Is this a bug in return type inference?

[Meta via Digitalmars-d]

On Sunday, 26 April 2015 at 20:21:32 UTC, Ali Çehreli wrote:
> Yes, a bug for floating types only. It seems that not the 
> common type but the first type is used among floating point 
> types. I wrote a short program to prove it to myself:
>
> import std.traits;
> import std.typetuple;
> import std.format;
>
> auto foo(A, B)(int n)
> {
>     if (n) {
>         return A(0);
>
>     } else {
>
>         return B(0);
>     }
> }
>
> void main()
> {
>     alias types = TypeTuple!(float, double, real);
>
>     foreach (A; types) {
>         foreach (B; types) {
>             alias ReturnType = typeof(foo!(A, B)(0));
>
>             pragma(msg, format("%s %s -> %s%s",
>                                A.stringof, B.stringof,
>                                ReturnType.stringof,
>                                (is (ReturnType == 
> CommonType!(A, B))
>                                 ? ""
>                                 : " <-- BUG")));
>         }
>     }
> }
>
> float float -> float
> float double -> float <-- BUG
> float real -> float <-- BUG
> double float -> double
> double double -> double
> double real -> double <-- BUG
> real float -> real
> real double -> real
> real real -> real
>
> Ali

https://issues.dlang.org/show_bug.cgi?id=14506