[fpc-pascal] Strange message about mixed signed expression

[Jürgen Hestermann]

Am 2014-01-21 18:43, schrieb Howard Page-Clark:
> On 21/01/2014 17:33, Jürgen Hestermann wrote:
>> I always wondered why I get a compiler message for the following code
>> ...
>>
>> if i+length(M)<length(F) then
>> ...
>> But where are signed expressions involved?
>
> Length is declared in the compiler/RTL to return an integer result.

Realy?
But why that?
It cannot be negative.
Using integer instead of unsigned values reduces the possible (positive) range
and produces such illogical (to me) compiler warnings.