private static OverloadResolutionResult<UnaryOperatorSignature> ResolveOverloads(UnaryOperatorKind kind, TypeSymbol operandType)
{
var builtInSignatures = GetBuiltInSignatures(kind);
if (TypeBuiltIn(operandType))
return OverloadResolution.Perform(builtInSignatures, operandType);
return OverloadResolutionResult<UnaryOperatorSignature>.None;
}