sqrt(2) must go

[Don]

In D2 prior to 2.048, sqrt(2) does not compile. The reason is that it's 
ambiguous whether it is sqrt(2.0), sqrt(2.0L), or sqrt(2.0f). This also 
applies to _any_ function which has overloads for more than one floating 
point type.

In D2 between versions 2.049 and the present, sqrt(2) compiles due to 
the request of a small number of people (2-3, I think). But still, no 
other floating point function works with integer literals.

The "bug" being fixed was
Bugzilla 4455: Taking the sqrt of an integer shouldn't require an 
explicit cast.

This compiles only due to an awful, undocumented hack in std.math. It 
doesn't work for any function other than sqrt. I protested strongly 
against this, but accepted it only on the proviso that we would fix 
integer literal conversions to floating point in _all_ cases, so that 
the hack could be removed.

However, when I proposed the fix on the newsgroup (integer literals 
should have a preferred conversion to double), it was *unanimously* 
rejected. Those who had argued for the hack were conspicuously absent.

The hack must go.