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
16 lines
542 B
Text
16 lines
542 B
Text
reset_grind_attrs%
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attribute [grind] List.not_mem_nil
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/--
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error: Tactic `grind` failed: the goal mentions the declaration `incList`, which is being defined. To avoid circular reasoning, try rewriting the goal to eliminate `incList` before using `grind`.
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as✝ : List Nat
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a : Nat
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as : List Nat
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⊢ ∀ (a : Nat), a ∈ (incList as).val → a > 0
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-/
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#guard_msgs (error) in
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def incList (as : List Nat) : { as : List Nat // ∀ a, a ∈ as → a > 0 } :=
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match as with
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| [] => ⟨[], by grind⟩
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| a::as => ⟨(incList as).1, by grind⟩
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