Invert LanguageFeature responsible for warning on coroutines

The problem was that LanguageVersionSettingsImpl.DEFAULT did not have
"WarnOnCoroutines" as a feature and so it was manually added to the settings,
but only in two places: in the compiler and in the IDE

compiler/tests-common/org/jetbrains/kotlin/checkers/AbstractDiagnosticsTest.kt

@@ -25,6 +25,7 @@ import org.jetbrains.kotlin.analyzer.common.DefaultAnalyzerFacade
 import org.jetbrains.kotlin.cli.jvm.compiler.CliLightClassGenerationSupport
 import org.jetbrains.kotlin.cli.jvm.compiler.JvmPackagePartProvider
 import org.jetbrains.kotlin.config.LanguageVersionSettings
+import org.jetbrains.kotlin.config.LanguageVersionSettingsImpl
 import org.jetbrains.kotlin.config.languageVersionSettings
 import org.jetbrains.kotlin.container.get
 import org.jetbrains.kotlin.context.ModuleContext
@@ -63,6 +64,7 @@ import org.jetbrains.kotlin.test.util.DescriptorValidator
 import org.jetbrains.kotlin.test.util.RecursiveDescriptorComparator
 import org.jetbrains.kotlin.test.util.RecursiveDescriptorComparator.RECURSIVE
 import org.jetbrains.kotlin.test.util.RecursiveDescriptorComparator.RECURSIVE_ALL
+import org.jetbrains.kotlin.utils.keysToMap
 import org.junit.Assert
 import java.io.File
 import java.util.*
@@ -198,7 +200,7 @@ abstract class AbstractDiagnosticsTest : BaseDiagnosticsTest() {
         // To be overridden by diagnostic-like tests.
     }
 
-    private fun loadLanguageVersionSettings(module: List<TestFile>): LanguageVersionSettings? {
+    private fun loadLanguageVersionSettings(module: List<TestFile>): LanguageVersionSettings {
         var result: LanguageVersionSettings? = null
         for (file in module) {
             val current = file.customLanguageVersionSettings
@@ -213,7 +215,11 @@ abstract class AbstractDiagnosticsTest : BaseDiagnosticsTest() {
             }
         }
 
-        return result
+        return result ?: BaseDiagnosticsTest.DiagnosticTestLanguageVersionSettings(
+                BaseDiagnosticsTest.DEFAULT_DIAGNOSTIC_TESTS_FEATURES.keysToMap { true },
+                LanguageVersionSettingsImpl.DEFAULT.apiVersion,
+                LanguageVersionSettingsImpl.DEFAULT.languageVersion
+        )
     }
 
     private fun checkDynamicCallDescriptors(expectedFile: File, testFiles: List<TestFile>) {
@@ -253,19 +259,15 @@ abstract class AbstractDiagnosticsTest : BaseDiagnosticsTest() {
             moduleContext: ModuleContext,
             files: List<KtFile>,
             moduleTrace: BindingTrace,
-            languageVersionSettings: LanguageVersionSettings?,
+            languageVersionSettings: LanguageVersionSettings,
             separateModules: Boolean
     ): AnalysisResult {
         @Suppress("NAME_SHADOWING")
         var files = files
 
-        val configuration =
-                if (languageVersionSettings != null)
-                    environment.configuration.copy().apply {
-                        this.languageVersionSettings = languageVersionSettings
-                    }
-                else
-                    environment.configuration
+        val configuration = environment.configuration.copy().apply {
+            this.languageVersionSettings = languageVersionSettings
+        }
 
         // New JavaDescriptorResolver is created for each module, which is good because it emulates different Java libraries for each module,
         // albeit with same class names

compiler/tests-common/org/jetbrains/kotlin/checkers/BaseDiagnosticsTest.kt

@@ -286,6 +286,10 @@ abstract class BaseDiagnosticsTest : KotlinMultiFileTestWithJava<TestModule, Tes
         val LANGUAGE_VERSION = "LANGUAGE_VERSION"
         private val LANGUAGE_PATTERN = Pattern.compile("([\\+\\-])(\\w+)\\s*")
 
+        val DEFAULT_DIAGNOSTIC_TESTS_FEATURES = listOf(
+                LanguageFeature.DoNotWarnOnCoroutines
+        )
+
         val API_VERSION_DIRECTIVE = "API_VERSION"
 
         val CHECK_TYPE_DIRECTIVE = "CHECK_TYPE"