Confusing class variable initialisation message is vague

Users
1

I have just spent time debugging some OO C routines, some C++ classes, and some Java classes.
So my brain was going to appreciate clear and concise error messages.

I was trying to debug something along the lines of this

class minBase
{
    param zero = 0:real;
    var a = zero;
    var b = zero;

    proc init(lo : R, hi : R)
    {
        (a, b) = if lo < hi then (lo, hi) else (hi, lo);
    }

    proc show()
    {
        writeln("a = ", a);
        writeln("b = ", b);
    }
}

The error message you get from the init routine is very vague, i.e.

t.chpl:36: In initializer:
t.chpl:38: error: field "a" used before it is initialized
t.chpl:38: error: field "b" used before it is initialized

So I thought, maybe a tuples works in reverse so I changed the ordering to use

(b, a)

Well, same error.

My question is - what ordering does a tuple imply? The error needs to talk about Out of Order initialization because clearly, "a" and "b" are not used before they are initialized.

Note that one fix is

const (_a, _b) = if lo < hi then (lo, hi) else (hi, lo);

a = lo;
b = hi;

But that is way too verbose.

2

This is a problem. Does it exist 1.25.1. Unfortunately, I cannot upgrade for a while yet.

Trying to define a class here with a finite state machine.

class minBracket1D
{
    .....
    enum state { commence, done, interior, exterior, golden, curbed };
    // OK, so I define my **enum**s and use one of them to initiialize `s`
    var s = state.commence;
    .....
    proc init(...parameters); // this is line 145

m2.chpl:145: internal error: UTI-MIS-0691 chpl version 1.22.0
Note: This source location is a guess.

Internal errors indicate a bug in the Chapel compiler ("It's us, not you"),
and we're sorry for the hassle. We would appreciate your reporting this bug --
please see IU Webmaster redirect for instructions. In the meantime,
the filename + line number above may be useful in working around the issue.

1 Like
3

For your first issue, you can work around this by adding a call to this.complete() like:

    proc init(lo : R, hi : R)
    {
        this.complete();
        (a, b) = if lo < hi then (lo, hi) else (hi, lo);
    }

See the docs on complete.

For the second error you've posted, I would need some more information. If you're still facing this error, could you open an issue on Github? Thanks

4

Hi Damian,

I think you're running into
Improve support for enums declared within classes · Issue #6871 · chapel-lang/chapel · GitHub with your enum issue.
It ought to work better if you define the enum outside of the class
declaration.

Thanks,
Lydia

1 Like