FIR checker: Merge FirConstDeclarationChecker with

FirConstPropertyChecker.

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

@@ -1,36 +0,0 @@
-/*
- * 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.fir.FirFakeSourceElementKind
-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.declarations.*
-import org.jetbrains.kotlin.lexer.KtTokens
-
-object FirConstDeclarationChecker : FirBasicDeclarationChecker() {
-    override fun check(declaration: FirDeclaration, context: CheckerContext, reporter: DiagnosticReporter) {
-        if (declaration !is FirVariable<*>) return
-        val source = declaration.source ?: return
-        if (source.kind is FirFakeSourceElementKind) return
-        val modifierList = with(FirModifierList) { source.getModifierList() }
-        val constModifier = modifierList?.modifiers?.firstOrNull { it.token == KtTokens.CONST_KEYWORD } ?: return
-
-        if (declaration.isVar) {
-            reporter.reportOn(constModifier.source, FirErrors.WRONG_MODIFIER_TARGET, constModifier.token, "vars", context)
-        }
-
-        // TODO: Implement checkers for these errors (see ConstModifierChecker in FE1.0):
-        // - CONST_VAL_NOT_TOP_LEVEL_OR_OBJECT
-        // - CONST_VAL_WITH_DELEGATE
-        // - CONST_VAL_WITH_GETTER
-        // - TYPE_CANT_BE_USED_FOR_CONST_VAL
-        // - CONST_VAL_WITHOUT_INITIALIZER
-        // - CONST_VAL_WITH_NON_CONST_INITIALIZER
-    }
-}

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

@@ -7,16 +7,27 @@ package org.jetbrains.kotlin.fir.analysis.checkers.declaration
 
 import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
+import org.jetbrains.kotlin.fir.analysis.checkers.declaration.FirModifierList.Companion.getModifierList
 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.declarations.FirProperty
 import org.jetbrains.kotlin.fir.declarations.FirRegularClass
 import org.jetbrains.kotlin.fir.declarations.isConst
+import org.jetbrains.kotlin.lexer.KtTokens
 
 object FirConstPropertyChecker : FirPropertyChecker() {
     override fun check(declaration: FirProperty, context: CheckerContext, reporter: DiagnosticReporter) {
         if (!declaration.isConst) return
+
+        if (declaration.isVar) {
+            val modifierList = with(FirModifierList) { declaration.source.getModifierList() }
+            val constModifier = modifierList?.modifiers?.firstOrNull { it.token == KtTokens.CONST_KEYWORD }
+            constModifier?.let {
+                reporter.reportOn(it.source, FirErrors.WRONG_MODIFIER_TARGET, it.token, "vars", context)
+            }
+        }
+
         val classKind = (context.containingDeclarations.lastOrNull() as? FirRegularClass)?.classKind
         if (classKind != ClassKind.OBJECT && context.containingDeclarations.size > 1) {
             reporter.reportOn(declaration.source, FirErrors.CONST_VAL_NOT_TOP_LEVEL_OR_OBJECT, context)

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

@@ -18,7 +18,6 @@ object CommonDeclarationCheckers : DeclarationCheckers() {
         FirModifierChecker,
         FirConflictsChecker,
         FirConflictingProjectionChecker,
-        FirConstDeclarationChecker,
     )
 
     override val memberDeclarationCheckers: Set<FirMemberDeclarationChecker> = setOf(