https://issues.dlang.org/show_bug.cgi?id=14462

          Issue ID: 14462
           Summary: cannot instantiate redBlackTree!int(); anymore
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Keywords: rejects-valid
          Severity: regression
          Priority: P1
         Component: DMD
          Assignee: nobody@puremagic.com
          Reporter: r.sagitario@gmx.de

>From druntime/benchmark/gcbecnh/tree2.d:

import std.container;

void main(string[] args)
{
    auto t = redBlackTree!int();
}

compile with dmd from git-HEAD:

tree2.d(18): Error: template std.container.rbtree.redBlackTree cannot deduce
function from argument types !(int)(), candidates are:
rbtree.d(1714):        std.container.rbtree.redBlackTree(E)(E[] elems...)
rbtree.d(1720):        std.container.rbtree.redBlackTree(bool allowDuplicates,
E)(E[] elems...)
rbtree.d(1726):        std.container.rbtree.redBlackTree(alias less, E)(E[]
elems...)
rbtree.d(1732):        std.container.rbtree.redBlackTree(alias less, bool
allowDuplicates, E)(E[] elems...) if (is(typeof(binaryFun!less

This works with dmd 2.067. Adding a function argument makes it compile, too. As there has been little changes to rbtree.d recently, it's probably a dmd regression.

--