private @Nullable T nextOrNull;

  /**
   * Creates a new iterator with the given first element, or, if {@code firstOrNull} is null,
   * creates a new empty iterator.
   */
  protected AbstractSequentialIterator(@Nullable T firstOrNull) {
    this.nextOrNull = firstOrNull;
  }

  /**
   * Returns the element that follows {@code previous}, or returns {@code null} if no elements

) {
  val commonName: Any?
    get() {
      return tbsCertificate.subject
        .flatten()
        .firstOrNull { it.type == ObjectIdentifiers.COMMON_NAME }
        ?.value
    }

  val organizationalUnitName: Any?
    get() {
      return tbsCertificate.subject
        .flatten()
        .firstOrNull { it.type == ObjectIdentifiers.ORGANIZATIONAL_UNIT_NAME }
        ?.value
    }

    val issuer = cert.issuerX500Principal
    val subjectCaCerts = subjectToCaCerts[issuer] ?: return null

    return subjectCaCerts.firstOrNull {
      try {
        cert.verify(it.publicKey)
        return@firstOrNull true
      } catch (_: Exception) {
        return@firstOrNull false
      }
    }
  }

  override fun equals(other: Any?): Boolean =
    other === this ||

  private @Nullable T nextOrNull;

  /**
   * Creates a new iterator with the given first element, or, if {@code firstOrNull} is null,
   * creates a new empty iterator.
   */
  protected AbstractSequentialIterator(@Nullable T firstOrNull) {
    this.nextOrNull = firstOrNull;
  }

  /**
   * Returns the element that follows {@code previous}, or returns {@code null} if no elements

  /** Returns the remote peer's principle, or null if that peer is anonymous. */
  @get:JvmName("peerPrincipal")
  val peerPrincipal: Principal?
    get() = (peerCertificates.firstOrNull() as? X509Certificate)?.subjectX500Principal

  @JvmName("-deprecated_peerPrincipal")
  @Deprecated(
    message = "moved to val",
    replaceWith = ReplaceWith(expression = "peerPrincipal"),

        "${declaringClass.baseQualifiedKotlinName}.${field.name}".let { fqn ->
            collectDescendantsOfType<KtProperty>()
                .firstOrNull { it.fqName?.asString() == fqn }
                .getSinceStatus(fallback)
        }

    private
    fun KtFile.getSince(declaringClass: CtClass, constructor: CtConstructor, fallback: String?): SinceTagStatus {

    val name = this.name
    return incoming.files.elements.map {
        require(it.size <= 1) {
            "Expected at most one file in configuration '$name' but found: $it"
        }
        it.firstOrNull()?.asFile
    }
}

fun NamedDomainObjectProvider<Configuration>.getSingleFileProvider(): Provider<File> {
    return this.flatMap { configuration ->
        configuration.getSingleFileProvider()
    }

                            if (versionsOfPatch.any { it.contains("-RC") }) {
                                add(versionsOfPatch.firstOrNull { it.contains("-RC") })
                            } else if (versionsOfPatch.any { it.contains("-Beta") }) {
                                add(versionsOfPatch.firstOrNull { it.contains("-Beta") })
                            }
                        }
                    }
                }

    constructorsSupplier.get().firstOrNull { c -> jvmSignature == c.signature?.toString() }?.let { predicate.match(it) } ?: false


private
fun hasFunctionAttribute(functionsSupplier: Supplier<MutableList<KmFunction>>, jvmSignature: String, predicate: AttributePredicate) =
    functionsSupplier.get().firstOrNull {
        jvmSignature == it.signature?.toString()

        classFilePathCandidatesFor(sourceName)
            .mapNotNull(::classBytesSupplierForFilePath)
            .firstOrNull()

    private
    fun classBytesSupplierForFilePath(classFilePath: String): ClassBytesSupplier? =
        classBytesIndex.asSequence().mapNotNull { it(classFilePath) }.firstOrNull()

    private
    fun sourceNamesFrom(entry: File): Sequence<String> =
        when {