WritableScope: got rid of mutability of implicit receiver

compiler/frontend/src/org/jetbrains/kotlin/descriptors/impl/MutableClassDescriptor.java

@@ -17,6 +17,7 @@
 package org.jetbrains.kotlin.descriptors.impl;
 
 import com.google.common.collect.Sets;
+import kotlin.KotlinPackage;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.jetbrains.kotlin.descriptors.*;
@@ -26,10 +27,7 @@ import org.jetbrains.kotlin.resolve.scopes.*;
 import org.jetbrains.kotlin.storage.LockBasedStorageManager;
 import org.jetbrains.kotlin.types.*;
 
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.List;
-import java.util.Set;
+import java.util.*;
 
 public class MutableClassDescriptor extends ClassDescriptorBase implements ClassDescriptorWithResolutionScopes {
     private final ClassKind kind;
@@ -48,7 +46,7 @@ public class MutableClassDescriptor extends ClassDescriptorBase implements Class
     private final Set<PropertyDescriptor> properties = Sets.newLinkedHashSet();
     private final Set<SimpleFunctionDescriptor> functions = Sets.newLinkedHashSet();
 
-    private final WritableScope writableScopeForMemberResolution;
+    private final MutableScopeForMemberResolution mutableScopeForMemberResolution;
     private final JetScope scopeForMemberResolution;
     // This scope contains type parameters but does not contain inner classes
     private final WritableScope scopeForSupertypeResolution;
@@ -72,18 +70,17 @@ public class MutableClassDescriptor extends ClassDescriptorBase implements Class
 
         RedeclarationHandler redeclarationHandler = RedeclarationHandler.DO_NOTHING;
 
-        setScopeForMemberLookup(new WritableScopeImpl(JetScope.Empty.INSTANCE$, this, redeclarationHandler, "MemberLookup", this)
+        setScopeForMemberLookup(new WritableScopeImpl(JetScope.Empty.INSTANCE$, this, redeclarationHandler, "MemberLookup", null, this)
                                         .changeLockLevel(WritableScope.LockLevel.BOTH));
         this.scopeForSupertypeResolution = new WritableScopeImpl(outerScope, this, redeclarationHandler, "SupertypeResolution")
                 .changeLockLevel(WritableScope.LockLevel.BOTH);
-        this.writableScopeForMemberResolution = new WritableScopeImpl(scopeForSupertypeResolution, this, redeclarationHandler, "MemberResolution")
-                .changeLockLevel(WritableScope.LockLevel.BOTH);
+        this.mutableScopeForMemberResolution = new MutableScopeForMemberResolution();
 
         if (kind == ClassKind.INTERFACE) {
             setUpScopeForInitializers(this);
         }
 
-        this.scopeForMemberResolution = new ChainedScope(this, "MemberResolutionWithStatic", writableScopeForMemberResolution, staticScope);
+        this.scopeForMemberResolution = new ChainedScope(this, "MemberResolutionWithStatic", mutableScopeForMemberResolution, staticScope);
     }
 
     @Nullable
@@ -227,7 +224,7 @@ public class MutableClassDescriptor extends ClassDescriptorBase implements Class
         for (FunctionDescriptor functionDescriptor : getConstructors()) {
             ((ConstructorDescriptorImpl) functionDescriptor).setReturnType(getDefaultType());
         }
-        writableScopeForMemberResolution.setImplicitReceiver(getThisAsReceiverParameter());
+        mutableScopeForMemberResolution.setImplicitReceiver(getThisAsReceiverParameter());
     }
 
     @Override
@@ -281,4 +278,41 @@ public class MutableClassDescriptor extends ClassDescriptorBase implements Class
     public String toString() {
         return DeclarationDescriptorImpl.toString(this);
     }
+
+    private class MutableScopeForMemberResolution extends AbstractScopeAdapter {
+        private ReceiverParameterDescriptor implicitReceiver = null;
+        private List<ReceiverParameterDescriptor> implicitReceiversHierarchy = null;
+
+        @NotNull
+        @Override
+        protected JetScope getWorkerScope() {
+            return scopeForSupertypeResolution;
+        }
+
+        @NotNull
+        @Override
+        public DeclarationDescriptor getContainingDeclaration() {
+            return MutableClassDescriptor.this;
+        }
+
+        public void setImplicitReceiver(@NotNull ReceiverParameterDescriptor implicitReceiver) {
+            if (this.implicitReceiver != null) {
+                throw new UnsupportedOperationException("Receiver redeclared");
+            }
+            if (this.implicitReceiversHierarchy != null) {
+                throw new UnsupportedOperationException("Receiver hierarchy already computed");
+            }
+            this.implicitReceiver = implicitReceiver;
+            this.implicitReceiversHierarchy = KotlinPackage.plus(Collections.singletonList(implicitReceiver), super.getImplicitReceiversHierarchy());
+        }
+
+        @NotNull
+        @Override
+        public List<ReceiverParameterDescriptor> getImplicitReceiversHierarchy() {
+            if (implicitReceiversHierarchy != null)
+                return implicitReceiversHierarchy;
+            else
+                return super.getImplicitReceiversHierarchy();
+        }
+    }
 }

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

@@ -80,11 +80,8 @@ public class FunctionDescriptorUtil {
             @NotNull FunctionDescriptor descriptor,
             @NotNull RedeclarationHandler redeclarationHandler
     ) {
-        WritableScope parameterScope = new WritableScopeImpl(outerScope, descriptor, redeclarationHandler, "Function inner scope", descriptor);
         ReceiverParameterDescriptor receiver = descriptor.getExtensionReceiverParameter();
-        if (receiver != null) {
-            parameterScope.setImplicitReceiver(receiver);
-        }
+        WritableScope parameterScope = new WritableScopeImpl(outerScope, descriptor, redeclarationHandler, "Function inner scope", receiver, descriptor);
         for (TypeParameterDescriptor typeParameter : descriptor.getTypeParameters()) {
             parameterScope.addClassifierDescriptor(typeParameter);
         }

compiler/frontend/src/org/jetbrains/kotlin/resolve/lazy/descriptors/LazyClassDescriptor.java

@@ -266,8 +266,7 @@ public class LazyClassDescriptor extends ClassDescriptorBase implements ClassDes
     @NotNull
     private JetScope computeScopeForMemberDeclarationResolution() {
         WritableScopeImpl thisScope = new WritableScopeImpl(JetScope.Empty.INSTANCE$, this, RedeclarationHandler.DO_NOTHING,
-                                                            "Scope with 'this' for " + getName(), this);
-        thisScope.setImplicitReceiver(this.getThisAsReceiverParameter());
+                                                            "Scope with 'this' for " + getName(), this.getThisAsReceiverParameter(), this);
         thisScope.changeLockLevel(WritableScope.LockLevel.READING);
 
         return new ChainedScope(

compiler/frontend/src/org/jetbrains/kotlin/resolve/lazy/descriptors/LazyScriptDescriptor.kt

@@ -81,8 +81,7 @@ public class LazyScriptDescriptor(
     override fun getScriptCodeDescriptor() = scriptCodeDescriptor()
 
     override fun getScopeForBodyResolution(): JetScope {
-        val parametersScope = WritableScopeImpl(JetScope.Empty, this, RedeclarationHandler.DO_NOTHING, "Parameters of " + this)
-        parametersScope.setImplicitReceiver(implicitReceiver)
+        val parametersScope = WritableScopeImpl(JetScope.Empty, this, RedeclarationHandler.DO_NOTHING, "Parameters of " + this, implicitReceiver)
         for (valueParameterDescriptor in getScriptCodeDescriptor().getValueParameters()) {
             parametersScope.addVariableDescriptor(valueParameterDescriptor)
         }

compiler/frontend/src/org/jetbrains/kotlin/resolve/scopes/JetScopeUtils.java

@@ -127,13 +127,11 @@ public final class JetScopeUtils {
         WritableScopeImpl result = new WritableScopeImpl(
                 outerScope, propertyDescriptor, redeclarationHandler,
                 "Property declaration inner scope",
+                receiver,
                 addLabelForProperty ? propertyDescriptor : null);
         for (TypeParameterDescriptor typeParameterDescriptor : typeParameters) {
             result.addClassifierDescriptor(typeParameterDescriptor);
         }
-        if (receiver != null) {
-            result.setImplicitReceiver(receiver);
-        }
         result.changeLockLevel(WritableScope.LockLevel.READING);
         return result;
     }

compiler/frontend/src/org/jetbrains/kotlin/resolve/scopes/WritableScope.kt

@@ -36,7 +36,5 @@ public trait WritableScope : JetScope {
     public fun addFunctionDescriptor(functionDescriptor: FunctionDescriptor)
 
     public fun addClassifierDescriptor(classifierDescriptor: ClassifierDescriptor)
-
-    public fun setImplicitReceiver(implicitReceiver: ReceiverParameterDescriptor)
 }
 

compiler/frontend/src/org/jetbrains/kotlin/resolve/scopes/WritableScopeImpl.kt

@@ -37,24 +37,27 @@ public class WritableScopeImpl @jvmOverloads constructor(
         private val ownerDeclarationDescriptor: DeclarationDescriptor,
         private val redeclarationHandler: RedeclarationHandler,
         private val debugName: String,
+        implicitReceiver: ReceiverParameterDescriptor? = null,
         private val labeledDeclaration: DeclarationDescriptor? = null
 ) : AbstractScopeAdapter(), WritableScope {
 
+    override val workerScope: JetScope = if (outerScope is WritableScope) outerScope.takeSnapshot() else outerScope
+
     private val addedDescriptors = SmartList<DeclarationDescriptor>()
 
     private var functionsByName: MutableMap<Name, IntList>? = null
     private var variablesAndClassifiersByName: MutableMap<Name, IntList>? = null
 
-    private var implicitReceiver: ReceiverParameterDescriptor? = null
-    private var implicitReceiverHierarchy: List<ReceiverParameterDescriptor>? = null
-
-    override fun getContainingDeclaration(): DeclarationDescriptor = ownerDeclarationDescriptor
+    private val implicitReceiverHierarchy = if (implicitReceiver != null)
+        listOf(implicitReceiver) + super<AbstractScopeAdapter>.getImplicitReceiversHierarchy()
+    else
+        super<AbstractScopeAdapter>.getImplicitReceiversHierarchy()
 
     private var lastSnapshot: Snapshot? = null
 
     private var lockLevel: WritableScope.LockLevel = WritableScope.LockLevel.WRITING
 
-    override val workerScope: JetScope = if (outerScope is WritableScope) outerScope.takeSnapshot() else outerScope
+    override fun getContainingDeclaration() = ownerDeclarationDescriptor
 
     override fun changeLockLevel(lockLevel: WritableScope.LockLevel): WritableScope {
         if (lockLevel.ordinal() < this.lockLevel.ordinal()) {
@@ -170,30 +173,7 @@ public class WritableScopeImpl @jvmOverloads constructor(
                ?: workerScope.getClassifier(name)
     }
 
-    override fun setImplicitReceiver(implicitReceiver: ReceiverParameterDescriptor) {
-        checkMayWrite()
-
-        if (this.implicitReceiver != null) {
-            throw UnsupportedOperationException("Receiver redeclared")
-        }
-        this.implicitReceiver = implicitReceiver
-    }
-
-    override fun getImplicitReceiversHierarchy(): List<ReceiverParameterDescriptor> {
-        checkMayRead()
-
-        if (implicitReceiverHierarchy == null) {
-            implicitReceiverHierarchy = computeImplicitReceiversHierarchy()
-        }
-        return implicitReceiverHierarchy!!
-    }
-
-    private fun computeImplicitReceiversHierarchy(): List<ReceiverParameterDescriptor> {
-        return if (implicitReceiver != null)
-            listOf(implicitReceiver!!) + super<AbstractScopeAdapter>.getImplicitReceiversHierarchy()
-        else
-            super<AbstractScopeAdapter>.getImplicitReceiversHierarchy()
-    }
+    override fun getImplicitReceiversHierarchy() = implicitReceiverHierarchy
 
     override fun getOwnDeclaredDescriptors(): Collection<DeclarationDescriptor> = addedDescriptors