Function extract_rust_impl

internal/cbm/extract_defs.c:4247–4345

// --- Rust impl block extraction ---

static void extract_rust_impl(CBMExtractCtx *ctx, TSNode node, const CBMLangSpec *spec) {
    CBMArena *a = ctx->arena;

    TSNode type_node = ts_node_child_by_field_name(node, TS_FIELD("type"));
    if (ts_node_is_null(type_node)) {
        return;
    }

    char *type_name = cbm_node_text(a, type_node, ctx->source);
    if (!type_name || !type_name[0]) {
        return;
    }
    /* Strip generic args from the implementing type: `Buffer<T>` → `Buffer`,
     * `Wrapper<T>` → `Wrapper`. The struct identity is the base name. */
    {
        char *lt = strchr(type_name, '<');
        if (lt) {
            *lt = '\0';
        }
    }

    // Check for "impl Trait for Struct" pattern
    TSNode trait_node = ts_node_child_by_field_name(node, TS_FIELD("trait"));
    if (!ts_node_is_null(trait_node)) {
        char *trait_name = cbm_node_text(a, trait_node, ctx->source);
        /* Strip generic args from the trait: `From<Feet>` → `From`,
         * `Index<usize>` → `Index`, `AsRef<str>` → `AsRef`. Qualified paths
         * like `io::Write` / `fmt::Display` have no `<` and are preserved. */
        if (trait_name) {
            char *lt = strchr(trait_name, '<');
            if (lt) {
                *lt = '\0';
            }
        }
        if (trait_name && trait_name[0]) {
            CBMImplTrait it;
            it.trait_name = trait_name;
            it.struct_name = type_name;
            cbm_impltrait_push(&ctx->result->impl_traits, a, it);
        }
    }

    const char *type_qn = cbm_fqn_compute(a, ctx->project, ctx->rel_path, type_name);

    // Extract methods inside impl body
    TSNode body = ts_node_child_by_field_name(node, TS_FIELD("body"));
    if (ts_node_is_null(body)) {
        return;
    }

    uint32_t count = ts_node_child_count(body);
    for (uint32_t i = 0; i < count; i++) {
        TSNode child = ts_node_child(body, i);
        if (ts_node_is_null(child)) {
            continue;
        }
        if (!cbm_kind_in_set(child, spec->function_node_types)) {
            continue;