Function body_writes_state 

pub fn body_writes_state(body: &Block, program: &TypedCommons) -> bool

[DECISION B]/[DECISION C] (#1165): does body reach a mutating Callee::Store write, or an unconditional Statement::Assign (:=), anywhere — including inside a nested if/match/lambda? Drives lower_commit_shape_ir’s own Transactional decision, and, as of #1196 (the #1187 emitter-cutover track’s own R6.5 stake), emit_agent‘s (bynk-emit/src/emitter/emit.rs) own real implicit-commit-wrapper decision too — its previous own name-matching block_writes_state (emitter.rs) is deleted, this function is its sole, direct replacement. The walk’s own shape is that deleted function’s own already-correct skeleton reused structurally, not re-derived: Block/If/Match are hand-matched so crossing a nested block re-enters the statement-aware case (an expr_children descent alone flattens a block straight to its statements’ values, losing the Statement::Assign tag), everywhere else recurses over expr_children’s total child iterator.

Unlike the deleted function’s own name-based mutating_op, this walk needs no per-kind receiver-name set: a Callee::Store { op, .. } already carries the field’s own resolved identity (the checker only ever records one for a method the field’s own kind actually declares), so op‘s membership in the shared mutating-verb constants ([DECISION C], emitter.rs) is unambiguous checked flat, across all four kinds’ lists at once — a locally-shadowed name that would false-positive mutating_op cannot false-positive here at all, the exact fix Decision B’s own Risk names, and the exact defect #1196_agent_write_detection_ via_resolved_callee’s own fixture pins at the emitted-output level.