675d2d5a11
This PR changes the rule for which projections become instances. Before, all parents along with all indirect ancestors that were represented as subobject fields would have their projections become instances. Now only projections for direct parents become instances. Features: - Only parents that are not ancestors of other parents get instances. This allows "discretionary" indirect parents to be inserted for the purpose of computing strict resolution orders when `structure.strictResolutionOrder` is enabled, without having an impact on typeclass synthesis. - Non-subobject projections are now theorems if the parent is a proposition. These are also no longer `@[reducible]`. Closes #2905
40 lines
1.3 KiB
Text
40 lines
1.3 KiB
Text
class AddCommGroup (α : Type) extends Zero α where
|
||
|
||
class Ring (α : Type) extends Zero α, AddCommGroup α
|
||
|
||
class Module (R : Type) (M : Type) [Zero R] [Zero M] where
|
||
|
||
instance (R : Type) [Zero R] : Module R R := ⟨⟩
|
||
|
||
structure Submodule (R : Type) (M : Type) [Zero R] [Zero M] [Module R M] : Type where
|
||
|
||
class HasQuotient (A : outParam <| Type) (B : Type) where
|
||
quotient' : B → Type
|
||
|
||
instance Submodule.hasQuotient {R : Type} {M : Type} [Ring R] [AddCommGroup M]
|
||
[Module R M]: HasQuotient M (Submodule R M) := ⟨fun _ => M⟩
|
||
|
||
def Synonym (M : Type) [Zero M] := M
|
||
|
||
instance Synonym.zero {G : Type} [Zero G] : Zero (Synonym G) := ⟨(Zero.zero : G)⟩
|
||
|
||
instance Synonym.addCommGroup {G : Type} [AddCommGroup G] : AddCommGroup (Synonym G) :=
|
||
{ Synonym.zero with }
|
||
|
||
instance Synonym.module (M : Type) {R : Type} [Zero R] [Zero M] [Module R M] :
|
||
Module R (Synonym M) := { }
|
||
|
||
variable (R : Type) [Ring R]
|
||
|
||
|
||
set_option maxSynthPendingDepth 2 in
|
||
/-- info: Submodule.hasQuotient -/
|
||
#guard_msgs in
|
||
#synth HasQuotient (Synonym (Synonym R)) (Submodule R (Synonym (Synonym R))) -- works
|
||
|
||
/-!
|
||
After https://github.com/leanprover/lean4/pull/5920 works without changing maxSynthPendingDepth.
|
||
-/
|
||
/-- info: Submodule.hasQuotient -/
|
||
#guard_msgs in
|
||
#synth HasQuotient (Synonym (Synonym R)) (Submodule R (Synonym (Synonym R)))
|