Fix minor compile warnings

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/JvmIrCodegenFactory.kt

@@ -31,7 +31,7 @@ class JvmIrCodegenFactory(private val phaseConfig: PhaseConfig) : CodegenFactory
 
         val psi2ir = Psi2IrTranslator(state.languageVersionSettings)
         val psi2irContext = psi2ir.createGeneratorContext(state.module, state.bindingContext, extensions = JvmGeneratorExtensions)
-        val irModuleFragment = psi2ir.generateModuleFragment(psi2irContext, files as Collection<KtFile>)
+        @Suppress("UNCHECKED_CAST") val irModuleFragment = psi2ir.generateModuleFragment(psi2irContext, files as Collection<KtFile>)
         JvmBackendFacade.doGenerateFilesInternal(state, errorHandler, irModuleFragment, psi2irContext, phaseConfig)
     }
 

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/codegen/IrInlineCodegen.kt

@@ -96,7 +96,7 @@ class IrInlineCodegen(
 
     private fun rememberClosure(irReference: IrFunctionReference, type: Type, parameter: ValueParameterDescriptor): LambdaInfo {
         //assert(InlineUtil.isInlinableParameterExpression(ktLambda)) { "Couldn't find inline expression in ${expression.text}" }
-        val expression = irReference.symbol.owner as IrFunction
+        val expression = irReference.symbol.owner
         return IrExpressionLambdaImpl(
             irReference, expression, typeMapper, parameter.isCrossinline, false/*TODO*/,
             parameter.type.isExtensionFunctionType

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/descriptors/SharedVariablesManager.kt

@@ -177,7 +177,7 @@ class JvmSharedVariablesManager(
             typeArgumentsCount = typeArgumentsCount,
             origin = SHARED_VARIABLE_CONSTRUCTOR_CALL_ORIGIN
         ).apply {
-            refConstructor.parentAsClass.typeParameters.mapIndexed { i, param ->
+            List(refConstructor.parentAsClass.typeParameters.size) { i ->
                 putTypeArgument(i, valueType)
             }
         }

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/MoveCompanionObjectFieldsLowering.kt

@@ -212,10 +212,10 @@ private class FieldReplacer(val replacementMap: Map<IrFieldSymbol, IrFieldSymbol
         } ?: super.visitGetField(expression)
 
     override fun visitSetField(expression: IrSetField): IrExpression =
-        replacementMap[expression.symbol]?.let { newSymbol ->
+        replacementMap[expression.symbol]?.let { _ ->
             IrSetFieldImpl(
                 expression.startOffset, expression.endOffset,
-                replacementMap[expression.symbol]!!,
+                replacementMap.getValue(expression.symbol),
                 /* receiver = */ null,
                 visitExpression(expression.value),
                 expression.type,