[FIR] Introduce OPTIONAL_EXPECTATION_NOT_ON_EXPECTED diagnostic

^KT-60892 Fixed

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KtFirDataClassConverters.kt

@@ -3630,6 +3630,12 @@ internal val KT_DIAGNOSTIC_CONVERTER = KtDiagnosticConverterBuilder.buildConvert
             token,
         )
     }
+    add(FirErrors.OPTIONAL_EXPECTATION_NOT_ON_EXPECTED) { firDiagnostic ->
+        OptionalExpectationNotOnExpectedImpl(
+            firDiagnostic as KtPsiDiagnostic,
+            token,
+        )
+    }
     add(FirErrors.INITIALIZER_REQUIRED_FOR_DESTRUCTURING_DECLARATION) { firDiagnostic ->
         InitializerRequiredForDestructuringDeclarationImpl(
             firDiagnostic as KtPsiDiagnostic,

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KtFirDiagnostics.kt

@@ -2541,6 +2541,10 @@ sealed interface KtFirDiagnostic<PSI : PsiElement> : KtDiagnosticWithPsi<PSI> {
         override val diagnosticClass get() = OptionalDeclarationUsageInNonCommonSource::class
     }
 
+    interface OptionalExpectationNotOnExpected : KtFirDiagnostic<PsiElement> {
+        override val diagnosticClass get() = OptionalExpectationNotOnExpected::class
+    }
+
     interface InitializerRequiredForDestructuringDeclaration : KtFirDiagnostic<KtDestructuringDeclaration> {
         override val diagnosticClass get() = InitializerRequiredForDestructuringDeclaration::class
     }

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KtFirDiagnosticsImpl.kt

@@ -3063,6 +3063,11 @@ internal class OptionalDeclarationUsageInNonCommonSourceImpl(
     token: KtLifetimeToken,
 ) : KtAbstractFirDiagnostic<PsiElement>(firDiagnostic, token), KtFirDiagnostic.OptionalDeclarationUsageInNonCommonSource
 
+internal class OptionalExpectationNotOnExpectedImpl(
+    firDiagnostic: KtPsiDiagnostic,
+    token: KtLifetimeToken,
+) : KtAbstractFirDiagnostic<PsiElement>(firDiagnostic, token), KtFirDiagnostic.OptionalExpectationNotOnExpected
+
 internal class InitializerRequiredForDestructuringDeclarationImpl(
     firDiagnostic: KtPsiDiagnostic,
     token: KtLifetimeToken,

compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/FirDiagnosticsList.kt

@@ -1240,6 +1240,8 @@ object DIAGNOSTICS_LIST : DiagnosticList("FirErrors") {
         val OPTIONAL_DECLARATION_OUTSIDE_OF_ANNOTATION_ENTRY by error<PsiElement>()
 
         val OPTIONAL_DECLARATION_USAGE_IN_NON_COMMON_SOURCE by error<PsiElement>()
+
+        val OPTIONAL_EXPECTATION_NOT_ON_EXPECTED by error<PsiElement>()
     }
 
     val DESTRUCTING_DECLARATION by object : DiagnosticGroup("Destructuring declaration") {

compiler/fir/checkers/gen/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrors.kt

@@ -651,6 +651,7 @@ object FirErrors {
     val ACTUAL_ANNOTATIONS_NOT_MATCH_EXPECT by warning3<KtElement, FirBasedSymbol<*>, FirBasedSymbol<*>, ExpectActualAnnotationsIncompatibilityType<FirAnnotation>>(SourceElementPositioningStrategies.DECLARATION_NAME_ONLY)
     val OPTIONAL_DECLARATION_OUTSIDE_OF_ANNOTATION_ENTRY by error0<PsiElement>()
     val OPTIONAL_DECLARATION_USAGE_IN_NON_COMMON_SOURCE by error0<PsiElement>()
+    val OPTIONAL_EXPECTATION_NOT_ON_EXPECTED by error0<PsiElement>()
 
     // Destructuring declaration
     val INITIALIZER_REQUIRED_FOR_DESTRUCTURING_DECLARATION by error0<KtDestructuringDeclaration>()

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

@@ -32,6 +32,7 @@ object CommonDeclarationCheckers : DeclarationCheckers() {
             FirPublishedApiChecker,
             FirOptInMarkedDeclarationChecker,
             FirExpectConsistencyChecker,
+            FirOptionalExpectationDeclarationChecker
         )
 
     override val callableDeclarationCheckers: Set<FirCallableDeclarationChecker>

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

@@ -0,0 +1,26 @@
+/*
+ * 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.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.FirDeclaration
+import org.jetbrains.kotlin.fir.declarations.FirMemberDeclaration
+import org.jetbrains.kotlin.fir.declarations.getAnnotationByClassId
+import org.jetbrains.kotlin.fir.declarations.utils.isExpect
+import org.jetbrains.kotlin.name.StandardClassIds
+
+object FirOptionalExpectationDeclarationChecker : FirBasicDeclarationChecker() {
+    override fun check(declaration: FirDeclaration, context: CheckerContext, reporter: DiagnosticReporter) {
+        if (declaration !is FirMemberDeclaration || !declaration.isExpect) {
+            declaration.getAnnotationByClassId(StandardClassIds.Annotations.OptionalExpectation, context.session)?.let {
+                reporter.reportOn(it.source, FirErrors.OPTIONAL_EXPECTATION_NOT_ON_EXPECTED, context)
+            }
+        }
+    }
+}

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrorsDefaultMessages.kt

@@ -437,6 +437,7 @@ import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.OPERATOR_MODIFIER
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.OPERATOR_RENAMED_ON_IMPORT
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.OPTIONAL_DECLARATION_OUTSIDE_OF_ANNOTATION_ENTRY
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.OPTIONAL_DECLARATION_USAGE_IN_NON_COMMON_SOURCE
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.OPTIONAL_EXPECTATION_NOT_ON_EXPECTED
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.OPT_IN_ARGUMENT_IS_NOT_MARKER
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.OPT_IN_CAN_ONLY_BE_USED_AS_ANNOTATION
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.OPT_IN_IS_NOT_ENABLED
@@ -1931,6 +1932,10 @@ object FirErrorsDefaultMessages : BaseDiagnosticRendererFactory() {
             OPTIONAL_DECLARATION_USAGE_IN_NON_COMMON_SOURCE,
             "Declaration annotated with '@OptionalExpectation' can only be used in common module sources"
         )
+        map.put(
+            OPTIONAL_EXPECTATION_NOT_ON_EXPECTED,
+            "'@OptionalExpectation' can only be used on an expected annotation class"
+        )
 
         // Destructuring declaration
         map.put(INITIALIZER_REQUIRED_FOR_DESTRUCTURING_DECLARATION, "Initializer required for destructuring declaration")

compiler/testData/diagnostics/tests/multiplatform/optionalExpectationDiagnostics.fir.kt

@@ -13,7 +13,7 @@ fun useInSignature(a: <!OPTIONAL_DECLARATION_OUTSIDE_OF_ANNOTATION_ENTRY!>A<!>)
 <!NO_ACTUAL_FOR_EXPECT{JVM}!><!WRONG_ANNOTATION_TARGET!>@OptionalExpectation<!>
 expect class NotAnAnnotationClass<!>
 
-@OptionalExpectation
+<!OPTIONAL_EXPECTATION_NOT_ON_EXPECTED!>@OptionalExpectation<!>
 annotation class NotAnExpectedClass
 
 annotation class InOtherAnnotation(val a: <!OPTIONAL_DECLARATION_OUTSIDE_OF_ANNOTATION_ENTRY!>A<!>)