117f73fc84
This PR adds a linter (`linter.unusedSimpArgs`) that complains when a simp argument (`simp [foo]`) is unused. It should do the right thing if the `simp` invocation is run multiple times, e.g. inside `all_goals`. It does not trigger when the `simp` call is inside a macro. The linter message contains a clickable hint to remove the simp argument. I chose to display a separate warning for each unused argument. This means that the user has to click multiple times to remove all of them (and wait for re-elaboration in between). But this just means multiple endorphine kicks, and the main benefit over a single warning that would have to span the whole argument list is that already the squigglies tell the users about unused arguments. This closes #4483. Making Init and Std clean wrt to this linter revealed close to 1000 unused simp args, a pleasant experience for anyone enjoying tidying things: #8905
20 lines
490 B
Text
20 lines
490 B
Text
def foo: {n: Nat} → Fin n → Nat
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| 0, _ => 0
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| n+1, _ => 0
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-- Local copy to make test more robust against staging issues
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@[simp] theorem Nat.succ_eq_add_one' (n : Nat) : succ n = n + 1 :=
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rfl
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theorem t3 {f: Fin (n+1)}:
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foo f = 0 := by
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dsimp only [←Nat.succ_eq_add_one' n] at f -- use `dsimp` to ensure we don't copy `f`
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trace_state
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simp only [foo]
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example {n: Nat} {f: Fin (n+1)}:
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foo f = 0 := by
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revert f
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rw[←Nat.succ_eq_add_one' n]
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intro f
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simp only [foo]
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