new error message in 2.066, type bool (const)

[Paul D Anderson via Digitalmars-d-learn]

Re-compiling existing code with version 2.066 generates a lot of 
errors complaining about implicit conversion to const. Typical is 
this call (inside a struct with properties 1 & 2):

        z.sign = x.sign ^ y.sign;
Error: None of the overloads of 'sign' are callable using 
argument types bool (const), candidates are:

1)      @property
        @safe
        bool sign() const
        {
                return signed;
        }

2)      @property
        @safe
        bool sign(in bool value)
        {
                signed = value;
                return signed;
        }

What changed? It ran okay with early beta versions, but not with 
the release.

Paul