[m-dev.] bug in type_info.c

[Tyson Richard DOWD]

> Hi Tyson,
> 
> Can you please review the following diff?
> Also, could you please add some more tests for type_info.c,
> including one that covers this case?
> I spotted this one only because gcc warned about it.
> 
> runtime/type_info.c:
> 	Fix a bug where the return value from a recursive call to
> 	type_info() was ignored.
> 
> Index: deep_copy.c
> ===================================================================
> RCS file: /home/staff/zs/imp/mercury/runtime/deep_copy.c,v
> retrieving revision 1.8
> diff -u -r1.8 deep_copy.c
> --- 1.8	1997/02/18 03:06:29
> +++ deep_copy.c	1997/02/18 15:33:44
> @@ -235,7 +235,8 @@
>              /* note: we treat no_tag types just like equivalences */
>  
>              if ((Word) entry_value < TYPELAYOUT_MAX_VARINT) {
> -                deep_copy(data, (Word *) type_info[(Word) entry_value],
> +                new_data = deep_copy(data,
> +		    (Word *) type_info[(Word) entry_value],
>                      lower_limit, upper_limit);
>              } else {
>                  new_type_info = make_type_info(type_info, 

This is correct, however the code is still not right - the code below
doesn't check for no_tag types correctly.

This is a result of a double-maintenance problem. Oliver Hutchison
is working on a more general fix for this (because he uses the same
code twice in his changes, making it a quadruple maintenance problem).

Commit this for now, but we should soon have a better fix.

-- 
       Tyson Dowd           # "Most people's C code should be indented
                            #  six feet downward and covered with 
     trd at cs.mu.oz.au        #  dirt."
http://www.cs.mu.oz.au/~trd # - Blair Houghton, on C code indentation