[Issue 3609] isNumeric causes a stack overlfow with mutable arrays

[d-bugmail at puremagic.com]

http://d.puremagic.com/issues/show_bug.cgi?id=3609


David Simcha <dsimcha at yahoo.com> changed:

           What    |Removed                     |Added
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                 CC|                            |dsimcha at yahoo.com


--- Comment #1 from David Simcha <dsimcha at yahoo.com> 2009-12-11 16:31:10 PST ---
I ran into this a few days, too and was meaning to file it.  isNumeric is
**completely** busted on D2, and it amazes me that noone noticed it until now. 
The problem is that isNumeric(string, bool) is overloaded against
isNumeric(...).  In D1, string is an alias for char[].  In D2, it's an alias
for immutable(char)[].  If the type that's input is not a string, it's sent to
isNumeric(...).  If it's a mutable char[] array in D2, the following is
executed:

    if (_arguments[0] == typeid(char[]))
        return isNumeric(va_arg!(char[])(_argptr));

Obviously, the intent here is to call the overload, but in D2 the overload
expects an immutable(char)[], leading to isNumeric(...) getting called again. 
Violia, infinite recursion and stack overflows.

I doubt anyone actually uses isNumeric(...), because its functionality should
really be handled at compile time w/ templates.  I doubt there are too many use
cases for having it be handled at runtime.  Therefore, I recommend dumping it
and templating isNumeric(string) to handle char[], wchar[], dchar[], and the
const and immutable flavors of these.  This would also fix bug 3610.

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