FIR: introduce Java vs Kotlin class conflicts checker #KT-44441 Fixed

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

@@ -28,7 +28,8 @@ object JvmDeclarationCheckers : DeclarationCheckers() {
     override val regularClassCheckers: Set<FirRegularClassChecker>
         get() = setOf(
             FirJvmRecordChecker,
-            FirJvmInlineApplicabilityChecker
+            FirJvmInlineApplicabilityChecker,
+            FirJvmConflictsChecker,
         )
 
     override val propertyCheckers: Set<FirPropertyChecker>

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

@@ -0,0 +1,24 @@
+/*
+ * Copyright 2010-2022 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.diagnostics.DiagnosticReporter
+import org.jetbrains.kotlin.diagnostics.reportOn
+import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
+import org.jetbrains.kotlin.fir.analysis.checkers.declaration.FirRegularClassChecker
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
+import org.jetbrains.kotlin.fir.declarations.FirRegularClass
+import org.jetbrains.kotlin.fir.declarations.utils.classId
+import org.jetbrains.kotlin.fir.java.javaSymbolProvider
+
+object FirJvmConflictsChecker : FirRegularClassChecker() {
+    override fun check(declaration: FirRegularClass, context: CheckerContext, reporter: DiagnosticReporter) {
+        val javaSymbol = context.session.javaSymbolProvider.getClassLikeSymbolByClassId(declaration.classId) ?: return
+        reporter.reportOn(
+            declaration.source, FirErrors.PACKAGE_OR_CLASSIFIER_REDECLARATION, listOf(declaration.symbol, javaSymbol), context
+        )
+    }
+}

compiler/fir/entrypoint/src/org/jetbrains/kotlin/fir/session/ComponentsContainers.kt

@@ -5,9 +5,6 @@
 
 package org.jetbrains.kotlin.fir.session
 
-import com.intellij.psi.PsiFile
-import org.jetbrains.kotlin.KtNodeTypes
-import org.jetbrains.kotlin.KtPsiSourceElement
 import org.jetbrains.kotlin.KtSourceElement
 import org.jetbrains.kotlin.config.JvmAnalysisFlags
 import org.jetbrains.kotlin.config.LanguageVersionSettings
@@ -30,7 +27,6 @@ import org.jetbrains.kotlin.fir.resolve.calls.ConeCallConflictResolverFactory
 import org.jetbrains.kotlin.fir.resolve.calls.FirSyntheticNamesProvider
 import org.jetbrains.kotlin.fir.resolve.calls.jvm.JvmCallConflictResolverFactory
 import org.jetbrains.kotlin.fir.resolve.inference.InferenceComponents
-import org.jetbrains.kotlin.fir.resolve.providers.firProvider
 import org.jetbrains.kotlin.fir.resolve.providers.impl.FirQualifierResolverImpl
 import org.jetbrains.kotlin.fir.resolve.providers.impl.FirTypeResolverImpl
 import org.jetbrains.kotlin.fir.resolve.transformers.FirPhaseCheckingPhaseManager

compiler/fir/entrypoint/src/org/jetbrains/kotlin/fir/session/FirSessionFactory.kt

@@ -197,6 +197,7 @@ object FirSessionFactory {
 
             val dependenciesSymbolProvider = FirDependenciesSymbolProviderImpl(this)
             val generatedSymbolsProvider = FirSwitchableExtensionDeclarationsSymbolProvider.create(this)
+            val javaSymbolProvider = JavaSymbolProvider(this, projectEnvironment.getFirJavaFacade(this, moduleData, javaSourcesScope))
             register(
                 FirSymbolProvider::class,
                 FirCompositeSymbolProvider(
@@ -206,12 +207,13 @@ object FirSessionFactory {
                         *(incrementalCompilationContext?.previousFirSessionsSymbolProviders?.toTypedArray() ?: emptyArray()),
                         symbolProviderForBinariesFromIncrementalCompilation,
                         generatedSymbolsProvider,
-                        JavaSymbolProvider(this, projectEnvironment.getFirJavaFacade(this, moduleData, javaSourcesScope)),
+                        javaSymbolProvider,
                         dependenciesSymbolProvider,
                         optionalAnnotationClassesProviderForBinariesFromIncrementalCompilation,
                     )
                 )
             )
+            register(JavaSymbolProvider::class, javaSymbolProvider)
 
             generatedSymbolsProvider?.let { register(FirSwitchableExtensionDeclarationsSymbolProvider::class, it) }
 

compiler/fir/java/src/org/jetbrains/kotlin/fir/java/JavaSymbolProvider.kt

@@ -57,3 +57,6 @@ class JavaSymbolProvider(
     @OptIn(FirSymbolProviderInternals::class)
     override fun getTopLevelPropertySymbolsTo(destination: MutableList<FirPropertySymbol>, packageFqName: FqName, name: Name) {}
 }
+
+val FirSession.javaSymbolProvider: JavaSymbolProvider by FirSession.sessionComponentAccessor()
+