src/vs/workbench/api/common/extHostTypes.ts/Position/constructor
class Position:	constructor(line: number, character: number) {
		if (line < 0) {
			throw illegalArgument('line must be non-negative');
		}
		if (character < 0) {
			throw illegalArgument('character must be non-negative');
		}
		this._line = line;
		this._character = character;
	}