febf6c10f0
This PR changes `Lean.Grind.CommRing` to inline the `NatCast` instance (i.e. to be provided by the user) rather than constructing one from the existing data. Without this change we can't construct instances in Mathlib that `grind` can use.
42 lines
1.1 KiB
Text
42 lines
1.1 KiB
Text
/-
|
|
Copyright (c) 2025 Lean FRO, LLC. or its affiliates. All Rights Reserved.
|
|
Released under Apache 2.0 license as described in the file LICENSE.
|
|
Authors: Kim Morrison
|
|
-/
|
|
module
|
|
|
|
prelude
|
|
import Init.Grind.CommRing.Basic
|
|
import Init.Data.Int.Lemmas
|
|
|
|
namespace Lean.Grind
|
|
|
|
instance : CommRing Int where
|
|
add_assoc := Int.add_assoc
|
|
add_comm := Int.add_comm
|
|
add_zero := Int.add_zero
|
|
neg_add_cancel := Int.add_left_neg
|
|
mul_assoc := Int.mul_assoc
|
|
mul_comm := Int.mul_comm
|
|
mul_one := Int.mul_one
|
|
left_distrib := Int.mul_add
|
|
zero_mul := Int.zero_mul
|
|
pow_zero _ := rfl
|
|
pow_succ _ _ := rfl
|
|
ofNat_succ _ := rfl
|
|
sub_eq_add_neg _ _ := Int.sub_eq_add_neg
|
|
|
|
instance : IsCharP Int 0 where
|
|
ofNat_eq_zero_iff {x} := by erw [Int.ofNat_eq_zero]; simp
|
|
|
|
instance : NoNatZeroDivisors Int where
|
|
no_nat_zero_divisors k a h₁ h₂ := by
|
|
cases Int.mul_eq_zero.mp h₂
|
|
next h =>
|
|
rw [← Int.natCast_zero] at h
|
|
have h : (k : Int).toNat = (↑0 : Int).toNat := congrArg Int.toNat h;
|
|
simp at h
|
|
contradiction
|
|
next => assumption
|
|
|
|
end Lean.Grind
|