feat: mutually dependent structure default values, and avoiding self-dependence#12841
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feat: mutually dependent structure default values, and avoiding self-dependence#12841
structure default values, and avoiding self-dependence#12841Conversation
…nce checking This PR changes the way default field values are elaborated in the `structure`/`class` commands so that they have all the fields in context. This allows the field defaults to be dependent on one another, which is already allowed for default values for inherited fields. Additionally, there is now an error that's logged if a field default depends on itself. Such fields will never be applicable. This fixes a bug reported by Aaron Liu [on Zulip](https://leanprover.zulipchat.com/#narrow/channel/270676-lean4/topic/default.20structure.20values.20can.20depend.20on.20themselves/near/578014370)
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structure default values, and self-dependence checkingstructure default values, and avoiding self-dependence
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…f-dependence (#12841) This PR changes the elaboration of the `structure`/`class` commands so that default values have later fields in context as well. This allows field defaults to depend on fields that come both before and after them. While this was already the case for inherited fields to some degree, it now applies uniformly to all fields. Additionally, when elaborating the default value for a field, all fields that depend on it are cleared from the context to avoid situations where the default value depends on itself. This addresses an issue reported by Aaron Liu [on Zulip](https://leanprover.zulipchat.com/#narrow/channel/270676-lean4/topic/default.20structure.20values.20can.20depend.20on.20themselves/near/578014370).
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This PR changes the elaboration of the
structure/classcommands so that default values have later fields in context as well. This allows field defaults to depend on fields that come both before and after them. While this was already the case for inherited fields to some degree, it now applies uniformly to all fields. Additionally, when elaborating the default value for a field, all fields that depend on it are cleared from the context to avoid situations where the default value depends on itself.This addresses an issue reported by Aaron Liu on Zulip.