public static bool TryConvertToArrowExpressionBody(
this BlockSyntax block,
SyntaxKind declarationKind,
LanguageVersion languageVersion,
ExpressionBodyPreference preference,
[NotNullWhen(true)] out ArrowExpressionClauseSyntax?arrowExpression,
out SyntaxToken semicolonToken)
{
// We can always use arrow-expression bodies in C# 7 or above.
// We can also use them in C# 6, but only a select set of member kinds.
var acceptableVersion =
languageVersion >= LanguageVersion.CSharp7 ||
(languageVersion >= LanguageVersion.CSharp6 && IsSupportedInCSharp6(declarationKind));
if (acceptableVersion &&
block.TryConvertToExpressionBody(languageVersion, preference, out var expression, out semicolonToken))
{
arrowExpression = SyntaxFactory.ArrowExpressionClause(expression);
var parent = block.GetRequiredParent();
if (parent.Kind() == SyntaxKind.GetAccessorDeclaration)
{
var comments = parent.GetLeadingTrivia().Where(t => !t.IsWhitespaceOrEndOfLine());
if (!comments.IsEmpty())
{
arrowExpression = arrowExpression.WithLeadingTrivia(
parent.GetLeadingTrivia());
}
}
return(true);
}
arrowExpression = null;
semicolonToken = default;
return(false);
}