Do not support LANGUAGE_VERSION directive in codegen tests

Test data of crossinline_1_2.txt has changed because now we do not
automatically enable 1.2 (with _all_ of its features) when we're
executing a common coroutines test with old coroutines; and so the
NewCapturedReceiverFieldNamingConvention language feature (which is
introduced in 1.3) is now enabled in this test

compiler/testData/codegen/box/coroutines/tailCallOptimizations/crossinline_1_2.txt

@@ -36,7 +36,7 @@ public final class CrossinlineKt$box$1$doResume$$inlined$filter$1$2$1 {
 
 @kotlin.Metadata
 public final class CrossinlineKt$box$1$doResume$$inlined$filter$1$2 {
-    synthetic final field receiver$0$inlined: Sink
+    synthetic final field $this_source$inlined: Sink
     synthetic final field this$0: CrossinlineKt$box$1$doResume$$inlined$filter$1
     inner class CrossinlineKt$box$1$doResume$$inlined$filter$1$2
     inner class CrossinlineKt$box$1$doResume$$inlined$filter$1$2$1
@@ -47,7 +47,7 @@ public final class CrossinlineKt$box$1$doResume$$inlined$filter$1$2 {
 
 @kotlin.Metadata
 public final class CrossinlineKt$box$1$doResume$$inlined$filter$1 {
-    synthetic final field receiver$0$inlined: SourceCrossinline
+    synthetic final field $this_filter$inlined: SourceCrossinline
     inner class CrossinlineKt$box$1$doResume$$inlined$filter$1
     inner class CrossinlineKt$box$1$doResume$$inlined$filter$1$1
     public method <init>(p0: SourceCrossinline): void
@@ -102,7 +102,7 @@ public final class CrossinlineKt$box$1$filter$$inlined$source$1$lambda$1$1 {
 
 @kotlin.Metadata
 public final class CrossinlineKt$box$1$filter$$inlined$source$1$lambda$1 {
-    synthetic final field receiver$0$inlined: Sink
+    synthetic final field $this_source$inlined: Sink
     synthetic final field this$0: CrossinlineKt$box$1$filter$$inlined$source$1
     inner class CrossinlineKt$box$1$filter$$inlined$source$1$lambda$1
     inner class CrossinlineKt$box$1$filter$$inlined$source$1$lambda$1$1
@@ -114,7 +114,7 @@ public final class CrossinlineKt$box$1$filter$$inlined$source$1$lambda$1 {
 @kotlin.Metadata
 public final class CrossinlineKt$box$1$filter$$inlined$source$1 {
     synthetic final field $predicate$inlined: kotlin.jvm.functions.Function1
-    synthetic final field receiver$0$inlined: SourceCrossinline
+    synthetic final field $this_filter$inlined: SourceCrossinline
     inner class CrossinlineKt$box$1$filter$$inlined$source$1
     inner class CrossinlineKt$box$1$filter$$inlined$source$1$1
     public method <init>(p0: SourceCrossinline, p1: kotlin.jvm.functions.Function1): void
@@ -221,7 +221,7 @@ public final class CrossinlineKt$filter$$inlined$source$1$lambda$1$1 {
 
 @kotlin.Metadata
 public final class CrossinlineKt$filter$$inlined$source$1$lambda$1 {
-    synthetic final field receiver$0$inlined: Sink
+    synthetic final field $this_source$inlined: Sink
     synthetic final field this$0: CrossinlineKt$filter$$inlined$source$1
     inner class CrossinlineKt$filter$$inlined$source$1$lambda$1
     inner class CrossinlineKt$filter$$inlined$source$1$lambda$1$1
@@ -233,7 +233,7 @@ public final class CrossinlineKt$filter$$inlined$source$1$lambda$1 {
 @kotlin.Metadata
 public final class CrossinlineKt$filter$$inlined$source$1 {
     synthetic final field $predicate$inlined: kotlin.jvm.functions.Function1
-    synthetic final field receiver$0$inlined: SourceCrossinline
+    synthetic final field $this_filter$inlined: SourceCrossinline
     inner class CrossinlineKt$filter$$inlined$source$1
     inner class CrossinlineKt$filter$$inlined$source$1$1
     public method <init>(p0: SourceCrossinline, p1: kotlin.jvm.functions.Function1): void

compiler/tests-common/tests/org/jetbrains/kotlin/codegen/CodegenTestCase.java

@@ -167,7 +167,7 @@ public abstract class CodegenTestCase extends KtUsefulTestCase {
             @NotNull String coroutinesPackage
     ) {
         LanguageVersionSettings explicitLanguageVersionSettings = null;
-        LanguageVersion explicitLanguageVersion = null;
+        boolean disableReleaseCoroutines = false;
 
         List<String> kotlinConfigurationFlags = new ArrayList<>(0);
         for (TestFile testFile : testFilesWithConfigurationDirectives) {
@@ -183,17 +183,18 @@ public abstract class CodegenTestCase extends KtUsefulTestCase {
 
             String version = InTextDirectivesUtils.findStringWithPrefixes(testFile.content, "// LANGUAGE_VERSION:");
             if (version != null) {
-                assertDirectivesToNull(explicitLanguageVersionSettings, explicitLanguageVersion);
+                throw new AssertionError(
-                explicitLanguageVersion = LanguageVersion.fromVersionString(version);
+                        "Do not use LANGUAGE_VERSION directive in compiler tests because it's prone to limiting the test\n" +
+                        "to a specific language version, which will become obsolete at some point and the test won't check\n" +
+                        "things like feature intersection with newer releases. Use `// !LANGUAGE: [+-]FeatureName` directive instead,\n" +
+                        "where FeatureName is an entry of the enum `LanguageFeature`\n"
+                );
             }
+
             if (!InTextDirectivesUtils.findLinesWithPrefixesRemoved(testFile.content, "// COMMON_COROUTINES_TEST").isEmpty()) {
-                assert(!testFile.content.contains("COROUTINES_PACKAGE")) : "Must replace COROUTINES_PACKAGE prior to tests compilation";
+                assert !testFile.content.contains("COROUTINES_PACKAGE") : "Must replace COROUTINES_PACKAGE prior to tests compilation";
-                if (!coroutinesPackage.isEmpty()) {
+                if (coroutinesPackage.equals("kotlin.coroutines.experimental")) {
-                    if (coroutinesPackage.equals("kotlin.coroutines.experimental")) {
+                    disableReleaseCoroutines = true;
-                        explicitLanguageVersion = LanguageVersion.KOTLIN_1_2;
-                    } else {
-                        explicitLanguageVersion = LanguageVersion.KOTLIN_1_3;
-                    }
                 }
             }
 
@@ -201,7 +202,7 @@ public abstract class CodegenTestCase extends KtUsefulTestCase {
 
             LanguageVersionSettings fileLanguageVersionSettings = parseLanguageVersionSettings(directives);
             if (fileLanguageVersionSettings != null) {
-                assertDirectivesToNull(explicitLanguageVersionSettings, null);
+                assert explicitLanguageVersionSettings == null : "Should not specify !LANGUAGE directive twice";
                 explicitLanguageVersionSettings = fileLanguageVersionSettings;
             }
         }
@@ -209,26 +210,19 @@ public abstract class CodegenTestCase extends KtUsefulTestCase {
         if (explicitLanguageVersionSettings != null) {
             CommonConfigurationKeysKt.setLanguageVersionSettings(configuration, explicitLanguageVersionSettings);
         }
-        else if (explicitLanguageVersion != null) {
+        else if (disableReleaseCoroutines) {
             CompilerTestLanguageVersionSettings compilerLanguageVersionSettings = new CompilerTestLanguageVersionSettings(
-                    Collections.emptyMap(),
+                    Collections.singletonMap(LanguageFeature.ReleaseCoroutines, LanguageFeature.State.DISABLED),
-                    ApiVersion.createByLanguageVersion(explicitLanguageVersion),
+                    ApiVersion.LATEST_STABLE,
-                    explicitLanguageVersion,
+                    LanguageVersion.LATEST_STABLE,
                     Collections.emptyMap()
             );
-            CommonConfigurationKeysKt.setLanguageVersionSettings(
+            CommonConfigurationKeysKt.setLanguageVersionSettings(configuration, compilerLanguageVersionSettings);
-                    configuration,
-                    compilerLanguageVersionSettings
-            );
         }
 
         updateConfigurationWithFlags(configuration, kotlinConfigurationFlags);
     }
 
-    private static void assertDirectivesToNull(@Nullable LanguageVersionSettings settings, @Nullable LanguageVersion version) {
-        assert settings == null && version == null : "Should not specify LANGUAGE_VERSION twice or together with !LANGUAGE directive";
-    }
-
     private static final Map<String, Class<?>> FLAG_NAMESPACE_TO_CLASS = ImmutableMap.of(
             "CLI", CLIConfigurationKeys.class,
             "JVM", JVMConfigurationKeys.class