[FIR] Let FirTopLevelFunctionsChecker run on all platforms

Use a session component to control platform specific suppression logic.

compiler/fir/checkers/checkers.js/src/org/jetbrains/kotlin/fir/analysis/js/checkers/FirJsPlatformDiagnosticSuppressor.kt

@@ -16,7 +16,7 @@ private fun FirDeclaration.isLexicallyInsideJsNative(context: CheckerContext): B
     return JsStandardClassIds.Annotations.nativeAnnotations.any { hasAnnotationOrInsideAnnotatedClass(it, context.session) }
 }
 
-object FirJsPlatformDiagnosticSuppressor : FirPlatformDiagnosticSuppressor {
+class FirJsPlatformDiagnosticSuppressor : FirPlatformDiagnosticSuppressor {
     override fun shouldReportNoBody(declaration: FirCallableDeclaration, context: CheckerContext) =
         !declaration.isLexicallyInsideJsNative(context)
 }

compiler/fir/checkers/checkers.js/src/org/jetbrains/kotlin/fir/analysis/js/checkers/JsDeclarationCheckers.kt

@@ -40,7 +40,6 @@ object JsDeclarationCheckers : DeclarationCheckers() {
 
     override val simpleFunctionCheckers: Set<FirSimpleFunctionChecker>
         get() = setOf(
-            FirJsTopLevelFunctionsChecker,
             FirJsNativeInvokeChecker,
             FirJsNativeGetterChecker,
             FirJsNativeSetterChecker,

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

@@ -1,13 +0,0 @@
-/*
- * 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.js.checkers.declaration
-
-import org.jetbrains.kotlin.fir.analysis.checkers.declaration.FirTopLevelFunctionsChecker
-import org.jetbrains.kotlin.fir.analysis.js.checkers.FirJsPlatformDiagnosticSuppressor
-
-object FirJsTopLevelFunctionsChecker : FirTopLevelFunctionsChecker() {
-    override val suppressor = FirJsPlatformDiagnosticSuppressor
-}

compiler/fir/checkers/checkers.jvm/src/org/jetbrains/kotlin/fir/analysis/jvm/checkers/JvmDeclarationCheckers.kt

@@ -51,9 +51,4 @@ object JvmDeclarationCheckers : DeclarationCheckers() {
         get() = setOf(
             FirUpperBoundsChecker,
         )
-
-    override val simpleFunctionCheckers: Set<FirSimpleFunctionChecker>
-        get() = setOf(
-            FirJvmTopLevelFunctionsChecker,
-        )
 }

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

@@ -1,13 +0,0 @@
-/*
- * 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.jvm.checkers.declaration
-
-import org.jetbrains.kotlin.fir.analysis.checkers.FirPlatformDiagnosticSuppressor
-import org.jetbrains.kotlin.fir.analysis.checkers.declaration.FirTopLevelFunctionsChecker
-
-object FirJvmTopLevelFunctionsChecker : FirTopLevelFunctionsChecker() {
-    override val suppressor = FirPlatformDiagnosticSuppressor.Default
-}

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

@@ -58,6 +58,7 @@ object CommonDeclarationCheckers : DeclarationCheckers() {
             FirMemberFunctionsChecker,
             FirDataObjectContentChecker,
             ContractSyntaxV2FunctionChecker,
+            FirTopLevelFunctionsChecker,
         )
 
     override val propertyCheckers: Set<FirPropertyChecker>

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

@@ -5,13 +5,10 @@
 
 package org.jetbrains.kotlin.fir.analysis.checkers
 
+import org.jetbrains.kotlin.fir.FirSessionComponent
 import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
 import org.jetbrains.kotlin.fir.declarations.FirCallableDeclaration
 
-interface FirPlatformDiagnosticSuppressor {
+interface FirPlatformDiagnosticSuppressor : FirSessionComponent {
     fun shouldReportNoBody(declaration: FirCallableDeclaration, context: CheckerContext): Boolean
-
-    object Default : FirPlatformDiagnosticSuppressor {
-        override fun shouldReportNoBody(declaration: FirCallableDeclaration, context: CheckerContext): Boolean = true
-    }
 }

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

@@ -8,6 +8,7 @@ package org.jetbrains.kotlin.fir.analysis.checkers.declaration
 import org.jetbrains.kotlin.KtFakeSourceElementKind
 import org.jetbrains.kotlin.diagnostics.DiagnosticReporter
 import org.jetbrains.kotlin.diagnostics.reportOn
+import org.jetbrains.kotlin.fir.FirSession
 import org.jetbrains.kotlin.fir.analysis.checkers.FirPlatformDiagnosticSuppressor
 import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
 import org.jetbrains.kotlin.fir.analysis.checkers.hasModifier
@@ -18,10 +19,10 @@ import org.jetbrains.kotlin.fir.declarations.utils.isExpect
 import org.jetbrains.kotlin.fir.declarations.utils.isExternal
 import org.jetbrains.kotlin.lexer.KtTokens
 
-// See old FE's [DeclarationsChecker]
-abstract class FirTopLevelFunctionsChecker : FirSimpleFunctionChecker() {
-    abstract val suppressor: FirPlatformDiagnosticSuppressor
+val FirSession.platformDiagnosticSuppressor: FirPlatformDiagnosticSuppressor? by FirSession.nullableSessionComponentAccessor()
 
+// See old FE's [DeclarationsChecker]
+object FirTopLevelFunctionsChecker : FirSimpleFunctionChecker() {
     override fun check(declaration: FirSimpleFunction, context: CheckerContext, reporter: DiagnosticReporter) {
         // Only report on top level callable declarations
         if (context.containingDeclarations.size > 1) return
@@ -32,7 +33,10 @@ abstract class FirTopLevelFunctionsChecker : FirSimpleFunctionChecker() {
         // So, our source of truth should be the full modifier list retrieved from the source.
         if (declaration.hasModifier(KtTokens.ABSTRACT_KEYWORD)) return
         if (declaration.isExternal) return
-        if (!declaration.hasBody && !declaration.isExpect && suppressor.shouldReportNoBody(declaration, context)) {
+        if (!declaration.hasBody &&
+            !declaration.isExpect &&
+            context.session.platformDiagnosticSuppressor?.shouldReportNoBody(declaration, context) != false
+        ) {
             reporter.reportOn(source, FirErrors.NON_MEMBER_FUNCTION_NO_BODY, declaration.symbol, context)
         }