lean4-htt/tests/lean/wfrecUnusedLet.lean
Joachim Breitner 117f73fc84
feat: linter.unusedSimpArgs (#8901)
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
2025-06-22 09:10:21 +00:00

10 lines
136 B
Text

def f (n : Nat) : Nat :=
if h : n = 0 then
1
else
let y := 42
2 * f (n-1)
decreasing_by
apply Nat.pred_lt h
#print f