a19ff61e15
This PR adds support for `structure` in `mutual` blocks, allowing inductive types defined by `inductive` and `structure` to be mutually recursive. The limitations are (1) that the parents in the `extends` clause must be defined before the `mutual` block and (2) mutually recursive classes are not allowed (a limitation shared by `class inductive`). There are also improvements to universe level inference for inductive types and structures. Breaking change: structure parents now elaborate with the structure in scope (fix: use qualified names or rename the structure to avoid shadowing), and structure parents no longer elaborate with autoimplicits enabled. Internally, this is a large refactor of both the `inductive` and `structure` commands. Common material is now in `Lean.Elab.MutualInductive`, and each command plugs into this mutual inductive elaboration framework with the logic specific to the respective command. For example, `structure` has code to add projections after the inductive types are added to the environment. Closes #4182
6 lines
207 B
Text
6 lines
207 B
Text
mvarAtDefaultValue.lean:5:7-5:8: error: failed to infer default value for field 'x'
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mvarAtDefaultValue.lean:8:7-8:8: error: don't know how to synthesize placeholder
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context:
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toA : A
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x : Nat := toA.x
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⊢ Nat
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