Support "default platform" in IDE via facet settings

idea/idea-analysis/idea-analysis.iml

@@ -33,5 +33,6 @@
     <orderEntry type="module" module-name="util" />
     <orderEntry type="module" module-name="idea-core" />
     <orderEntry type="module" module-name="idea-jps-common" />
+    <orderEntry type="module" module-name="cli-common" />
   </component>
 </module>

idea/idea-analysis/src/org/jetbrains/kotlin/idea/project/AnalyzerFacadeProvider.kt

@@ -17,6 +17,7 @@
 package org.jetbrains.kotlin.idea.project
 
 import org.jetbrains.kotlin.analyzer.AnalyzerFacade
+import org.jetbrains.kotlin.analyzer.common.DefaultAnalyzerFacade
 import org.jetbrains.kotlin.idea.caches.resolve.JsAnalyzerFacade
 import org.jetbrains.kotlin.js.resolve.JsPlatform
 import org.jetbrains.kotlin.resolve.TargetPlatform
@@ -29,8 +30,9 @@ object AnalyzerFacadeProvider {
     // otherwise we would be forced to add casts on the call site of setupResolverForProject
     fun getAnalyzerFacade(targetPlatform: TargetPlatform): AnalyzerFacade<JvmPlatformParameters> {
         return when (targetPlatform) {
-            is JvmPlatform -> JvmAnalyzerFacade
+            JvmPlatform -> JvmAnalyzerFacade
             JsPlatform -> JsAnalyzerFacade
+            TargetPlatform.Default -> DefaultAnalyzerFacade
             else -> throw IllegalArgumentException("Unsupported platform: $targetPlatform")
         }
     }

idea/idea-analysis/src/org/jetbrains/kotlin/idea/project/Platform.kt

@@ -18,7 +18,9 @@ package org.jetbrains.kotlin.idea.project
 
 import com.intellij.openapi.module.Module
 import com.intellij.openapi.module.ModuleUtilCore
+import com.sampullara.cli.Argument
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
+import org.jetbrains.kotlin.cli.common.arguments.CommonCompilerArguments
 import org.jetbrains.kotlin.config.*
 import org.jetbrains.kotlin.idea.caches.resolve.getResolutionFacade
 import org.jetbrains.kotlin.psi.KtElement
@@ -30,13 +32,26 @@ val KtElement.platform: TargetPlatform
 val KtElement.builtIns: KotlinBuiltIns
     get() = getResolutionFacade().moduleDescriptor.builtIns
 
+private val multiPlatformProjectsArg: String by lazy {
+    "-" + CommonCompilerArguments::multiPlatform.annotations.filterIsInstance<Argument>().single().value
+}
+
 val Module.languageVersionSettings: LanguageVersionSettings
     get() {
-        val versionInfo = KotlinFacetSettingsProvider.getInstance(project).getSettings(this).versionInfo
+        val facetSettings = KotlinFacetSettingsProvider.getInstance(project).getSettings(this)
+        val versionInfo = facetSettings.versionInfo
         val languageVersion = versionInfo.languageLevel ?: LanguageVersion.LATEST
         val apiVersion = versionInfo.apiLevel ?: languageVersion
-        return LanguageVersionSettingsImpl(languageVersion, ApiVersion.createByLanguageVersion(apiVersion))
+
+        val extraLanguageFeatures =
+                if (versionInfo.targetPlatformKind == TargetPlatformKind.Default ||
+                    // TODO: this is a dirty hack, parse arguments correctly here
+                    facetSettings.compilerInfo.compilerSettings?.additionalArguments?.contains(multiPlatformProjectsArg) == true)
+                    listOf(LanguageFeature.MultiPlatformProjects)
+                else emptyList()
+
+        return LanguageVersionSettingsImpl(languageVersion, ApiVersion.createByLanguageVersion(apiVersion), extraLanguageFeatures)
     }
 
 val KtElement.languageVersionSettings: LanguageVersionSettings
-    get() = ModuleUtilCore.findModuleForPsiElement(this)?.languageVersionSettings ?: LanguageVersionSettingsImpl.DEFAULT
+    get() = ModuleUtilCore.findModuleForPsiElement(this)?.languageVersionSettings ?: LanguageVersionSettingsImpl.DEFAULT

idea/idea-analysis/src/org/jetbrains/kotlin/idea/project/ProjectStructureUtil.java

@@ -44,6 +44,7 @@ public class ProjectStructureUtil {
     private ProjectStructureUtil() {
     }
 
+    @NotNull
     /* package */ static TargetPlatform getCachedPlatformForModule(@NotNull final Module module) {
         CachedValue<TargetPlatform> result = module.getUserData(PLATFORM_FOR_MODULE);
         if (result == null) {
@@ -74,6 +75,9 @@ public class ProjectStructureUtil {
         if (kind instanceof TargetPlatformKind.JavaScript) {
             return JsPlatform.INSTANCE;
         }
+        if (kind instanceof TargetPlatformKind.Default) {
+            return TargetPlatform.Default.INSTANCE;
+        }
         return null;
     }