T-Tier3-Dissolution gate #2: narrow trivial-constructor mirror retirement

docs/r3-program-plan.md

@@ -141,7 +141,7 @@ Per openai-pro meta-review on PR #1808 sha `cf249389` ([#issuecomment-4384405832
 
 **INVARIANTS §P2 vs this taxonomy:** Where a gate’s Pass condition is **substrate boundary discipline** (“landed” only when declaration + realization + **generated** consumer proof exist; INVARIANTS §P2), **CONSUMER_LANDED** in this ledger means that **generated** bar — a hand-written integration ratchet alone ratchets **DECLARED** substrate progress without claiming §P2 landed (see §1.8 **#17**).
 
-**Status at HEAD**: per §1.8 canonical ledger Status column — most gates are **DECLARED**; `pb_self_compile_fixed_point` is a canonical CONSUMER_LANDED exemplar (R1 horizon Pass = current `verification.dag` + `test_runner` evaluation). **`method_template_projection_emit_shim_retirement_coherence` (§1.8 #97)**, **`omni_layers_share_one_node_tree` (§1.8 #28)**, and **`anthropic_wire_typed_serde_alignment` (§1.8 #29)** are **CONSUMER_LANDED + PASSING** via the integration tests / ratchets cited in the §1.8 ledger rows. **`numeric_abstract_carriers_landed` (§1.8 #17)** is **DECLARED** — carriers + lowering + hand-written ratchet are landed; **CONSUMER_LANDED** (§P2 sense: generated consumer proof) is **not** claimed until that generator exists. `tier3_*_mirror_dissolved` gates remain **DECLARED** at HEAD (T-Tier3-Dissolution lane work in flight per §3 lane status; consumer count / mirror-symbol count test not yet authored). Per-gate status updates flow through §1.8 ledger as Mgrs land consumer infrastructure per their lane scope; all 16 NEW gates added 2026-05-06 in PR #1808 are DECLARED-only.
+**Status at HEAD**: per §1.8 canonical ledger Status column — most gates are **DECLARED**; `pb_self_compile_fixed_point` is a canonical CONSUMER_LANDED exemplar (R1 horizon Pass = current `verification.dag` + `test_runner` evaluation). **`method_template_projection_emit_shim_retirement_coherence` (§1.8 #97)**, **`omni_layers_share_one_node_tree` (§1.8 #28)**, and **`anthropic_wire_typed_serde_alignment` (§1.8 #29)** are **CONSUMER_LANDED + PASSING** via the integration tests / ratchets cited in the §1.8 ledger rows. **`numeric_abstract_carriers_landed` (§1.8 #17)** is **DECLARED** — carriers + lowering + hand-written ratchet are landed; **CONSUMER_LANDED** (§P2 sense: generated consumer proof) is **not** claimed until that generator exists. `tier3_*_mirror_dissolved` gates are advancing through T-Tier3-Dissolution per §1.8 row-level Status: **#1** `tier3_termination_mirror_dissolved` and **#4** `tier3_effect_carrier_mirror_dissolved` are **CONSUMER_LANDED + PASSING** at HEAD; **#2** `tier3_computation_mirror_dissolved` and **#3** `tier3_induction_mirror_dissolved` are **CONSUMER_LANDED** (narrow-slice receipts per their §1.8 Notes — wider mirror dissolution remains lane-tracked pending evaluated `std.termination` / `std.computation` / `std.induction` block bodies). Per-gate status updates flow through the §1.8 ledger as Mgrs land consumer infrastructure per their lane scope; the 16 NEW gates added 2026-05-06 in PR #1808 were DECLARED-only at that time — current Status for each row is the §1.8 ledger value, not this paragraph.
 
 **R3 close criteria implies CONSUMER_LANDED for all R3-load-bearing §1.8 gates** (103 enumerated **minus** **#11** canvas-deferred per Director (a)-disposition 2026-05-09 = **102 R3-load-bearing**; #81/#82/#95 carve-promoted-IN-R3 per Director ratification 2026-05-09 c#4412330468; +6 T-WAD FULL R3 gates #98–#103 per Director (b) ledger-sync disposition msg_2a68a4b5 — see §1.5 above): declarations alone don't satisfy `r3_debt_paydown_zero_remaining` or the substrate-gap-class closures or the demonstration principle. Per Brian directive `feedback_no_textual_enforcement_bridges` + Director poke-hole 2026-05-06 finding 1.1 (demo-gate minimum bar) — closure requires runtime-executable verification, not document-level claims.
 
@@ -225,7 +225,7 @@ This principle is NOT a separate lane; it's a per-lane gate-shape requirement ap
 | # | Gate ID | Family | Owner Lane | Status | Notes |
 |---|---|---|---|---|---|
 | 1 | `tier3_termination_mirror_dissolved` | state-check | T-Tier3-Dissolution | **CONSUMER_LANDED + PASSING** (2026-05-12 — public `DescentEvidence` lattice-operation mirror helpers retired from `src/v3/compiler/src/dag.rs`; ratchet `termination_lattice_rust_mirror_dissolved` keeps the Rust mirror dissolved while `src/v3/std/termination.dag` remains the authority; Phase-1 `bench_termination_mirror` registration and frozen baseline row removed) | r3-structure.md §Acceptance |
-| 2 | `tier3_computation_mirror_dissolved` | state-check | T-Tier3-Dissolution | DECLARED | r3-structure.md §Acceptance |
+| 2 | `tier3_computation_mirror_dissolved` | state-check | T-Tier3-Dissolution | **CONSUMER_LANDED** (2026-05-12 — narrow trivial-constructor slice: `pub fn tree_size_bound` and `pub fn forever_iteration_bound` retired from `src/v3/compiler/src/dag.rs` `mod computation`; ratchet `tier3_computation_mirror_trivial_constructors_dissolved` in `m2_substrate_inhabitance_test.rs` forbids reintroduction; `Forever` constant inlined as `i64::MAX` in `constant_bound_value`. Wider mirror dissolution — `lower_call_pattern`, `type_iteration_dimension`, `size_bound_param`, `is_constant_bound`, `constant_bound_value`, `algebra_profile_to_dimension` — remains pending evaluated `std.computation` block bodies and stays tracked under T-Tier3-Dissolution.) | r3-structure.md §Acceptance |
 | 3 | `tier3_induction_mirror_dissolved` | state-check | T-Tier3-Dissolution | **CONSUMER_LANDED** (PR #2678 squash 2026-05-11 — merry-wolf-735 T-Tier3 induction mirror retirement; scope-verified per R-7 vs C1 Phase-1 baseline now landed via PR #2702) | r3-structure.md §Acceptance |
 | 4 | `tier3_effect_carrier_mirror_dissolved` | state-check | T-Tier3-Dissolution | **CONSUMER_LANDED + PASSING** (PR #2679 squash `6897445b` 2026-05-11 — warm-ibex-579 retired `workflow_idempotency.rs`, co-located Lane 2b idempotency projection in `dag/effects.rs` with P5/P2 receipts + bootstrap `ArrowBody::Unparsed` ratchet test) | r3-structure.md §Acceptance |
 | 5 | `lens_apply_dot_rs_retired` | state-check | T-LensProducer-Retirement | DECLARED | gated on PB-Runtime interpreter-as-data |

src/v3/compiler/src/dag.rs

@@ -119,10 +119,6 @@ mod computation {
         Forever,
     }
 
-    pub fn tree_size_bound(param: String) -> SizeBound {
-        SizeBound::TreeSize { param }
-    }
-
     /// 🟡 SCAFFOLD — `CallPattern` coproduct (`docs/modeling-discipline.md` §4).
     ///
     /// Authority: `src/v3/std/computation.dag`. Peano shrink payloads are proof-grade (terminal
@@ -270,17 +266,16 @@ mod computation {
         )
     }
 
-    /// Signed `Int` top iterate count (`i64::MAX`) for [`SizeBound::Forever`] / `repeat(max_int)`.
-    pub fn forever_iteration_bound() -> i64 {
-        i64::MAX
-    }
-
     /// `None` when `bound` is not constant (`ExplicitCount*` / `Forever` only).
+    ///
+    /// `Forever` materializes as signed-`Int` top (`i64::MAX`) per `std.computation`
+    /// `repeat(max_int)`; the prior `forever_iteration_bound()` Rust mirror was retired
+    /// (Tier3 gate #2 narrow slice — see `tier3_computation_mirror_trivial_constructors_dissolved`).
     pub fn constant_bound_value(bound: &SizeBound) -> Option<i64> {
         match bound {
             SizeBound::ExplicitCountZero => Some(0),
             SizeBound::ExplicitCountPositive { steps } => Some(positive_descent_count(steps)),
-            SizeBound::Forever => Some(forever_iteration_bound()),
+            SizeBound::Forever => Some(i64::MAX),
             _ => None,
         }
     }
@@ -339,10 +334,9 @@ mod effects;
 mod ports;
 
 pub use computation::{
-    algebra_profile_to_dimension, constant_bound_value, forever_iteration_bound, is_constant_bound,
-    lower_call_pattern, size_bound_param, tree_size_bound, type_iteration_dimension,
-    AlgebraProfile, CallPattern, IterationDimension, IterationPrimitive, LoweringTarget,
-    ShrinkFactor, SizeBound,
+    algebra_profile_to_dimension, constant_bound_value, is_constant_bound, lower_call_pattern,
+    size_bound_param, type_iteration_dimension, AlgebraProfile, CallPattern, IterationDimension,
+    IterationPrimitive, LoweringTarget, ShrinkFactor, SizeBound,
 };
 
 pub use effects::{

src/v3/compiler/tests/integration/m2_substrate_inhabitance_test.rs

@@ -4,9 +4,9 @@ use v3_compiler::compile_to_dag;
 use v3_compiler::dag::{
     algebra_profile_to_dimension, constant_bound_value, is_constant_bound, literal_bits_int,
     lower_call_pattern, per_call_descent_evidence, per_call_pattern_at, positive_amount_from_i64,
-    size_bound_param, tree_size_bound, type_iteration_dimension, AlgebraProfile, ArrowBody,
-    AtomPayload, CallPattern, CardinalityBound, DescentEvidence, FieldMap, FieldValue, Interval,
-    IntervalWidth, IterationDimension, IterationPrimitive, LoweringTarget, PositiveDescentAmount,
+    size_bound_param, type_iteration_dimension, AlgebraProfile, ArrowBody, AtomPayload,
+    CallPattern, CardinalityBound, DescentEvidence, FieldMap, FieldValue, Interval, IntervalWidth,
+    IterationDimension, IterationPrimitive, LoweringTarget, PositiveDescentAmount,
     PositiveIntervalWidth, ProportionalDivisor, ShrinkFactor, SizeBound, SubValueRelation,
     TypeConnective, ValueBody,
 };
@@ -514,6 +514,32 @@ fn termination_lattice_rust_mirror_dissolved() {
     }
 }
 
+#[test]
+fn tier3_computation_mirror_trivial_constructors_dissolved() {
+    // Gate `tier3_computation_mirror_dissolved` (R3 §1.8 gate #2, narrow slice):
+    // the trivial host-Rust mirror entrypoints for `std.computation` declarations
+    // whose Rust definition added no information beyond direct variant construction
+    // (`tree_size_bound` returned `SizeBound::TreeSize { param }`;
+    //  `forever_iteration_bound` returned the `i64::MAX` literal) have been retired
+    // from `src/v3/compiler/src/dag.rs`. `src/v3/std/computation.dag` remains the
+    // single authority for these names and their bootstrap body spans stay pinned
+    // by `computation_lowering_functions_preserve_std_body_spans`.
+    //
+    // Wider mirror dissolution (`lower_call_pattern`, `type_iteration_dimension`,
+    // `size_bound_param`, `is_constant_bound`, `constant_bound_value`,
+    // `algebra_profile_to_dimension`) requires evaluated `std.computation` block
+    // bodies and stays tracked in the T-Tier3-Dissolution lane; this ratchet
+    // forbids only reintroduction of the trivial-constructor mirrors above.
+    let dag_rs = include_str!("../../src/dag.rs");
+    for forbidden in ["pub fn tree_size_bound", "pub fn forever_iteration_bound"] {
+        assert!(
+            !dag_rs.contains(forbidden),
+            "`dag.rs` must not export trivial `std.computation` mirror helper `{forbidden}`; \
+             `src/v3/std/computation.dag` is the authority (R3 gate #2 narrow slice)"
+        );
+    }
+}
+
 #[test]
 fn e_p_per_call_descent_evidence_side_table_reads_recursive_call() {
     let dag = compile_to_dag(
@@ -1740,7 +1766,9 @@ fn computation_lowering_rust_mirror_matches_dag_authority() {
 
 #[test]
 fn computation_size_bound_helpers_match_dag_authority() {
-    let tree = tree_size_bound(String::from("node"));
+    let tree = SizeBound::TreeSize {
+        param: String::from("node"),
+    };
     let collection = SizeBound::CollectionSize {
         param: String::from("items"),
     };