[FIR] Get rid of unnecessary allocations

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

@@ -40,10 +40,11 @@ object FirRepeatableAnnotationChecker : FirBasicDeclarationChecker() {
     private val REPEATABLE_ANNOTATION_CONTAINER_NAME = Name.identifier(JvmAbi.REPEATABLE_ANNOTATION_CONTAINER_NAME)
 
     override fun check(declaration: FirDeclaration, context: CheckerContext, reporter: DiagnosticReporter) {
+        val annotations = declaration.annotations
+        if (annotations.isEmpty()) return
         val annotationsMap = hashMapOf<ConeKotlinType, MutableList<AnnotationUseSiteTarget?>>()
 
         val session = context.session
-        val annotations = declaration.annotations
         for (annotation in annotations) {
             val classId = annotation.classId ?: continue
             val annotationClassId = annotation.toAnnotationClassId() ?: continue

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/cfa/FirPropertyInitializationAnalyzer.kt

@@ -40,7 +40,7 @@ object FirPropertyInitializationAnalyzer : AbstractFirPropertyInitializationChec
             symbolFir == null || symbolFir.initializer == null && symbolFir.delegate == null
         }
 
-        val localProperties = properties.filter { it.fir.initializer == null && it.fir.delegate == null }.toSet()
+        val localProperties = properties.filterTo(mutableSetOf()) { it.fir.initializer == null && it.fir.delegate == null }
 
         val reporterVisitor = PropertyReporter(localData, localProperties, capturedWrites, reporter, context)
         graph.traverse(TraverseDirection.Forward, reporterVisitor)

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/cfa/util/PropertyInitializationInfoCollector.kt

@@ -21,9 +21,12 @@ class PropertyInitializationInfoCollector(
         node: CFGNode<*>,
         data: Collection<Pair<EdgeLabel, PathAwarePropertyInitializationInfo>>
     ): PathAwarePropertyInitializationInfo {
-        if (data.isEmpty()) return PathAwarePropertyInitializationInfo.EMPTY
-        return data.map { (label, info) -> info.applyLabel(node, label) }
-            .reduce(PathAwarePropertyInitializationInfo::merge)
+        var result: PathAwarePropertyInitializationInfo? = null
+        for ((label, info) in data) {
+            val resultItem = info.applyLabel(node, label)
+            result = result?.merge(resultItem) ?: resultItem
+        }
+        return result ?: PathAwarePropertyInitializationInfo.EMPTY
     }
 
     override fun visitVariableAssignmentNode(

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

@@ -19,7 +19,9 @@ fun checkUnderscoreDiagnostics(
     reporter: DiagnosticReporter,
     isExpression: Boolean
 ) {
-    if (source != null && (source.kind is KtRealSourceElementKind || source.kind is KtFakeSourceElementKind.ReferenceInAtomicQualifiedAccess)) {
+    val sourceKind = source?.kind ?: return
+
+    if (sourceKind is KtRealSourceElementKind || sourceKind is KtFakeSourceElementKind.ReferenceInAtomicQualifiedAccess) {
         with(SourceNavigator.forSource(source)) {
             if (source.getRawIdentifier()?.isUnderscore == true) {
                 reporter.reportOn(

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

@@ -18,7 +18,7 @@ import org.jetbrains.kotlin.fir.types.type
 object FirPropertyTypeParametersChecker : FirPropertyChecker() {
 
     override fun check(declaration: FirProperty, context: CheckerContext, reporter: DiagnosticReporter) {
-        val boundsByName = declaration.typeParameters.map { it.name to it.bounds }.toMap()
+        val boundsByName = declaration.typeParameters.associate { it.name to it.bounds }
         val usedTypes = HashSet<ConeKotlinType>()
         fun collectAllTypes(type: ConeKotlinType) {
             if (usedTypes.add(type)) {

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/expression/FirExpressionAnnotationChecker.kt

@@ -32,9 +32,12 @@ object FirExpressionAnnotationChecker : FirBasicExpressionChecker() {
             expression is FirBlock && expression.source?.kind == KtFakeSourceElementKind.DesugaredForLoop
         ) return
 
+        val annotations = expression.annotations
+        if (annotations.isEmpty()) return
+
         val annotationsMap = hashMapOf<ConeKotlinType, MutableList<AnnotationUseSiteTarget?>>()
 
-        for (annotation in expression.annotations) {
+        for (annotation in annotations) {
             val useSiteTarget = annotation.useSiteTarget ?: expression.getDefaultUseSiteTarget(annotation, context)
             val existingTargetsForAnnotation = annotationsMap.getOrPut(annotation.annotationTypeRef.coneType) { arrayListOf() }
 

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/expression/FirUnderscoreChecker.kt

@@ -29,8 +29,10 @@ object FirUnderscoreChecker : FirBasicExpressionChecker() {
                 checkResolvedToUnderscoreNamedCatchParameter(expression, context, reporter)
             }
             is FirResolvedQualifier -> {
-                for (reservedUnderscoreDiagnostic in expression.nonFatalDiagnostics.filterIsInstance<ConeUnderscoreUsageWithoutBackticks>()) {
-                    reporter.reportOn(reservedUnderscoreDiagnostic.source, FirErrors.UNDERSCORE_USAGE_WITHOUT_BACKTICKS, context)
+                for (reservedUnderscoreDiagnostic in expression.nonFatalDiagnostics) {
+                    if (reservedUnderscoreDiagnostic is ConeUnderscoreUsageWithoutBackticks) {
+                        reporter.reportOn(reservedUnderscoreDiagnostic.source, FirErrors.UNDERSCORE_USAGE_WITHOUT_BACKTICKS, context)
+                    }
                 }
             }
         }

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/collectors/AbstractDiagnosticCollector.kt

@@ -41,16 +41,24 @@ abstract class AbstractDiagnosticCollector(
         private val SUPPRESS_NAMES_NAME = Name.identifier("names")
 
         fun getDiagnosticsSuppressedForContainer(annotationContainer: FirAnnotationContainer): List<String>? {
-            val annotations = annotationContainer.annotations.filter {
-                val type = it.annotationTypeRef.coneType as? ConeClassLikeType ?: return@filter false
-                type.lookupTag.classId == StandardClassIds.Annotations.Suppress
-            }
-            if (annotations.isEmpty()) return null
-            return annotations.flatMap { annotationCall ->
-                annotationCall.findArgumentByName(SUPPRESS_NAMES_NAME)?.unwrapVarargValue()?.mapNotNull {
-                    (it as? FirConstExpression<*>)?.value as? String?
-                } ?: emptyList()
+            var result: MutableList<String>? = null
+
+            for (annotation in annotationContainer.annotations) {
+                val type = annotation.annotationTypeRef.coneType as? ConeClassLikeType ?: continue
+                if (type.lookupTag.classId != StandardClassIds.Annotations.Suppress) continue
+                val argumentValues = annotation.findArgumentByName(SUPPRESS_NAMES_NAME)?.unwrapVarargValue() ?: continue
+
+                for (argumentValue in argumentValues) {
+                    val value = (argumentValue as? FirConstExpression<*>)?.value as? String ?: continue
+
+                    if (result == null) {
+                        result = mutableListOf()
+                    }
+                    result.add(value)
+                }
             }
+
+            return result
         }
     }
 }

compiler/fir/java/src/org/jetbrains/kotlin/fir/java/scopes/JavaClassMembersEnhancementScope.kt

@@ -24,7 +24,7 @@ class JavaClassMembersEnhancementScope(
     private val overriddenFunctions = mutableMapOf<FirNamedFunctionSymbol, Collection<FirNamedFunctionSymbol>>()
     private val overriddenProperties = mutableMapOf<FirPropertySymbol, Collection<FirPropertySymbol>>()
 
-    private val overrideBindCache = mutableMapOf<Name, Map<FirCallableSymbol<*>?, List<FirCallableSymbol<*>>>>()
+    private val overrideBindCache = mutableMapOf<Name, Map<FirCallableSymbol<*>?, List<FirCallableDeclaration>>>()
     private val signatureEnhancement = FirSignatureEnhancement(owner.fir, session) {
         overriddenMembers(name)
     }
@@ -66,12 +66,14 @@ class JavaClassMembersEnhancementScope(
 
     private fun FirCallableDeclaration.overriddenMembers(name: Name): List<FirCallableDeclaration> {
         val backMap = overrideBindCache.getOrPut(name) {
-            useSiteMemberScope
-                .overrideByBase
-                .toList()
-                .groupBy({ (_, key) -> key }, { (value) -> value })
+            val result = mutableMapOf<FirCallableSymbol<*>?, MutableList<FirCallableDeclaration>>()
+            for ((key, value) in useSiteMemberScope.overrideByBase) {
+                val resultItem = result.getOrPut(value) { mutableListOf() }
+                resultItem.add(key.fir)
+            }
+            result
         }
-        return backMap[this.symbol]?.map { it.fir } ?: emptyList()
+        return backMap[this.symbol] ?: emptyList()
     }
 
     override fun processClassifiersByNameWithSubstitution(name: Name, processor: (FirClassifierSymbol<*>, ConeSubstitutor) -> Unit) {