public override void VisitBinaryOperatorExpression(BinaryOperatorExpression binaryOperatorExpression)
{
base.VisitBinaryOperatorExpression(binaryOperatorExpression);
if (binaryOperatorExpression.Operator != BinaryOperatorType.NullCoalescing)
{
//The issue is not applicable
return;
}
var parentFunction = GetParentFunctionNode(binaryOperatorExpression);
var analysis = GetAnalysis(parentFunction);
NullValueStatus leftStatus = analysis.GetExpressionResult(binaryOperatorExpression.Left);
if (leftStatus == NullValueStatus.DefinitelyNotNull)
{
AddIssue(new CodeIssue(binaryOperatorExpression.OperatorToken.StartLocation,
binaryOperatorExpression.Right.EndLocation,
ctx.TranslateString("Redundant ??. Left side is never null."),
ctx.TranslateString("Remove redundant right side"),
script => {
script.Replace(binaryOperatorExpression, binaryOperatorExpression.Left.Clone());
})
{
IssueMarker = IssueMarker.GrayOut
});
return;
}
if (leftStatus == NullValueStatus.DefinitelyNull)
{
AddIssue(new CodeIssue(binaryOperatorExpression.Left.StartLocation,
binaryOperatorExpression.OperatorToken.EndLocation,
ctx.TranslateString("Redundant ??. Left side is always null."),
ctx.TranslateString("Remove redundant left side"),
script => {
script.Replace(binaryOperatorExpression, binaryOperatorExpression.Right.Clone());
}));
return;
}
NullValueStatus rightStatus = analysis.GetExpressionResult(binaryOperatorExpression.Right);
if (rightStatus == NullValueStatus.DefinitelyNull)
{
AddIssue(new CodeIssue(binaryOperatorExpression.OperatorToken.StartLocation,
binaryOperatorExpression.Right.EndLocation,
ctx.TranslateString("Redundant ??. Right side is always null."),
ctx.TranslateString("Remove redundant right side"),
script => {
script.Replace(binaryOperatorExpression, binaryOperatorExpression.Left.Clone());
}));
return;
}
}
public static bool IsDefiniteValue(this NullValueStatus self)
{
return(self == NullValueStatus.DefinitelyNull || self == NullValueStatus.DefinitelyNotNull);
}
