Fields of enums and unions should be allowed to overlap #2168
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RalfJung
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Feb 12, 2026
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LGTM with the nit fixed -- the only change here is fixing what clearly looks like an editorial issue. |
Co-authored-by: Ralf Jung <post@ralfj.de>
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Lol this seems to have been wrong for years (#1152 landed in 2022) and nobody complained in all that time that union fields apparently must be disjoint?^^ |
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This fixes a bug that we currently say that fields of enums and unions must not overlap.
As mentioned in #2166 (comment) there is currently no exception for uninhabited types. We should determine whether such an exception should be added, but this is a pre-existing problem so let's not block this PR on that.
This PR does not add any statement about overlap for fields of the same variant of an enum because the uninhabited type concern should be addressed first before we say anything about enums.