kotlinx-metadata: support experimental context receivers

libraries/kotlinx-metadata/jvm/ChangeLog.md

@@ -4,6 +4,8 @@
 
 - kotlinx-metadata-jvm can no longer be used on JVM 1.6, and now requires JVM 1.8 or later.
 - Add `Flag.Type.IS_DEFINITELY_NON_NULL`.
+- Add `KmClass.contextReceiverTypes`, `KmFunction.contextReceiverTypes`, `KmProperty.contextReceiverTypes`
+  - The API is experimental and requires `@ExperimentalContextReceivers` on the usages.
 
 ## 0.4.2
 

libraries/kotlinx-metadata/jvm/src/kotlinx/metadata/jvm/jvmExtensionVisitors.kt

@@ -222,7 +222,7 @@ open class JvmPropertyExtensionVisitor @JvmOverloads constructor(
     /**
      * Visits the JVM signature of a synthetic method which is generated when a delegated property's delegate object is
      * optimized out, e.g. because it is constant; in that case, a copy of that object can be obtained on demand by calling
-     * this method. It takes up to two arguments - the property's receivers.
+     * this method. It takes the property's receivers as arguments.
      *
      * Example: `JvmMethodSignature("getX$delegate", "(LMyClass;)LMyDelegate;")`
      *

libraries/kotlinx-metadata/src/kotlinx/metadata/OptInMarkers.kt

@@ -0,0 +1,11 @@
+/*
+ * Copyright 2010-2022 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package kotlinx.metadata
+
+@RequiresOptIn(
+    "The API uses experimental feature \"context receivers\" (see KEEP-259) and may be changed or removed in any future release."
+)
+annotation class ExperimentalContextReceivers

libraries/kotlinx-metadata/src/kotlinx/metadata/impl/readers.kt

@@ -46,6 +46,7 @@ class ReadContext(
         }
 }
 
+@OptIn(ExperimentalContextReceivers::class)
 fun ProtoBuf.Class.accept(
     v: KmClassVisitor,
     strings: NameResolver,
@@ -100,6 +101,10 @@ fun ProtoBuf.Class.accept(
         v.visitInlineClassUnderlyingType(underlyingType.typeFlags)?.let { underlyingType.accept(it, c) }
     }
 
+    for (contextReceiverType in contextReceiverTypes(c.types)) {
+        v.visitContextReceiverType(contextReceiverType.typeFlags)?.let { contextReceiverType.accept(it, c) }
+    }
+
     for (versionRequirement in versionRequirementList) {
         v.visitVersionRequirement()?.let { acceptVersionRequirementVisitor(versionRequirement, it, c) }
     }
@@ -214,6 +219,7 @@ private fun ProtoBuf.Constructor.accept(v: KmConstructorVisitor, c: ReadContext)
     v.visitEnd()
 }
 
+@OptIn(ExperimentalContextReceivers::class)
 private fun ProtoBuf.Function.accept(v: KmFunctionVisitor, outer: ReadContext) {
     val c = outer.withTypeParameters(typeParameterList)
 
@@ -225,6 +231,10 @@ private fun ProtoBuf.Function.accept(v: KmFunctionVisitor, outer: ReadContext) {
         v.visitReceiverParameterType(receiverType.typeFlags)?.let { receiverType.accept(it, c) }
     }
 
+    for (contextReceiverType in contextReceiverTypes(c.types)) {
+        v.visitContextReceiverType(contextReceiverType.typeFlags)?.let { contextReceiverType.accept(it, c) }
+    }
+
     for (parameter in valueParameterList) {
         v.visitValueParameter(parameter.flags, c[parameter.name])?.let { parameter.accept(it, c) }
     }
@@ -248,6 +258,7 @@ private fun ProtoBuf.Function.accept(v: KmFunctionVisitor, outer: ReadContext) {
     v.visitEnd()
 }
 
+@OptIn(ExperimentalContextReceivers::class)
 fun ProtoBuf.Property.accept(v: KmPropertyVisitor, outer: ReadContext) {
     val c = outer.withTypeParameters(typeParameterList)
 
@@ -259,6 +270,10 @@ fun ProtoBuf.Property.accept(v: KmPropertyVisitor, outer: ReadContext) {
         v.visitReceiverParameterType(receiverType.typeFlags)?.let { receiverType.accept(it, c) }
     }
 
+    for (contextReceiverType in contextReceiverTypes(c.types)) {
+        v.visitContextReceiverType(contextReceiverType.typeFlags)?.let { contextReceiverType.accept(it, c) }
+    }
+
     if (hasSetterValueParameter()) {
         val parameter = setterValueParameter
         v.visitSetterParameter(parameter.flags, c[parameter.name])?.let { parameter.accept(it, c) }

libraries/kotlinx-metadata/src/kotlinx/metadata/impl/writers.kt

@@ -158,6 +158,10 @@ private fun writeFunction(c: WriteContext, flags: Flags, name: String, output: (
         override fun visitReceiverParameterType(flags: Flags): KmTypeVisitor? =
             writeType(c, flags) { t.receiverType = it.build() }
 
+        @ExperimentalContextReceivers
+        override fun visitContextReceiverType(flags: Flags): KmTypeVisitor =
+            writeType(c, flags) { t.addContextReceiverType(it) }
+
         override fun visitValueParameter(flags: Flags, name: String): KmValueParameterVisitor? =
             writeValueParameter(c, flags, name) { t.addValueParameter(it) }
 
@@ -195,6 +199,10 @@ fun writeProperty(
     override fun visitReceiverParameterType(flags: Flags): KmTypeVisitor? =
         writeType(c, flags) { t.receiverType = it.build() }
 
+    @ExperimentalContextReceivers
+    override fun visitContextReceiverType(flags: Flags): KmTypeVisitor =
+        writeType(c, flags) { t.addContextReceiverType(it) }
+
     override fun visitSetterParameter(flags: Flags, name: String): KmValueParameterVisitor? =
         writeValueParameter(c, flags, name) { t.setterValueParameter = it.build() }
 
@@ -464,6 +472,10 @@ open class ClassWriter(stringTable: StringTable, contextExtensions: List<WriteCo
     override fun visitInlineClassUnderlyingType(flags: Flags): KmTypeVisitor? =
         writeType(c, flags) { t.inlineClassUnderlyingType = it.build() }
 
+    @ExperimentalContextReceivers
+    override fun visitContextReceiverType(flags: Flags): KmTypeVisitor =
+        writeType(c, flags) { t.addContextReceiverType(it) }
+
     override fun visitVersionRequirement(): KmVersionRequirementVisitor? =
         writeVersionRequirement(c) { t.addVersionRequirement(it) }
 

libraries/kotlinx-metadata/src/kotlinx/metadata/nodes.kt

@@ -103,6 +103,12 @@ class KmClass : KmClassVisitor(), KmDeclarationContainer {
      */
     var inlineClassUnderlyingType: KmType? = null
 
+    /**
+     * Types of context receivers of the class.
+     */
+    @ExperimentalContextReceivers
+    val contextReceiverTypes: MutableList<KmType> = ArrayList(0)
+
     /**
      * Version requirements on this class.
      */
@@ -157,6 +163,10 @@ class KmClass : KmClassVisitor(), KmDeclarationContainer {
     override fun visitInlineClassUnderlyingType(flags: Flags): KmTypeVisitor =
         KmType(flags).also { inlineClassUnderlyingType = it }
 
+    @ExperimentalContextReceivers
+    override fun visitContextReceiverType(flags: Flags): KmTypeVisitor =
+        KmType(flags).addTo(contextReceiverTypes)
+
     override fun visitVersionRequirement(): KmVersionRequirementVisitor =
         KmVersionRequirement().addTo(versionRequirements)
 
@@ -168,6 +178,7 @@ class KmClass : KmClassVisitor(), KmDeclarationContainer {
      *
      * @param visitor the visitor which will visit data in this class
      */
+    @OptIn(ExperimentalContextReceivers::class)
     fun accept(visitor: KmClassVisitor) {
         visitor.visit(flags, name)
         typeParameters.forEach { visitor.visitTypeParameter(it.flags, it.name, it.id, it.variance)?.let(it::accept) }
@@ -182,6 +193,7 @@ class KmClass : KmClassVisitor(), KmDeclarationContainer {
         sealedSubclasses.forEach(visitor::visitSealedSubclass)
         inlineClassUnderlyingPropertyName?.let(visitor::visitInlineClassUnderlyingPropertyName)
         inlineClassUnderlyingType?.let { visitor.visitInlineClassUnderlyingType(it.flags)?.let(it::accept) }
+        contextReceiverTypes.forEach { visitor.visitContextReceiverType(it.flags)?.let(it::accept) }
         versionRequirements.forEach { visitor.visitVersionRequirement()?.let(it::accept) }
         extensions.forEach { visitor.visitExtensions(it.type)?.let(it::accept) }
         visitor.visitEnd()
@@ -360,6 +372,12 @@ class KmFunction(
      */
     var receiverParameterType: KmType? = null
 
+    /**
+     * Types of context receivers of the function.
+     */
+    @ExperimentalContextReceivers
+    val contextReceiverTypes: MutableList<KmType> = ArrayList(0)
+
     /**
      * Value parameters of the function.
      */
@@ -389,6 +407,10 @@ class KmFunction(
     override fun visitReceiverParameterType(flags: Flags): KmTypeVisitor =
         KmType(flags).also { receiverParameterType = it }
 
+    @ExperimentalContextReceivers
+    override fun visitContextReceiverType(flags: Flags): KmTypeVisitor =
+        KmType(flags).addTo(contextReceiverTypes)
+
     override fun visitValueParameter(flags: Flags, name: String): KmValueParameterVisitor =
         KmValueParameter(flags, name).addTo(valueParameters)
 
@@ -409,9 +431,11 @@ class KmFunction(
      *
      * @param visitor the visitor which will visit data in this function
      */
+    @OptIn(ExperimentalContextReceivers::class)
     fun accept(visitor: KmFunctionVisitor) {
         typeParameters.forEach { visitor.visitTypeParameter(it.flags, it.name, it.id, it.variance)?.let(it::accept) }
         receiverParameterType?.let { visitor.visitReceiverParameterType(it.flags)?.let(it::accept) }
+        contextReceiverTypes.forEach { visitor.visitContextReceiverType(it.flags)?.let(it::accept) }
         valueParameters.forEach { visitor.visitValueParameter(it.flags, it.name)?.let(it::accept) }
         visitor.visitReturnType(returnType.flags)?.let(returnType::accept)
         versionRequirements.forEach { visitor.visitVersionRequirement()?.let(it::accept) }
@@ -447,6 +471,12 @@ class KmProperty(
      */
     var receiverParameterType: KmType? = null
 
+    /**
+     * Types of context receivers of the property.
+     */
+    @ExperimentalContextReceivers
+    val contextReceiverTypes: MutableList<KmType> = ArrayList(0)
+
     /**
      * Value parameter of the setter of this property, if this is a `var` property.
      */
@@ -471,6 +501,10 @@ class KmProperty(
     override fun visitReceiverParameterType(flags: Flags): KmTypeVisitor =
         KmType(flags).also { receiverParameterType = it }
 
+    @ExperimentalContextReceivers
+    override fun visitContextReceiverType(flags: Flags): KmTypeVisitor =
+        KmType(flags).addTo(contextReceiverTypes)
+
     override fun visitSetterParameter(flags: Flags, name: String): KmValueParameterVisitor =
         KmValueParameter(flags, name).also { setterParameter = it }
 
@@ -488,9 +522,11 @@ class KmProperty(
      *
      * @param visitor the visitor which will visit data in this property
      */
+    @OptIn(ExperimentalContextReceivers::class)
     fun accept(visitor: KmPropertyVisitor) {
         typeParameters.forEach { visitor.visitTypeParameter(it.flags, it.name, it.id, it.variance)?.let(it::accept) }
         receiverParameterType?.let { visitor.visitReceiverParameterType(it.flags)?.let(it::accept) }
+        contextReceiverTypes.forEach { visitor.visitContextReceiverType(it.flags)?.let(it::accept) }
         setterParameter?.let { visitor.visitSetterParameter(it.flags, it.name)?.let(it::accept) }
         visitor.visitReturnType(returnType.flags)?.let(returnType::accept)
         versionRequirements.forEach { visitor.visitVersionRequirement()?.let(it::accept) }

libraries/kotlinx-metadata/src/kotlinx/metadata/visitors.kt

@@ -149,6 +149,15 @@ abstract class KmClassVisitor @JvmOverloads constructor(delegate: KmClassVisitor
     open fun visitInlineClassUnderlyingType(flags: Flags): KmTypeVisitor? =
         delegate?.visitInlineClassUnderlyingType(flags)
 
+    /**
+     * Visits the type of a context receiver of the class.
+     *
+     * @param flags type flags, consisting of [Flag.Type] flags
+     */
+    @ExperimentalContextReceivers
+    open fun visitContextReceiverType(flags: Flags): KmTypeVisitor? =
+        delegate?.visitContextReceiverType(flags)
+
     /**
      * Visits the version requirement on this class.
      */
@@ -319,6 +328,15 @@ abstract class KmFunctionVisitor @JvmOverloads constructor(private val delegate:
     open fun visitReceiverParameterType(flags: Flags): KmTypeVisitor? =
         delegate?.visitReceiverParameterType(flags)
 
+    /**
+     * Visits the type of a context receiver of the function.
+     *
+     * @param flags type flags, consisting of [Flag.Type] flags
+     */
+    @ExperimentalContextReceivers
+    open fun visitContextReceiverType(flags: Flags): KmTypeVisitor? =
+        delegate?.visitContextReceiverType(flags)
+
     /**
      * Visits a value parameter of the function.
      *
@@ -391,6 +409,15 @@ abstract class KmPropertyVisitor @JvmOverloads constructor(private val delegate:
     open fun visitReceiverParameterType(flags: Flags): KmTypeVisitor? =
         delegate?.visitReceiverParameterType(flags)
 
+    /**
+     * Visits the type of a context receiver of the property.
+     *
+     * @param flags type flags, consisting of [Flag.Type] flags
+     */
+    @ExperimentalContextReceivers
+    open fun visitContextReceiverType(flags: Flags): KmTypeVisitor? =
+        delegate?.visitContextReceiverType(flags)
+
     /**
      * Visits a value parameter of the setter of this property, if this is a `var` property.
      *

libraries/tools/kotlinp/src/org/jetbrains/kotlin/kotlinp/printers.kt

@@ -7,7 +7,6 @@ package org.jetbrains.kotlin.kotlinp
 
 import kotlinx.metadata.*
 import kotlinx.metadata.jvm.*
-import java.util.*
 
 private object SpecialCharacters {
     const val TYPE_ALIAS_MARKER = '^'
@@ -18,6 +17,7 @@ private fun visitFunction(settings: KotlinpSettings, sb: StringBuilder, flags: F
         val typeParams = mutableListOf<String>()
         val params = mutableListOf<String>()
         var receiverParameterType: String? = null
+        val contextReceiverTypes = mutableListOf<String>()
         var returnType: String? = null
         val versionRequirements = mutableListOf<String>()
         var jvmSignature: JvmMemberSignature? = null
@@ -27,6 +27,10 @@ private fun visitFunction(settings: KotlinpSettings, sb: StringBuilder, flags: F
         override fun visitReceiverParameterType(flags: Flags): KmTypeVisitor? =
             printType(flags) { receiverParameterType = it }
 
+        @ExperimentalContextReceivers
+        override fun visitContextReceiverType(flags: Flags): KmTypeVisitor =
+            printType(flags) { contextReceiverTypes.add(it) }
+
         override fun visitTypeParameter(
             flags: Flags, name: String, id: Int, variance: KmVariance
         ): KmTypeParameterVisitor? =
@@ -68,6 +72,9 @@ private fun visitFunction(settings: KotlinpSettings, sb: StringBuilder, flags: F
             if (jvmSignature != null) {
                 sb.appendLine("  // signature: $jvmSignature")
             }
+            if (contextReceiverTypes.isNotEmpty()) {
+                sb.appendLine(contextReceiverTypes.joinToString(prefix = "  context(", postfix = ")"))
+            }
             sb.append("  ")
             sb.appendFlags(flags, FUNCTION_FLAGS_MAP)
             sb.append("fun ")
@@ -96,6 +103,7 @@ private fun visitProperty(
     object : KmPropertyVisitor() {
         val typeParams = mutableListOf<String>()
         var receiverParameterType: String? = null
+        val contextReceiverTypes = mutableListOf<String>()
         var returnType: String? = null
         var setterParameter: String? = null
         val versionRequirements = mutableListOf<String>()
@@ -109,6 +117,10 @@ private fun visitProperty(
         override fun visitReceiverParameterType(flags: Flags): KmTypeVisitor? =
             printType(flags) { receiverParameterType = it }
 
+        @ExperimentalContextReceivers
+        override fun visitContextReceiverType(flags: Flags): KmTypeVisitor =
+            printType(flags) { contextReceiverTypes.add(it) }
+
         override fun visitTypeParameter(flags: Flags, name: String, id: Int, variance: KmVariance): KmTypeParameterVisitor? =
             printTypeParameter(settings, flags, name, id, variance) { typeParams.add(it) }
 
@@ -169,6 +181,9 @@ private fun visitProperty(
             if (isMovedFromInterfaceCompanion) {
                 sb.appendLine("  // is moved from interface companion")
             }
+            if (contextReceiverTypes.isNotEmpty()) {
+                sb.appendLine(contextReceiverTypes.joinToString(prefix = "  context(", postfix = ")"))
+            }
             sb.append("  ")
             sb.appendFlags(flags, PROPERTY_FLAGS_MAP)
             sb.append(if (Flag.Property.IS_VAR(flags)) "var " else "val ")
@@ -711,6 +726,7 @@ class ClassPrinter(private val settings: KotlinpSettings) : KmClassVisitor(), Ab
     private var name: ClassName? = null
     private val typeParams = mutableListOf<String>()
     private val supertypes = mutableListOf<String>()
+    private val contextReceiverTypes = mutableListOf<String>()
     private val versionRequirements = mutableListOf<String>()
     private var anonymousObjectOriginName: String? = null
 
@@ -726,6 +742,9 @@ class ClassPrinter(private val settings: KotlinpSettings) : KmClassVisitor(), Ab
         for (versionRequirement in versionRequirements) {
             result.appendLine("// $versionRequirement")
         }
+        if (contextReceiverTypes.isNotEmpty()) {
+            result.appendLine(contextReceiverTypes.joinToString(prefix = "context(", postfix = ")"))
+        }
         result.appendFlags(flags!!, CLASS_FLAGS_MAP)
         result.append(name)
         if (typeParams.isNotEmpty()) {
@@ -789,6 +808,10 @@ class ClassPrinter(private val settings: KotlinpSettings) : KmClassVisitor(), Ab
             sb.appendLine("  // underlying type: $it")
         }
 
+    @ExperimentalContextReceivers
+    override fun visitContextReceiverType(flags: Flags): KmTypeVisitor =
+        printType(flags) { contextReceiverTypes.add(it) }
+
     override fun visitVersionRequirement(): KmVersionRequirementVisitor? =
         printVersionRequirement { versionRequirements.add(it) }
 

libraries/tools/kotlinp/test/org/jetbrains/kotlin/kotlinp/test/KotlinpTestGenerated.java

@@ -34,6 +34,11 @@ public class KotlinpTestGenerated extends AbstractKotlinpTest {
         runTest("libraries/tools/kotlinp/testData/Annotations.kt");
     }
 
+    @TestMetadata("ContextReceivers.kt")
+    public void testContextReceivers() throws Exception {
+        runTest("libraries/tools/kotlinp/testData/ContextReceivers.kt");
+    }
+
     @TestMetadata("Contracts.kt")
     public void testContracts() throws Exception {
         runTest("libraries/tools/kotlinp/testData/Contracts.kt");

libraries/tools/kotlinp/testData/ContextReceivers.kt

@@ -0,0 +1,11 @@
+// !LANGUAGE: +ContextReceivers
+
+interface A
+interface B
+
+context(A) class C {
+    context(B) fun f() {}
+}
+
+context(A) fun g() {}
+context(B) val h: Int get() = 42

libraries/tools/kotlinp/testData/ContextReceivers.txt

@@ -0,0 +1,50 @@
+// A.class
+// ------------------------------------------
+public abstract interface A : kotlin/Any {
+
+  // module name: test-module
+}
+// B.class
+// ------------------------------------------
+public abstract interface B : kotlin/Any {
+
+  // module name: test-module
+}
+// C.class
+// ------------------------------------------
+// requires compiler version 1.6.20 (level=ERROR)
+context(A)
+public final class C : kotlin/Any {
+
+  // signature: <init>(LA;)V
+  public constructor()
+
+  // requires compiler version 1.6.20 (level=ERROR)
+  // signature: f(LB;)V
+  context(B)
+  public final fun f(): kotlin/Unit
+
+  // module name: test-module
+}
+// ContextReceiversKt.class
+// ------------------------------------------
+package {
+
+  // requires compiler version 1.6.20 (level=ERROR)
+  // signature: g(LA;)V
+  context(A)
+  public final fun g(): kotlin/Unit
+
+  // requires compiler version 1.6.20 (level=ERROR)
+  // getter: getH(LB;)I
+  context(B)
+  public final val h: kotlin/Int
+    public final /* non-default */ get
+}
+// META-INF/test-module.kotlin_module
+// ------------------------------------------
+module {
+  package <root> {
+    ContextReceiversKt
+  }
+}