[FIR] Reuse calculated values and clean up code

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

@@ -32,10 +32,11 @@ object FirImportsChecker : FirFileChecker() {
     override fun check(declaration: FirFile, context: CheckerContext, reporter: DiagnosticReporter) {
         declaration.imports.forEach { import ->
             if (import is FirErrorImport) return@forEach
-            if (import.isAllUnder && import !is FirResolvedImport) {
-                checkAllUnderFromEnumEntry(import, context, reporter)
-            }
-            if (!import.isAllUnder) {
+            if (import.isAllUnder) {
+                if (import !is FirResolvedImport) {
+                    checkAllUnderFromEnumEntry(import, context, reporter)
+                }
+            } else {
                 checkCanBeImported(import, context, reporter)
                 if (import is FirResolvedImport) {
                     checkOperatorRename(import, context, reporter)

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

@@ -109,8 +109,9 @@ object FirUninitializedEnumChecker : FirQualifiedAccessExpressionChecker() {
             it.getContainingClassSymbol(context.session) == enumClassSymbol
         }?.symbol ?: return
 
-        val enumMemberProperties = enumClassSymbol.declarationSymbols.filterIsInstance<FirPropertySymbol>()
-        val enumEntries = enumClassSymbol.declarationSymbols.filterIsInstance<FirEnumEntrySymbol>()
+        val declarationSymbols = enumClassSymbol.declarationSymbols
+        val enumMemberProperties = declarationSymbols.filterIsInstance<FirPropertySymbol>()
+        val enumEntries = declarationSymbols.filterIsInstance<FirEnumEntrySymbol>()
 
         // When checking enum member properties, accesses to enum entries in lazy delegation is legitimate, e.g.,
         //   enum JvmTarget(...) {

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/extended/ArrayEqualityCanBeReplacedWithEquals.kt

@@ -22,8 +22,9 @@ object ArrayEqualityCanBeReplacedWithEquals : FirBasicExpressionChecker() {
     override fun check(expression: FirStatement, context: CheckerContext, reporter: DiagnosticReporter) {
         if (expression !is FirEqualityOperatorCall) return
         if (expression.operation != FirOperation.EQ && expression.operation != FirOperation.NOT_EQ) return
-        val left = expression.arguments.getOrNull(0) ?: return
-        val right = expression.arguments.getOrNull(1) ?: return
+        val arguments = expression.arguments
+        val left = arguments.getOrNull(0) ?: return
+        val right = arguments.getOrNull(1) ?: return
 
         if (left.typeRef.coneType.classId != StandardClassIds.Array) return
         if (right.typeRef.coneType.classId != StandardClassIds.Array) return

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/extended/CanBeReplacedWithOperatorAssignmentChecker.kt

@@ -66,7 +66,7 @@ object CanBeReplacedWithOperatorAssignmentChecker : FirVariableAssignmentChecker
 
     }
 
-    fun lightTreeMatcher(
+    private fun lightTreeMatcher(
         variable: LighterASTNode,
         expression: LighterASTNode,
         source: KtLightSourceElement,

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

@@ -176,7 +176,8 @@ abstract class AbstractDiagnosticCollectorVisitor(
         // Assuming no errors, the children of FirResolvedTypeRef (currently this can be FirAnnotationCalls) will also be present
         // as children in delegatedTypeRef. We should make sure those elements are only visited once, otherwise diagnostics will be
         // collected twice: once through resolvedTypeRef's children and another through resolvedTypeRef.delegatedTypeRef's children.
-        if (resolvedTypeRef.type is ConeClassErrorType) {
+        val resolvedTypeRefType = resolvedTypeRef.type
+        if (resolvedTypeRefType is ConeClassErrorType) {
             super.visitResolvedTypeRef(resolvedTypeRef, data)
         }
         if (resolvedTypeRef.source?.kind is KtFakeSourceElementKind) return
@@ -184,7 +185,7 @@ abstract class AbstractDiagnosticCollectorVisitor(
         //the note about is just wrong
         //if we don't visit resolved type we can't make any diagnostics on them
         //so here we check resolvedTypeRef
-        if (resolvedTypeRef.type !is ConeClassErrorType) {
+        if (resolvedTypeRefType !is ConeClassErrorType) {
             withAnnotationContainer(resolvedTypeRef) {
                 checkElement(resolvedTypeRef)
             }
@@ -319,13 +320,14 @@ abstract class AbstractDiagnosticCollectorVisitor(
     inline fun <R> withAnnotationContainer(annotationContainer: FirAnnotationContainer, block: () -> R): R {
         val existingContext = context
         addSuppressedDiagnosticsToContext(annotationContainer)
-        if (annotationContainer.annotations.isNotEmpty()) {
+        val notEmptyAnnotations = annotationContainer.annotations.isNotEmpty()
+        if (notEmptyAnnotations) {
             context = context.addAnnotationContainer(annotationContainer)
         }
         return try {
             block()
         } finally {
-            if (annotationContainer.annotations.isNotEmpty()) {
+            if (notEmptyAnnotations) {
                 existingContext.dropAnnotationContainer()
             }
             context = existingContext

compiler/fir/fir-deserialization/src/org/jetbrains/kotlin/fir/deserialization/AbstractFirDeserializedSymbolProvider.kt

@@ -120,7 +120,7 @@ abstract class AbstractFirDeserializedSymbolProvider(
         return getPackageParts(classId.packageFqName).firstNotNullOfOrNull { part ->
             val ids = part.typeAliasNameIndex[classId.shortClassName]
             if (ids == null || ids.isEmpty()) return@firstNotNullOfOrNull null
-            val aliasProto = ids.map { part.proto.getTypeAlias(it) }.single()
+            val aliasProto = part.proto.getTypeAlias(ids.single())
             part.context.memberDeserializer.loadTypeAlias(aliasProto).symbol
         }
     }

compiler/fir/java/src/org/jetbrains/kotlin/fir/java/enhancement/SignatureEnhancement.kt

@@ -76,8 +76,9 @@ class FirSignatureEnhancement(
     ): FirFunctionSymbol<*> {
         return enhancements.getOrPut(function) {
             enhance(function, name).also { enhancedVersion ->
-                (enhancedVersion.fir.initialSignatureAttr as? FirSimpleFunction)?.let {
-                    enhancedVersion.fir.initialSignatureAttr = enhancedFunction(it.symbol, it.name).fir
+                val enhancedVersionFir = enhancedVersion.fir
+                (enhancedVersionFir.initialSignatureAttr as? FirSimpleFunction)?.let {
+                    enhancedVersionFir.initialSignatureAttr = enhancedFunction(it.symbol, it.name).fir
                 }
             }
         } as FirFunctionSymbol<*>

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

@@ -52,7 +52,7 @@ class JavaClassUseSiteMemberScope(
     private val typeParameterStack = klass.javaTypeParameterStack
     private val specialFunctions = hashMapOf<Name, Collection<FirNamedFunctionSymbol>>()
     private val syntheticPropertyByNameMap = hashMapOf<Name, FirSyntheticPropertySymbol>()
-    
+
     private val canUseSpecialGetters: Boolean by lazy { !klass.hasKotlinSuper(session) }
 
     private val callableNamesCached by lazy(LazyThreadSafetyMode.PUBLICATION) {
@@ -161,11 +161,8 @@ class JavaClassUseSiteMemberScope(
         scope: FirScope,
     ): FirNamedFunctionSymbol? {
         val specialGetterName = if (canUseSpecialGetters) getBuiltinSpecialPropertyGetterName() else null
-        if (specialGetterName != null) {
-            return findGetterByName(specialGetterName.asString(), scope)
-        }
-
-        return findGetterByName(JvmAbi.getterName(fir.name.asString()), scope)
+        val name = specialGetterName?.asString() ?: JvmAbi.getterName(fir.name.asString())
+        return findGetterByName(name, scope)
     }
 
     private fun FirPropertySymbol.findGetterByName(