Improve diagnostic message for UNSUPPORTED_FEATURE

Render lowercase words separated by spaces instead of CamelCase in the
diagnostic message

compiler/frontend/src/org/jetbrains/kotlin/config/LanguageVersionSettings.kt

@@ -31,6 +31,10 @@ enum class LanguageFeature(val sinceVersion: LanguageVersion) {
     DestructuringLambdaParameters(KOTLIN_1_1),
     ;
 
+    val presentableText: String
+        // E.g. "DestructuringLambdaParameters" -> ["Destructuring", "Lambda", "Parameters"] -> "destructuring lambda parameters"
+        get() = name.split("(?<!^)(?=[A-Z])".toRegex()).joinToString(separator = " ", transform = String::toLowerCase)
+
     companion object {
         @JvmStatic
         fun fromString(str: String) = values().find { it.name == str }

compiler/frontend/src/org/jetbrains/kotlin/diagnostics/rendering/DefaultErrorMessages.java

@@ -21,6 +21,7 @@ import kotlin.jvm.functions.Function1;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.jetbrains.annotations.TestOnly;
+import org.jetbrains.kotlin.config.LanguageFeature;
 import org.jetbrains.kotlin.diagnostics.Diagnostic;
 import org.jetbrains.kotlin.diagnostics.DiagnosticFactory;
 import org.jetbrains.kotlin.diagnostics.Errors;
@@ -505,7 +506,13 @@ public class DefaultErrorMessages {
         MAP.put(UNSAFE_IMPLICIT_INVOKE_CALL, "Reference has a nullable type ''{0}'', use explicit ''?.invoke()'' to make a function-like call instead", RENDER_TYPE);
         MAP.put(AMBIGUOUS_LABEL, "Ambiguous label");
         MAP.put(UNSUPPORTED, "Unsupported [{0}]", STRING);
-        MAP.put(UNSUPPORTED_FEATURE, "{0} are unsupported at this language level", TO_STRING);
+        MAP.put(UNSUPPORTED_FEATURE, "The feature is only available since Kotlin {0}", new DiagnosticParameterRenderer<LanguageFeature>() {
+            @NotNull
+            @Override
+            public String render(LanguageFeature feature, @NotNull RenderingContext renderingContext) {
+                return feature.getSinceVersion().getVersionString() + ": " + feature.getPresentableText();
+            }
+        });
         MAP.put(EXCEPTION_FROM_ANALYZER, "Internal Error occurred while analyzing this expression:\n{0}", THROWABLE);
         MAP.put(UNNECESSARY_SAFE_CALL, "Unnecessary safe call on a non-null receiver of type {0}", RENDER_TYPE);
         MAP.put(UNEXPECTED_SAFE_CALL, "Safe-call is not allowed here");

compiler/tests-common/org/jetbrains/kotlin/resolve/lazy/JvmResolveUtil.kt

@@ -65,7 +65,11 @@ object JvmResolveUtil {
 
     @JvmStatic
     fun analyze(files: Collection<KtFile>, environment: KotlinCoreEnvironment): AnalysisResult =
-            analyze(environment.project, files, environment.configuration) { scope ->
+            analyze(files, environment, environment.configuration)
+
+    @JvmStatic
+    fun analyze(files: Collection<KtFile>, environment: KotlinCoreEnvironment, configuration: CompilerConfiguration): AnalysisResult =
+            analyze(environment.project, files, configuration) { scope ->
                 JvmPackagePartProvider(environment, scope)
             }
 

idea/testData/diagnosticMessage/unsupportedFeature.kt

@@ -0,0 +1,7 @@
+// !DIAGNOSTICS_NUMBER: 1
+// !DIAGNOSTICS: UNSUPPORTED_FEATURE
+// LANGUAGE_VERSION: 1.0
+
+fun test() {
+    mapOf("1" to "2").forEach { (key, value) -> }
+}

idea/testData/diagnosticMessage/unsupportedFeature1.txt

@@ -0,0 +1,2 @@
+<!-- unsupportedFeature1 -->
+The feature is only available since Kotlin 1.1: destructuring lambda parameters

idea/tests/org/jetbrains/kotlin/idea/highlighter/AbstractDiagnosticMessageJsTest.java

@@ -23,6 +23,8 @@ import org.jetbrains.kotlin.cli.jvm.compiler.EnvironmentConfigFiles;
 import org.jetbrains.kotlin.cli.jvm.compiler.KotlinCoreEnvironment;
 import org.jetbrains.kotlin.config.CommonConfigurationKeys;
 import org.jetbrains.kotlin.config.CompilerConfiguration;
+import org.jetbrains.kotlin.config.LanguageVersion;
+import org.jetbrains.kotlin.config.LanguageVersionSettingsImpl;
 import org.jetbrains.kotlin.idea.test.PluginTestCaseBase;
 import org.jetbrains.kotlin.js.analyze.TopDownAnalyzerFacadeForJS;
 import org.jetbrains.kotlin.js.config.JSConfigurationKeys;
@@ -45,8 +47,8 @@ public abstract class AbstractDiagnosticMessageJsTest extends AbstractDiagnostic
 
     @NotNull
     @Override
-    protected AnalysisResult analyze(@NotNull KtFile file) {
-        return TopDownAnalyzerFacadeForJS.analyzeFiles(singletonList(file), getConfig());
+    protected AnalysisResult analyze(@NotNull KtFile file, @Nullable LanguageVersion explicitLanguageVersion) {
+        return TopDownAnalyzerFacadeForJS.analyzeFiles(singletonList(file), getConfig(explicitLanguageVersion));
     }
 
     @NotNull
@@ -62,12 +64,15 @@ public abstract class AbstractDiagnosticMessageJsTest extends AbstractDiagnostic
     }
 
     @NotNull
-    private JsConfig getConfig() {
+    private JsConfig getConfig(@Nullable LanguageVersion explicitLanguageVersion) {
         CompilerConfiguration configuration = getEnvironment().getConfiguration().copy();
         configuration.put(CommonConfigurationKeys.MODULE_NAME, KotlinTestUtils.TEST_MODULE_NAME);
         configuration.put(JSConfigurationKeys.LIBRARY_FILES, LibrarySourcesConfig.JS_STDLIB);
         configuration.put(CommonConfigurationKeys.DISABLE_INLINE, true);
         configuration.put(JSConfigurationKeys.UNIT_TEST_CONFIG, true);
+        if (explicitLanguageVersion != null) {
+            configuration.put(CommonConfigurationKeys.LANGUAGE_VERSION_SETTINGS, new LanguageVersionSettingsImpl(explicitLanguageVersion));
+        }
         return new LibrarySourcesConfig(getProject(), configuration);
     }
 }

idea/tests/org/jetbrains/kotlin/idea/highlighter/AbstractDiagnosticMessageTest.java

@@ -24,6 +24,10 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.jetbrains.kotlin.analyzer.AnalysisResult;
 import org.jetbrains.kotlin.cli.jvm.compiler.KotlinCoreEnvironment;
+import org.jetbrains.kotlin.config.CommonConfigurationKeys;
+import org.jetbrains.kotlin.config.CompilerConfiguration;
+import org.jetbrains.kotlin.config.LanguageVersion;
+import org.jetbrains.kotlin.config.LanguageVersionSettingsImpl;
 import org.jetbrains.kotlin.diagnostics.Diagnostic;
 import org.jetbrains.kotlin.diagnostics.DiagnosticFactory;
 import org.jetbrains.kotlin.diagnostics.Errors;
@@ -35,11 +39,13 @@ import org.jetbrains.kotlin.resolve.BindingContext;
 import org.jetbrains.kotlin.resolve.jvm.diagnostics.ErrorsJvm;
 import org.jetbrains.kotlin.resolve.lazy.JvmResolveUtil;
 import org.jetbrains.kotlin.test.ConfigurationKind;
+import org.jetbrains.kotlin.test.InTextDirectivesUtils;
 import org.jetbrains.kotlin.test.KotlinTestUtils;
 import org.jetbrains.kotlin.test.KotlinTestWithEnvironment;
 
 import java.io.File;
 import java.lang.reflect.Field;
+import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -73,8 +79,12 @@ public abstract class AbstractDiagnosticMessageTest extends KotlinTestWithEnviro
     }
 
     @NotNull
-    protected AnalysisResult analyze(@NotNull KtFile file) {
-        return JvmResolveUtil.analyze(file, getEnvironment());
+    protected AnalysisResult analyze(@NotNull KtFile file, @Nullable LanguageVersion explicitLanguageVersion) {
+        CompilerConfiguration configuration = getEnvironment().getConfiguration();
+        if (explicitLanguageVersion != null) {
+            configuration.put(CommonConfigurationKeys.LANGUAGE_VERSION_SETTINGS, new LanguageVersionSettingsImpl(explicitLanguageVersion));
+        }
+        return JvmResolveUtil.analyze(Collections.singleton(file), getEnvironment(), configuration);
     }
 
     public void doTest(String filePath) throws Exception {
@@ -87,8 +97,11 @@ public abstract class AbstractDiagnosticMessageTest extends KotlinTestWithEnviro
         final Set<DiagnosticFactory<?>> diagnosticFactories = getDiagnosticFactories(directives);
         MessageType messageType = getMessageTypeDirective(directives);
 
+        String explicitLanguageVersion = InTextDirectivesUtils.findStringWithPrefixes(fileData, "// LANGUAGE_VERSION:");
+        LanguageVersion version = explicitLanguageVersion == null ? null : LanguageVersion.fromVersionString(explicitLanguageVersion);
+
         KtFile psiFile = KotlinTestUtils.createFile(fileName, KotlinTestUtils.doLoadFile(getTestDataPath(), fileName), getProject());
-        AnalysisResult analysisResult = analyze(psiFile);
+        AnalysisResult analysisResult = analyze(psiFile, version);
         BindingContext bindingContext = analysisResult.getBindingContext();
 
         List<Diagnostic> diagnostics = ContainerUtil.filter(bindingContext.getDiagnostics().all(), new Condition<Diagnostic>() {

idea/tests/org/jetbrains/kotlin/idea/highlighter/DiagnosticMessageTestGenerated.java

@@ -269,6 +269,12 @@ public class DiagnosticMessageTestGenerated extends AbstractDiagnosticMessageTes
         doTest(fileName);
     }
 
+    @TestMetadata("unsupportedFeature.kt")
+    public void testUnsupportedFeature() throws Exception {
+        String fileName = KotlinTestUtils.navigationMetadata("idea/testData/diagnosticMessage/unsupportedFeature.kt");
+        doTest(fileName);
+    }
+
     @TestMetadata("unusedParameter.kt")
     public void testUnusedParameter() throws Exception {
         String fileName = KotlinTestUtils.navigationMetadata("idea/testData/diagnosticMessage/unusedParameter.kt");