[BUG] Wasm_of_ocaml program fails to validate in Safari 18.4

[TyOverby]

When attempting to run a program of mine in sarari 18.4 (README_wasm_of_ocaml.md says that safari 18.2 and above should work.), I get this validation error:

Unhandled Promise Rejection: CompileError: WebAssembly.Module doesn't validate: tail call function index 674 return type mismatch: expected (ref eq), got (ref <array:0>), in function at index 485

I can't publish the code that triggers this, but a similar error occurs in CAMLBOY

[TyOverby]

Interestingly, on Safari Technology Preview, CAMLBOY runs just fine, but my program completely crashes the tab that it's in without even printing to the console

[TyOverby]

Fwiw, I’m not super worried about this issue, I just wanted to see if wasm_of_ocaml would work on other browsers. Feel free to resolve this issue by updating the documentation

[vouillon]

I should update the documentation, indeed.
I think the typing issue has been fixed by this PR: WebKit/WebKit#42206
It might be interesting to test a bit our code with Safari / JavaScriptCore and file bug reports. It is not very easy for me since I don't have a Mac, and the jsc shell is quite limited compared to node. Anyway, I was able to get a crash as well .

[vouillon]

I think your crash issue has been fixed by WebKit/WebKit#45616.
I have made some tests in #1991 and I have not seen any other issue.
So, I think wasm_of_ocaml will work with Safari 18.6, and maybe already work with Safari 18.5.

[hhugo]

@TyOverby, can you confirm this is fixed ?

[TyOverby]

Confirmed to be resolved in Safari Tech Preview as of Release 221 (WebKit 20622.1.15.19.2).

Not yet fixed in mainline Safari.