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
104 lines
2.7 KiB
Text
104 lines
2.7 KiB
Text
/-!
|
||
# Tests of universe constraint testing in the `inductive` command
|
||
-/
|
||
|
||
set_option pp.mvars false
|
||
set_option pp.universes true
|
||
|
||
/-!
|
||
Given the resultant type, infer that the `x` parameter is `Type`.
|
||
-/
|
||
inductive T0 : Type where
|
||
| mk (x : PUnit.{_+1})
|
||
/-- info: T0.mk (x : PUnit.{1}) : T0 -/
|
||
#guard_msgs in #check T0.mk
|
||
|
||
/-!
|
||
Given the resultant type, infer that the `x` parameter is `Type` as well.
|
||
-/
|
||
inductive T1 : Type where
|
||
| mk (x : PUnit.{_+1} × PUnit.{_+1})
|
||
/-- info: T1.mk (x : Prod.{0, 0} PUnit.{1} PUnit.{1}) : T1 -/
|
||
#guard_msgs in #check T1.mk
|
||
|
||
/-!
|
||
Given the resultant type is `Prop`, do not do this inference. Get two universe levels.
|
||
-/
|
||
inductive T3 : Prop where
|
||
| mk (x : PUnit.{_+1} × PUnit.{_+1})
|
||
/-- info: T3.mk.{u_1, u_2} (x : Prod.{u_1, u_2} PUnit.{u_1 + 1} PUnit.{u_2 + 1}) : T3.{u_1, u_2} -/
|
||
#guard_msgs in #check T3.mk
|
||
|
||
/-!
|
||
Given the resultant type, fail to infer a level for `PUnit` if there's not a unique solution.
|
||
-/
|
||
/--
|
||
error: invalid universe level in constructor 'E0.mk', parameter 'x' has type
|
||
PUnit.{u_1}
|
||
at universe level
|
||
u_1
|
||
which is not less than or equal to the inductive type's resulting universe level
|
||
1
|
||
-/
|
||
#guard_msgs in
|
||
inductive E0 : Type where
|
||
| mk (x : PUnit)
|
||
|
||
/-!
|
||
Given the resultant type, fail to infer a level for `PUnit` if there's not a unique solution.
|
||
-/
|
||
/--
|
||
error: invalid universe level in constructor 'E1.mk', parameter 'x' has type
|
||
Prod.{u_1, u_2} PUnit.{u_1 + 1} PUnit.{u_2 + 1}
|
||
at universe level
|
||
max (u_1+1) (u_2+1)
|
||
which is not less than or equal to the inductive type's resulting universe level
|
||
2
|
||
-/
|
||
#guard_msgs in
|
||
inductive E1 : Type 1 where
|
||
| mk (x : PUnit × PUnit)
|
||
|
||
/-!
|
||
`Sort` polymorphism is not allowed.
|
||
-/
|
||
/--
|
||
error: invalid universe polymorphic resulting type, the resulting universe is not 'Prop', but it may be 'Prop' for some parameter values:
|
||
Sort u
|
||
Possible solution: use levels of the form 'max 1 _' or '_ + 1' to ensure the universe is of the form 'Type _'.
|
||
-/
|
||
#guard_msgs in
|
||
inductive P (α : Sort u) : Sort u where
|
||
| mk (x : α)
|
||
|
||
/-!
|
||
Errors for `structure` are specialized to talking about fields.
|
||
-/
|
||
/--
|
||
error: invalid universe level for field 'α', has type
|
||
Type
|
||
at universe level
|
||
2
|
||
which is not less than or equal to the structure's resulting universe level
|
||
1
|
||
-/
|
||
#guard_msgs in
|
||
structure A : Type where
|
||
α : Type
|
||
|
||
/-!
|
||
Errors for `structure` talk about parent projection fields too.
|
||
(Note: it could easily point to `A'` and say the error is field `α`.)
|
||
-/
|
||
structure A' where
|
||
α : Type
|
||
/--
|
||
error: invalid universe level for field 'toA'', has type
|
||
A'
|
||
at universe level
|
||
2
|
||
which is not less than or equal to the structure's resulting universe level
|
||
1
|
||
-/
|
||
#guard_msgs in
|
||
structure B extends A' : Type
|