Workaround for @asin labels in uncurried externals.
#6527
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Examples like this: ``` @obj external makeOptions: ( ~objectMode: @as(json`false`) _, ~name: string, unit, ) => int = "" ``` change the arity of the function. The arity of uncurried functions is determined at parsing type. This means that this peculiarity of externals affects parsing. This PR gives an approximate workaround based on the labelled arg having `@as`, and the type being `_` (the any type). Fixes #6517
jscomp/syntax/src/res_core.ml
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| let has_as = | ||
| Ext_list.exists typ.ptyp_attributes (fun (x, _) -> x.txt = "as") | ||
| in | ||
| if typ_is_any && has_as then arity - 1 else arity |
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I think there can be multiple @as() _, right?
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This is inside a fold for each argument.
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This check is approximate: does not check that we're inside an external.
The same construction inside a normal type annotation which is not an external should have no effect (in that the rest of the compiler ignores it).
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It would be good to deprecate this whole construction in future.
Kind of hesitant to go for this workaround, unless it's really needed to unbreak something.
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Yeah we should get rid of this eventually. But for v11 we should have it imo.
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OK I've guarded it to only apply inside externals, so it won't accidentally break in the corner case where the annotations are used outside externals by mistake.
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This is safe enough to merge now. |
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I'm not very familiar with building the compiler from source, so I'm not sure whether this works on rescript-nodejs (after changing It failed, then I tried removing the external check and it worked, then I put it back and it still worked 🙃 (also there is a second uncurried error I didn't notice earlier, I might need to log another bug for that) |
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I've gone back and forth a few times and I can only assume something was out of date when it seemed to not work. It's working great, thank you. I logged a new ticket for the other error (completely unrelated to this issue, I just hadn't noticed it because I was focused on this one). |
Examples like this:
change the arity of the function.
The arity of uncurried functions is determined at parsing type. This means that this peculiarity of externals affects parsing. This PR gives an approximate workaround based on the labelled arg having
@as, and the type being_(the any type).Fixes #6517