[m-rev.] for review: report an error for obviously redundant functional dependencies

[Zoltan Somogyi]

On Sat, 20 Sep 2025 14:33:03 +1000, Julien Fischer <jfischer at opturion.com> wrote:
> Question for reviewers: should these be warnings rather than errors?

A redundant variable occurence should be a warning, but a misspelt
variable name should be an error (because the correct spelling is missing).
Since the compiler is not telepathic, either is justifable. I think the problem
is rare enough that the choice does not matter that much, but like you,
I prefer it being an error.

> +            CommonTypeVarsPieces ++
> +            color_as_incorrect([
> +                words(choose_number(CommonTypeVars, "occurs", "occur")),
> +                words("in both the domain and range of a functional
> dependency.")

I would make two cosmetic changes here. First, I would change the text to say
"both the domain and THE range of THE SAME functional dependency".
Second, I would color as incorrect only the "both the domain and the range"
part.

The diff is otherwise fine.

Zoltan.