SA1119 is broken with pattern matching

[nicholassuter]

This statement generates a violation of SA1119

var x = new object();
if (!(x is int i))
    throw new Exception("Woopsie");
Console.WriteLine("is an int");

The proposed fix is

var x = new object();
if (!x is int i)
    throw new Exception("Woopsie");
Console.WriteLine("is an int");

This generates a CS0023 (Operator '!' cannot be applied to operand of type 'object') compiler error.

The workaround is disabling this rule (or not using the StyleCop analyzer...)

[TimSirmovics]

I am also experiencing this issue.

This code triggers SA1119:

if (!(WebRequest.Create(fileUri) is FtpWebRequest ftpWebRequest))
    throw new InvalidLogicException("Cannot cast WebRequest as FtpWebRequest");

But removing the paranthesis changes the meaning of the code and causes a compiler error.

[vweijsters]

@nicholassuter and @TimSirmovics: Which version of StyleCop.Analyzers produced this result? I've tried the provided examples with version 1.1.0-beta004 and that is working as intended, not producing any warnings.

[TimSirmovics]

Latest stable, v1.0.2

It appears this has been addressed in #2372

[sharwell]

Duplicate of #2372