S1125: Faulty code fix on C# pattern matching in conditional operator

[rangp]

Description

A bit of an exotic error. The following conditional expression

var isSuccess = y is ISuccessEvaluator evaluator ? evaluator.Evaluate(result) : true;

results in a S1125 warning "remove the unnecessary boolean literal(s)" . The suggested code fix would result in:

var isSuccess = !y is ISuccessEvaluator evaluator || evaluator.Evaluate(result);

which produces a compiler error "! cannot be applied to operand of type "[whatever type y is]".

Expected behavior

var isSuccess = !(y is ISuccessEvaluator evaluator) || evaluator.Evaluate(result);

is the code fix that will not throw a compiler error. The braces are necessary in this instance because otherwise the compiler will try to apply the negation to type y which is not a bool.

Known workarounds

Add the braces manually after applying the code fix

Related information

• SonarC# Version 7.16.0.8981
• Visual Studio Version VS 2019 Version 16.2.0 Preview 3.0