Are there size limits on the binary ast as produced by --dump-ast?

[rleonid]

I'm running to a weird bug that is resolved by removing that argument and compiling from the generated source.

[ghost]

I think it's quite large, what error are you getting?

[rleonid]

The concrete error is

File "_none_", line 1:
Error: Unbound value Nativeint
Hint: Did you mean nativeint?

when compiling the branch in this PR. For context I'm using a ppx and cppo to generate [mono|di]morphic higher level functions (ex. fold_left, map ...) for Bigarrays (Array1.t's in the current work). I've manually compiled the code successfully without that flag against the generated code (it is 47700 lines) that I grabbed with -dsource so something seems fishy.

Maybe this should be filed under dune but is there a way to have dune omit this flag and go the slower text route? I'm fine with special casing a custom pp'ing rule?

[ghost]

The error doesn't look right, it should be something like Unbound constructor Nativeint or Unbound module Native, but not Unbound value since it is syntactically not possible to write an identifier starting with a capital letter.

My guess is that the generated AST is wrong, however when pretty printed, the printer prints something that ends up being valid OCaml code.

--dump-ast is necessary, it is the default mode for ppx rewriters. It means the the output will be a marshaled Parsetree.structure/signature value rather than source code. This has two advantages:

• it should be faster since you don't do the parsing twice
• locations are preserved, so errors and backtraces point to the right place in the original code rather than somewhere in the generated code that the user cannot see

[rleonid]

You were right, I was initially deceived into thinking that the ppx was correct because it worked for many other kinds and then started breaking with Nativeint. Thank you.

[ghost]

No problem. One way to make it easier to debug such errors would be to extend the invariants checks that are performed by the compiler to also check identifiers:

https://github.com/ocaml/ocaml/blob/trunk/parsing/ast_invariants.mli

[rleonid]

Thanks again, that's super helpful. I did not know about them.