Row 1b: derive Clone bound for call-forwarding fn/impl signatures

dag/test/claim/trait_bound_witness_test.dag

@@ -18,3 +18,31 @@ fn w_current_defect_reproduces_bare_generic_no_clone_impl() -> Bool {
 test fn current_defect_reproduces_bare_generic_no_clone_impl() -> Bool {
   w_current_defect_reproduces_bare_generic_no_clone_impl()
 }
+
+data call_forwarding_clone_bound_witness_note: String = "gunbc dashboard node://adhoc-574e999b-39c, Row 1b. Proves v1_call_forwarding_clone_bound_param_names / v1_call_forwarding_clone_bound_wrapper_param_names (src/v1/trait_bound_witness.dag, TraitBoundWitnessScope BoundedToDirectSingleCallLambdaBody) through the real emit pipeline via compile_dag_rust_emit_check, same discipline as the sibling RC-match witness above -- no v1.compiler import. Fixture is traced to reproduce src/v2/std/staging.dag's real cached_stage<A, B> shape (compound-arity CacheProbe<B> forwarded from a wrapper's lambda body directly into an already-derived-Clone-bounded callee, resolve_probe<A, B>), one of the census's 51-error board rows (docs/probes/materialization_carriers_rebaseline_2026-08-19.md). w_call_forwarding_derives_clone_bound_from_callee asserts the fixed emitted shape `fn cached_stage<A: Clone, B: Clone>(` and the absence of the pre-fix bare `fn cached_stage<A, B>(`, confirmed against a live gunbc compile of the real staging.dag module this session (v2_std_staging.rs). w_call_forwarding_scope_excludes_match_wrapped_body is the declared-boundary negative control (DESIGN.md S4b rung honesty, S6 no hypothetical generality): a function whose body is a lambda wrapping a MATCH whose arm is the call (not a lambda whose body IS directly the call) stays bare -- reproducing src/v2/compiler/materialization_carriers.dag's real cached_stage_governed<A, B> shape, confirmed unbounded against a live compile this session. That residual gap does not manifest as a rustc error in the census entrypoint's dependency closure (cached_stage_governed has zero callers there, and its own generic body never itself requires A: Clone / B: Clone to typecheck), so it is recorded here as a declared, non-silent scope boundary rather than fixed -- fixing it would require the same recursive body-walker (mirroring emit_rust_expr_if/emit_rust_expr_let's accessor shapes) that BoundedToDirectSingleCallLambdaBody's own note already names as its next-rung trigger, and is deliberately not built in this PR (DESIGN.md S6)."
+
+fn w_call_forwarding_derives_clone_bound_from_callee() -> Bool {
+  compile_dag_rust_emit_check(
+    "module fn_clone_bound_witness.call_forwarding\ntype CacheProbe<B>\n  = Miss\n  | Hit { value: B }\n\nfn resolve_probe<A, B>(probe: CacheProbe<B>, stage: fn(A) -> B, x: A) -> B {\n  match probe {\n    Hit { value: hit } => hit\n    Miss => stage(x)\n  }\n}\n\nfn cached_stage<A, B>(lookup: fn(A) -> CacheProbe<B>, stage: fn(A) -> B) -> fn(A) -> B {\n  fn(x) {\n    resolve_probe(probe: lookup(x), stage: stage, x: x)\n  }\n}\n",
+    "src/fn_clone_bound_witness_call_forwarding.rs",
+    ["fn cached_stage<A: Clone, B: Clone>("],
+    ["fn cached_stage<A, B>("]
+  )
+}
+
+test fn call_forwarding_derives_clone_bound_from_callee() -> Bool {
+  w_call_forwarding_derives_clone_bound_from_callee()
+}
+
+fn w_call_forwarding_scope_excludes_match_wrapped_body() -> Bool {
+  compile_dag_rust_emit_check(
+    "module fn_clone_bound_witness.call_forwarding_match_wrapped\ntype CacheProbe<B>\n  = Miss\n  | Hit { value: B }\n\nfn resolve_probe<A, B>(probe: CacheProbe<B>, stage: fn(A) -> B, x: A) -> B {\n  match probe {\n    Hit { value: hit } => hit\n    Miss => stage(x)\n  }\n}\n\nfn cached_stage_governed<A, B>(governed: Bool, lookup: fn(A) -> CacheProbe<B>, stage: fn(A) -> B) -> fn(A) -> B {\n  fn(x) {\n    match governed {\n      true => resolve_probe(probe: lookup(x), stage: stage, x: x)\n      false => stage(x)\n    }\n  }\n}\n",
+    "src/fn_clone_bound_witness_call_forwarding_match_wrapped.rs",
+    ["fn cached_stage_governed<A, B>("],
+    ["fn cached_stage_governed<A: Clone, B: Clone>("]
+  )
+}
+
+test fn call_forwarding_scope_excludes_match_wrapped_body() -> Bool {
+  w_call_forwarding_scope_excludes_match_wrapped_body()
+}

src/v1/04_emit_info.dag

@@ -72,9 +72,12 @@ fn collect_type_node_import_surface_names(n: Node, source_indices: Map<String, N
   dedupe_nonempty_strings(items: concat(own, concat(child_names, inferred_names)))
 }
 
+data emit_graph_fn_decl_items_note: String = "fn_decl_items mirrors type_decl_items (dashboard node adhoc-574e999b-39c): a fn-name-keyed lookup into the SAME typed (post-04_infer, .inferred-populated) module items build_emit_graph_info already folds over, so a caller-side Clone-bound derivation (v1.compiler.trait_bound_witness) can resolve a callee-by-name and re-run emit_fn_def's own derivation on the callee's real declaration Node — never a second, parallel re-parse or re-inference of the callee."
+
 type EmitGraphInfo {
   type_summaries: Map<String, TypeSummary>
   type_decl_items: Map<String, Node>
+  fn_decl_items: Map<String, Node>
   recursive_type_set: Set<String>
   fielded_variants: Set<String>
   positional_payload_variants: Set<String>
@@ -101,6 +104,7 @@ type EmitGraphInfo {
 type EmitInfoBuildState {
   type_summaries: Map<String, TypeSummary>
   type_decl_items: Map<String, Node>
+  fn_decl_items: Map<String, Node>
 }
 
 data empty_emit_graph_info_ord_fallback_note: String = "Conservatism: render paths without EmitGraphInfo pass empty_emit_graph_info(); bare-ref BTreeSet Ord eligibility fails closed (lookup_emit_type_decl -> Absent) and surfaces compile_error! at probe time — nine call sites inherit this, loud not silent widen."
@@ -109,6 +113,7 @@ fn empty_emit_graph_info() -> EmitGraphInfo {
   EmitGraphInfo {
     type_summaries: empty_map(),
     type_decl_items: empty_map(),
+    fn_decl_items: empty_map(),
     recursive_type_set: empty_set(),
     fielded_variants: empty_set(),
     positional_payload_variants: empty_set(),
@@ -133,6 +138,7 @@ fn emit_info_with_fn_type_context(emit_info: EmitGraphInfo, generic_param_names:
   EmitGraphInfo {
     type_summaries: emit_info.type_summaries,
     type_decl_items: emit_info.type_decl_items,
+    fn_decl_items: emit_info.fn_decl_items,
     recursive_type_set: emit_info.recursive_type_set,
     fielded_variants: emit_info.fielded_variants,
     positional_payload_variants: emit_info.positional_payload_variants,
@@ -156,6 +162,7 @@ fn emit_info_with_fn_return(emit_info: EmitGraphInfo, fn_return_type: Node?) ->
   EmitGraphInfo {
     type_summaries: emit_info.type_summaries,
     type_decl_items: emit_info.type_decl_items,
+    fn_decl_items: emit_info.fn_decl_items,
     recursive_type_set: emit_info.recursive_type_set,
     fielded_variants: emit_info.fielded_variants,
     positional_payload_variants: emit_info.positional_payload_variants,
@@ -203,6 +210,12 @@ fn emit_graph_records_type_decl(item: Node, source_indices: Map<String, NewlineI
   }
 }
 
+data emit_graph_records_fn_decl_note: String = "Same criterion as v1.compiler.emit_core_support's is_function_item (05_emit_rust.dag's top-level item dispatch), duplicated here rather than imported: this module (v1.compiler.infer_emit_info) is upstream of v1.compiler.emit_core_support in the DAG (04_emit_info.dag has no import of 05_emit_core_support.dag today), and emit_graph_records_type_decl beside it already establishes the precedent of a locally-scoped duplicate one-line item-shape predicate at this stage rather than reaching downstream for one (DESIGN.md S3 -- a fact's home is its layer, and both predicates answer 'what item shape reaches this stage's fold', not 'what does emit_core_support export')."
+
+fn emit_graph_records_fn_decl(item: Node) -> Bool {
+  item.body != none && item.type_annotation == none
+}
+
 fn derive_variant_to_enum(type_summaries: Map<String, TypeSummary>) -> Map<String, String> {
   map_values(type_summaries) |> fold(init: empty_map(), f: (acc, summary) =>
     match summary.repr {
@@ -439,7 +452,17 @@ fn add_emit_item_summary(state: EmitInfoBuildState, item: Node, source_indices:
   let state = if decl_name != "" && emit_graph_records_type_decl(item: item, source_indices: source_indices) {
     EmitInfoBuildState {
       type_summaries: state.type_summaries,
-      type_decl_items: map_insert(state.type_decl_items, decl_name, item)
+      type_decl_items: map_insert(state.type_decl_items, decl_name, item),
+      fn_decl_items: state.fn_decl_items
+    }
+  } else {
+    state
+  }
+  let state = if decl_name != "" && emit_graph_records_fn_decl(item: item) {
+    EmitInfoBuildState {
+      type_summaries: state.type_summaries,
+      type_decl_items: state.type_decl_items,
+      fn_decl_items: map_insert(state.fn_decl_items, decl_name, item)
     }
   } else {
     state
@@ -476,7 +499,8 @@ fn add_emit_item_summary(state: EmitInfoBuildState, item: Node, source_indices:
       let next_summaries = map_insert(with_variants, summary.name, summary)
       EmitInfoBuildState {
         type_summaries: next_summaries,
-        type_decl_items: state.type_decl_items
+        type_decl_items: state.type_decl_items,
+        fn_decl_items: state.fn_decl_items
       }
     Absent => state
   }

src/v1/04_infer.dag

@@ -9647,14 +9647,15 @@ fn build_enum_variant_shape_sets(modules: List<TypedModule>, type_summaries: Map
 fn build_emit_graph_info(modules: List<TypedModule>) -> EmitGraphInfo {
   let init = EmitInfoBuildState {
     type_summaries: empty_map(),
-    type_decl_items: empty_map()
+    type_decl_items: empty_map(),
+    fn_decl_items: empty_map()
   }
   let built_raw = modules |> fold(init: init, f: (state, typed_module) =>
     typed_module.items |> fold(init: state, f: (inner_state, item) =>
       add_emit_item_summary(state: inner_state, item: item, source_indices: typed_module.type_env.source_indices)
     )
   )
-  let built = EmitInfoBuildState { type_summaries: close_fn_fields(summaries: built_raw.type_summaries), type_decl_items: built_raw.type_decl_items }
+  let built = EmitInfoBuildState { type_summaries: close_fn_fields(summaries: built_raw.type_summaries), type_decl_items: built_raw.type_decl_items, fn_decl_items: built_raw.fn_decl_items }
   let all_recursive = modules |> fold(init: empty_set(), f: (acc, m) =>
     fold(map_keys(m.type_env.recursive_type_set), init: acc, f: (inner, ident) =>
       set_insert(inner, intern_str(table: m.type_env.intern_table, id: ident))
@@ -9665,6 +9666,7 @@ fn build_emit_graph_info(modules: List<TypedModule>) -> EmitGraphInfo {
   EmitGraphInfo {
     type_summaries: built.type_summaries,
     type_decl_items: built.type_decl_items,
+    fn_decl_items: built.fn_decl_items,
     recursive_type_set: all_recursive,
     fielded_variants: variant_shapes.fielded,
     positional_payload_variants: variant_shapes.positional_payload,