First token in line

gistfile1.cs

internal static bool IsFirstInLine_1(this SyntaxToken token)
{
    return token.HasLeadingTrivia || token.GetLocation()?.GetMappedLineSpan().StartLinePosition.Character == 0;
}

internal static bool IsFirstInLine_2(this SyntaxToken token)
{
    var prevToken = token.GetPreviousToken();
    var leadingTriviaList = prevToken.TrailingTrivia.AddRange(token.LeadingTrivia);

    var isFirstOnLine = false;
    if (prevToken.GetLocation().GetLineSpan().EndLinePosition.Line < token.GetLocation().GetLineSpan().StartLinePosition.Line)
    {
        var done = false;
        for (var i = leadingTriviaList.Count - 1; !done && (i >= 0); i--)
        {
            switch (leadingTriviaList[i].Kind())
            {
                case SyntaxKind.WhitespaceTrivia:
                    break;

                case SyntaxKind.EndOfLineTrivia:
                    isFirstOnLine = true;
                    done = true;
                    break;

                default:
                    done = true;
                    break;
            }
        }
    }
    
    return isFirstOnLine;
}

internal static bool? IsFirstInLine_3(this SyntaxToken clause)
{
    var fileLinePositionSpan = clause.GetLocation().GetLineSpan();
    if (!fileLinePositionSpan.IsValid)
    {
        return null;
    }

    var startLine = fileLinePositionSpan.StartLinePosition.Line;
    var previousToken = clause.GetPreviousToken();
    if (previousToken.IsMissing)
    {
        return true;
    }

    var endLineOfPreviousToken = previousToken.GetLocation().GetLineSpan().EndLinePosition.Line;
    return startLine > endLineOfPreviousToken;
}