[FIR] Put new contract syntax under feauture flag

^KT-55171 Fixed

analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosisCompilerFirTestdataTestGenerated.java

@@ -1385,6 +1385,12 @@ public class DiagnosisCompilerFirTestdataTestGenerated extends AbstractDiagnosis
                 runTest("compiler/fir/analysis-tests/testData/resolve/contracts/contractFromOtherModule_samePackage.kt");
             }
 
+            @Test
+            @TestMetadata("disabledFeature.kt")
+            public void testDisabledFeature() throws Exception {
+                runTest("compiler/fir/analysis-tests/testData/resolve/contracts/disabledFeature.kt");
+            }
+
             @Test
             @TestMetadata("genericContract.kt")
             public void testGenericContract() throws Exception {

compiler/fir/analysis-tests/legacy-fir-tests/tests-gen/org/jetbrains/kotlin/fir/LazyBodyIsNotTouchedTilContractsPhaseTestGenerated.java

@@ -1208,6 +1208,11 @@ public class LazyBodyIsNotTouchedTilContractsPhaseTestGenerated extends Abstract
             runTest("compiler/fir/analysis-tests/testData/resolve/contracts/contractFromOtherModule_samePackage.kt");
         }
 
+        @TestMetadata("disabledFeature.kt")
+        public void testDisabledFeature() throws Exception {
+            runTest("compiler/fir/analysis-tests/testData/resolve/contracts/disabledFeature.kt");
+        }
+
         @TestMetadata("genericContract.kt")
         public void testGenericContract() throws Exception {
             runTest("compiler/fir/analysis-tests/testData/resolve/contracts/genericContract.kt");

compiler/fir/analysis-tests/testData/resolve/contracts/contractFromOtherModule.kt

@@ -1,3 +1,4 @@
+// LANGUAGE: +ContractSyntaxV2
 // SKIP_JAVAC
 // This directive is needed to skip this test in LazyBodyIsNotTouchedTilContractsPhaseTestGenerated,
 //  because it fails to parse module structure of multimodule test

compiler/fir/analysis-tests/testData/resolve/contracts/contractFromOtherModule_samePackage.kt

@@ -1,3 +1,4 @@
+// LANGUAGE: +ContractSyntaxV2
 // SKIP_JAVAC
 // This directive is needed to skip this test in LazyBodyIsNotTouchedTilContractsPhaseTestGenerated,
 //  because it fails to parse module structure of multimodule test

compiler/fir/analysis-tests/testData/resolve/contracts/disabledFeature.fir.txt

@@ -0,0 +1,34 @@
+FILE: disabledFeature.kt
+    public final inline fun <reified T> requreIsInstance(value: R|kotlin/Any|): R|kotlin/Unit|
+        [R|Contract description]
+         <
+            Returns(WILDCARD) -> value is T
+        >
+     {
+        when () {
+            (R|<local>/value| !is R|T|) ->  {
+                throw R|java/lang/IllegalArgumentException.IllegalArgumentException|()
+            }
+        }
+
+    }
+    public final val R|kotlin/Any?|.myLength: R|kotlin/Int?|
+        public get(): R|kotlin/Int?|
+            [R|Contract description]
+             <
+            >
+         {
+            ^ (this@R|/myLength| as? R|kotlin/String|)?.{ $subj$.R|kotlin/String.length| }
+        }
+    public final fun test_1(x: R|kotlin/Any|): R|kotlin/Unit| {
+        R|/requreIsInstance|<R|kotlin/String|>(R|<local>/x|)
+        R|<local>/x|.R|kotlin/String.length|
+    }
+    public final fun test_2(x: R|kotlin/Any|): R|kotlin/Unit| {
+        when () {
+            !=(R|<local>/x|.R|/myLength|, Null(null)) ->  {
+                R|<local>/x|.<Unresolved name: length>#
+            }
+        }
+
+    }

compiler/fir/analysis-tests/testData/resolve/contracts/disabledFeature.kt

@@ -0,0 +1,26 @@
+// LANGUAGE: -ContractSyntaxV2
+// WITH_STDLIB
+
+import kotlin.contracts.*
+
+inline fun <reified T> requreIsInstance(value: Any) contract <!UNSUPPORTED_FEATURE!>[
+    returns() implies (value is T)
+]<!> {
+    if (value !is T) throw IllegalArgumentException()
+}
+
+val Any?.myLength: Int?
+    get() contract <!UNSUPPORTED_FEATURE!>[
+        <!ERROR_IN_CONTRACT_DESCRIPTION!>returnsNotNull() implies (this@length is String)<!>
+    ]<!> = (this as? String)?.length
+
+fun test_1(x: Any) {
+    requreIsInstance<String>(x)
+    x.length
+}
+
+fun test_2(x: Any) {
+    if (x.myLength != null) {
+        x.<!UNRESOLVED_REFERENCE!>length<!>
+    }
+}

compiler/fir/analysis-tests/testData/resolve/contracts/genericContract.kt

@@ -1,3 +1,4 @@
+// LANGUAGE: +ContractSyntaxV2
 // WITH_STDLIB
 
 import kotlin.contracts.*

compiler/fir/analysis-tests/testData/resolveWithStdlib/contracts/fromSource/good/variousContracts/newSyntax/functionsWithContract.kt

@@ -1,3 +1,4 @@
+// LANGUAGE: +ContractSyntaxV2
 import kotlin.contracts.*
 
 fun test1(arg: Any?) contract [

compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirDiagnosticTestGenerated.java

@@ -1385,6 +1385,12 @@ public class FirDiagnosticTestGenerated extends AbstractFirDiagnosticTest {
                 runTest("compiler/fir/analysis-tests/testData/resolve/contracts/contractFromOtherModule_samePackage.kt");
             }
 
+            @Test
+            @TestMetadata("disabledFeature.kt")
+            public void testDisabledFeature() throws Exception {
+                runTest("compiler/fir/analysis-tests/testData/resolve/contracts/disabledFeature.kt");
+            }
+
             @Test
             @TestMetadata("genericContract.kt")
             public void testGenericContract() throws Exception {

compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirDiagnosticsWithLightTreeTestGenerated.java

@@ -1385,6 +1385,12 @@ public class FirDiagnosticsWithLightTreeTestGenerated extends AbstractFirDiagnos
                 runTest("compiler/fir/analysis-tests/testData/resolve/contracts/contractFromOtherModule_samePackage.kt");
             }
 
+            @Test
+            @TestMetadata("disabledFeature.kt")
+            public void testDisabledFeature() throws Exception {
+                runTest("compiler/fir/analysis-tests/testData/resolve/contracts/disabledFeature.kt");
+            }
+
             @Test
             @TestMetadata("genericContract.kt")
             public void testGenericContract() throws Exception {

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/CommonDeclarationCheckers.kt

@@ -56,6 +56,7 @@ object CommonDeclarationCheckers : DeclarationCheckers() {
             FirTailrecFunctionChecker,
             FirMemberFunctionsChecker,
             FirDataObjectContentChecker,
+            ContractSyntaxV2FunctionChecker,
         )
 
     override val propertyCheckers: Set<FirPropertyChecker>
@@ -73,6 +74,7 @@ object CommonDeclarationCheckers : DeclarationCheckers() {
             FirDelegateUsesExtensionPropertyTypeParameterChecker,
             FirTopLevelPropertiesChecker,
             FirLocalExtensionPropertyChecker,
+            ContractSyntaxV2PropertyChecker,
         )
 
     override val backingFieldCheckers: Set<FirBackingFieldChecker>

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/NiceContractSyntaxChecker.kt

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2010-2023 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.fir.analysis.checkers.declaration
+
+import org.jetbrains.kotlin.KtNodeTypes
+import org.jetbrains.kotlin.config.LanguageFeature
+import org.jetbrains.kotlin.diagnostics.DiagnosticReporter
+import org.jetbrains.kotlin.diagnostics.reportOn
+import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
+import org.jetbrains.kotlin.fir.declarations.FirContractDescriptionOwner
+import org.jetbrains.kotlin.fir.declarations.FirProperty
+import org.jetbrains.kotlin.fir.declarations.FirSimpleFunction
+
+object ContractSyntaxV2FunctionChecker : FirSimpleFunctionChecker() {
+    override fun check(declaration: FirSimpleFunction, context: CheckerContext, reporter: DiagnosticReporter) {
+        checkFeatureIsEnabled(declaration, context, reporter)
+    }
+}
+
+object ContractSyntaxV2PropertyChecker : FirPropertyChecker() {
+    override fun check(declaration: FirProperty, context: CheckerContext, reporter: DiagnosticReporter) {
+        declaration.getter?.let { checkFeatureIsEnabled(it, context, reporter) }
+        declaration.setter?.let { checkFeatureIsEnabled(it, context, reporter) }
+    }
+}
+
+private fun checkFeatureIsEnabled(declaration: FirContractDescriptionOwner, context: CheckerContext, reporter: DiagnosticReporter) {
+    val source = declaration.contractDescription.source ?: return
+    if (source.elementType != KtNodeTypes.CONTRACT_EFFECT_LIST) return
+    val languageVersionSettings = context.languageVersionSettings
+    if (!languageVersionSettings.supportsFeature(LanguageFeature.ContractSyntaxV2)) {
+        reporter.reportOn(source, FirErrors.UNSUPPORTED_FEATURE, LanguageFeature.ContractSyntaxV2 to languageVersionSettings, context)
+    }
+}

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/contracts/FirAbstractContractResolveTransformerDispatcher.kt

@@ -245,6 +245,7 @@ abstract class FirAbstractContractResolveTransformerDispatcher(
 
             val legacyRawContractDescription = buildLegacyRawContractDescription {
                 this.contractCall = contractCall
+                this.source = contractDescription.source
             }
 
             owner.replaceContractDescription(legacyRawContractDescription)

compiler/testData/diagnostics/testsWithStdLib/contracts/newSyntax/complexContractDescription.fir.kt

@@ -1,3 +1,4 @@
+// LANGUAGE: +ContractSyntaxV2
 // !DIAGNOSTICS: -UNUSED_VARIABLE
 
 import kotlin.contracts.*

compiler/testData/diagnostics/testsWithStdLib/contracts/newSyntax/complexContractDescription.kt

@@ -1,3 +1,4 @@
+// LANGUAGE: +ContractSyntaxV2
 // !DIAGNOSTICS: -UNUSED_VARIABLE
 
 import kotlin.contracts.*

compiler/testData/diagnostics/testsWithStdLib/contracts/newSyntax/onelineFunctionsContractDescription.fir.kt

@@ -1,10 +1,11 @@
+// LANGUAGE: +ContractSyntaxV2
 import kotlin.contracts.*
 
 fun calculateNumber(block: () -> Int): Int contract [
     callsInPlace(block, InvocationKind.EXACTLY_ONCE)
 ] = block()
 
-fun <R> calculateResult(num: Int?, calculate: (Int?) -> R): R contract [
+fun <R> calculateResult(num: Int?, calculate: (Int?) -> R): R contract <!WRONG_IMPLIES_CONDITION!>[
     callsInPlace(calculate, InvocationKind.EXACTLY_ONCE),
     returns() implies (num != null)
-] = calculate(num)
+]<!> = calculate(num)

compiler/testData/diagnostics/testsWithStdLib/contracts/newSyntax/onelineFunctionsContractDescription.kt

@@ -1,3 +1,4 @@
+// LANGUAGE: +ContractSyntaxV2
 import kotlin.contracts.*
 
 fun calculateNumber(block: () -> Int): Int contract <!UNSUPPORTED!>[

compiler/testData/diagnostics/testsWithStdLib/contracts/newSyntax/propertyAccessorsContractDescription.fir.kt

@@ -1,3 +1,4 @@
+// LANGUAGE: +ContractSyntaxV2
 import kotlin.contracts.*
 
 class A {

compiler/testData/diagnostics/testsWithStdLib/contracts/newSyntax/propertyAccessorsContractDescription.kt

@@ -1,3 +1,4 @@
+// LANGUAGE: +ContractSyntaxV2
 import kotlin.contracts.*
 
 class A {

compiler/testData/diagnostics/testsWithStdLib/contracts/newSyntax/simpleFunctionsContractDescription.fir.kt

@@ -1,3 +1,4 @@
+// LANGUAGE: +ContractSyntaxV2
 import kotlin.contracts.*
 
 fun printStr(str: String?) contract [

compiler/testData/diagnostics/testsWithStdLib/contracts/newSyntax/simpleFunctionsContractDescription.kt

@@ -1,3 +1,4 @@
+// LANGUAGE: +ContractSyntaxV2
 import kotlin.contracts.*
 
 fun printStr(str: String?) contract <!UNSUPPORTED!>[

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

@@ -325,6 +325,7 @@ enum class LanguageFeature(
     CustomEqualsInValueClasses(sinceVersion = null, kind = OTHER), // KT-24874
     InlineLateinit(sinceVersion = null, kind = OTHER), // KT-23814
     EnableDfaWarningsInK2(sinceVersion = null, kind = OTHER), // KT-50965
+    ContractSyntaxV2(sinceVersion = null, kind = UNSTABLE_FEATURE), // KT-56127
     ;
 
     init {