Reorder LanguageFeature entries according to sinceVersion

compiler/tests/org/jetbrains/kotlin/code/CodeConformanceTest.kt

@@ -8,6 +8,7 @@ package org.jetbrains.kotlin.code
 import com.intellij.openapi.util.io.FileUtil
 import com.intellij.openapi.util.io.systemIndependentPath
 import junit.framework.TestCase
+import org.jetbrains.kotlin.config.LanguageFeature
 import java.io.File
 import java.util.*
 import java.util.regex.Pattern
@@ -379,6 +380,20 @@ class CodeConformanceTest : TestCase() {
 
         }
     }
+
+    fun testLanguageFeatureOrder() {
+        val values = enumValues<LanguageFeature>()
+        val enabledFeatures = values.filter { it.sinceVersion != null && it.defaultState == LanguageFeature.State.ENABLED }
+
+        if (enabledFeatures.sortedBy { it.sinceVersion!! } != enabledFeatures) {
+            val (a, b) = enabledFeatures.zipWithNext().first { (a, b) -> a.sinceVersion!! > b.sinceVersion!! }
+            fail(
+                "Please make sure LanguageFeature entries are sorted by sinceVersion to improve readability & reduce confusion.\n" +
+                        "The feature $b is out of order; its sinceVersion is ${b.sinceVersion}, yet it comes after $a, whose " +
+                        "sinceVersion is ${a.sinceVersion}.\n"
+            )
+        }
+    }
 }
 
 private fun String.ensureFileOrEndsWithSlash() =

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

@@ -18,6 +18,9 @@ enum class LanguageFeature(
     val kind: Kind = OTHER // NB: default value OTHER doesn't force pre-releaseness (see KDoc)
 ) {
     // Note: names of these entries are also used in diagnostic tests and in user-visible messages (see presentableText below)
+
+    // 1.1
+
     TypeAliases(KOTLIN_1_1),
     BoundCallableReferences(KOTLIN_1_1, ApiVersion.KOTLIN_1_1),
     LocalDelegatedProperties(KOTLIN_1_1, ApiVersion.KOTLIN_1_1),
@@ -40,6 +43,8 @@ enum class LanguageFeature(
     NoDelegationToJavaDefaultInterfaceMembers(KOTLIN_1_1),
     DefaultImportOfPackageKotlinComparisons(KOTLIN_1_1),
 
+    // 1.2
+
     ArrayLiteralsInAnnotations(KOTLIN_1_2),
     InlineDefaultFunctionalParameters(KOTLIN_1_2),
     SoundSmartCastsAfterTry(KOTLIN_1_2),
@@ -57,6 +62,8 @@ enum class LanguageFeature(
     ExpectedTypeFromCast(KOTLIN_1_2),
     DefaultMethodsCallFromJava6TargetError(KOTLIN_1_2),
 
+    // 1.3
+
     RestrictionOfValReassignmentViaBackingField(KOTLIN_1_3, kind = BUG_FIX),
     NestedClassesInEnumEntryShouldBeInner(KOTLIN_1_3, kind = BUG_FIX),
     ProhibitDataClassesOverridingCopy(KOTLIN_1_3, kind = BUG_FIX),
@@ -88,6 +95,8 @@ enum class LanguageFeature(
     ExtendedMainConvention(KOTLIN_1_3),
     ExperimentalBuilderInference(KOTLIN_1_3),
 
+    // 1.4
+
     DslMarkerOnFunctionTypeReceiver(KOTLIN_1_4, kind = BUG_FIX),
     RestrictReturnStatementTarget(KOTLIN_1_4, kind = BUG_FIX),
     NoConstantValueAttributeForNonConstVals(KOTLIN_1_4, kind = BUG_FIX),
@@ -116,7 +125,6 @@ enum class LanguageFeature(
     AllowAssigningArrayElementsToVarargsInNamedFormForFunctions(KOTLIN_1_4),
     AllowNullOperatorsForResult(KOTLIN_1_4),
     AllowResultInReturnType(KOTLIN_1_4, defaultState = State.DISABLED),
-    AllowNullOperatorsForResultAndResultReturnTypeByDefault(KOTLIN_1_5, defaultState = State.ENABLED),
     PreferJavaFieldOverload(KOTLIN_1_4),
     AllowContractsForNonOverridableMembers(KOTLIN_1_4),
     AllowReifiedGenericsInContracts(KOTLIN_1_4),
@@ -128,27 +136,51 @@ enum class LanguageFeature(
     MangleClassMembersReturningInlineClasses(KOTLIN_1_4),
     ImproveReportingDiagnosticsOnProtectedMembersOfBaseClass(KOTLIN_1_4, kind = BUG_FIX, defaultState = State.ENABLED),
 
+    NewInference(KOTLIN_1_4),
+
+    // In the next block, features can be enabled only along with new inference
+    // v----------------------------------------------------------------------v
+    SamConversionForKotlinFunctions(KOTLIN_1_4),
+    SamConversionPerArgument(KOTLIN_1_4),
+    FunctionReferenceWithDefaultValueAsOtherType(KOTLIN_1_4),
+    SuspendConversion(KOTLIN_1_4, defaultState = State.DISABLED),
+    UnitConversion(KOTLIN_1_4, defaultState = State.DISABLED),
+    OverloadResolutionByLambdaReturnType(KOTLIN_1_4),
+    ContractsOnCallsWithImplicitReceiver(KOTLIN_1_4),
+    BooleanElvisBoundSmartCasts(KOTLIN_1_3, defaultState = State.DISABLED), // see KT-26357 for details
+    NewDataFlowForTryExpressions(KOTLIN_1_4, defaultState = State.DISABLED),
+    ReferencesToSyntheticJavaProperties(KOTLIN_1_3, defaultState = State.DISABLED),
+    // ^----------------------------------------------------------------------^
+
+    // 1.5
+
     ProhibitSpreadOnSignaturePolymorphicCall(KOTLIN_1_5, kind = BUG_FIX),
     ProhibitInvisibleAbstractMethodsInSuperclasses(KOTLIN_1_5, kind = BUG_FIX),
     ProhibitNonReifiedArraysAsReifiedTypeArguments(KOTLIN_1_5, kind = BUG_FIX),
     ProhibitVarargAsArrayAfterSamArgument(KOTLIN_1_5, kind = BUG_FIX),
     CorrectSourceMappingSyntax(KOTLIN_1_5, kind = UNSTABLE_FEATURE),
     ProperArrayConventionSetterWithDefaultCalls(KOTLIN_1_5, kind = OTHER),
-    DisableCompatibilityModeForNewInference(KOTLIN_1_5, defaultState = LanguageFeature.State.DISABLED),
+    DisableCompatibilityModeForNewInference(KOTLIN_1_5, defaultState = State.DISABLED),
-    AdaptedCallableReferenceAgainstReflectiveType(KOTLIN_1_5, defaultState = LanguageFeature.State.DISABLED),
+    AdaptedCallableReferenceAgainstReflectiveType(KOTLIN_1_5, defaultState = State.DISABLED),
     InferenceCompatibility(KOTLIN_1_5, kind = BUG_FIX),
     RequiredPrimaryConstructorDelegationCallInEnums(KOTLIN_1_5, kind = BUG_FIX),
     ApproximateAnonymousReturnTypesInPrivateInlineFunctions(KOTLIN_1_5, kind = BUG_FIX),
     ForbidReferencingToUnderscoreNamedParameterOfCatchBlock(KOTLIN_1_5, kind = BUG_FIX),
     UseCorrectExecutionOrderForVarargArguments(KOTLIN_1_5, kind = BUG_FIX),
     JvmRecordSupport(KOTLIN_1_5),
-
+    AllowNullOperatorsForResultAndResultReturnTypeByDefault(KOTLIN_1_5, defaultState = State.ENABLED),
     AllowSealedInheritorsInDifferentFilesOfSamePackage(KOTLIN_1_5),
     SealedInterfaces(KOTLIN_1_5),
     JvmIrEnabledByDefault(KOTLIN_1_5),
+    JvmInlineValueClasses(KOTLIN_1_5, defaultState = State.ENABLED, kind = OTHER),
+    SuspendFunctionsInFunInterfaces(KOTLIN_1_5, defaultState = State.ENABLED, kind = OTHER),
+    SamWrapperClassesAreSynthetic(KOTLIN_1_5, defaultState = State.ENABLED, kind = BUG_FIX),
+    StrictOnlyInputTypesChecks(KOTLIN_1_5),
+
     // Disabled until the breaking change is approved by the committee, see KT-10884.
     PackagePrivateFileClassesWithAllPrivateMembers(KOTLIN_1_5, defaultState = State.DISABLED),
-    StrictOnlyInputTypesChecks(sinceVersion = KOTLIN_1_5),
+
+    // 1.6
 
     /*
      * Improvements include the following:
@@ -170,6 +202,9 @@ enum class LanguageFeature(
     ApproximateIntegerLiteralTypesInReceiverPosition(KOTLIN_1_6),
     ProperCheckAnnotationsTargetInTypeUsePositions(KOTLIN_1_6, kind = BUG_FIX),
 
+    DefinitelyNotNullTypeParameters(KOTLIN_1_6),
+    ProhibitUsingNullableTypeParameterAgainstNotNullAnnotated(KOTLIN_1_6, kind = BUG_FIX),
+
     // Temporarily disabled, see KT-27084/KT-22379
     SoundSmartcastFromLoopConditionForLoopAssignedVariables(sinceVersion = null, kind = BUG_FIX),
 
@@ -180,38 +215,13 @@ enum class LanguageFeature(
         "https://kotlinlang.org/docs/diagnostics/experimental-coroutines",
         State.ENABLED_WITH_WARNING
     ),
-
     MultiPlatformProjects(sinceVersion = null, defaultState = State.DISABLED),
+    InlineClasses(KOTLIN_1_3, defaultState = State.ENABLED_WITH_WARNING, kind = UNSTABLE_FEATURE),
 
-    NewInference(sinceVersion = KOTLIN_1_4),
-
-    // In the next block, features can be enabled only along with new inference
-    SamConversionForKotlinFunctions(sinceVersion = KOTLIN_1_4),
-    SamConversionPerArgument(sinceVersion = KOTLIN_1_4),
-    FunctionReferenceWithDefaultValueAsOtherType(sinceVersion = KOTLIN_1_4),
-    SuspendConversion(sinceVersion = KOTLIN_1_4, defaultState = State.DISABLED),
-    UnitConversion(sinceVersion = KOTLIN_1_4, defaultState = State.DISABLED),
-    OverloadResolutionByLambdaReturnType(sinceVersion = KOTLIN_1_4),
-    ContractsOnCallsWithImplicitReceiver(sinceVersion = KOTLIN_1_4),
-
-    BooleanElvisBoundSmartCasts(sinceVersion = KOTLIN_1_3, defaultState = State.DISABLED), // see KT-26357 for details
-    NewDataFlowForTryExpressions(sinceVersion = KOTLIN_1_4, defaultState = State.DISABLED),
-    ReferencesToSyntheticJavaProperties(sinceVersion = KOTLIN_1_3, defaultState = State.DISABLED),
-    // ------
-    // Next features can be enabled regardless of new inference
-
-    InlineClasses(sinceVersion = KOTLIN_1_3, defaultState = State.ENABLED_WITH_WARNING, kind = UNSTABLE_FEATURE),
-    JvmInlineValueClasses(sinceVersion = KOTLIN_1_5, defaultState = State.ENABLED, kind = OTHER),
-    SuspendFunctionsInFunInterfaces(sinceVersion = KOTLIN_1_5, defaultState = State.ENABLED, kind = OTHER),
-    SamWrapperClassesAreSynthetic(sinceVersion = KOTLIN_1_5, defaultState = State.ENABLED, kind = BUG_FIX),
-
-    // 1.6
-    DefinitelyNotNullTypeParameters(sinceVersion = KOTLIN_1_6),
-    ProhibitUsingNullableTypeParameterAgainstNotNullAnnotated(sinceVersion = KOTLIN_1_6, kind = BUG_FIX),
     ;
 
     val presentableName: String
-    // E.g. "DestructuringLambdaParameters" -> ["Destructuring", "Lambda", "Parameters"] -> "destructuring lambda parameters"
+        // E.g. "DestructuringLambdaParameters" -> ["Destructuring", "Lambda", "Parameters"] -> "destructuring lambda parameters"
         get() = name.split("(?<!^)(?=[A-Z])".toRegex()).joinToString(separator = " ", transform = String::lowercase)
 
     val presentableText get() = if (hintUrl == null) presentableName else "$presentableName (See: $hintUrl)"
@@ -345,7 +355,7 @@ interface LanguageVersionSettings {
     fun supportsFeature(feature: LanguageFeature): Boolean =
         getFeatureSupport(feature).let {
             it == LanguageFeature.State.ENABLED ||
-            it == LanguageFeature.State.ENABLED_WITH_WARNING
+                    it == LanguageFeature.State.ENABLED_WITH_WARNING
         }
 
     fun isPreRelease(): Boolean