Package modules should not introduce new symbols

[Ogi-kun]

Module packages are allowed to combine overload sets, but they should never introduce new public symbols.

Consider the following package:

lib
  | a.d
  | b.d
  | package.d

// lib/a.d
module lib.a;
void fooA();

// lib/b.d
module lib.b;
void fooB();

// lib/package.d
module lib;
public import lib.a;
public import lib.b;
void bar();

If the user wants to use lib.bar, he is forced to also import lib.a and lib.b.

The solution is to move bar to a separate module that the package module will publicly import. This module may have some generic name like lib/utils.d, or the same name as the package: lib/lib.d.

Offending modules in Phobos:

• std.container
• std.digest
• std.experimental.allocator
• std.format
• std.range
• std.regex
• std.uni

[rikkimax]

std.uni is meant to be split.

Its not a fun job, but it is a task that has to be done.