Re: Simple Ada question

[John English <je@bton.ac.uk>]

Ehud Lamm wrote:
> On Sun, 21 May 2000, Robert Dewar wrote:
> 
> |In article <3923B647.82A765D4@bton.ac.uk>,
> |John English <je@bton.ac.uk> wrote:
> |> I've seen enough students fall over this one that I wonder if a
> |> compiler warning should be issued if the loop index has the same
> |> name as a variable in the enclosing scope...
> |
> |In practice, GNAT will almost always give a warning in this
> |case. If the outer variable is not referenced at all, then
> |that will certainly generate a warning. If the outer variable
> |is referenced after the loop, then a warning will be generated
> |about reference to an uninitialized variable.
> |
> |This will not catch 100% of cases, but it's very close
> 
> Actually a student came to me saying "I found a compiler bug" it says that
> i is not referenced, where as I clearly use it in the for loop....

Which is why I think a more explicit warning might be a good thing:
"loop index uses the same name as an existing object" or something
like that (although I'm sure the wording could be improved...) since
this is nearly always an indication of an error where the writer
believes that the two names will refer to the same thing.

Just a thought...

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