Function prototype overloading does not work ?

[Hipreme]

On Wednesday, 19 January 2022 at 08:47:27 UTC, Enjoys Math wrote:
> ```
> module expr;
>
> import dots;
> import operator;
> import equation;
> import var;
> import var_expr;
> import zz_const;
>
> class Expr
> {
> public:
>    void opBinary(string op)(string s) const
>    {
>       static if (op == "+")
>       {
>          Expr right = null;
>
>          if (s == ".." || s == "..." || s == "....")
>          {
>             right = new Dots();
>          }
>
>          if (right !is null)
>             return new Op("+", [this, right]);
>       }
>    }
>
>    override string toString() const
>    {
>       assert(0);
>    }
>
>    Expr sub(Expr x, Expr y)
>    {
>       if (this == x)
>          return y;
>       return this;
>    }
>
>    Expr sub(Expr x, ref Var y)
>    {
>       return sub(x, new VarExpr(y));
>    }
>
>    Expr sub(ref Var x, Expr y)
>    {
>       return sub(new VarExpr(x), y);
>    }
>
>    Expr sub(int x, Expr y)
>    {
>       return sub(ZZ(x), y);
>    }
>
>    Expr sub(Expr x, int y)
>    {
>       return sub(x, ZZ(y));
>    }
>
>    Expr sub(ref Var x, ref Var y)
>    {
>       return sub(new VarExpr(x), new VarExpr(y));
>    }
>
>    Expr sub(ref Var x, int y)
>    {
>       return sub(new VarExpr(x), ZZ(y));
>    }
>
>    Expr sub(int x, ref Var y)
>    {
>       return sub(ZZ(x), new VarExpr(y));
>    }
>
>    override bool opEquals(Object o) {
>       return this is o;
>    }
> }
> ```
> See all the overloads I had to make to sub in order to bypass 
> identity assignment for classes.  I.e. Var can't be of type 
> Expr.  Anyway, this approach is not working because code 
> calling `Expr.sub(int, Var)` is not seeing the definitions.  It 
> says no function matching those args, but clearly there are!


Firstly, in my opinion, you should be using `auto ref` which will 
do the same thing as generating by reference and by value 
declarations. Or you could even use `in` as the compiler will 
optimize the call for passing it by reference.

Now, you could have some self contained example for we being able 
to test it