List objects are 1-based

[Arthurvdv]

Based on https://www.linkedin.com/posts/brad-prendergast_msdy365bc-businesscentral-activity-7216601980108984322-O42I

Example

local procedure MyProcedure()
var
    myList: List of [Integer];
    i: Integer;
begin
    for i := 0 to myList.Count() do ;
end;

local procedure MyProcedure()
var
    myList: List of [Integer];
begin
    myList.Get(0);
end;

List objects are 1-based, so raise a diagnostic on possible cases of trying to retrieve the 0 index. Maybe even default as a warning?

Coincidentally today one of our internal PR's had this 😲

[rvanbekkum]

Could be nice indeed, but you need to be very sure that it concerns an 'invalid' list access.
For List.Get(i) it might be much harder to detect whether it is actually an issue.

[Arthurvdv]

For now I'm going to start simple with these two scenario's

myList.Get(0);

for i := 0 to myList.Count() do;

You are right about the 'invalid' list access. and there are undoubtedly more complex possibilities, like the List.Get(i) you've mentioned. In these scenario's it's not always possible to determine the value of i for the code analyzer.