[Patch, fortran] PRs 20862, 23152, 25053, 25063, 25064, 25066, 25067, 25068, 25069, 25307 data transfer constraints

[Paul Thomas]

Tobi,

>
>Here and immediately below a 'default INTEGER' is required, not a 'default
>integer kind'.  Actually, a scalar-default-in-var is required, so you should
>tighten up that check some more.
>  
>
I will duly check for scalar-default-int-variable, as in R924.

> Is it not also an error if an internal unit is expr->ts.type == 
> BT_CHARACTER
>
>&& expr->expr_type != BT_CHARACTER.
>  
>
I presume that you mean, EXPR_VARIABLE for the latter?  I think that is 
already picked up but will make sure.

>What about 'No', 'nO', 'yeS' etc.?  Fortunately, libiberty provides
>strncasecmp :-)
>  
>
Oh Joy! Thanks for the tip.

>Apart from that this is ok.
>  
>
Thank you, Tobi.

>I believe introducing a gfc_is_writable (gfc_expr *), which encapsulates
>checks for INTENT(IN), constness, non-localness (in PURE procedures) and
>EXPR_VARIABLE would be a good idea, there are several places where we have to
>check if an expression may be written to, e.g. when passing them to
>INTENT(OUT) arguments or as internal-io unit.
>  
>
OK - that's for another time, since I would have to gather them all such 
instances up.

Many, many thanks, Tobi.

Paul