37650f9147
Previously `decreasing_with` failed if `simp_wf` closes the goal on its own. This can cause undesired regressions when new `simp` lemmas are introduced. Closes #2018.
25 lines
524 B
Text
25 lines
524 B
Text
def works (l : List α) : List α :=
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match l with
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| [] => []
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| _::tail =>
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works tail
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decreasing_by decreasing_tactic -- to force well-founded recursion
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-- Both of these appear in mathlib
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@[simp]
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theorem add_zero (n : Nat) : n + 0 = n := by sorry
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@[simp]
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theorem lt_add_iff_pos_left (a : Nat) {b : Nat} :
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a < b + a ↔ 0 < b
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:= by sorry
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-- Breaking this:
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def should_still_work (l : List α) : List α :=
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match l with
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| [] => []
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| _::tail =>
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should_still_work tail
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decreasing_by decreasing_tactic
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