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lean4/tests/elab/grind_constProp.lean
Garmelon 08eb78a5b2 chore: switch to new test/bench suite (#12590)
This PR sets up the new integrated test/bench suite. It then migrates
all benchmarks and some related tests to the new suite. There's also
some documentation and some linting.

For now, a lot of the old tests are left alone so this PR doesn't become
even larger than it already is. Eventually, all tests should be migrated
to the new suite though so there isn't a confusing mix of two systems.
2026-02-25 13:51:53 +00:00

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module
reset_grind_attrs%
@[expose] public section -- TODO: remove after we fix congr_eq
attribute [grind cases] Or
attribute [grind =] List.length_nil List.length_cons Option.getD
abbrev Var := String
inductive Val where
| int (i : Int)
| bool (b : Bool)
deriving DecidableEq, Repr
instance : Coe Bool Val where
coe b := .bool b
instance : OfNat Val n where
ofNat := .int n
inductive BinOp where
| eq | and | lt | add | sub
deriving Repr
inductive UnaryOp where
| not
deriving Repr
inductive Expr where
| val (v : Val)
| var (x : Var)
| bin (lhs : Expr) (op : BinOp) (rhs : Expr)
| una (op : UnaryOp) (arg : Expr)
deriving Repr
@[simp, grind =] def BinOp.eval : BinOp Val Val Option Val
| .eq, v₁, v₂ => some (.bool (v₁ = v₂))
| .and, .bool b₁, .bool b₂ => some (.bool (b₁ && b₂))
| .lt, .int i₁, .int i₂ => some (.bool (i₁ < i₂))
| .add, .int i₁, .int i₂ => some (.int (i₁ + i₂))
| .sub, .int i₁, .int i₂ => some (.int (i₁ - i₂))
| _, _, _ => none
@[simp, grind =] def UnaryOp.eval : UnaryOp Val Option Val
| .not, .bool b => some (.bool !b)
| _, _ => none
inductive Stmt where
| skip
| assign (x : Var) (e : Expr)
| seq (s₁ s₂ : Stmt)
| ite (c : Expr) (e t : Stmt)
| while (c : Expr) (b : Stmt)
infix:150 " ::= " => Stmt.assign
infixr:130 ";; " => Stmt.seq
abbrev State := List (Var × Val)
@[simp] def State.update (σ : State) (x : Var) (v : Val) : State :=
match σ with
| [] => [(x, v)]
| (y, w)::σ => if x = y then (x, v)::σ else (y, w) :: update σ x v
@[simp] def State.find? (σ : State) (x : Var) : Option Val :=
match σ with
| [] => none
| (y, v) :: σ => if x = y then some v else find? σ x
def State.get (σ : State) (x : Var) : Val :=
σ.find? x |>.getD (.int 0)
@[simp] def State.erase (σ : State) (x : Var) : State :=
match σ with
| [] => []
| (y, v) :: σ => if x = y then erase σ x else (y, v) :: erase σ x
section
attribute [local grind] State.update State.find? State.get State.erase
@[simp, grind =] theorem State.find?_nil (x : Var) : find? [] x = none := by
grind
@[simp] theorem State.find?_update_self (σ : State) (x : Var) (v : Val) : (σ.update x v).find? x = some v := by
induction σ using State.update.induct x <;> grind
@[simp] theorem State.find?_update (σ : State) (v : Val) (h : x z) : (σ.update x v).find? z = σ.find? z := by
induction σ using State.update.induct x <;> grind
@[grind =] theorem State.find?_update_eq (σ : State) (v : Val)
: (σ.update x v).find? z = if x = z then some v else σ.find? z := by
grind only [= find?_update_self, = find?_update, cases Or]
@[grind] theorem State.get_of_find? {σ : State} (h : σ.find? x = some v) : σ.get x = v := by
grind
@[simp] theorem State.find?_erase_self (σ : State) (x : Var) : (σ.erase x).find? x = none := by
induction σ using State.erase.induct x <;> grind
@[simp] theorem State.find?_erase (σ : State) (h : x z) : (σ.erase x).find? z = σ.find? z := by
induction σ using State.erase.induct x <;> grind
@[simp, grind =] theorem State.find?_erase_eq (σ : State)
: (σ.erase x).find? z = if x = z then none else σ.find? z := by
grind only [= find?_erase_self, = find?_erase, cases Or]
theorem State.length_erase_le (σ : State) (x : Var) : (σ.erase x).length σ.length := by
induction σ using erase.induct x <;> grind
grind_pattern State.length_erase_le => (σ.erase x).length
def State.length_erase_lt (σ : State) (x : Var) : (σ.erase x).length < σ.length.succ := by
grind
end
syntax ident "" term : term
macro_rules
| `($id:ident $v:term) => `(($(Lean.quote id.getId.toString), $v:term))
example : State.get [x .int 10, y .int 20] "x" = .int 10 := rfl
example : State.get [x 10, y 20] "x" = 10 := rfl
example : State.get [x 10, y true] "y" = true := rfl
@[simp, grind =] def Expr.eval (σ : State) : Expr Option Val
| val v => some v
| var x => σ.get x
| bin lhs op rhs => match lhs.eval σ, rhs.eval σ with
| some v₁, some v₂ => op.eval v₁ v₂ -- BinOp.eval : BinOp → Val → Val → Option Val
| _, _ => none
| una op arg => match arg.eval σ with
| some v => op.eval v
| _ => none
@[simp, grind =] def evalTrue (c : Expr) (σ : State) : Prop := c.eval σ = some (Val.bool true)
@[simp, grind =] def evalFalse (c : Expr) (σ : State) : Prop := c.eval σ = some (Val.bool false)
section
set_option hygiene false -- HACK: allow forward reference in notation
local notation:60 "(" σ ", " s ")" "" σ':60 => Bigstep σ s σ'
inductive Bigstep : State Stmt State Prop where
| skip : (σ, .skip) σ
| assign: e.eval σ = some v (σ, x ::= e) σ.update x v
| seq : (σ₁, s₁) σ₂ (σ₂, s₂) σ₃ (σ₁, s₁ ;; s₂) σ₃
| ifTrue : evalTrue c σ₁ (σ₁, t) σ₂ (σ₁, .ite c t e) σ₂
| ifFalse : evalFalse c σ₁ (σ₁, e) σ₂ (σ₁, .ite c t e) σ₂
| whileTrue : evalTrue c σ₁ (σ₁, b) σ₂ (σ₂, .while c b) σ₃ (σ₁, .while c b) σ₃
| whileFalse : evalFalse c σ (σ, .while c b) σ
end
notation:60 "(" σ ", " s ")" "" σ':60 => Bigstep σ s σ'
/- This proof can be automated using forward reasoning. -/
theorem Bigstem.det (h₁ : (σ, s) σ₁) (h₂ : (σ, s) σ₂) : σ₁ = σ₂ := by
induction h₁ generalizing σ₂ <;> grind [Bigstep]
abbrev EvalM := ExceptT String (StateM State)
def evalExpr (e : Expr) : EvalM Val := do
match e.eval ( get) with
| some v => return v
| none => throw "failed to evaluate"
@[simp, grind =] def Stmt.eval (stmt : Stmt) (fuel : Nat := 100) : EvalM Unit := do
match fuel with
| 0 => throw "out of fuel"
| fuel+1 =>
match stmt with
| skip => return ()
| assign x e => let v evalExpr e; modify fun s => s.update x v
| seq s₁ s₂ => s₁.eval fuel; s₂.eval fuel
| ite c e t =>
match ( evalExpr c) with
| .bool true => e.eval fuel
| .bool false => t.eval fuel
| _ => throw "Boolean expected"
| .while c b =>
match ( evalExpr c) with
| .bool true => b.eval fuel; stmt.eval fuel
| .bool false => return ()
| _ => throw "Boolean expected"
@[simp, grind =] def BinOp.simplify : BinOp Expr Expr Expr
| .eq, .val v₁, .val v₂ => .val (.bool (v₁ = v₂))
| .and, .val (.bool a), .val (.bool b) => .val (.bool (a && b))
| .lt, .val (.int a), .val (.int b) => .val (.bool (a < b))
| .add, .val (.int a), .val (.int b) => .val (.int (a + b))
| .sub, .val (.int a), .val (.int b) => .val (.int (a - b))
| op, a, b => .bin a op b
@[simp, grind =] def UnaryOp.simplify : UnaryOp Expr Expr
| .not, .val (.bool b) => .val (.bool !b)
| op, a => .una op a
@[simp, grind =] def Expr.simplify : Expr Expr
| bin lhs op rhs => op.simplify lhs.simplify rhs.simplify
| una op arg => op.simplify arg.simplify
| e => e
@[grind] theorem BinaryOp.simplify_eval (op : BinOp) : (op.simplify a b).eval σ = (Expr.bin a op b).eval σ := by
grind [BinOp.simplify.eq_def]
@[grind] theorem UnaryOp.simplify_eval (op : UnaryOp) : (op.simplify a).eval σ = (Expr.una op a).eval σ := by
grind [UnaryOp.simplify.eq_def]
/--
info: Try this:
[apply] (fun_induction Expr.simplify) <;> grind
-/
#guard_msgs (info) in
example (e : Expr) : e.simplify.eval σ = e.eval σ := by
try? (max := 1)
@[simp, grind =] theorem Expr.eval_simplify (e : Expr) : e.simplify.eval σ = e.eval σ := by
induction e using Expr.simplify.induct <;> grind
@[simp, grind =] def Stmt.simplify : Stmt Stmt
| skip => skip
| assign x e => assign x e.simplify
| seq s₁ s₂ => seq s₁.simplify s₂.simplify
| ite c e t =>
match c.simplify with
| .val (.bool true) => e.simplify
| .val (.bool false) => t.simplify
| c' => ite c' e.simplify t.simplify
| .while c b =>
match c.simplify with
| .val (.bool false) => skip
| c' => .while c' b.simplify
theorem Stmt.simplify_correct (h : (σ, s) σ') : (σ, s.simplify) σ' := by
induction h <;> grind [=_ Expr.eval_simplify, intro Bigstep]
@[simp, grind =] def Expr.constProp (e : Expr) (σ : State) : Expr :=
match e with
| val v => val v
| var x => match σ.find? x with
| some v => val v
| none => var x
| bin lhs op rhs => bin (lhs.constProp σ) op (rhs.constProp σ)
| una op arg => una op (arg.constProp σ)
@[simp, grind =] theorem Expr.constProp_nil (e : Expr) : e.constProp [] = e := by
induction e <;> grind
@[simp, grind =] def State.join (σ₁ σ₂ : State) : State :=
match σ₁ with
| [] => []
| (x, v) :: σ₁ =>
let σ₁' := erase σ₁ x -- Must remove duplicates. Alternative design: carry invariant that input state at constProp has no duplicates
have : (erase σ₁ x).length < σ₁.length.succ := length_erase_lt ..
match σ₂.find? x with
| some w => if v = w then (x, v) :: join σ₁' σ₂ else join σ₁' σ₂
| none => join σ₁' σ₂
termination_by σ₁.length
local notation "" => []
@[simp, grind =] def Stmt.constProp (s : Stmt) (σ : State) : Stmt × State :=
match s with
| skip => (skip, σ)
| assign x e => match (e.constProp σ).simplify with
| (.val v) => (assign x (.val v), σ.update x v)
| e' => (assign x e', σ.erase x)
| seq s₁ s₂ => match s₁.constProp σ with
| (s₁', σ₁) => match s₂.constProp σ₁ with
| (s₂', σ₂) => (seq s₁' s₂', σ₂)
| ite c s₁ s₂ =>
match s₁.constProp σ, s₂.constProp σ with
| (s₁', σ₁), (s₂', σ₂) => (ite (c.constProp σ) s₁' s₂', σ₁.join σ₂)
| .while c b => (.while (c.constProp ) (b.constProp ).1, )
def State.le (σ₁ σ₂ : State) : Prop :=
x : Var v : Val, σ₁.find? x = some v σ₂.find? x = some v
infix:50 "" => State.le
@[grind] theorem State.le_refl (σ : State) : σ σ :=
fun _ _ h => h
section
attribute [local grind] State.le State.erase State.find? State.update
theorem State.le_trans : σ₁ σ₂ σ₂ σ₃ σ₁ σ₃ := by
grind
@[grind] theorem State.bot_le (σ : State) : σ := by
grind
theorem State.erase_le_cons (h : σ' σ) : σ'.erase x ((x, v) :: σ) := by
grind
theorem State.cons_le_cons (h : σ' σ) : (x, v) :: σ' (x, v) :: σ := by
grind
theorem State.cons_le_of_eq (h₁ : σ' σ) (h₂ : σ.find? x = some v) : (x, v) :: σ' σ := by
grind
@[grind] theorem State.erase_le (σ : State) : σ.erase x σ := by
grind
@[grind!] theorem State.join_le_left (σ₁ σ₂ : State) : σ₁.join σ₂ σ₁ := by
induction σ₁ using State.join.induct σ₂ <;> grind
@[grind] theorem State.join_le_left_of (h : σ₁ σ₂) (σ₃ : State) : σ₁.join σ₃ σ₂ := by
grind
/--
info: Try this:
[apply] (fun_induction join) <;> grind
-/
#guard_msgs (info) in
open State in
example (σ₁ σ₂ : State) : σ₁.join σ₂ σ₂ := by
try? (max := 1)
@[grind!] theorem State.join_le_right (σ₁ σ₂ : State) : σ₁.join σ₂ σ₂ := by
fun_induction join <;> grind
@[grind] theorem State.join_le_right_of (h : σ₁ σ₂) (σ₃ : State) : σ₃.join σ₁ σ₂ := by
grind
@[grind] theorem not_cons_le_nil : ¬ (x, v) :: σ [] := by
-- Remark: `grind` fails here because it is not capable of "guessing" that we need to instantiate the hypothesis with `x`
intro h; have h := @h x; simp at h
theorem State.eq_bot (h : σ ) : σ = := by
grind [cases Prod, cases List]
theorem State.erase_le_of_le_cons (h : σ' (x, v) :: σ) : σ'.erase x σ := by
grind
@[grind ] theorem State.erase_le_update (h : σ' σ) : σ'.erase x σ.update x v := by
grind
@[grind =>] theorem State.update_le_update (h : σ' σ) : σ'.update x v σ.update x v := by
grind
@[grind! =>] theorem Expr.eval_constProp_of_sub (e : Expr) (h : σ' σ) : (e.constProp σ').eval σ = e.eval σ := by
induction e <;> grind
@[grind =>] theorem Expr.eval_constProp_of_eq_of_sub {e : Expr} (h₂ : σ' σ) : (e.constProp σ').eval σ = e.eval σ := by
grind
@[grind =>] theorem Stmt.constProp_sub (h₁ : (σ₁, s) σ₂) (h₂ : σ₁' σ₁) : (s.constProp σ₁').2 σ₂ := by
induction h₁ generalizing σ₁' with grind [=_ Expr.eval_simplify]
end
@[grind] theorem Stmt.constProp_correct (h₁ : (σ₁, s) σ₂) (h₂ : σ₁' σ₁) : (σ₁, (s.constProp σ₁').1) σ₂ := by
induction h₁ generalizing σ₁' <;> grind [=_ Expr.eval_simplify, intro Bigstep]
@[grind] def Stmt.constPropagation (s : Stmt) : Stmt :=
(s.constProp ).1
theorem Stmt.constPropagation_correct (h : (σ, s) σ') : (σ, s.constPropagation) σ' := by
grind