Change overriddenDescriptors' type from Set to Collection

So that the easiest way of constructing a HashSet in the implementation will be
not the only possible way to implement getOverriddenDescriptors(). If there's
not too many overridden descriptors, an implementation may decide to return a
small list for example instead

compiler/frontend/src/org/jetbrains/kotlin/resolve/OverrideResolver.java

@@ -518,7 +518,7 @@ public class OverrideResolver {
 
         JetModifierList modifierList = member.getModifierList();
         boolean hasOverrideNode = modifierList != null && modifierList.hasModifier(JetTokens.OVERRIDE_KEYWORD);
-        Set<? extends CallableMemberDescriptor> overriddenDescriptors = declared.getOverriddenDescriptors();
+        Collection<? extends CallableMemberDescriptor> overriddenDescriptors = declared.getOverriddenDescriptors();
 
         if (hasOverrideNode) {
             checkOverridesForMemberMarkedOverride(declared, true, new CheckOverrideReportStrategy() {
@@ -580,7 +580,7 @@ public class OverrideResolver {
             boolean checkIfOverridesNothing,
             @NotNull CheckOverrideReportStrategy reportError
     ) {
-        Set<? extends CallableMemberDescriptor> overriddenDescriptors = declared.getOverriddenDescriptors();
+        Collection<? extends CallableMemberDescriptor> overriddenDescriptors = declared.getOverriddenDescriptors();
 
         for (CallableMemberDescriptor overridden : overriddenDescriptors) {
             if (overridden == null) continue;
@@ -872,11 +872,10 @@ public class OverrideResolver {
     }
 
     @NotNull
-    public static <D extends CallableMemberDescriptor> Set<D> getDirectlyOverriddenDeclarations(@NotNull D descriptor) {
+    public static <D extends CallableMemberDescriptor> Collection<D> getDirectlyOverriddenDeclarations(@NotNull D descriptor) {
-        Set<D> result = Sets.newHashSet();
+        Set<D> result = new LinkedHashSet<D>();
         //noinspection unchecked
-        Set<D> overriddenDescriptors = (Set<D>) descriptor.getOverriddenDescriptors();
+        for (D overriddenDescriptor : (Collection<D>) descriptor.getOverriddenDescriptors()) {
-        for (D overriddenDescriptor : overriddenDescriptors) {
             CallableMemberDescriptor.Kind kind = overriddenDescriptor.getKind();
             if (kind == DECLARATION) {
                 result.add(overriddenDescriptor);

core/descriptors/src/org/jetbrains/kotlin/descriptors/CallableDescriptor.java

@@ -22,8 +22,8 @@ import org.jetbrains.annotations.Nullable;
 import org.jetbrains.kotlin.types.JetType;
 import org.jetbrains.kotlin.types.TypeSubstitutor;
 
+import java.util.Collection;
 import java.util.List;
-import java.util.Set;
 
 public interface CallableDescriptor extends DeclarationDescriptorWithVisibility, DeclarationDescriptorNonRoot {
     @Nullable
@@ -66,8 +66,6 @@ public interface CallableDescriptor extends DeclarationDescriptorWithVisibility,
      */
     boolean hasSynthesizedParameterNames();
 
-    // Workaround for KT-4609 Wildcard types (super/extends) shouldn't be loaded as nullable
-    @KotlinSignature("fun getOverriddenDescriptors(): Set<out CallableDescriptor>")
     @NotNull
-    Set<? extends CallableDescriptor> getOverriddenDescriptors();
+    Collection<? extends CallableDescriptor> getOverriddenDescriptors();
 }

core/descriptors/src/org/jetbrains/kotlin/descriptors/CallableMemberDescriptor.java

@@ -16,16 +16,14 @@
 
 package org.jetbrains.kotlin.descriptors;
 
-import jet.runtime.typeinfo.KotlinSignature;
 import org.jetbrains.annotations.NotNull;
 
-import java.util.Set;
+import java.util.Collection;
 
 public interface CallableMemberDescriptor extends CallableDescriptor, MemberDescriptor {
-    @KotlinSignature("fun getOverriddenDescriptors(): MutableSet<out CallableMemberDescriptor>")
     @NotNull
     @Override
-    Set<? extends CallableMemberDescriptor> getOverriddenDescriptors();
+    Collection<? extends CallableMemberDescriptor> getOverriddenDescriptors();
 
     @NotNull
     @Override

core/descriptors/src/org/jetbrains/kotlin/descriptors/FunctionDescriptor.java

@@ -19,7 +19,7 @@ package org.jetbrains.kotlin.descriptors;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.kotlin.types.TypeSubstitutor;
 
-import java.util.Set;
+import java.util.Collection;
 
 public interface FunctionDescriptor extends CallableMemberDescriptor {
     @Override
@@ -35,7 +35,7 @@ public interface FunctionDescriptor extends CallableMemberDescriptor {
 
     @Override
     @NotNull
-    Set<? extends FunctionDescriptor> getOverriddenDescriptors();
+    Collection<? extends FunctionDescriptor> getOverriddenDescriptors();
 
     @NotNull
     @Override

core/descriptors/src/org/jetbrains/kotlin/descriptors/PropertyAccessorDescriptor.java

@@ -18,7 +18,7 @@ package org.jetbrains.kotlin.descriptors;
 
 import org.jetbrains.annotations.NotNull;
 
-import java.util.Set;
+import java.util.Collection;
 
 public interface PropertyAccessorDescriptor extends FunctionDescriptor {
     boolean hasBody();
@@ -31,7 +31,7 @@ public interface PropertyAccessorDescriptor extends FunctionDescriptor {
 
     @Override
     @NotNull
-    Set<? extends PropertyAccessorDescriptor> getOverriddenDescriptors();
+    Collection<? extends PropertyAccessorDescriptor> getOverriddenDescriptors();
 
     @NotNull
     PropertyDescriptor getCorrespondingProperty();

core/descriptors/src/org/jetbrains/kotlin/descriptors/PropertyDescriptor.java

@@ -20,8 +20,8 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.jetbrains.kotlin.types.TypeSubstitutor;
 
+import java.util.Collection;
 import java.util.List;
-import java.util.Set;
 
 public interface PropertyDescriptor extends VariableDescriptor, CallableMemberDescriptor {
     @Nullable
@@ -49,7 +49,7 @@ public interface PropertyDescriptor extends VariableDescriptor, CallableMemberDe
 
     @NotNull
     @Override
-    Set<? extends PropertyDescriptor> getOverriddenDescriptors();
+    Collection<? extends PropertyDescriptor> getOverriddenDescriptors();
 
     @Override
     PropertyDescriptor substitute(@NotNull TypeSubstitutor substitutor);

core/descriptors/src/org/jetbrains/kotlin/descriptors/PropertyGetterDescriptor.java

@@ -18,7 +18,7 @@ package org.jetbrains.kotlin.descriptors;
 
 import org.jetbrains.annotations.NotNull;
 
-import java.util.Set;
+import java.util.Collection;
 
 public interface PropertyGetterDescriptor extends PropertyAccessorDescriptor {
     @NotNull
@@ -27,5 +27,5 @@ public interface PropertyGetterDescriptor extends PropertyAccessorDescriptor {
 
     @Override
     @NotNull
-    Set<? extends PropertyGetterDescriptor> getOverriddenDescriptors();
+    Collection<? extends PropertyGetterDescriptor> getOverriddenDescriptors();
 }

core/descriptors/src/org/jetbrains/kotlin/descriptors/PropertySetterDescriptor.java

@@ -18,7 +18,7 @@ package org.jetbrains.kotlin.descriptors;
 
 import org.jetbrains.annotations.NotNull;
 
-import java.util.Set;
+import java.util.Collection;
 
 public interface PropertySetterDescriptor extends PropertyAccessorDescriptor {
     @NotNull
@@ -27,5 +27,5 @@ public interface PropertySetterDescriptor extends PropertyAccessorDescriptor {
 
     @Override
     @NotNull
-    Set<? extends PropertySetterDescriptor> getOverriddenDescriptors();
+    Collection<? extends PropertySetterDescriptor> getOverriddenDescriptors();
 }

core/descriptors/src/org/jetbrains/kotlin/descriptors/ValueParameterDescriptor.java

@@ -21,7 +21,7 @@ import org.jetbrains.annotations.Nullable;
 import org.jetbrains.kotlin.name.Name;
 import org.jetbrains.kotlin.types.JetType;
 
-import java.util.Set;
+import java.util.Collection;
 
 public interface ValueParameterDescriptor extends VariableDescriptor, ParameterDescriptor {
     @NotNull
@@ -58,5 +58,5 @@ public interface ValueParameterDescriptor extends VariableDescriptor, ParameterD
      */
     @NotNull
     @Override
-    Set<? extends ValueParameterDescriptor> getOverriddenDescriptors();
+    Collection<? extends ValueParameterDescriptor> getOverriddenDescriptors();
 }

core/descriptors/src/org/jetbrains/kotlin/descriptors/impl/AbstractReceiverParameterDescriptor.java

@@ -26,9 +26,9 @@ import org.jetbrains.kotlin.types.JetType;
 import org.jetbrains.kotlin.types.TypeSubstitutor;
 import org.jetbrains.kotlin.types.Variance;
 
+import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
-import java.util.Set;
 
 public abstract class AbstractReceiverParameterDescriptor extends DeclarationDescriptorImpl implements ReceiverParameterDescriptor {
     private static final Name RECEIVER_PARAMETER_NAME = Name.special("<this>");
@@ -100,7 +100,7 @@ public abstract class AbstractReceiverParameterDescriptor extends DeclarationDes
 
     @NotNull
     @Override
-    public Set<? extends CallableDescriptor> getOverriddenDescriptors() {
+    public Collection<? extends CallableDescriptor> getOverriddenDescriptors() {
         return Collections.emptySet();
     }
 

core/descriptors/src/org/jetbrains/kotlin/descriptors/impl/ConstructorDescriptorImpl.java

@@ -22,9 +22,9 @@ import org.jetbrains.kotlin.descriptors.*;
 import org.jetbrains.kotlin.descriptors.annotations.Annotations;
 import org.jetbrains.kotlin.name.Name;
 
+import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
-import java.util.Set;
 
 import static org.jetbrains.kotlin.descriptors.ReceiverParameterDescriptor.NO_RECEIVER_PARAMETER;
 
@@ -101,7 +101,7 @@ public class ConstructorDescriptorImpl extends FunctionDescriptorImpl implements
 
     @NotNull
     @Override
-    public Set<? extends FunctionDescriptor> getOverriddenDescriptors() {
+    public Collection<? extends FunctionDescriptor> getOverriddenDescriptors() {
         return Collections.emptySet();
     }
 

core/descriptors/src/org/jetbrains/kotlin/descriptors/impl/FunctionDescriptorImpl.java

@@ -27,10 +27,7 @@ import org.jetbrains.kotlin.types.JetType;
 import org.jetbrains.kotlin.types.TypeSubstitutor;
 import org.jetbrains.kotlin.types.Variance;
 
-import java.util.ArrayList;
+import java.util.*;
-import java.util.LinkedHashSet;
-import java.util.List;
-import java.util.Set;
 
 public abstract class FunctionDescriptorImpl extends DeclarationDescriptorNonRootImpl implements FunctionDescriptor {
     private List<TypeParameterDescriptor> typeParameters;
@@ -120,7 +117,7 @@ public abstract class FunctionDescriptorImpl extends DeclarationDescriptorNonRoo
 
     @NotNull
     @Override
-    public Set<? extends FunctionDescriptor> getOverriddenDescriptors() {
+    public Collection<? extends FunctionDescriptor> getOverriddenDescriptors() {
         return overriddenFunctions;
     }
 

core/descriptors/src/org/jetbrains/kotlin/descriptors/impl/PropertyAccessorDescriptorImpl.java

@@ -23,10 +23,7 @@ import org.jetbrains.kotlin.descriptors.annotations.Annotations;
 import org.jetbrains.kotlin.name.Name;
 import org.jetbrains.kotlin.types.TypeSubstitutor;
 
-import java.util.Collections;
+import java.util.*;
-import java.util.LinkedHashSet;
-import java.util.List;
-import java.util.Set;
 
 public abstract class PropertyAccessorDescriptorImpl extends DeclarationDescriptorNonRootImpl implements PropertyAccessorDescriptor {
 
@@ -142,8 +139,8 @@ public abstract class PropertyAccessorDescriptorImpl extends DeclarationDescript
     }
 
     @NotNull
-    protected Set<PropertyAccessorDescriptor> getOverriddenDescriptors(boolean isGetter) {
+    protected Collection<PropertyAccessorDescriptor> getOverriddenDescriptors(boolean isGetter) {
-        Set<? extends PropertyDescriptor> overriddenProperties = getCorrespondingProperty().getOverriddenDescriptors();
+        Collection<? extends PropertyDescriptor> overriddenProperties = getCorrespondingProperty().getOverriddenDescriptors();
         // LinkedHashSet for determinism
         Set<PropertyAccessorDescriptor> overriddenAccessors = new LinkedHashSet<PropertyAccessorDescriptor>();
         for (PropertyDescriptor overriddenProperty : overriddenProperties) {

core/descriptors/src/org/jetbrains/kotlin/descriptors/impl/PropertyDescriptorImpl.java

@@ -325,7 +325,7 @@ public class PropertyDescriptorImpl extends VariableDescriptorWithInitializerImp
 
     @NotNull
     @Override
-    public Set<? extends PropertyDescriptor> getOverriddenDescriptors() {
+    public Collection<? extends PropertyDescriptor> getOverriddenDescriptors() {
         return overriddenProperties;
     }
 

core/descriptors/src/org/jetbrains/kotlin/descriptors/impl/PropertyGetterDescriptorImpl.java

@@ -23,9 +23,9 @@ import org.jetbrains.kotlin.descriptors.annotations.Annotations;
 import org.jetbrains.kotlin.name.Name;
 import org.jetbrains.kotlin.types.JetType;
 
+import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
-import java.util.Set;
 
 public class PropertyGetterDescriptorImpl extends PropertyAccessorDescriptorImpl implements PropertyGetterDescriptor {
     private JetType returnType;
@@ -57,8 +57,8 @@ public class PropertyGetterDescriptorImpl extends PropertyAccessorDescriptorImpl
     @NotNull
     @Override
     @SuppressWarnings("unchecked")
-    public Set<? extends PropertyGetterDescriptor> getOverriddenDescriptors() {
+    public Collection<? extends PropertyGetterDescriptor> getOverriddenDescriptors() {
-        return (Set) super.getOverriddenDescriptors(true);
+        return (Collection) super.getOverriddenDescriptors(true);
     }
 
     @NotNull

core/descriptors/src/org/jetbrains/kotlin/descriptors/impl/PropertySetterDescriptorImpl.java

@@ -23,9 +23,9 @@ import org.jetbrains.kotlin.descriptors.annotations.Annotations;
 import org.jetbrains.kotlin.name.Name;
 import org.jetbrains.kotlin.types.JetType;
 
+import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
-import java.util.Set;
 
 import static org.jetbrains.kotlin.resolve.descriptorUtil.DescriptorUtilPackage.getBuiltIns;
 
@@ -73,8 +73,8 @@ public class PropertySetterDescriptorImpl extends PropertyAccessorDescriptorImpl
     @NotNull
     @Override
     @SuppressWarnings("unchecked")
-    public Set<? extends PropertySetterDescriptor> getOverriddenDescriptors() {
+    public Collection<? extends PropertySetterDescriptor> getOverriddenDescriptors() {
-        return (Set) super.getOverriddenDescriptors(false);
+        return (Collection) super.getOverriddenDescriptors(false);
     }
 
     @NotNull

core/descriptors/src/org/jetbrains/kotlin/descriptors/impl/ValueParameterDescriptorImpl.java

@@ -27,8 +27,8 @@ import org.jetbrains.kotlin.resolve.constants.ConstantValue;
 import org.jetbrains.kotlin.types.JetType;
 import org.jetbrains.kotlin.types.TypeSubstitutor;
 
+import java.util.Collection;
 import java.util.Collections;
-import java.util.Set;
 
 public class ValueParameterDescriptorImpl extends VariableDescriptorImpl implements ValueParameterDescriptor {
     private final boolean declaresDefaultValue;
@@ -122,8 +122,8 @@ public class ValueParameterDescriptorImpl extends VariableDescriptorImpl impleme
 
     @NotNull
     @Override
-    public Set<? extends ValueParameterDescriptor> getOverriddenDescriptors() {
+    public Collection<? extends ValueParameterDescriptor> getOverriddenDescriptors() {
-        Set<? extends CallableDescriptor> overriddenFunctions = getContainingDeclaration().getOverriddenDescriptors();
+        Collection<? extends CallableDescriptor> overriddenFunctions = getContainingDeclaration().getOverriddenDescriptors();
         if (overriddenFunctions.isEmpty()) return Collections.emptySet();
 
         return KotlinPackage.toSet(KotlinPackage.map(overriddenFunctions, new Function1<CallableDescriptor, ValueParameterDescriptor>() {

core/descriptors/src/org/jetbrains/kotlin/descriptors/impl/VariableDescriptorImpl.java

@@ -23,9 +23,9 @@ import org.jetbrains.kotlin.descriptors.annotations.Annotations;
 import org.jetbrains.kotlin.name.Name;
 import org.jetbrains.kotlin.types.JetType;
 
+import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
-import java.util.Set;
 
 public abstract class VariableDescriptorImpl extends DeclarationDescriptorNonRootImpl implements VariableDescriptor {
     protected JetType outType;
@@ -77,7 +77,7 @@ public abstract class VariableDescriptorImpl extends DeclarationDescriptorNonRoo
 
     @NotNull
     @Override
-    public Set<? extends CallableDescriptor> getOverriddenDescriptors() {
+    public Collection<? extends CallableDescriptor> getOverriddenDescriptors() {
         return Collections.emptySet();
     }
 

core/descriptors/src/org/jetbrains/kotlin/resolve/DescriptorUtils.java

@@ -443,7 +443,7 @@ public class DescriptorUtils {
     @NotNull
     public static <D extends CallableMemberDescriptor> D unwrapFakeOverride(@NotNull D descriptor) {
         while (descriptor.getKind() == CallableMemberDescriptor.Kind.FAKE_OVERRIDE) {
-            Set<? extends CallableMemberDescriptor> overridden = descriptor.getOverriddenDescriptors();
+            Collection<? extends CallableMemberDescriptor> overridden = descriptor.getOverriddenDescriptors();
             if (overridden.isEmpty()) {
                 throw new IllegalStateException("Fake override should have at least one overridden descriptor: " + descriptor);
             }

core/descriptors/src/org/jetbrains/kotlin/resolve/OverridingUtil.java

@@ -447,7 +447,7 @@ public class OverridingUtil {
 
     @Nullable
     private static Visibility computeVisibilityToInherit(@NotNull CallableMemberDescriptor memberDescriptor) {
-        Set<? extends CallableMemberDescriptor> overriddenDescriptors = memberDescriptor.getOverriddenDescriptors();
+        Collection<? extends CallableMemberDescriptor> overriddenDescriptors = memberDescriptor.getOverriddenDescriptors();
         Visibility maxVisibility = findMaxVisibility(overriddenDescriptors);
         if (maxVisibility == null) {
             return null;

idea/src/org/jetbrains/kotlin/idea/refactoring/CallableRefactoring.kt

@@ -59,7 +59,7 @@ public abstract class CallableRefactoring<T: CallableDescriptor>(
         return false
     }
 
-    private fun getClosestModifiableDescriptors(): Set<CallableDescriptor> {
+    private fun getClosestModifiableDescriptors(): Collection<CallableDescriptor> {
         return when (kind) {
             DECLARATION -> {
                 Collections.singleton(callableDescriptor)

js/js.translator/src/org/jetbrains/kotlin/js/translate/utils/JsDescriptorUtils.java

@@ -135,14 +135,13 @@ public final class JsDescriptorUtils {
 
     @Nullable
     public static FunctionDescriptor getOverriddenDescriptor(@NotNull FunctionDescriptor functionDescriptor) {
-        Set<? extends FunctionDescriptor> overriddenDescriptors = functionDescriptor.getOverriddenDescriptors();
+        Collection<? extends FunctionDescriptor> overriddenDescriptors = functionDescriptor.getOverriddenDescriptors();
         if (overriddenDescriptors.isEmpty()) {
             return null;
         }
-        else {
+
-            //TODO: for now translator can't deal with multiple inheritance good enough
+        //TODO: for now translator can't deal with multiple inheritance good enough
-            return overriddenDescriptors.iterator().next();
+        return overriddenDescriptors.iterator().next();
-        }
     }
 
     private static boolean isDefaultAccessor(@Nullable PropertyAccessorDescriptor accessorDescriptor) {