Re: Function hijack on selective import

[Adam D. Ruppe via Digitalmars-d-learn]

The mistake you're making is using a constraint when you should 
try a specialization:

int signbit(T:Custom)(T x)
{
    return 0;
}


That means to use this specialized function when T is Custom. 
Now, you just need to merge the overload sets:

import std.math;
alias signbit = std.math.signbit; // this merges local signbit 
with std.math.signbit


and boom it should compile and call your version.