[C++ PATCH] Improve location info [1/many]

[Jason Merrill]

On 08/01/2014 07:59 AM, Marek Polacek wrote:

Thanks for taking this on, sorry it's taken so long to respond.

> +convert_like_real (location_t loc, conversion *convs, tree expr, tree fn,
> +		   int argnum, int inner, bool issue_conversion_warnings,
>   		   bool c_cast_p, tsubst_flags_t complain)
>   {
>     tree totype = convs->type;
>     diagnostic_t diag_kind;
>     int flags;
> -  location_t loc = EXPR_LOC_OR_LOC (expr, input_location);

I'm afraid I think this will be a regression for many callers: for 
instance, with a ?: expression this will change conversion diagnostics 
to have the same location as the ?: as a whole rather than the location 
of the subexpression being converted.  Same for build_new_op_1, and all 
the calls where now you pass input_location.

Furthermore, the arguments should have their own locations in 
EXPR_LOCATION; I don't think we need to track them separately.  If their 
locations are wrong that's something to fix directly, rather than adding 
a special case for function arguments.

So I think I'd like to drop the arg_loc/convert_like changes from this 
patch.

> +	      pedwarn (loc, 0, "deducing %qT as %qT",

> +	      if (permerror (loc, "passing %qT as %<this%> "

These should use the location of the argument, not the call.

There are also a lot of added uses of input_location, which makes me 
uncomfortable.  For build_operator_new_call and build_new_1, I think we 
want the location of the 'new' token.   For build_op_call_1, we can use 
the '(', and so on.

Jason