29 lines
706 B
Text
29 lines
706 B
Text
import Lean
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-- The `cases` tactic does not use `Lean.Meta.cases` under the hood,
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-- so it is unaffected by this issue. We define a tactic
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-- `mcases` that delegates to `Lean.Meta.cases`.
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syntax (name := mcases) "mcases" ident : tactic
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namespace Lean.Elab.Tactic
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@[tactic mcases]
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def evalMcases : Tactic
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| `(tactic| mcases $hyp) => do
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let hyp ← getFVarId hyp
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liftMetaTactic fun goal => do
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let goals ← Lean.Meta.cases goal hyp
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return goals.map (·.mvarId) |>.toList
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| _ => unreachable!
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end Lean.Elab.Tactic
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example : True := by
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let h : ∃ n, n = 0 := ⟨0, rfl⟩
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mcases h
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sorry -- sorry
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example : True := by
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have h : ∃ n, n = 0 := ⟨0, rfl⟩
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mcases h
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apply True.intro
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