Always false float comparisons

[Jens Mueller via Digitalmars-d]

Walter Bright via Digitalmars-d wrote:
> Don Clugston pointed out in his DConf 2016 talk that:
> 
>     float f = 1.30;
>     assert(f == 1.30);
> 
> will always be false since 1.30 is not representable as a float. However,
> 
>     float f = 1.30;
>     assert(f == cast(float)1.30);
> 
> will be true.
> 
> So, should the compiler emit a warning for the former case?

Since

assert(f == 1.30f);

passes I find the root cause lies in the implicit type conversion from
float to double. Warning for those comparisons should be fine. Shouldn't
mix them anyway.
I wonder what's the difference between 1.30f and cast(float)1.30.

Jens