J2K serialization: fix compilation and prettify

compiler/serialization/src/org/jetbrains/kotlin/serialization/AnnotationSerializer.kt

@@ -25,66 +25,62 @@ import org.jetbrains.kotlin.serialization.ProtoBuf.Annotation.Argument.Value.Typ
 import org.jetbrains.kotlin.types.ErrorUtils
 
 class AnnotationSerializer(private val stringTable: StringTable) {
-    fun serializeAnnotation(annotation: AnnotationDescriptor): ProtoBuf.Annotation {
-        return with(ProtoBuf.Annotation.newBuilder()) {
-            val annotationClass = annotation.type.constructor.declarationDescriptor as? ClassDescriptor
-                                  ?: error("Annotation type is not a class: ${annotation.type}")
-            if (ErrorUtils.isError(annotationClass)) {
-                error("Unresolved annotation type: ${annotation.type}")
-            }
-
-            setId(stringTable.getFqNameIndex(annotationClass))
-
-            for ((parameter, value) in annotation.allValueArguments) {
-                val argument = ProtoBuf.Annotation.Argument.newBuilder()
-                argument.setNameId(stringTable.getStringIndex(parameter.name.asString()))
-                argument.setValue(valueProto(value))
-                addArgument(argument)
-            }
-
-            build()
+    fun serializeAnnotation(annotation: AnnotationDescriptor): ProtoBuf.Annotation = ProtoBuf.Annotation.newBuilder().apply {
+        val annotationClass = annotation.type.constructor.declarationDescriptor as? ClassDescriptor
+                              ?: error("Annotation type is not a class: ${annotation.type}")
+        if (ErrorUtils.isError(annotationClass)) {
+            error("Unresolved annotation type: ${annotation.type}")
         }
-    }
 
-    fun valueProto(constant: ConstantValue<*>): Value.Builder = with(Value.newBuilder()) {
+        id = stringTable.getFqNameIndex(annotationClass)
+
+        for ((parameter, value) in annotation.allValueArguments) {
+            val argument = ProtoBuf.Annotation.Argument.newBuilder()
+            argument.nameId = stringTable.getStringIndex(parameter.name.asString())
+            argument.setValue(valueProto(value))
+            addArgument(argument)
+        }
+    }.build()
+
+    fun valueProto(constant: ConstantValue<*>): Value.Builder = Value.newBuilder().apply {
         constant.accept(object : AnnotationArgumentVisitor<Unit, Unit> {
             override fun visitAnnotationValue(value: AnnotationValue, data: Unit) {
-                setType(Type.ANNOTATION)
-                setAnnotation(serializeAnnotation(value.value))
+                type = Type.ANNOTATION
+                annotation = serializeAnnotation(value.value)
             }
 
             override fun visitArrayValue(value: ArrayValue, data: Unit) {
-                setType(Type.ARRAY)
+                type = Type.ARRAY
                 for (element in value.value) {
                     addArrayElement(valueProto(element).build())
                 }
             }
 
             override fun visitBooleanValue(value: BooleanValue, data: Unit) {
-                setType(Type.BOOLEAN)
+                type = Type.BOOLEAN
                 setIntValue(if (value.value) 1 else 0)
             }
 
             override fun visitByteValue(value: ByteValue, data: Unit) {
-                setType(Type.BYTE)
-                setIntValue(value.value.toLong())
+                type = Type.BYTE
+                intValue = value.value.toLong()
             }
 
             override fun visitCharValue(value: CharValue, data: Unit) {
-                setType(Type.CHAR)
-                setIntValue(value.value.toLong())
+                type = Type.CHAR
+                intValue = value.value.toLong()
             }
 
             override fun visitDoubleValue(value: DoubleValue, data: Unit) {
-                setType(Type.DOUBLE)
-                setDoubleValue(value.value)
+                type = Type.DOUBLE
+                doubleValue = value.value
             }
 
             override fun visitEnumValue(value: EnumValue, data: Unit) {
-                setType(Type.ENUM)
+                type = Type.ENUM
                 val enumEntry = value.value
-                setClassId(stringTable.getFqNameIndex(enumEntry.containingDeclaration as ClassDescriptor))
-                setEnumValueId(stringTable.getStringIndex(enumEntry.name.asString()))
+                classId = stringTable.getFqNameIndex(enumEntry.containingDeclaration as ClassDescriptor)
+                enumValueId = stringTable.getStringIndex(enumEntry.name.asString())
             }
 
             override fun visitErrorValue(value: ErrorValue, data: Unit) {
@@ -92,13 +88,13 @@ class AnnotationSerializer(private val stringTable: StringTable) {
             }
 
             override fun visitFloatValue(value: FloatValue, data: Unit) {
-                setType(Type.FLOAT)
-                setFloatValue(value.value)
+                type = Type.FLOAT
+                floatValue = value.value
             }
 
             override fun visitIntValue(value: IntValue, data: Unit) {
-                setType(Type.INT)
-                setIntValue(value.value.toLong())
+                type = Type.INT
+                intValue = value.value.toLong()
             }
 
             override fun visitKClassValue(value: KClassValue?, data: Unit?) {
@@ -107,8 +103,8 @@ class AnnotationSerializer(private val stringTable: StringTable) {
             }
 
             override fun visitLongValue(value: LongValue, data: Unit) {
-                setType(Type.LONG)
-                setIntValue(value.value)
+                type = Type.LONG
+                intValue = value.value
             }
 
             override fun visitNullValue(value: NullValue, data: Unit) {
@@ -116,16 +112,14 @@ class AnnotationSerializer(private val stringTable: StringTable) {
             }
 
             override fun visitShortValue(value: ShortValue, data: Unit) {
-                setType(Type.SHORT)
-                setIntValue(value.value.toLong())
+                type = Type.SHORT
+                intValue = value.value.toLong()
             }
 
             override fun visitStringValue(value: StringValue, data: Unit) {
-                setType(Type.STRING)
-                setStringValue(stringTable.getStringIndex(value.value))
+                type = Type.STRING
+                stringValue = stringTable.getStringIndex(value.value)
             }
         }, Unit)
-
-        this
     }
 }

compiler/serialization/src/org/jetbrains/kotlin/serialization/DescriptorSerializer.kt

@@ -27,9 +27,7 @@ import org.jetbrains.kotlin.resolve.MemberComparator
 import org.jetbrains.kotlin.resolve.constants.NullValue
 import org.jetbrains.kotlin.types.*
 import org.jetbrains.kotlin.utils.Interner
-import org.jetbrains.kotlin.utils.rethrow
 import java.io.ByteArrayOutputStream
-import java.io.IOException
 import java.util.*
 
 class DescriptorSerializer private constructor(
@@ -37,38 +35,30 @@ class DescriptorSerializer private constructor(
         private val typeParameters: Interner<TypeParameterDescriptor>,
         private val extension: SerializerExtension,
         private val typeTable: MutableTypeTable,
-        private val serializeTypeTableToFunction: Boolean) {
-
+        private val serializeTypeTableToFunction: Boolean
+) {
     fun serialize(message: MessageLite): ByteArray {
-        try {
-            val result = ByteArrayOutputStream()
-            stringTable.serializeTo(result)
-            message.writeTo(result)
-            return result.toByteArray()
-        }
-        catch (e: IOException) {
-            throw rethrow(e)
-        }
-
+        return ByteArrayOutputStream().apply {
+            stringTable.serializeTo(this)
+            message.writeTo(this)
+        }.toByteArray()
     }
 
-    private fun createChildSerializer(callable: CallableDescriptor): DescriptorSerializer {
-        return DescriptorSerializer(callable, Interner(typeParameters), extension, typeTable, false)
-    }
+    private fun createChildSerializer(callable: CallableDescriptor): DescriptorSerializer =
+            DescriptorSerializer(callable, Interner(typeParameters), extension, typeTable, serializeTypeTableToFunction = false)
 
     val stringTable: StringTable
         get() = extension.stringTable
 
-    private fun useTypeTable(): Boolean {
-        return extension.shouldUseTypeTable()
-    }
+    private fun useTypeTable(): Boolean = extension.shouldUseTypeTable()
 
     fun classProto(classDescriptor: ClassDescriptor): ProtoBuf.Class.Builder {
         val builder = ProtoBuf.Class.newBuilder()
 
-        val flags = Flags.getClassFlags(hasAnnotations(classDescriptor), classDescriptor.visibility, classDescriptor.modality,
-                                        classDescriptor.kind, classDescriptor.isInner, classDescriptor.isCompanionObject,
-                                        classDescriptor.isData)
+        val flags = Flags.getClassFlags(
+                hasAnnotations(classDescriptor), classDescriptor.visibility, classDescriptor.modality, classDescriptor.kind,
+                classDescriptor.isInner, classDescriptor.isCompanionObject, classDescriptor.isData
+        )
         if (flags != builder.flags) {
             builder.flags = flags
         }
@@ -99,11 +89,9 @@ class DescriptorSerializer private constructor(
             if (descriptor is CallableMemberDescriptor) {
                 if (descriptor.kind == CallableMemberDescriptor.Kind.FAKE_OVERRIDE) continue
 
-                if (descriptor is PropertyDescriptor) {
-                    builder.addProperty(propertyProto(descriptor))
-                }
-                else if (descriptor is FunctionDescriptor) {
-                    builder.addFunction(functionProto(descriptor))
+                when (descriptor) {
+                    is PropertyDescriptor -> builder.addProperty(propertyProto(descriptor))
+                    is FunctionDescriptor -> builder.addFunction(functionProto(descriptor))
                 }
             }
         }
@@ -149,37 +137,32 @@ class DescriptorSerializer private constructor(
         val isConst = descriptor.isConst
 
         val compileTimeConstant = descriptor.compileTimeInitializer
-        val hasConstant = !(compileTimeConstant == null || compileTimeConstant is NullValue)
+        val hasConstant = compileTimeConstant != null && compileTimeConstant !is NullValue
 
-        val hasAnnotations = !descriptor.annotations.getAllAnnotations().isEmpty()
+        val hasAnnotations = descriptor.annotations.getAllAnnotations().isNotEmpty()
 
-        val propertyFlags = Flags.getAccessorFlags(
-                hasAnnotations,
-                descriptor.visibility,
-                descriptor.modality,
-                false,
-                false)
+        val propertyFlags = Flags.getAccessorFlags(hasAnnotations, descriptor.visibility, descriptor.modality, false, false)
 
-        val getter = descriptor.getGetter()
+        val getter = descriptor.getter
         if (getter != null) {
             hasGetter = true
-            val accessorFlags = getAccessorFlags(getter!!)
+            val accessorFlags = getAccessorFlags(getter)
             if (accessorFlags != propertyFlags) {
                 builder.getterFlags = accessorFlags
             }
         }
 
-        val setter = descriptor.getSetter()
+        val setter = descriptor.setter
         if (setter != null) {
             hasSetter = true
-            val accessorFlags = getAccessorFlags(setter!!)
+            val accessorFlags = getAccessorFlags(setter)
             if (accessorFlags != propertyFlags) {
                 builder.setterFlags = accessorFlags
             }
 
-            if (!setter!!.isDefault()) {
-                val setterLocal = local.createChildSerializer(setter!!)
-                for (valueParameterDescriptor in setter!!.getValueParameters()) {
+            if (!setter.isDefault) {
+                val setterLocal = local.createChildSerializer(setter)
+                for (valueParameterDescriptor in setter.valueParameters) {
                     builder.setSetterValueParameter(setterLocal.valueParameter(valueParameterDescriptor))
                 }
             }
@@ -187,7 +170,8 @@ class DescriptorSerializer private constructor(
 
         val flags = Flags.getPropertyFlags(
                 hasAnnotations, descriptor.visibility, descriptor.modality, descriptor.kind, descriptor.isVar,
-                hasGetter, hasSetter, hasConstant, isConst, lateInit)
+                hasGetter, hasSetter, hasConstant, isConst, lateInit
+        )
         if (flags != builder.flags) {
             builder.flags = flags
         }
@@ -226,9 +210,8 @@ class DescriptorSerializer private constructor(
         val local = createChildSerializer(descriptor)
 
         val flags = Flags.getFunctionFlags(
-                hasAnnotations(descriptor), descriptor.visibility, descriptor.modality, descriptor.kind,
-                descriptor.isOperator, descriptor.isInfix, descriptor.isInline, descriptor.isTailrec,
-                descriptor.isExternal, descriptor.isSuspend
+                hasAnnotations(descriptor), descriptor.visibility, descriptor.modality, descriptor.kind, descriptor.isOperator,
+                descriptor.isInfix, descriptor.isInline, descriptor.isTailrec, descriptor.isExternal, descriptor.isSuspend
         )
         if (flags != builder.flags) {
             builder.flags = flags
@@ -237,11 +220,9 @@ class DescriptorSerializer private constructor(
         builder.name = getSimpleNameIndex(descriptor.name)
 
         if (useTypeTable()) {
-            //noinspection ConstantConditions
             builder.returnTypeId = local.typeId(descriptor.returnType!!)
         }
         else {
-            //noinspection ConstantConditions
             builder.setReturnType(local.type(descriptor.returnType!!))
         }
 
@@ -337,8 +318,10 @@ class DescriptorSerializer private constructor(
     private fun valueParameter(descriptor: ValueParameterDescriptor): ProtoBuf.ValueParameter.Builder {
         val builder = ProtoBuf.ValueParameter.newBuilder()
 
-        val flags = Flags.getValueParameterFlags(hasAnnotations(descriptor), descriptor.declaresDefaultValue(),
-                                                 descriptor.isCrossinline, descriptor.isNoinline, descriptor.isCoroutine)
+        val flags = Flags.getValueParameterFlags(
+                hasAnnotations(descriptor), descriptor.declaresDefaultValue(),
+                descriptor.isCrossinline, descriptor.isNoinline, descriptor.isCoroutine
+        )
         if (flags != builder.flags) {
             builder.flags = flags
         }
@@ -399,9 +382,7 @@ class DescriptorSerializer private constructor(
         return builder
     }
 
-    private fun typeId(type: KotlinType): Int {
-        return typeTable[type(type)]
-    }
+    private fun typeId(type: KotlinType): Int = typeTable[type(type)]
 
     private fun type(type: KotlinType): ProtoBuf.Type.Builder {
         val builder = ProtoBuf.Type.newBuilder()
@@ -416,7 +397,7 @@ class DescriptorSerializer private constructor(
 
             val lowerBound = type(flexibleType.lowerBound)
             val upperBound = type(flexibleType.upperBound)
-            extension.serializeFlexibleType(flexibleType, lowerBound, upperBound);
+            extension.serializeFlexibleType(flexibleType, lowerBound, upperBound)
             if (useTypeTable()) {
                 lowerBound.flexibleUpperBoundId = typeTable[upperBound]
             }
@@ -427,24 +408,21 @@ class DescriptorSerializer private constructor(
         }
 
         val descriptor = type.constructor.declarationDescriptor
-        if (descriptor is ClassDescriptor) {
-            val possiblyInnerType = type.buildPossiblyInnerType() ?: error("possiblyInnerType should not be null in case of class")
-
-            fillFromPossiblyInnerType(builder, possiblyInnerType)
-        }
-        else if (descriptor is TypeParameterDescriptor) {
-            if (descriptor.containingDeclaration === containingDeclaration) {
-                builder.typeParameterName = getSimpleNameIndex(descriptor.name)
-            }
-            else {
-                builder.typeParameter = getTypeParameterId(descriptor)
+        when (descriptor) {
+            is ClassDescriptor, is TypeAliasDescriptor -> {
+                val possiblyInnerType = type.buildPossiblyInnerType() ?: error("possiblyInnerType should not be null: $type")
+                fillFromPossiblyInnerType(builder, possiblyInnerType)
             }
+            is TypeParameterDescriptor -> {
+                if (descriptor.containingDeclaration === containingDeclaration) {
+                    builder.typeParameterName = getSimpleNameIndex(descriptor.name)
+                }
+                else {
+                    builder.typeParameter = getTypeParameterId(descriptor)
+                }
 
-            assert(type.arguments.isEmpty()) { "Found arguments for type constructor build on type parameter: " + descriptor }
-        }
-        else if (descriptor is TypeAliasDescriptor) {
-            val possiblyInnerType = type.buildPossiblyInnerType() ?: error("possiblyInnerType should not be null in case of type alias")
-            fillFromPossiblyInnerType(builder, possiblyInnerType)
+                assert(type.arguments.isEmpty()) { "Found arguments for type constructor build on type parameter: $descriptor" }
+            }
         }
 
         if (type.isMarkedNullable != builder.nullable) {
@@ -466,16 +444,12 @@ class DescriptorSerializer private constructor(
         return builder
     }
 
-    private fun fillFromPossiblyInnerType(
-            builder: ProtoBuf.Type.Builder,
-            type: PossiblyInnerType) {
+    private fun fillFromPossiblyInnerType(builder: ProtoBuf.Type.Builder, type: PossiblyInnerType) {
         val classifierDescriptor = type.classifierDescriptor
         val classifierId = getClassifierId(classifierDescriptor)
-        if (classifierDescriptor is ClassDescriptor) {
-            builder.className = classifierId
-        }
-        else if (classifierDescriptor is TypeAliasDescriptor) {
-            builder.typeAliasName = classifierId
+        when (classifierDescriptor) {
+            is ClassDescriptor -> builder.className = classifierId
+            is TypeAliasDescriptor -> builder.typeAliasName = classifierId
         }
 
         for (projection in type.arguments) {
@@ -491,7 +465,6 @@ class DescriptorSerializer private constructor(
             else {
                 builder.setOuterType(outerBuilder)
             }
-
         }
     }
 
@@ -519,24 +492,22 @@ class DescriptorSerializer private constructor(
         return builder
     }
 
-    @JvmOverloads fun packageProto(
-            fragments: Collection<PackageFragmentDescriptor>,
-            skip: Function1<DeclarationDescriptor, Boolean>? = null): ProtoBuf.Package.Builder {
+    @JvmOverloads
+    fun packageProto(
+            fragments: Collection<PackageFragmentDescriptor>, skip: ((DeclarationDescriptor) -> Boolean)? = null
+    ): ProtoBuf.Package.Builder {
         val builder = ProtoBuf.Package.newBuilder()
 
-        val members = ArrayList<DeclarationDescriptor>()
-        for (fragment in fragments) {
-            members.addAll(DescriptorUtils.getAllDescriptors(fragment.getMemberScope()))
+        val members = fragments.flatMap { fragment ->
+            DescriptorUtils.getAllDescriptors(fragment.getMemberScope())
         }
 
         for (declaration in sort(members)) {
-            if (skip != null && skip.invoke(declaration)) continue
+            if (skip?.invoke(declaration) == true) continue
 
-            if (declaration is PropertyDescriptor) {
-                builder.addProperty(propertyProto(declaration))
-            }
-            else if (declaration is FunctionDescriptor) {
-                builder.addFunction(functionProto(declaration))
+            when (declaration) {
+                is PropertyDescriptor -> builder.addProperty(propertyProto(declaration))
+                is FunctionDescriptor -> builder.addFunction(functionProto(declaration))
             }
         }
 
@@ -554,14 +525,10 @@ class DescriptorSerializer private constructor(
         val builder = ProtoBuf.Package.newBuilder()
 
         for (declaration in sort(members)) {
-            if (declaration is PropertyDescriptor) {
-                builder.addProperty(propertyProto(declaration))
-            }
-            else if (declaration is FunctionDescriptor) {
-                builder.addFunction(functionProto(declaration))
-            }
-            else if (declaration is TypeAliasDescriptor) {
-                builder.addTypeAlias(typeAliasProto(declaration))
+            when (declaration) {
+                is PropertyDescriptor -> builder.addProperty(propertyProto(declaration))
+                is FunctionDescriptor -> builder.addFunction(functionProto(declaration))
+                is TypeAliasDescriptor -> builder.addTypeAlias(typeAliasProto(declaration))
             }
         }
 
@@ -575,27 +542,24 @@ class DescriptorSerializer private constructor(
         return builder
     }
 
-    private fun getClassifierId(descriptor: ClassifierDescriptorWithTypeParameters): Int {
-        return stringTable.getFqNameIndex(descriptor)
-    }
+    private fun getClassifierId(descriptor: ClassifierDescriptorWithTypeParameters): Int =
+            stringTable.getFqNameIndex(descriptor)
 
-    private fun getSimpleNameIndex(name: Name): Int {
-        return stringTable.getStringIndex(name.asString())
-    }
+    private fun getSimpleNameIndex(name: Name): Int =
+            stringTable.getStringIndex(name.asString())
 
-    private fun getTypeParameterId(descriptor: TypeParameterDescriptor): Int {
-        return typeParameters.intern(descriptor)
-    }
+    private fun getTypeParameterId(descriptor: TypeParameterDescriptor): Int =
+            typeParameters.intern(descriptor)
 
     companion object {
         @JvmStatic
         fun createTopLevel(extension: SerializerExtension): DescriptorSerializer {
-            return DescriptorSerializer(null, Interner<TypeParameterDescriptor>(), extension, MutableTypeTable(), false)
+            return DescriptorSerializer(null, Interner(), extension, MutableTypeTable(), serializeTypeTableToFunction = false)
         }
 
         @JvmStatic
         fun createForLambda(extension: SerializerExtension): DescriptorSerializer {
-            return DescriptorSerializer(null, Interner<TypeParameterDescriptor>(), extension, MutableTypeTable(), true)
+            return DescriptorSerializer(null, Interner(), extension, MutableTypeTable(), serializeTypeTableToFunction = true)
         }
 
         @JvmStatic
@@ -614,7 +578,8 @@ class DescriptorSerializer private constructor(
                     Interner(parentSerializer.typeParameters),
                     parentSerializer.extension,
                     MutableTypeTable(),
-                    false)
+                    serializeTypeTableToFunction = false
+            )
             for (typeParameter in descriptor.declaredTypeParameters) {
                 serializer.typeParameters.intern(typeParameter)
             }
@@ -627,37 +592,28 @@ class DescriptorSerializer private constructor(
                     accessor.visibility,
                     accessor.modality,
                     !accessor.isDefault,
-                    accessor.isExternal)
+                    accessor.isExternal
+            )
         }
 
-        private fun variance(variance: Variance): ProtoBuf.TypeParameter.Variance {
-            when (variance) {
-                Variance.INVARIANT -> return ProtoBuf.TypeParameter.Variance.INV
-                Variance.IN_VARIANCE -> return ProtoBuf.TypeParameter.Variance.IN
-                Variance.OUT_VARIANCE -> return ProtoBuf.TypeParameter.Variance.OUT
-            }
-            throw IllegalStateException("Unknown variance: " + variance)
+        private fun variance(variance: Variance): ProtoBuf.TypeParameter.Variance = when (variance) {
+            Variance.INVARIANT -> ProtoBuf.TypeParameter.Variance.INV
+            Variance.IN_VARIANCE -> ProtoBuf.TypeParameter.Variance.IN
+            Variance.OUT_VARIANCE -> ProtoBuf.TypeParameter.Variance.OUT
         }
 
-        private fun projection(projectionKind: Variance): ProtoBuf.Type.Argument.Projection {
-            when (projectionKind) {
-                Variance.INVARIANT -> return ProtoBuf.Type.Argument.Projection.INV
-                Variance.IN_VARIANCE -> return ProtoBuf.Type.Argument.Projection.IN
-                Variance.OUT_VARIANCE -> return ProtoBuf.Type.Argument.Projection.OUT
-            }
-            throw IllegalStateException("Unknown projectionKind: " + projectionKind)
+        private fun projection(projectionKind: Variance): ProtoBuf.Type.Argument.Projection = when (projectionKind) {
+            Variance.INVARIANT -> ProtoBuf.Type.Argument.Projection.INV
+            Variance.IN_VARIANCE -> ProtoBuf.Type.Argument.Projection.IN
+            Variance.OUT_VARIANCE -> ProtoBuf.Type.Argument.Projection.OUT
         }
 
-        private fun hasAnnotations(descriptor: Annotated): Boolean {
-            return !descriptor.annotations.isEmpty()
-        }
+        private fun hasAnnotations(descriptor: Annotated): Boolean = !descriptor.annotations.isEmpty()
 
-        fun <T : DeclarationDescriptor> sort(descriptors: Collection<T>): List<T> {
-            val result = ArrayList(descriptors)
-            //NOTE: the exact comparator does matter here
-            Collections.sort(result, MemberComparator.INSTANCE)
-            return result
-
-        }
+        fun <T : DeclarationDescriptor> sort(descriptors: Collection<T>): List<T> =
+                ArrayList(descriptors).apply {
+                    //NOTE: the exact comparator does matter here
+                    Collections.sort(this, MemberComparator.INSTANCE)
+                }
     }
 }

compiler/serialization/src/org/jetbrains/kotlin/serialization/SerializerExtension.kt

@@ -23,9 +23,7 @@ import org.jetbrains.kotlin.types.KotlinType
 abstract class SerializerExtension {
     abstract val stringTable: StringTable
 
-    open fun shouldUseTypeTable(): Boolean {
-        return false
-    }
+    open fun shouldUseTypeTable(): Boolean = false
 
     open fun serializeClass(descriptor: ClassDescriptor, proto: ProtoBuf.Class.Builder) {
     }
@@ -58,6 +56,6 @@ abstract class SerializerExtension {
     }
 
     open fun serializeErrorType(type: KotlinType, builder: ProtoBuf.Type.Builder) {
-        throw IllegalStateException("Cannot serialize error type: " + type)
+        throw IllegalStateException("Cannot serialize error type: $type")
     }
 }

compiler/serialization/src/org/jetbrains/kotlin/serialization/SerializerExtensionBase.kt

@@ -21,11 +21,9 @@ import org.jetbrains.kotlin.resolve.constants.NullValue
 import org.jetbrains.kotlin.types.KotlinType
 
 open class KotlinSerializerExtensionBase(private val protocol: SerializerExtensionProtocol) : SerializerExtension() {
-    private val stringTable = StringTableImpl()
+    override final val stringTable = StringTableImpl()
     private val annotationSerializer = AnnotationSerializer(stringTable)
 
-    override fun getStringTable(): StringTableImpl = stringTable
-
     override fun serializeClass(descriptor: ClassDescriptor, proto: ProtoBuf.Class.Builder) {
         for (annotation in descriptor.annotations) {
             proto.addExtension(protocol.classAnnotation, annotationSerializer.serializeAnnotation(annotation))
@@ -77,4 +75,4 @@ open class KotlinSerializerExtensionBase(private val protocol: SerializerExtensi
             proto.addExtension(protocol.typeParameterAnnotation, annotationSerializer.serializeAnnotation(annotation))
         }
     }
-}
+}

compiler/serialization/src/org/jetbrains/kotlin/serialization/StringTableImpl.kt

@@ -18,22 +18,16 @@ package org.jetbrains.kotlin.serialization
 
 import org.jetbrains.kotlin.descriptors.ClassDescriptor
 import org.jetbrains.kotlin.descriptors.ClassifierDescriptorWithTypeParameters
-import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
 import org.jetbrains.kotlin.descriptors.PackageFragmentDescriptor
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
-import org.jetbrains.kotlin.types.ErrorUtils
-import org.jetbrains.kotlin.utils.*
-import org.jetbrains.kotlin.utils.Interner
-
-import java.io.IOException
-import java.io.OutputStream
-
 import org.jetbrains.kotlin.serialization.ProtoBuf.QualifiedNameTable.QualifiedName
+import org.jetbrains.kotlin.types.ErrorUtils
+import org.jetbrains.kotlin.utils.Interner
+import java.io.OutputStream
 
 class StringTableImpl : StringTable {
     private class FqNameProto(val fqName: QualifiedName.Builder) {
-
         override fun hashCode(): Int {
             var result = 13
             result = 31 * result + fqName.parentQualifiedName
@@ -42,47 +36,43 @@ class StringTableImpl : StringTable {
             return result
         }
 
-        override fun equals(obj: Any?): Boolean {
-            if (obj == null || javaClass != obj.javaClass) return false
+        override fun equals(other: Any?): Boolean {
+            if (other == null || other !is FqNameProto) return false
 
-            val other = (obj as FqNameProto).fqName
-            return fqName.parentQualifiedName == other.parentQualifiedName
-                   && fqName.shortName == other.shortName
-                   && fqName.kind == other.kind
+            val otherFqName = other.fqName
+            return fqName.parentQualifiedName == otherFqName.parentQualifiedName
+                   && fqName.shortName == otherFqName.shortName
+                   && fqName.kind == otherFqName.kind
         }
     }
 
     private val strings = Interner<String>()
     private val qualifiedNames = Interner<FqNameProto>()
 
-    fun getSimpleNameIndex(name: Name): Int {
-        return getStringIndex(name.asString())
-    }
+    fun getSimpleNameIndex(name: Name): Int = getStringIndex(name.asString())
 
-    override fun getStringIndex(string: String): Int {
-        return strings.intern(string)
-    }
+    override fun getStringIndex(string: String): Int = strings.intern(string)
 
     override fun getFqNameIndex(descriptor: ClassifierDescriptorWithTypeParameters): Int {
         if (ErrorUtils.isError(descriptor)) {
-            throw IllegalStateException("Cannot get FQ name of error class: " + descriptor)
+            throw IllegalStateException("Cannot get FQ name of error class: $descriptor")
         }
 
         val builder = QualifiedName.newBuilder()
         builder.kind = QualifiedName.Kind.CLASS
 
         val containingDeclaration = descriptor.containingDeclaration
-        if (containingDeclaration is PackageFragmentDescriptor) {
-            val packageFqName = containingDeclaration.fqName
-            if (!packageFqName.isRoot) {
-                builder.parentQualifiedName = getPackageFqNameIndex(packageFqName)
+        when (containingDeclaration) {
+            is PackageFragmentDescriptor -> {
+                val packageFqName = containingDeclaration.fqName
+                if (!packageFqName.isRoot) {
+                    builder.parentQualifiedName = getPackageFqNameIndex(packageFqName)
+                }
             }
-        }
-        else if (containingDeclaration is ClassDescriptor) {
-            builder.parentQualifiedName = getFqNameIndex(containingDeclaration)
-        }
-        else {
-            throw IllegalStateException("Cannot get FQ name of local class: " + descriptor)
+            is ClassDescriptor -> {
+                builder.parentQualifiedName = getFqNameIndex(containingDeclaration)
+            }
+            else -> throw IllegalStateException("Cannot get FQ name of local class: " + descriptor)
         }
 
         builder.shortName = getStringIndex(descriptor.name.asString())
@@ -118,14 +108,8 @@ class StringTableImpl : StringTable {
     }
 
     override fun serializeTo(output: OutputStream) {
-        try {
-            val protos = buildProto()
-            protos.first.writeDelimitedTo(output)
-            protos.second.writeDelimitedTo(output)
-        }
-        catch (e: IOException) {
-            throw rethrow(e)
-        }
-
+        val (strings, qualifiedNames) = buildProto()
+        strings.writeDelimitedTo(output)
+        qualifiedNames.writeDelimitedTo(output)
     }
 }