Issue with duplicated use of variable named e (or other name shadowing nullary functions)

[rok-cesnovar]

There are a few issues with duplicated use of e variable name.

transformed data {
    vector[3] e;
    vector[3] e;
}

compiles to C++ (it should not), and then fails with the C++ compiler (as expected).

parameters {
    vector[3] e;
    vector[3] e;
}

is an exception in stanc3:

Uncaught exception:
  
  ("Map.of_alist_exn: duplicate key" e)

Raised at Base__Error.raise in file "src/error.ml" (inlined), line 8, characters 14-30
Called from Base__Map.Tree0.Of_foldable.of_foldable_exn in file "src/map.ml", line 1266, characters 8-143
Called from Base__Map.Using_comparator.of_alist_exn in file "src/map.ml", line 2242, characters 25-63
Called from Core_kernel__Map.Creators.of_alist_exn in file "src/map.ml" (inlined), line 236, characters 27-74
Called from Stan_math_backend__Transform_Mir.add_reads in file "src/stan_math_backend/Transform_Mir.ml", line 302, characters 18-46
Called from Stan_math_backend__Transform_Mir.trans_prog in file "src/stan_math_backend/Transform_Mir.ml", line 543, characters 6-69
Called from Dune__exe__Stanc.use_file in file "src/stanc/stanc.ml", line 236, characters 8-38
Called from Dune__exe__Stanc in file "src/stanc/stanc.ml", line 283, characters 9-16

For completeness:

transformed parameters {
    vector[3] e;
}

and

transformed data {
    vector[3] e;
}

work fine.

[WardBrian]

I’m guessing this is related to #1011? Does the same thing happen with the name pi for example?

[rok-cesnovar]

Yep, so I would guess all nullary functions are affected.

I should also add that both work fine (semantic error in stanc3) with the stanc3 in the 2.28.1 release (which is the same as the one for 2.28.2).

[WardBrian]

I will take a look next week. It’s probably just an issue of orders of the checks

[rok-cesnovar]

Yeah, no rush. Happy thanksgiving break Brian! :)