fix: interaction between simp and backward.whnf.reducibleClassField#12622
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leodemoura merged 1 commit intomasterfrom Feb 20, 2026
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fix: interaction between simp and backward.whnf.reducibleClassField#12622leodemoura merged 1 commit intomasterfrom
simp and backward.whnf.reducibleClassField#12622leodemoura merged 1 commit intomasterfrom
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This PR fixes a bug where `simp` made no progress on class projection reductions when `backward.whnf.reducibleClassField` is `true`. The issue was in `reduceProjFn?`: for class projections applied to constructor instances (`Class.projFn (Class.mk ...)`), the code called `reduceProjCont? (← unfoldDefinitionAny? e)`. The helper `reduceProjCont?` expects the unfolded result to have a `.proj` head so it can apply `reduceProj?`. However, when `reducibleClassField` is enabled, `unfoldDefault` in WHNF.lean already reduces the `.proj` node during unfolding. The fully-reduced result no longer has a `.proj` head, so `reduceProjCont?` discards it and returns `none`. The fix uses `unfoldDefinitionAny?` directly, bypassing `reduceProjCont?`. The dsimp traversal revisits the result (via `.visit`) and handles any remaining `.proj` nodes naturally. Co-Authored-By: Claude Opus 4.6 <[email protected]>
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The two-step `simp only [...]; simp [LE.le]` workaround is no longer needed after #12622 fixed `reduceProjFn?` in simp. Restore the clean single-step `simp [LE.le, IntN.le]` proofs for all five signed integer types (Int8/16/32/64/ISize). Co-Authored-By: Claude Opus 4.6 <[email protected]>
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The two-step `simp only [...]; simp [LE.le]` workaround is no longer needed after #12622 fixed `reduceProjFn?` in simp. Restore the clean single-step `simp [LE.le, IntN.le]` proofs for all five signed integer types (Int8/16/32/64/ISize). Co-Authored-By: Claude Opus 4.6 <[email protected]>
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This PR fixes a bug where
simpmade no progress on class projection reductions whenbackward.whnf.reducibleClassFieldistrue.reduceProjFn?, for class projections applied to constructor instances (Class.projFn (Class.mk ...)), the code calledreduceProjCont? (← unfoldDefinitionAny? e). The helperreduceProjCont?expects the unfolded result to have a.projhead so it can applyreduceProj?. However, whenreducibleClassFieldis enabled,unfoldDefaultin WHNF.lean already reduces the.projnode during unfolding, soreduceProjCont?discards the fully-reduced result.unfoldDefinitionAny?directly, bypassingreduceProjCont?. The dsimp traversal revisits the result (via.visit) and handles any remaining.projnodes naturally.🤖 Generated with Claude Code