e450a02621
This PR changes the `show t` tactic to match its documentation. Previously it was a synonym for `change t`, but now it finds the first goal that unifies with the term `t` and moves it to the front of the goal list.
160 lines
2.4 KiB
Text
160 lines
2.4 KiB
Text
/-!
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# Testing the new behavior of the `show` tactic
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Implemented in PR #7395.
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-/
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/-!
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`show` can change a single goal to a definitionally equivalent one.
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-/
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/--
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error: unsolved goals
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x : Nat
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⊢ x - 0 = 3 - 3
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-/
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#guard_msgs in
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example : x = 0 := by
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show x - 0 = 3 - 3
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/-!
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`show` on a single goal fails if the pattern is not defeq to the target.
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-/
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/--
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error: 'show' tactic failed, pattern
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x = 1
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is not definitionally equal to target
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x = 0
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-/
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#guard_msgs in
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example : x = 0 := by
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show x = 1
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/-!
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`show` on multiple goals picks the first that matches.
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-/
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/--
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error: unsolved goals
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case refine_2
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x : Nat
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⊢ x = 1
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case refine_1
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x : Nat
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⊢ x = 0
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-/
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#guard_msgs in
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example : x = 0 ∧ x = 1 := by
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and_intros
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show _ = 1
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/-!
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The matching goal is moved to the front and the order of the others is preserved.
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-/
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/--
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error: unsolved goals
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case refine_2.refine_2.refine_1
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x : Nat
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⊢ x = 2
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case refine_1
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x : Nat
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⊢ x = 0
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case refine_2.refine_1
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x : Nat
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⊢ x = 1
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case refine_2.refine_2.refine_2
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x : Nat
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⊢ x = 3
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-/
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#guard_msgs in
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example : x = 0 ∧ x = 1 ∧ x = 2 ∧ x = 3 := by
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and_intros
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show _ = 2
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/-!
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All goals are first elaborated without error recovery.
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-/
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/--
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error: unsolved goals
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case refine_2.refine_2
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a : Unit
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⊢ a = ()
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case refine_1
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⊢ () = ()
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case refine_2.refine_1
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⊢ () = ()
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-/
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#guard_msgs in
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example : () = () ∧ () = () ∧ (∀ a, a = ()) := by
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and_intros; all_goals try intro a
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show a = _
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/-!
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The first goal is re-elaborated with error recovery.
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-/
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/--
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error: unknown identifier 'a'
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---
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error: unsolved goals
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case refine_1
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⊢ sorry = ()
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case refine_2
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⊢ () = ()
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-/
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#guard_msgs in
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example : () = () ∧ () = () := by
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and_intros
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show a = _
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/-!
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If all unifications fail, the error is from the first goal with a mention that the later goals
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also weren't defeq.
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-/
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/--
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error: 'show' tactic failed, no goals unify with the given pattern.
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In the first goal, the pattern
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x = 4
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is not definitionally equal to the target
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x = 1
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(Errors for other goals omitted)
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-/
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#guard_msgs in
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example : x = 1 ∧ x = 2 ∧ x = 3 := by
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and_intros
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show x = 4
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/-!
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`show` also works when a mentioned variable only exists in some goals.
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-/
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/--
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error: unsolved goals
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case refine_2.refine_2
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c : Nat
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⊢ c = 1
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case refine_1
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a : Nat
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⊢ a = 1
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case refine_2.refine_1
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b : Nat
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⊢ b = 1
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-/
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#guard_msgs in
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example : (∀ a, a = 1) ∧ (∀ b, b = 1) ∧ (∀ c, c = 1) := by
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and_intros; all_goals unhygienic intro
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show c = _
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