() && PsiManager.getInstance(project).isInProject(myCollectionExpression);
+    return myCollectionExpression.isValid() && PsiManager.getInstance(project).isInProject(myCollectionExpression) &&
+        myExpressionToReplace.isValid() && PsiManager.getInstance(project).isInProject(myExpressionToReplace);
   }
 
   @Override
@@ -63,7 +68,7 @@ public class ConvertCollectionToArrayFix implements IntentionAction {
     PsiElementFactory factory = JavaPsiFacade.getInstance(project).getElementFactory();
     String replacement = ParenthesesUtils.getText(myCollectionExpression, ParenthesesUtils.POSTFIX_PRECEDENCE) +
                          ".toArray(" + myNewArrayText + ")";
-    myCollectionExpression.replace(factory.createExpressionFromText(replacement, myCollectionExpression));
+    myExpressionToReplace.replace(factory.createExpressionFromText(replacement, myCollectionExpression));
   }
 
   @Override

java/java-impl/src/com/intellij/codeInsight/intention/impl/config/QuickFixFactoryImpl.java

@@ -867,8 +867,10 @@ public class QuickFixFactoryImpl extends QuickFixFactory {
 
   @NotNull
   @Override
-  public IntentionAction createCollectionToArrayFix(@NotNull PsiExpression collectionExpression, @NotNull PsiArrayType arrayType) {
-    return new ConvertCollectionToArrayFix(collectionExpression, arrayType);
+  public IntentionAction createCollectionToArrayFix(@NotNull PsiExpression collectionExpression,
+                                                    @NotNull PsiExpression expressionToReplace,
+                                                    @NotNull PsiArrayType arrayType) {
+    return new ConvertCollectionToArrayFix(collectionExpression, expressionToReplace, arrayType);
   }
 
   @NotNull

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/convertCollectionToArray/afterToArrayPresent.java

@@ -0,0 +1,22 @@
+// "Apply conversion '.toArray(new Test.User[0])'" "true"
+
+import java.util.List;
+
+class Test {
+  interface User {
+
+  }
+
+  interface Query {
+
+    List<?> getResultList();
+  }
+
+  public User[] getAllUsers(Query readQuery) {
+    List<?> result = readQuery.getResultList();
+    return (result != null) ? result.toArray(new User[0]) : new User[0];
+  }
+
+  public static void main(String[] args) {
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/convertCollectionToArray/beforeReturnInconvertible.java

@@ -0,0 +1,10 @@
+// "Apply conversion '.toArray(new java.lang.String[0])'" "false"
+
+import java.util.*;
+class Return {
+  String[] foo() {
+    List<Number> list = new ArrayList<>();
+    list.add(1);
+    return list<caret>;
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/convertCollectionToArray/beforeToArrayPresent.java

@@ -0,0 +1,22 @@
+// "Apply conversion '.toArray(new Test.User[0])'" "true"
+
+import java.util.List;
+
+class Test {
+  interface User {
+
+  }
+
+  interface Query {
+
+    List<?> getResultList();
+  }
+
+  public User[] getAllUsers(Query readQuery) {
+    List<?> result = readQuery.getResultList();
+    return (result != null) ? result.toAr<caret>ray() : new User[0];
+  }
+
+  public static void main(String[] args) {
+  }
+}