[FIR] Add DECLARATION_CANT_BE_INLINED diagnostic

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

@@ -1173,6 +1173,8 @@ object DIAGNOSTICS_LIST : DiagnosticList("FirErrors") {
         val SUPER_CALL_FROM_PUBLIC_INLINE by warning<KtElement>(PositioningStrategy.REFERENCE_BY_QUALIFIED) {
             parameter<Symbol>("symbol")
         }
+
+        val DECLARATION_CANT_BE_INLINED by error<KtDeclaration>(PositioningStrategy.DECLARATION_SIGNATURE)
     }
 
     val IMPORTS by object : DiagnosticGroup("Imports") {

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

@@ -608,6 +608,7 @@ object FirErrors {
     val PROTECTED_CALL_FROM_PUBLIC_INLINE by warning2<KtElement, FirBasedSymbol<*>, FirBasedSymbol<*>>(SourceElementPositioningStrategies.REFERENCE_BY_QUALIFIED)
     val PRIVATE_CLASS_MEMBER_FROM_INLINE by error2<KtElement, FirBasedSymbol<*>, FirBasedSymbol<*>>(SourceElementPositioningStrategies.REFERENCE_BY_QUALIFIED)
     val SUPER_CALL_FROM_PUBLIC_INLINE by warning1<KtElement, FirBasedSymbol<*>>(SourceElementPositioningStrategies.REFERENCE_BY_QUALIFIED)
+    val DECLARATION_CANT_BE_INLINED by error0<KtDeclaration>(SourceElementPositioningStrategies.DECLARATION_SIGNATURE)
 
     // Imports
     val CANNOT_ALL_UNDER_IMPORT_FROM_SINGLETON by error1<KtImportDirective, Name>(SourceElementPositioningStrategies.IMPORT_LAST_NAME)

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

@@ -56,6 +56,7 @@ object CommonDeclarationCheckers : DeclarationCheckers() {
             FirPropertyTypeParametersChecker,
             FirInitializerTypeMismatchChecker,
             FirDelegatedPropertyChecker,
+            FirInlinePropertyChecker,
         )
 
     override val classCheckers: Set<FirClassChecker>

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

@@ -11,6 +11,7 @@ import org.jetbrains.kotlin.descriptors.Visibilities
 import org.jetbrains.kotlin.fir.*
 import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
 import org.jetbrains.kotlin.fir.analysis.checkers.context.PersistentCheckerContext
+import org.jetbrains.kotlin.fir.analysis.checkers.context.findClosest
 import org.jetbrains.kotlin.fir.analysis.checkers.isInlineOnly
 import org.jetbrains.kotlin.fir.analysis.checkers.unsubstitutedScope
 import org.jetbrains.kotlin.fir.analysis.checkers.util.checkChildrenWithCustomVisitor
@@ -50,6 +51,7 @@ object FirInlineDeclarationChecker : FirFunctionChecker() {
         checkInlineFunctionBody(declaration, effectiveVisibility, context, reporter)
         checkParameters(declaration, context, reporter)
         checkNothingToInline(declaration, context, reporter)
+        checkCanBeInlined(declaration, effectiveVisibility, context, reporter)
     }
 
     private fun checkInlineFunctionBody(
@@ -405,4 +407,22 @@ object FirInlineDeclarationChecker : FirFunctionChecker() {
 
         reporter.reportOn(function.source, FirErrors.NOTHING_TO_INLINE, context)
     }
+
+    private fun checkCanBeInlined(
+        declaration: FirFunction,
+        effectiveVisibility: EffectiveVisibility,
+        context: CheckerContext,
+        reporter: DiagnosticReporter
+    ) {
+        if (declaration !is FirSimpleFunction) return
+        if (declaration.containingClass() == null) return
+        if (effectiveVisibility == EffectiveVisibility.PrivateInClass) return
+        val isFinal = when (declaration) {
+            is FirPropertyAccessor -> context.findClosest<FirProperty>()?.isFinal ?: declaration.isFinal
+            else -> declaration.isFinal
+        }
+        if (!isFinal) {
+            reporter.reportOn(declaration.source, FirErrors.DECLARATION_CANT_BE_INLINED, context)
+        }
+    }
 }

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

@@ -0,0 +1,30 @@
+/*
+ * Copyright 2010-2021 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.descriptors.EffectiveVisibility
+import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
+import org.jetbrains.kotlin.fir.analysis.diagnostics.DiagnosticReporter
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
+import org.jetbrains.kotlin.fir.analysis.diagnostics.reportOn
+import org.jetbrains.kotlin.fir.containingClass
+import org.jetbrains.kotlin.fir.declarations.FirProperty
+import org.jetbrains.kotlin.fir.declarations.utils.effectiveVisibility
+import org.jetbrains.kotlin.fir.declarations.utils.isFinal
+import org.jetbrains.kotlin.fir.declarations.utils.isInline
+
+object FirInlinePropertyChecker : FirPropertyChecker() {
+
+    override fun check(declaration: FirProperty, context: CheckerContext, reporter: DiagnosticReporter) {
+        if (declaration.containingClass() == null) return
+        if (declaration.effectiveVisibility == EffectiveVisibility.PrivateInClass) return
+
+        if (!declaration.isFinal && (declaration.getter?.isInline == true || declaration.setter?.isInline == true)) {
+            reporter.reportOn(declaration.source, FirErrors.DECLARATION_CANT_BE_INLINED, context)
+        }
+
+    }
+}

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

@@ -112,6 +112,7 @@ import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.DATA_CLASS_NOT_PR
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.DATA_CLASS_OVERRIDE_CONFLICT
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.DATA_CLASS_VARARG_PARAMETER
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.DATA_CLASS_WITHOUT_PARAMETERS
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.DECLARATION_CANT_BE_INLINED
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.DELEGATED_PROPERTY_INSIDE_INLINE_CLASS
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.DELEGATED_PROPERTY_IN_INTERFACE
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.DELEGATE_SPECIAL_FUNCTION_AMBIGUITY
@@ -928,6 +929,7 @@ class FirDefaultErrorMessages {
             map.put(INLINE_CLASS_CANNOT_IMPLEMENT_INTERFACE_BY_DELEGATION, "Inline class cannot implement an interface by delegation")
             map.put(INLINE_CLASS_CANNOT_EXTEND_CLASSES, "Inline class cannot extend classes")
             map.put(INLINE_CLASS_CANNOT_BE_RECURSIVE, "Inline class cannot be recursive")
+            map.put(DECLARATION_CANT_BE_INLINED, "'inline' modifier is not allowed on virtual members. Only private or final members can be inlined")
             map.put(RESERVED_MEMBER_INSIDE_INLINE_CLASS, "Member with the name ''{0}'' is reserved for future releases", TO_STRING)
             map.put(
                 SECONDARY_CONSTRUCTOR_WITH_BODY_INSIDE_INLINE_CLASS,

compiler/testData/diagnostics/tests/inline/nonVirtualMembersWithInline.fir.kt

@@ -1,47 +0,0 @@
-// !DIAGNOSTICS: -UNUSED_EXPRESSION -UNUSED_PARAMETER -UNUSED_VARIABLE -NOTHING_TO_INLINE
-
-inline private fun a() {}
-
-inline fun b() {}
-
-inline public fun c() {}
-
-abstract class A {
-    inline private fun good1() {}
-    inline public final fun good2() {}
-    inline protected final fun good3() {}
-    inline final fun good4() {}
-
-
-    inline open protected fun wrong1() {}
-
-    inline open public fun wrong2() {}
-
-    inline open fun wrong3() {}
-
-    inline abstract protected fun wrong4()
-
-    inline abstract public fun wrong5()
-
-    inline abstract fun wrong6()
-}
-
-
-interface B {
-
-    inline private fun good1() {}
-
-    inline fun wrong1() {}
-
-    inline open fun wrong2() {}
-
-    inline open public fun wrong3() {}
-
-    inline open fun wrong4() {}
-
-    inline fun wrong5()
-
-    inline public fun wrong6()
-
-    inline fun wrong7()
-}

compiler/testData/diagnostics/tests/inline/nonVirtualMembersWithInline.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !DIAGNOSTICS: -UNUSED_EXPRESSION -UNUSED_PARAMETER -UNUSED_VARIABLE -NOTHING_TO_INLINE
 
 inline private fun a() {}

compiler/testData/diagnostics/tests/inline/overrideWithInline.fir.kt

@@ -34,12 +34,12 @@ class CDerived : IBase {
 
 open class COpen : IBase {
     override inline final fun foo() {}
-    override inline fun bar() {}
+    <!DECLARATION_CANT_BE_INLINED!>override inline fun bar()<!> {}
     override inline final fun <reified T> qux(x: T) {}
 
     open class COpenNested : IBase {
         override inline final fun foo() {}
-        override inline fun bar() {}
+        <!DECLARATION_CANT_BE_INLINED!>override inline fun bar()<!> {}
         override inline final fun <reified T> qux(x: T) {}
     }
 
@@ -52,7 +52,7 @@ open class COpen : IBase {
     fun aMethod() {
         open class COpenLocal : IBase {
             override inline final fun foo() {}
-            override inline fun bar() {}
+            <!DECLARATION_CANT_BE_INLINED!>override inline fun bar()<!> {}
             override inline final fun <reified T> qux(x: T) {}
         }
     }

compiler/testData/diagnostics/tests/inline/property/virtualProperty.fir.kt

@@ -1,38 +0,0 @@
-final class FinalProperty {
-    inline val valProp: Int
-        get() = 1
-
-    val valProp_1: Int
-        inline get() = 1
-
-    inline var varProp: Int
-        get() = 1
-        set(p: Int) {}
-
-    var varProp_2: Int
-        get() = 1
-        inline set(p: Int) {}
-}
-
-
-open class OpenProperty {
-    inline open val valProp: Int
-        get() = 1
-
-    open val valProp_1: Int
-        inline get() = 1
-
-    inline open var varProp: Int
-        get() = 1
-        set(p: Int) {}
-
-    open var varProp_2: Int
-        get() = 1
-        inline set(p: Int) {}
-}
-
-
-interface AbstractProperty {
-    inline abstract val valProp: Int
-    inline abstract var varProp: Int
-}

compiler/testData/diagnostics/tests/inline/property/virtualProperty.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 final class FinalProperty {
     inline val valProp: Int
         get() = 1

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

@@ -3167,6 +3167,12 @@ internal val KT_DIAGNOSTIC_CONVERTER = KtDiagnosticConverterBuilder.buildConvert
             token,
         )
     }
+    add(FirErrors.DECLARATION_CANT_BE_INLINED) { firDiagnostic ->
+        DeclarationCantBeInlinedImpl(
+            firDiagnostic as FirPsiDiagnostic,
+            token,
+        )
+    }
     add(FirErrors.CANNOT_ALL_UNDER_IMPORT_FROM_SINGLETON) { firDiagnostic ->
         CannotAllUnderImportFromSingletonImpl(
             firDiagnostic.a,

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

@@ -2210,6 +2210,10 @@ sealed class KtFirDiagnostic<PSI : PsiElement> : KtDiagnosticWithPsi<PSI> {
         abstract val symbol: KtSymbol
     }
 
+    abstract class DeclarationCantBeInlined : KtFirDiagnostic<KtDeclaration>() {
+        override val diagnosticClass get() = DeclarationCantBeInlined::class
+    }
+
     abstract class CannotAllUnderImportFromSingleton : KtFirDiagnostic<KtImportDirective>() {
         override val diagnosticClass get() = CannotAllUnderImportFromSingleton::class
         abstract val objectName: Name

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

@@ -3567,6 +3567,13 @@ internal class SuperCallFromPublicInlineImpl(
     override val firDiagnostic: FirPsiDiagnostic by weakRef(firDiagnostic)
 }
 
+internal class DeclarationCantBeInlinedImpl(
+    firDiagnostic: FirPsiDiagnostic,
+    override val token: ValidityToken,
+) : KtFirDiagnostic.DeclarationCantBeInlined(), KtAbstractFirDiagnostic<KtDeclaration> {
+    override val firDiagnostic: FirPsiDiagnostic by weakRef(firDiagnostic)
+}
+
 internal class CannotAllUnderImportFromSingletonImpl(
     override val objectName: Name,
     firDiagnostic: FirPsiDiagnostic,