34bd6e8bfd
This PR improves the error messages produced by the `split` tactic, including suggesting syntax fixes and related tactics with which it might be confused. Note that, to avoid clashing with the new error message styling conventions used in these messages, this PR also updates the formatting of the message produced by `throwTacticEx`. Closes #6224
120 lines
3.2 KiB
Text
120 lines
3.2 KiB
Text
/-! # `split` tactic errors
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Assesses error messages and hints produced by the `split` tactic.
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-/
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/--
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error: Tactic `split` failed: Specifying a term to split is not supported yet
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Hint: To apply `split` at the hypothesis `h`, use `split at h`:
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split a̲t̲ ̲h
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-/
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#guard_msgs in
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example : False := by
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have h : if True then True else True := trivial
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split h
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/-- error: Tactic `split` failed: Specifying a term to split is not supported yet -/
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#guard_msgs in
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example (x y : Bool) : (if x && y then 1 else 2) > (if x || y then 0 else 1) := by
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split x && y
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/--
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error: Tactic `split` failed: Could not split an `if` or `match` expression in the goal
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Hint: Use `set_option trace.split.failure true` to display additional diagnostic information
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⊢ False
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-/
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#guard_msgs in
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example : False := by
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split
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/--
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error: Tactic `split` failed: Could not split the goal or any of the following hypotheses: `h1`
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Note: `split at *` does not attempt to split at non-propositional hypotheses or those on which other hypotheses depend. It may still be possible to manually split a hypothesis using `split at`
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Hint: Use `set_option trace.split.failure true` to display additional diagnostic information
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h1 : True
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⊢ False
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-/
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#guard_msgs in
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example : False := by
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have h1 : True := trivial
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split at *
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/--
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error: Tactic `split` failed: Could not split an `if` or `match` expression in the type `p ∧ q` of `h`
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Hint: If you meant to destruct this conjunction, use the `cases` tactic instead
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Hint: Use `set_option trace.split.failure true` to display additional diagnostic information
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p q : Prop
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h : p ∧ q
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⊢ p
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-/
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#guard_msgs in
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example {p q : Prop} (h : p ∧ q) : p := by
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split at h
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/--
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error: Tactic `split` failed: Could not split an `if` or `match` expression in the type `Equivalence R` of `h`
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Hint: If you meant to destruct this structure, use the `cases` tactic instead
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Hint: Use `set_option trace.split.failure true` to display additional diagnostic information
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α : Sort u_1
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R : α → α → Prop
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h : Equivalence R
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⊢ False
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-/
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#guard_msgs in
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example {R : α → α → Prop} (h : Equivalence R) : False := by
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split at h
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/--
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error: Tactic `split` failed: Could not split the goal or any of the following hypotheses: `t`, `use_dep`
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Note: `split at *` does not attempt to split at non-propositional hypotheses or those on which other hypotheses depend. It may still be possible to manually split a hypothesis using `split at`
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t : True
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dep : if 1 ≥ 0 then True else False
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use_dep : dep = dep
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⊢ False
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-/
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#guard_msgs in
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example : False := by
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have t : True := trivial
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have dep : if 1 ≥ 0 then True else False := by simp
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have use_dep : dep = dep := rfl
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set_option trace.split.failure true in
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split at *
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/--
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error: Tactic `split` failed: Could not split an `if` or `match` expression in the type `Nat` of `x`
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x : Nat := if true = true then 3 else 4
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⊢ False
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-/
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#guard_msgs in
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example : False := by
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let x := if true then 3 else 4
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set_option trace.split.failure true in
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split at x
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/--
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error: Tactic `split` failed: Could not split an `if` or `match` expression in the type `True` of `h`
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Hint: Use `set_option trace.split.failure true` to display additional diagnostic information
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h : True
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⊢ False
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-/
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#guard_msgs in
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example : False := by
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have h : True := trivial
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split at h
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