Ignore zero-sized types in wasm future-compat warning #139498
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This commit fixes a false positive of the warning triggered for rust-lang#138762 and the fix is to codify that zero-sized types are "safe" in both the old and new ABIs.
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r? @wesleywiser rustbot has assigned @wesleywiser. Use |
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alexcrichton
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I've additionally tagged this for a beta backport since the false positive is currently in beta too. |
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jieyouxu
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Apr 8, 2025
| @@ -111,6 +111,11 @@ fn wasm_abi_safe<'tcx>(tcx: TyCtxt<'tcx>, arg: &ArgAbi<'tcx, Ty<'tcx>>) -> bool | |||
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| // Zero-sized types are dropped in both ABIs, so they're safe | |||
| if arg.layout.size.bytes() == 0 { | |||
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Question: can this use arg.layout.is_zst() or arg.layout.is_1zst() (does alignment matter here?)?
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Sorry I'm pretty unfamiliar with this code so I fear I probably am not the best to answer this. AFAIK any zero-sized-type will be omitted in the old/new ABI so I don't believe alignment matters, so I don't know which of these methods for testing for a zst is best.
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This commit fixes a false positive of the warning triggered for #138762 and the fix is to codify that zero-sized types are "safe" in both the old and new ABIs.