Signed word lengths and indexes

[bearophile]

I have found a Reddit discussion few days old:
http://www.reddit.com/r/programming/comments/cdwz5/the_perils_of_unsigned_iteration_in_cc/

It contains this, that I quote (I have no idea if it's true), plus follow-ups:

>At Google using uints of all kinds for anything other than bitmasks or other inherently bit-y, non computable things is strongly discouraged. This includes things like array sizes, and the warnings for conversion of size_t to int are disabled. I think it's a good call.<

I have expressed similar ideas here:
http://d.puremagic.com/issues/show_bug.cgi?id=3843

Unless someone explains me why I am wrong, I will keep thinking that using unsigned words to represent lengths and indexes, as D does, is wrong and unsafe, and using signed words (I think C# uses ints for that purpose) in D is a better design choice.

In a language as greatly numerically unsafe as D (silly C-derived conversion rules, fixed-sized numbers used everywhere on default, no runtime numerical overflows) the usage of unsigned numbers can be justified inside bit vectors, bitwise operations, and few other similar situations only.

If D wants to be "a systems programming language. Its focus is on combining the power and high performance of C and C++ with the programmer productivity of modern languages like Ruby and Python." it must understand that numerical safety is one of the not secondary things that make those languages as Ruby and Python more productive.

Bye,
bearophile