If you specify an attribute value using an expression, the expression must evaluate to true or false. The Code Analyzer is unable to determine the value of the expression assigned to the attribute.

Use an expression for the value of the attribute that evaluates to logical true or false. Do not use any definitions from the class file in the expression, including any constant properties, static methods, and local functions.

You can set the value of the attribute to true by specifying the attribute name alone or the value to false by preceding its name with a tilde (~). You can also assign true or false to the attribute name.

For more information, see Expressions in Attribute Specifications.