Support OptionalExpectation (#2040)

backend.native/cli.bc/src/org/jetbrains/kotlin/cli/bc/K2Native.kt

@@ -13,6 +13,7 @@ import org.jetbrains.kotlin.cli.common.CLICompiler
 import org.jetbrains.kotlin.cli.common.CLITool
 import org.jetbrains.kotlin.cli.common.CommonCompilerPerformanceManager
 import org.jetbrains.kotlin.cli.common.ExitCode
+import org.jetbrains.kotlin.cli.common.config.addKotlinSourceRoot
 import org.jetbrains.kotlin.cli.common.config.addKotlinSourceRoots
 import org.jetbrains.kotlin.cli.common.config.kotlinSourceRoots
 import org.jetbrains.kotlin.cli.common.messages.CompilerMessageSeverity.ERROR
@@ -108,7 +109,10 @@ class K2Native : CLICompiler<K2NativeCompilerArguments>() {
             arguments    : K2NativeCompilerArguments,
             services     : Services) {
 
-        configuration.addKotlinSourceRoots(arguments.freeArgs)
+        val commonSources = arguments.commonSources?.toSet().orEmpty()
+        arguments.freeArgs.forEach {
+            configuration.addKotlinSourceRoot(it, it in commonSources)
+        }
 
         with(KonanConfigKeys) {
             with(configuration) {

backend.native/tests/build.gradle

@@ -2301,6 +2301,15 @@ task mpp_default_args(type: RunStandaloneKonanTest) {
     flags = ['-tr', '-Xmulti-platform']
 }
 
+task mpp_optional_expectation(type: RunStandaloneKonanTest) {
+    source = "codegen/mpp/mpp_optional_expectation.kt"
+    def outputRoot = project.ext."$outputSourceSetName"
+    flags = [
+            '-Xmulti-platform',
+            "-Xcommon-sources=${file("$outputRoot/$name/mpp_optional_expectation.kt")}"
+    ]
+}
+
 task unit1(type: RunKonanTest) {
     goldValue = "First\nkotlin.Unit\n"
     source = "codegen/basics/unit1.kt"

backend.native/tests/codegen/mpp/mpp_optional_expectation.kt

@@ -0,0 +1,10 @@
+@file:Suppress("EXPERIMENTAL_API_USAGE_ERROR")
+@OptionalExpectation
+expect annotation class Optional()
+
+@Optional
+fun foo() { println(42) }
+
+fun main(args: Array<String>) {
+    foo()
+}