On 6/27/20 1:40 AM, Thomas Koenig via Fortran wrote:
Hi Mark,
Use -fdec-add-missing-indexes to enable feature. Also enabled by fdec.
A warning that the lower bound is being used for a mission dimension
is output unless suppressed by using -Wno-missing-index.
This is... seriously problematic. I forsee all sorts of not-so-funny
interactions with more modern features.
What do people actually do with this kind of code? What kind of test
cases do you have that "work" with this?
And people would actually want to save a few keystrokes so they don't
have to write A(N,M,1) instead of A(N,M)? And is this even the right
fix, how sure are you of the semantics; is there documentation for
this feature (maybe on Bitsavers)? If not, this is not be done.
If this goes in at all, I want this rejected with any modern Fortran
feature, i.e. it should not be contain
- allocatable arrays
- coarrays
- pointers
- derived types
- CLASS
- assumed-shape arrays
- assumed-rank arrays (well, it probably doesn't make sense)
- KIND=4 characters
- as an argument to any of the array intrinsics like MATMUL,
EOSHIFT, ...
but even with these restrictions, I will still take a lot of convincing
that this make sense.
Just imagine what will happen if people specify -fdec for some
relatively benign reason (for example because they want -fdec-math)
and start not finding bugs in their code because of this feature.
Best regards
Thomas
Please stop fixing problematic DEC programs by using the compiler as the
pet tool. Use an editor or python or some suitable tool to initialize
arrays properly.
I appreciate the effort, but need things run by here before the effort
so you can spend the effort on really true compiler bugs, and not on the
wishes of perhaps a paying customer.
We should never have caved on the previous DEC enhancement.
Just my humble opinion.
Jerry
