Leverage existing psi2ir function declaration generator in plugin

This seems to be the only reasonable way to provide function declarations with
_correctly_ substituted type parameters without rewriting logic from scratch;
correctly scoped type parameters in IR are now required in serialization
plugin by all backends.

Also fix some missing upper bounds.

plugins/kotlin-serialization/kotlin-serialization-compiler/build.gradle.kts

@@ -13,6 +13,7 @@ dependencies {
     compileOnly(project(":compiler:frontend"))
     compileOnly(project(":compiler:backend"))
     compileOnly(project(":compiler:ir.backend.common"))
+    compileOnly(project(":compiler:ir.psi2ir"))
     compileOnly(project(":js:js.frontend"))
     compileOnly(project(":js:js.translator"))
 

plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/ir/GeneratorHelpers.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2018 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Copyright 2010-2020 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.
  */
 
@@ -26,6 +26,11 @@ import org.jetbrains.kotlin.ir.types.typeWith
 import org.jetbrains.kotlin.ir.util.*
 import org.jetbrains.kotlin.js.resolve.diagnostics.findPsi
 import org.jetbrains.kotlin.name.Name
+import org.jetbrains.kotlin.psi2ir.Psi2IrConfiguration
+import org.jetbrains.kotlin.psi2ir.generators.DeclarationGenerator
+import org.jetbrains.kotlin.psi2ir.generators.FunctionGenerator
+import org.jetbrains.kotlin.psi2ir.generators.GeneratorContext
+import org.jetbrains.kotlin.psi2ir.generators.GeneratorExtensions
 import org.jetbrains.kotlin.resolve.descriptorUtil.classId
 import org.jetbrains.kotlin.types.*
 import org.jetbrains.kotlin.types.typeUtil.isTypeParameter
@@ -50,6 +55,24 @@ interface IrBuilderExtension {
             }
     }
 
+    private fun createFunctionGenerator(): FunctionGenerator = with(compilerContext) {
+        return FunctionGenerator(
+            DeclarationGenerator(
+                GeneratorContext(
+                    Psi2IrConfiguration(),
+                    moduleDescriptor,
+                    bindingContext,
+                    languageVersionSettings,
+                    symbolTable,
+                    GeneratorExtensions(),
+                    typeTranslator,
+                    typeTranslator.constantValueGenerator,
+                    irBuiltIns
+                )
+            )
+        )
+    }
+
     fun IrClass.contributeFunction(
         descriptor: FunctionDescriptor,
         declareNew: Boolean = true,
@@ -59,9 +82,16 @@ interface IrBuilderExtension {
             descriptor
         ) else compilerContext.symbolTable.referenceSimpleFunction(descriptor).owner
         f.parent = this
-        f.returnType = descriptor.returnType!!.toIrType()
-        if (declareNew) f.createParameterDeclarations(this.thisReceiver!!)
-        f.body = DeclarationIrBuilder(compilerContext, f.symbol, this.startOffset, this.endOffset).irBlockBody(this.startOffset, this.endOffset) { bodyGen(f) }
+        if (declareNew) {
+            f.buildWithScope {
+                createFunctionGenerator().generateFunctionParameterDeclarationsAndReturnType(f, null, null)
+            }
+        }
+
+        f.body = DeclarationIrBuilder(compilerContext, f.symbol, this.startOffset, this.endOffset).irBlockBody(
+            this.startOffset,
+            this.endOffset
+        ) { bodyGen(f) }
         this.addMember(f)
     }
 
@@ -347,7 +377,7 @@ interface IrBuilderExtension {
             SERIALIZABLE_PLUGIN_ORIGIN,
             this,
             type.toIrType(),
-            null
+            (this as? ValueParameterDescriptor)?.varargElementType?.toIrType()
         ).also {
             it.parent = this@createParameterDeclarations
         }
@@ -372,6 +402,7 @@ interface IrBuilderExtension {
                 it
             ).also { typeParameter ->
                 typeParameter.parent = this
+                typeParameter.superTypes.addAll(it.upperBounds.map { it.toIrType() })
             }
         }
     }

plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/ir/SerializableCompanionIrGenerator.kt

@@ -1,3 +1,8 @@
+/*
+ * Copyright 2010-2020 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 org.jetbrains.kotlinx.serialization.compiler.backend.ir
 
 import org.jetbrains.kotlin.descriptors.*
@@ -111,21 +116,23 @@ class SerializableCompanionIrGenerator(
                     && it.returnType != null && isKSerializer(it.returnType)
         } ?: return
         irClass.contributeFunction(serialFactoryDescriptor) { factory ->
+            val kSerializerStarType = factory.returnType
             val array = factory.valueParameters.first()
             val argsSize = serializableDescriptor.declaredTypeParameters.size
             val arrayGet =
                 compilerContext.builtIns.array.getFuncDesc("get").single()
             val arrayGetSymbol = compilerContext.symbolTable.referenceFunction(arrayGet)
 
-            val outAnyNullable = makeTypeProjection(compilerContext.irBuiltIns.anyNType, Variance.OUT_VARIANCE).type
-
-            val serializers: List<IrExpression> = (0 until argsSize).map { irInvoke(irGet(array), arrayGetSymbol, irInt(it)) }
+            val serializers: List<IrExpression> = (0 until argsSize).map {
+                irInvoke(irGet(array), arrayGetSymbol, irInt(it), typeHint = kSerializerStarType)
+            }
             val serializerCall = compilerContext.symbolTable.referenceSimpleFunction(getterDescriptor)
             val call = irInvoke(
                 IrGetValueImpl(startOffset, endOffset, factory.dispatchReceiverParameter!!.symbol),
                 serializerCall,
-                List(argsSize) { outAnyNullable },
-                serializers
+                List(argsSize) { compilerContext.irBuiltIns.anyNType },
+                serializers,
+                returnTypeHint = kSerializerStarType
             )
             +irReturn(call)
             patchSerializableClassWithMarkerAnnotation(companionDescriptor)

plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/ir/SerializerForEnumsGenerator.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Copyright 2010-2020 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.
  */
 
@@ -7,13 +7,13 @@ package org.jetbrains.kotlinx.serialization.compiler.backend.ir
 
 import org.jetbrains.kotlin.descriptors.ClassDescriptor
 import org.jetbrains.kotlin.descriptors.FunctionDescriptor
-import org.jetbrains.kotlin.incremental.components.NoLookupLocation
 import org.jetbrains.kotlin.ir.builders.*
 import org.jetbrains.kotlin.ir.declarations.IrClass
 import org.jetbrains.kotlin.ir.declarations.IrVariable
 import org.jetbrains.kotlin.ir.expressions.IrExpression
 import org.jetbrains.kotlin.ir.expressions.impl.IrGetValueImpl
 import org.jetbrains.kotlin.ir.symbols.IrFunctionSymbol
+import org.jetbrains.kotlin.ir.util.defaultType
 import org.jetbrains.kotlin.ir.util.functions
 import org.jetbrains.kotlin.ir.util.properties
 import org.jetbrains.kotlin.ir.util.referenceFunction
@@ -61,7 +61,12 @@ class SerializerForEnumsGenerator(
             compilerContext.builtIns.array.getFuncDesc("get").single()
         val arrayGetSymbol = compilerContext.symbolTable.referenceFunction(arrayGet)
         val getValueByOrdinal =
-            irInvoke(getValues, arrayGetSymbol, irInvoke(irGet(loadFunc.valueParameters[0]), decode, serialDescGetter))
+            irInvoke(
+                getValues,
+                arrayGetSymbol,
+                irInvoke(irGet(loadFunc.valueParameters[0]), decode, serialDescGetter),
+                typeHint = serializableIrClass.defaultType
+            )
         +irReturn(getValueByOrdinal)
     }
 

plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/resolve/KSerializerDescriptorResolver.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2010-2020 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 org.jetbrains.kotlinx.serialization.compiler.resolve
@@ -460,7 +449,7 @@ object KSerializerDescriptorResolver {
             declaresDefaultValue = false,
             isCrossinline = false,
             isNoinline = false,
-            varargElementType = serializerClass.defaultType,
+            varargElementType = kSerializerStarType,
             source = f.source
         )