IR: do not use Ir*Impl elements where it's not necessary

(cherry picked from commit f9abf365ced93599ff9f4ce38472d89813232228)

backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/BuiltInFictitiousFunctionIrClassFactory.kt

@@ -119,7 +119,7 @@ internal class BuiltInFictitiousFunctionIrClassFactory(
         }
     }
 
-    private fun createTypeParameter(descriptor: TypeParameterDescriptor) =
+    private fun createTypeParameter(descriptor: TypeParameterDescriptor): IrTypeParameter =
             symbolTable?.declareGlobalTypeParameter(
                     SYNTHETIC_OFFSET, SYNTHETIC_OFFSET, DECLARATION_ORIGIN_FUNCTION_CLASS,
                     descriptor

backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/Context.kt

@@ -126,7 +126,7 @@ internal class SpecialDeclarationsFactory(val context: Context) {
     }
 
     private fun createBridge(function: IrSimpleFunction,
-                             bridgeDirections: BridgeDirections) = WrappedSimpleFunctionDescriptor().let { descriptor ->
+                             bridgeDirections: BridgeDirections): IrSimpleFunction = WrappedSimpleFunctionDescriptor().let { descriptor ->
         val startOffset = function.startOffset
         val endOffset = function.endOffset
         val returnType = when (bridgeDirections.array[0]) {

backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/cgen/CBridgeGen.kt

@@ -1207,7 +1207,7 @@ private class ObjCBlockPointerValuePassing(
         }
     }
 
-    private fun IrBuilderWithScope.generateKotlinFunctionClass(): IrConstructorImpl {
+    private fun IrBuilderWithScope.generateKotlinFunctionClass(): IrConstructor {
         val symbols = stubs.symbols
 
         val classDescriptor = WrappedClassDescriptor()

backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/cgen/CBridgeGenUtils.kt

@@ -9,7 +9,10 @@ import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.descriptors.Visibilities
 import org.jetbrains.kotlin.ir.IrStatement
 import org.jetbrains.kotlin.ir.builders.*
-import org.jetbrains.kotlin.ir.declarations.*
+import org.jetbrains.kotlin.ir.declarations.IrDeclarationOrigin
+import org.jetbrains.kotlin.ir.declarations.IrFunction
+import org.jetbrains.kotlin.ir.declarations.IrValueParameter
+import org.jetbrains.kotlin.ir.declarations.IrVariable
 import org.jetbrains.kotlin.ir.declarations.impl.IrFunctionImpl
 import org.jetbrains.kotlin.ir.declarations.impl.IrValueParameterImpl
 import org.jetbrains.kotlin.ir.descriptors.WrappedSimpleFunctionDescriptor
@@ -21,7 +24,9 @@ import org.jetbrains.kotlin.ir.symbols.impl.IrSimpleFunctionSymbolImpl
 import org.jetbrains.kotlin.ir.symbols.impl.IrValueParameterSymbolImpl
 import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.ir.types.impl.*
-import org.jetbrains.kotlin.ir.util.*
+import org.jetbrains.kotlin.ir.util.constructors
+import org.jetbrains.kotlin.ir.util.irBuilder
+import org.jetbrains.kotlin.ir.util.irCatch
 import org.jetbrains.kotlin.name.Name
 
 internal class CFunctionBuilder {
@@ -101,7 +106,7 @@ private fun createKotlinBridge(
         cBridgeName: String,
         stubs: KotlinStubs,
         isExternal: Boolean
-): IrFunctionImpl {
+): IrFunction {
     val bridgeDescriptor = WrappedSimpleFunctionDescriptor()
     @Suppress("DEPRECATION") val bridge = IrFunctionImpl(
             startOffset,

backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/CallableReferenceLowering.kt

@@ -8,13 +8,16 @@ package org.jetbrains.kotlin.backend.konan.lower
 import org.jetbrains.kotlin.backend.common.FileLoweringPass
 import org.jetbrains.kotlin.backend.common.IrElementTransformerVoidWithContext
 import org.jetbrains.kotlin.backend.common.ir.*
-import org.jetbrains.kotlin.backend.common.lower.*
+import org.jetbrains.kotlin.backend.common.lower.createIrBuilder
-import org.jetbrains.kotlin.backend.konan.Context
-import org.jetbrains.kotlin.backend.konan.descriptors.synthesizedName
 import org.jetbrains.kotlin.backend.common.pop
 import org.jetbrains.kotlin.backend.common.push
+import org.jetbrains.kotlin.backend.konan.Context
+import org.jetbrains.kotlin.backend.konan.descriptors.synthesizedName
 import org.jetbrains.kotlin.backend.konan.llvm.functionName
-import org.jetbrains.kotlin.descriptors.*
+import org.jetbrains.kotlin.descriptors.ClassKind
+import org.jetbrains.kotlin.descriptors.Modality
+import org.jetbrains.kotlin.descriptors.ReceiverParameterDescriptor
+import org.jetbrains.kotlin.descriptors.Visibilities
 import org.jetbrains.kotlin.ir.IrElement
 import org.jetbrains.kotlin.ir.IrStatement
 import org.jetbrains.kotlin.ir.builders.*
@@ -156,7 +159,7 @@ internal class CallableReferenceLowering(val context: Context): FileLoweringPass
             typeParam.symbol to functionReference.getTypeArgument(typeParam.index)!!
         }
 
-        private val functionReferenceClass = WrappedClassDescriptor().let {
+        private val functionReferenceClass: IrClass = WrappedClassDescriptor().let {
             IrClassImpl(
                     startOffset,endOffset,
                     DECLARATION_ORIGIN_FUNCTION_REFERENCE_IMPL,
@@ -251,7 +254,7 @@ internal class CallableReferenceLowering(val context: Context): FileLoweringPass
             return BuiltFunctionReference(functionReferenceClass, constructor)
         }
 
-        private fun buildConstructor() = WrappedClassConstructorDescriptor().let {
+        private fun buildConstructor(): IrConstructor = WrappedClassConstructorDescriptor().let {
             IrConstructorImpl(
                     startOffset, endOffset,
                     DECLARATION_ORIGIN_FUNCTION_REFERENCE_IMPL,
@@ -304,7 +307,7 @@ internal class CallableReferenceLowering(val context: Context): FileLoweringPass
         private val IrFunction.fullName: String
             get() = parent.fqNameForIrSerialization.child(Name.identifier(functionName)).asString()
 
-        private fun buildInvokeMethod(superFunction: IrSimpleFunction) = WrappedSimpleFunctionDescriptor().let {
+        private fun buildInvokeMethod(superFunction: IrSimpleFunction): IrSimpleFunction = WrappedSimpleFunctionDescriptor().let {
             IrFunctionImpl(
                     startOffset, endOffset,
                     DECLARATION_ORIGIN_FUNCTION_REFERENCE_IMPL,

backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/EnumClassLowering.kt

@@ -17,10 +17,7 @@ import org.jetbrains.kotlin.backend.konan.llvm.IntrinsicType
 import org.jetbrains.kotlin.backend.konan.llvm.tryGetIntrinsicType
 import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.ir.builders.*
-import org.jetbrains.kotlin.ir.declarations.IrClass
+import org.jetbrains.kotlin.ir.declarations.*
-import org.jetbrains.kotlin.ir.declarations.IrEnumEntry
-import org.jetbrains.kotlin.ir.declarations.IrFile
-import org.jetbrains.kotlin.ir.declarations.IrFunction
 import org.jetbrains.kotlin.ir.declarations.impl.IrPropertyImpl
 import org.jetbrains.kotlin.ir.expressions.*
 import org.jetbrains.kotlin.ir.expressions.IrStatementOrigin.ARGUMENTS_REORDERING_FOR_CALL
@@ -214,7 +211,7 @@ internal class EnumClassLowering(val context: Context) : ClassLoweringPass {
 
         private val createUninitializedInstance = context.ir.symbols.createUninitializedInstance.owner
 
-        private fun createSyntheticValuesPropertyDeclaration(enumEntries: List<IrEnumEntry>): IrPropertyImpl {
+        private fun createSyntheticValuesPropertyDeclaration(enumEntries: List<IrEnumEntry>): IrProperty {
             val startOffset = irClass.startOffset
             val endOffset = irClass.endOffset
 

backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/EnumConstructorsLowering.kt

@@ -106,7 +106,7 @@ internal class EnumConstructorsLowering(val context: Context) : ClassLoweringPas
             return loweredEnumConstructor
         }
 
-        private fun lowerEnumConstructor(constructor: IrConstructor): IrConstructorImpl {
+        private fun lowerEnumConstructor(constructor: IrConstructor): IrConstructor {
             val startOffset = constructor.startOffset
             val endOffset = constructor.endOffset
             val loweredConstructor = WrappedClassConstructorDescriptor(
@@ -133,7 +133,7 @@ internal class EnumConstructorsLowering(val context: Context) : ClassLoweringPas
                 }
             }
 
-            fun createSynthesizedValueParameter(index: Int, name: String, type: IrType) =
+            fun createSynthesizedValueParameter(index: Int, name: String, type: IrType): IrValueParameter =
                     WrappedValueParameterDescriptor().let {
                         IrValueParameterImpl(
                                 startOffset, endOffset,

backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/TestProcessor.kt

@@ -335,7 +335,7 @@ internal class TestProcessor (val context: Context) {
      */
     private fun buildObjectGetter(objectSymbol: IrClassSymbol,
                                   owner: IrClass,
-                                  getterName: Name) = WrappedSimpleFunctionDescriptor().let { descriptor ->
+                                  getterName: Name): IrSimpleFunction = WrappedSimpleFunctionDescriptor().let { descriptor ->
         IrFunctionImpl(
                 owner.startOffset, owner.endOffset,
                 TEST_SUITE_GENERATED_MEMBER,
@@ -374,7 +374,7 @@ internal class TestProcessor (val context: Context) {
      */
     private fun buildInstanceGetter(classSymbol: IrClassSymbol,
                                     owner: IrClass,
-                                    getterName: Name) = WrappedSimpleFunctionDescriptor().let { descriptor ->
+                                    getterName: Name): IrSimpleFunction = WrappedSimpleFunctionDescriptor().let { descriptor ->
         IrFunctionImpl(
                 owner.startOffset, owner.endOffset,
                 TEST_SUITE_GENERATED_MEMBER,
@@ -424,7 +424,7 @@ internal class TestProcessor (val context: Context) {
                                            testSuite: IrClassSymbol,
                                            owner: IrClass,
                                            functions: Collection<TestFunction>,
-                                           ignored: Boolean) = WrappedClassConstructorDescriptor().let { descriptor ->
+                                           ignored: Boolean): IrConstructor = WrappedClassConstructorDescriptor().let { descriptor ->
         IrConstructorImpl(
                 testSuite.owner.startOffset, testSuite.owner.endOffset,
                 TEST_SUITE_GENERATED_MEMBER,
@@ -477,7 +477,7 @@ internal class TestProcessor (val context: Context) {
      */
     private fun buildClassSuite(testClass: IrClass,
                                 testCompanion: IrClass?,
-                                functions: Collection<TestFunction>) = WrappedClassDescriptor().let { descriptor ->
+                                functions: Collection<TestFunction>): IrClass = WrappedClassDescriptor().let { descriptor ->
         IrClassImpl(
                 testClass.startOffset, testClass.endOffset,
                 TEST_SUITE_CLASS,