fix: fun_induction rejecting names for all hypotheses with let and generalizing - #14475
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…d `generalizing` This PR fixes a spurious "Too many variable names provided" error from `fun_induction` (and `induction`/`cases`) when an alternative had a `let`-bound field, so that all hypotheses of such an alternative can now be named. The error came from `getNumExplicitFields`, which counted nameable fields with a telescope that reduces `let` bindings away and then over-reads into later binders, disagreeing with the `introN` that actually names them. It now introduces the fields via the same `introN` path and counts the explicit (and `let`-bound) ones, so the count and the naming can no longer diverge. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_019PWpd2DPNidwHGtS7mvGpf
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…d `generalizing` (#14475) This PR fixes a spurious "Too many variable names provided" error from `fun_induction` (and `induction`/`cases`) when an alternative had a `let`-bound field, so that all hypotheses of such an alternative can now be named. The error came from `getNumExplicitFields`, which counted nameable fields with a telescope that reduces `let` bindings away and then over-reads into later binders, disagreeing with the `introN` that actually names them. It now introduces the fields via the same `introN` path and counts the explicit (and `let`-bound) ones, so the count and the naming can no longer diverge. Fixes: #14472 Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
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This PR fixes a spurious "Too many variable names provided" error from
fun_induction(andinduction/cases) when an alternative had alet-bound field, so that all hypotheses of such an alternative can now be named.The error came from
getNumExplicitFields, which counted nameable fields with a telescope that reducesletbindings away and then over-reads into later binders, disagreeing with theintroNthat actually names them. It now introduces the fields via the sameintroNpath and counts the explicit (andlet-bound) ones, so the count and the naming can no longer diverge.Fixes: #14472
Co-Authored-By: Claude Opus 4.8 noreply@anthropic.com