opCmp with template type not working.

[user1234]

On Tuesday, 3 November 2020 at 02:55:46 UTC, Jonathan Levi wrote:
> This is not working as expected:
>> bool opCmp(string op, U)(U rhs) {
>
> As it does work with:
>> auto opBinary(string op, U)(U rhs) {
>
>
> With:
>
>> struct X {
>>     int x;
>>     auto opBinary(string op, U)(U rhs) {
>>             return mixin("x "~op~" rhs");
>>         }
>>     bool opCmp(string op, U)(U rhs) {
>>         return mixin("x "~op~" rhs");
>>     }
>> }
>
> This compiles:
>> X(5) + 4
> This does not:
>> X(5) < 4
>
> Full example code: https://run.dlang.io/is/Beflkt
>
> Is this a Bug?

opCmp should return a signed integer. This allows to match well 
with the x86 flag register and do fast comparison with integers 
types (in which case just substract rhs to lhs and you're good)