[FIR] FirDeclarationInspector -> FirDeclarationCollector<T>

Makes more sense when you only want to collect
declarations of certain type.

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

@@ -128,14 +128,15 @@ private fun groupTopLevelByName(declarations: List<FirDeclaration>): Map<Name, D
 /**
  * Collects FirDeclarations for further analysis.
  */
-class FirDeclarationInspector(
+class FirDeclarationCollector<D : FirDeclaration>(
-    private val context: CheckerContext,
+    internal val context: CheckerContext,
 ) {
-    private val session: FirSession get() = context.sessionHolder.session
+    internal val session: FirSession get() = context.sessionHolder.session
 
-    val declarationConflictingSymbols: HashMap<FirDeclaration, SmartSet<FirBasedSymbol<*>>> = hashMapOf()
+    val declarationConflictingSymbols: HashMap<D, SmartSet<FirBasedSymbol<*>>> = hashMapOf()
+}
 
-    fun collectClassMembers(klass: FirRegularClass) {
+fun FirDeclarationCollector<FirDeclaration>.collectClassMembers(klass: FirRegularClass) {
     val otherDeclarations = mutableMapOf<String, MutableList<FirDeclaration>>()
     val functionDeclarations = mutableMapOf<String, MutableList<FirDeclaration>>()
 
@@ -156,9 +157,17 @@ class FirDeclarationInspector(
         map.getOrPut(representation, ::mutableListOf).also {
             it.add(declaration)
 
+private fun <D : FirDeclaration> FirDeclarationCollector<D>.collect(
+    declaration: D,
+    representation: String,
+    map: MutableMap<String, MutableList<D>>,
+) {
+    map.getOrPut(representation, ::mutableListOf).also {
+        it.add(declaration)
+
         val conflicts = SmartSet.create<FirBasedSymbol<*>>()
         for (otherDeclaration in it) {
-                if (otherDeclaration != declaration && !isOverloadable(declaration, otherDeclaration)) {
+            if (otherDeclaration != declaration && !isOverloadable(declaration, otherDeclaration, session)) {
                 conflicts.add(otherDeclaration.symbol)
                 declarationConflictingSymbols.getOrPut(otherDeclaration) { SmartSet.create() }.add(declaration.symbol)
             }
@@ -188,7 +197,7 @@ class FirDeclarationInspector(
  */
 @OptIn(SymbolInternals::class)
 @Suppress("GrazieInspection")
-    fun collectTopLevel(file: FirFile, packageMemberScope: FirPackageMemberScope) {
+fun FirDeclarationCollector<FirDeclaration>.collectTopLevel(file: FirFile, packageMemberScope: FirPackageMemberScope) {
 
     for ((declarationName, group) in groupTopLevelByName(file.declarations)) {
         val groupHasClassLikesOrProperties = group.classLikes.isNotEmpty() || group.properties.isNotEmpty()
@@ -227,6 +236,7 @@ class FirDeclarationInspector(
                 if (conflictingSymbol.classKind == ClassKind.OBJECT || conflictingSymbol.classKind == ClassKind.ENUM_ENTRY) return
 
                 conflictingSymbol.lazyResolveToPhase(FirResolvePhase.STATUS)
+
                 val classWithSameName = conflictingSymbol.fir
                 classWithSameName.unsubstitutedScope(context).processDeclaredConstructors { constructor ->
                     val ctorRepresentation = FirRedeclarationPresenter.represent(constructor.fir, classWithSameName)
@@ -276,7 +286,7 @@ class FirDeclarationInspector(
     }
 }
 
-    private fun collectTopLevelConflict(
+private fun FirDeclarationCollector<FirDeclaration>.collectTopLevelConflict(
     declaration: FirDeclaration,
     declarationPresentation: String,
     containingFile: FirFile,
@@ -297,17 +307,17 @@ class FirDeclarationInspector(
             else -> null
         }
     if (!conflicting.isCollectable()) return
-        if (areCompatibleMainFunctions(declaration, containingFile, conflicting, actualConflictingFile)) return
+    if (areCompatibleMainFunctions(declaration, containingFile, conflicting, actualConflictingFile, session)) return
     if (
         conflicting is FirMemberDeclaration &&
         !session.visibilityChecker.isVisible(conflicting, session, containingFile, emptyList(), dispatchReceiver = null)
     ) return
-        if (isOverloadable(declaration, conflicting)) return
+    if (isOverloadable(declaration, conflicting, session)) return
 
     declarationConflictingSymbols.getOrPut(declaration) { SmartSet.create() }.add(conflictingSymbol)
 }
 
-    private fun FirSimpleFunction.representsMainFunctionAllowingConflictingOverloads(): Boolean {
+private fun FirSimpleFunction.representsMainFunctionAllowingConflictingOverloads(session: FirSession): Boolean {
     if (name != StandardNames.MAIN || !symbol.callableId.isTopLevel || !hasMainFunctionStatus) return false
     if (receiverParameter != null || typeParameters.isNotEmpty()) return false
     if (valueParameters.isEmpty()) return true
@@ -320,16 +330,19 @@ class FirDeclarationInspector(
 }
 
 private fun areCompatibleMainFunctions(
-        declaration1: FirDeclaration, file1: FirFile, declaration2: FirDeclaration, file2: FirFile?,
+    declaration1: FirDeclaration, file1: FirFile,
+    declaration2: FirDeclaration, file2: FirFile?,
+    session: FirSession,
 ) = file1 != file2
         && declaration1 is FirSimpleFunction
         && declaration2 is FirSimpleFunction
-            && declaration1.representsMainFunctionAllowingConflictingOverloads()
+        && declaration1.representsMainFunctionAllowingConflictingOverloads(session)
-            && declaration2.representsMainFunctionAllowingConflictingOverloads()
+        && declaration2.representsMainFunctionAllowingConflictingOverloads(session)
 
 private fun isOverloadable(
     declaration: FirDeclaration,
     conflicting: FirDeclaration,
+    session: FirSession,
 ): Boolean {
     if (isExpectAndActual(declaration, conflicting)) return true
 
@@ -342,8 +355,6 @@ class FirDeclarationInspector(
             session.declarationOverloadabilityHelper.isOverloadable(declaration, conflicting)
 }
 
-}
-
 /** Checks for redeclarations of value and type parameters, and local variables. */
 fun checkForLocalRedeclarations(elements: List<FirElement>, context: CheckerContext, reporter: DiagnosticReporter) {
     if (elements.size <= 1) return

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

@@ -9,8 +9,10 @@ import org.jetbrains.kotlin.KtFakeSourceElementKind
 import org.jetbrains.kotlin.diagnostics.DiagnosticReporter
 import org.jetbrains.kotlin.diagnostics.reportOn
 import org.jetbrains.kotlin.fir.FirNameConflictsTrackerComponent
-import org.jetbrains.kotlin.fir.analysis.checkers.FirDeclarationInspector
+import org.jetbrains.kotlin.fir.analysis.checkers.FirDeclarationCollector
 import org.jetbrains.kotlin.fir.analysis.checkers.checkForLocalRedeclarations
+import org.jetbrains.kotlin.fir.analysis.checkers.collectClassMembers
+import org.jetbrains.kotlin.fir.analysis.checkers.collectTopLevel
 import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
 import org.jetbrains.kotlin.fir.declarations.*
@@ -27,7 +29,7 @@ object FirConflictsDeclarationChecker : FirBasicDeclarationChecker() {
     override fun check(declaration: FirDeclaration, context: CheckerContext, reporter: DiagnosticReporter) {
         when (declaration) {
             is FirFile -> {
-                val inspector = FirDeclarationInspector(context)
+                val inspector = FirDeclarationCollector<FirDeclaration>(context)
                 checkFile(declaration, inspector, context)
                 reportConflicts(reporter, context, inspector.declarationConflictingSymbols)
             }
@@ -35,7 +37,7 @@ object FirConflictsDeclarationChecker : FirBasicDeclarationChecker() {
                 if (declaration.source?.kind !is KtFakeSourceElementKind) {
                     checkForLocalRedeclarations(declaration.typeParameters, context, reporter)
                 }
-                val inspector = FirDeclarationInspector(context)
+                val inspector = FirDeclarationCollector<FirDeclaration>(context)
                 inspector.collectClassMembers(declaration)
                 reportConflicts(reporter, context, inspector.declarationConflictingSymbols)
             }
@@ -46,7 +48,6 @@ object FirConflictsDeclarationChecker : FirBasicDeclarationChecker() {
                     }
                     checkForLocalRedeclarations(declaration.typeParameters, context, reporter)
                 }
-                return
             }
         }
     }
@@ -76,7 +77,7 @@ object FirConflictsDeclarationChecker : FirBasicDeclarationChecker() {
         }
     }
 
-    private fun checkFile(file: FirFile, inspector: FirDeclarationInspector, context: CheckerContext) {
+    private fun checkFile(file: FirFile, inspector: FirDeclarationCollector<FirDeclaration>, context: CheckerContext) {
         val packageMemberScope: FirPackageMemberScope = context.sessionHolder.scopeSession.getOrBuild(file.packageFqName, PACKAGE_MEMBER) {
             FirPackageMemberScope(file.packageFqName, context.sessionHolder.session)
         }