NilError.swift

public struct NilError: Error, CustomStringConvertible {

	let file: String

	let line: Int

	public init(file: String = #file, line: Int = #line) {
		self.file = file
		self.line = line
	}

	public var description: String {
		return "Nil returned at " + (file) + ":\(line)"
	}

}

extension Optional {
	public func unwrap(file: String = #file, line: Int = #line) throws -> Wrapped {
		guard let result = self else {
			throw NilError(file: file, line: line)
		}
		return result
	}
}