3f80e530d3
This PR modifies pretty printing of `fun` binders, suppressing the safe shadowing feature among the binders in the same `fun`. For example, rather than pretty printing as `fun x x => 0`, we now see `fun x x_1 => 0`. The calculation is done per `fun`, so for example `fun x => id fun x => 0` pretty prints as-is, taking advantage of safe shadowing. The motivation for this change is that many users have reported that safe shadowing within the same `fun` is confusing.
108 lines
2 KiB
Text
108 lines
2 KiB
Text
/-!
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# Tests of delaborator 'safe shadowing' feature
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-/
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set_option linter.unusedVariables false
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def f (x x : Nat) :=
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match x with
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| 0 => x + 1
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| Nat.succ _ => x + 2
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def f' :=
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fun (x : Nat) => id fun (x : Nat) =>
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match x with
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| 0 => x + 1
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| Nat.succ _ => x + 2
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variable {α : Type}
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/-- info: fun a => a : α → α -/
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#guard_msgs in
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#check fun (a : α) => a
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/-- info: fun {α} a => a : {α : Sort u_1} → α → α -/
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#guard_msgs in
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#check fun {α} (a : α) => a
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/-!
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This would be safe shadowing, but since it's in the same `fun` it is confusing to have repeated variable names.
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-/
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/-- info: fun x x_1 => x_1 : Nat → Nat → Nat -/
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#guard_msgs in
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#check fun (x x : Nat) => x
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/-!
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Splitting up the `fun`, safe shadowing applies again.
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-/
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/-- info: fun x => id fun x => x : Nat → Nat → Nat -/
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#guard_msgs in
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#check fun (x : Nat) => id fun (x : Nat) => x
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/-!
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Same lambda, no safe shadowing.
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-/
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/--
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info: def f : Nat → Nat → Nat :=
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fun x x_1 =>
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match x_1 with
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| 0 => x_1 + 1
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| n.succ => x_1 + 2
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-/
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#guard_msgs in
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#print f
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/-!
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Split up lambda, uses safe shadowing.
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-/
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/--
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info: def f' : Nat → Nat → Nat :=
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fun x =>
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id fun x =>
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match x with
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| 0 => x + 1
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| n.succ => x + 2
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-/
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#guard_msgs in
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#print f'
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/-!
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The within-same-fun safe shadowing suppression does not take outer `let` into account.
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-/
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/--
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info: let x := 1;
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fun x x_1 => x_1 : Nat → Nat → Nat
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-/
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#guard_msgs in
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#check let x := 1; fun (x x : Nat) => x
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set_option pp.safeShadowing false
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/-- info: fun {α_1} a => a : {α_1 : Sort u_1} → α_1 → α_1 -/
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#guard_msgs in
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#check fun {α} (a : α) => a
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/-- info: fun x x_1 => x_1 : Nat → Nat → Nat -/
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#guard_msgs in
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#check fun (x x : Nat) => x
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/--
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info: def f : Nat → Nat → Nat :=
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fun x x_1 =>
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match x_1 with
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| 0 => x_1 + 1
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| n.succ => x_1 + 2
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-/
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#guard_msgs in
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#print f
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/--
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info: def f' : Nat → Nat → Nat :=
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fun x =>
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id fun x_1 =>
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match x_1 with
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| 0 => x_1 + 1
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| n.succ => x_1 + 2
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-/
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#guard_msgs in
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#print f'
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