cce6ce9577
This PR fixes #12245 where `grind` works on `Fin n` but fails on `Fin (n + 1)`. The `outParam` argument (e.g., the `range` parameter of `ToInt`) was included as a relevant position in the e-matching pattern. The `grind` normalizer rewrites `↑(n + 1)` to `↑n + 1` inside the range expression, causing the pattern to no longer match. Since `outParam` arguments are uniquely determined by type class resolution, they can be safely wildcarded in patterns — the same reasoning that already applies to instance-implicit arguments. Reproducer from the issue: ```lean example {n : Nat} {a : Fin (n + 1)} {b : Nat} (hb : b < n + 1) (h : (a : Nat) < b) : a < ⟨b, hb⟩ := by grind -- fails without fix ``` 🤖 Generated with [Claude Code](https://claude.com/claude-code) --------- Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
19 lines
846 B
Text
19 lines
846 B
Text
-- Issue #12245: grind works on Fin n but fails on Fin (n + 1)
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-- The fix is in `getPatternArgKinds`: `outParam` arguments are now treated as support
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-- in e-matching patterns. After the next toolchain update, the `attribute` line below
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-- can be removed.
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example {n : Nat} {a : Fin n} {b : Nat} (hb : b < n)
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(h : (a : Nat) < b) : a < ⟨b, hb⟩ := by grind
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example {n : Nat} {a : Fin (n + 1)} {b : Nat} (hb : b < n + 1)
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(h : (a : Nat) < b) : a < ⟨b, hb⟩ := by grind
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example {n : Nat} {a : Fin (n + 2)} {b : Nat} (hb : b < n + 2)
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(h : (a : Nat) < b) : a < ⟨b, hb⟩ := by grind
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example {n m : Nat} {a : Fin (n + m)} {b : Nat} (hb : b < n + m)
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(h : (a : Nat) < b) : a < ⟨b, hb⟩ := by grind
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example {n : Nat} {a : Fin (n * 2 + 1)} {b : Nat} (hb : b < n * 2 + 1)
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(h : (a : Nat) < b) : a < ⟨b, hb⟩ := by grind
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