Function hijack on selective import

[H. S. Teoh]

On Tue, Jan 16, 2018 at 07:14:00PM +0000, rumbu via Digitalmars-d-learn wrote:
> On Tuesday, 26 December 2017 at 20:21:11 UTC, Adam D. Ruppe wrote:
> > On Tuesday, 26 December 2017 at 19:41:47 UTC, rumbu wrote:
> > > "Custom" is a templated struct. I cannot imagine all the
> > > instantiations of Custom to write template specialisations for
> > > each of them.
> > 
> > You can specialize on templated structs generically.
> > 
> > int foo(T : Bar!(X, Y), X, Y)
> > 
> > that kind of thing covers any case of Bar!(X,y)
> 
> Even specialized, now I have another problem:
> 
> std.math:
> 
> int signbit(X)(X x) { ... }
> 
> mylibrary:
> 
> int signbit(D: Decimal!bits, int bits) { ... }
> 
> =============
> 
> end user:
> 
> import std.math;
> import mylibrary;
> 
> Decimal!32 d;
> float f;
> 
> auto y = signbit(f); //ok, call to std.math.signbit
> auto x = signbit(d); //error, also calls std.math.signbit

Arguably, this is a defect in Phobos.  Looking at the definition of
std.math.signbit, it's obvious that it's only meant to handle built-in
floating-point types, yet there are no sig constraints to that effect.

Fix: https://github.com/dlang/phobos/pull/6040


T

-- 
The computer is only a tool. Unfortunately, so is the user. -- Armaphine, K5