This requires a few pieces:
* Make node tags use `Fin n` intead of natural numbers. This makes
it possible to build a finite lattice over AST nodes, and also
ensure automatic, total indexing from CFG nodes into the AST that
created them. For this, use the elaborator to derive the ordering
statements etc. where possible.
* Adjust the forward framework to enable proofs that don't just state
correctness on the environment, but also on an arbitrary additional
state accumulated from traversing the trace.
* State the reaching definition analysis's correctness in terms
of this new framework.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Convert every theorem to lemma (mathlib's default) except the headline results a
reader of each module seeks out: analyze_correct (Forward/Sign/Constant),
aFix_eq/aFix_le (Fixedpoint), trace (Language), and Stmt.cfg_sufficient
(Language/Properties). lemma and theorem are interchangeable keywords, so no
references change.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Introduce a finite-height lattice instance for Bool, then build the
reaching-definitions analysis on top of the forward framework:
* Spa/Lattice/Bool.lean: FiniteHeightLattice Bool (the two-element
lattice false ≤ true), making FiniteMap A Bool ks a finite-height
"power set" lattice for free.
* Spa/Analysis/Reaching.lean: DefSet prog = FiniteMap prog.State Bool
prog.states as the per-variable lattice of definition sites, with a
StmtEvaluator whose transfer function performs a strong update
(assignment to k at node s sets k's def-set to {s}).
The analysis computes a least fixed point and produces correct
reaching-definitions sets. Soundness (relating def-sets to actual
execution provenance) is deferred; not yet exposed in Spa.lean.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
