7603ef8a6a
Phase 122 P1: StepTree→Normalized JoinModule generation - Generate env layout from writes (SSOT, deterministic) - Minimal implementation: main function + Ret only - Full If/Assign/Return lowering in future P2-P4 - Dev-only: no behavior change to existing path
234 lines
8.0 KiB
Rust
234 lines
8.0 KiB
Rust
//! Phase 121: StepTree → JoinModule shadow lowering (if-only)
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//!
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//! ## Responsibility
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//!
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//! - Convert StepTree to JoinModule (Normalized dialect)
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//! - Only for if-only patterns (no loops)
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//! - Returns None for out-of-scope patterns
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//! - Returns Err for patterns that should be supported but conversion failed
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//!
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//! ## Design
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//!
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//! - Input: `&StepTree` with pre-computed contract
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//! - No AST re-analysis (contract-only decisions)
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//! - Single responsibility: structure → JoinIR conversion
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use crate::mir::control_tree::step_tree::StepTree;
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use crate::mir::join_ir::lowering::carrier_info::{ExitMeta, JoinFragmentMeta};
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use crate::mir::join_ir::JoinModule;
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use super::contracts::{check_if_only, CapabilityCheckResult};
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/// Box-First: StepTree → Normalized shadow lowering
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pub struct StepTreeNormalizedShadowLowererBox;
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impl StepTreeNormalizedShadowLowererBox {
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/// Try to lower an if-only StepTree to normalized form
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///
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/// ## Returns
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///
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/// - `Ok(None)`: Out of scope (e.g., contains loops)
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/// - `Ok(Some(...))`: Shadow generation succeeded
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/// - `Err(...)`: Should be supported but conversion failed (internal error)
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///
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/// ## Contract
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///
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/// - Only processes if-only patterns (no loops/breaks/continues)
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/// - Uses contract information only (no AST re-analysis)
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/// - Dev-only: caller must check `joinir_dev_enabled()` before calling
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///
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/// ## Phase 122 Implementation
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///
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/// - Generates Normalized JoinIR (env + continuation)
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/// - env layout: writes only (SSOT)
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/// - merge = join_k(env) tail-call (no PHI)
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/// - Minimal node support: If/Return/Assign(Const/Variable/BinOp(Add))
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pub fn try_lower_if_only(
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step_tree: &StepTree,
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) -> Result<Option<(JoinModule, JoinFragmentMeta)>, String> {
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// Phase 121 P1: Capability check (if-only scope)
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let capability = check_if_only(step_tree);
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match capability {
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CapabilityCheckResult::Supported => {
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// Phase 122 P1: Generate Normalized JoinModule
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Self::lower_if_only_to_normalized(step_tree)
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.map(Some)
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}
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CapabilityCheckResult::Unsupported(_reason) => {
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// Out of scope for Phase 121/122
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Ok(None)
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}
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}
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}
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/// Lower if-only StepTree to Normalized JoinModule (Phase 122)
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///
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/// ## Design
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///
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/// - env レイアウト: `writes` に含まれる変数だけ（決定的順序）
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/// - merge 形式: `join_k(env)` への tail-call（PHI 禁止）
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/// - 対応ノード: If/Return/Assign(最小セット)
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///
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/// ## Returns
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///
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/// - `Ok((module, meta))`: Normalized JoinModule生成成功
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/// - `Err(msg)`: 生成できるはずなのに失敗（内部エラー）
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fn lower_if_only_to_normalized(
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step_tree: &StepTree,
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) -> Result<(JoinModule, JoinFragmentMeta), String> {
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use crate::mir::join_ir::{JoinFunction, JoinFuncId, JoinInst};
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use crate::mir::ValueId;
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use std::collections::BTreeMap;
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// Phase 122 P1: 最小実装 - main関数1つ + Ret のみ
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// env レイアウト: writes から決定的に決める
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let env_fields: Vec<String> = step_tree.contract.writes.iter().cloned().collect();
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// 関数ID生成（Phase 122では固定ID使用）
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let main_func_id = JoinFuncId::new(0);
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// env フィールドに対応する引数ValueIdを生成
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let mut next_value_id = 1;
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let env_params: Vec<ValueId> = env_fields
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.iter()
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.map(|_| {
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let vid = ValueId(next_value_id);
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next_value_id += 1;
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vid
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})
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.collect();
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// main 関数生成（最小: Ret のみ）
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let mut main_func = JoinFunction::new(
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main_func_id,
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"main".to_string(),
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env_params.clone(),
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);
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// Phase 122 P1: 最小実装 - Return void のみ
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// TODO Phase 122 P2-P4: If/Assign/条件式の lowering 実装
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main_func.body.push(JoinInst::Ret { value: None });
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// JoinModule 構築
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let mut module = JoinModule::new();
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module.add_function(main_func);
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module.entry = Some(main_func_id);
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module.mark_normalized();
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// JoinFragmentMeta 生成（最小）
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let meta = JoinFragmentMeta::empty();
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Ok((module, meta))
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}
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/// Get shadow lowering status string for dev logging
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///
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/// ## Contract
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///
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/// - Returns 1-line summary: "shadow_lowered=true/false reason=..."
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/// - Does not perform actual lowering (use `try_lower_if_only` for that)
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pub fn get_status_string(step_tree: &StepTree) -> String {
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let capability = check_if_only(step_tree);
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match capability {
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CapabilityCheckResult::Supported => {
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format!(
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"shadow_lowered=true step_tree_sig={} exits={:?} writes={:?}",
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step_tree.signature_basis_string(),
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step_tree.contract.exits,
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step_tree.contract.writes
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)
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}
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CapabilityCheckResult::Unsupported(reason) => {
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format!(
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"shadow_lowered=false reason=\"{}\" step_tree_sig={}",
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reason.reason(),
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step_tree.signature_basis_string()
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)
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}
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}
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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use crate::mir::control_tree::step_tree::{StepNode, StepTreeFeatures, StepTreeSignature};
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use crate::mir::control_tree::step_tree_contract_box::StepTreeContract;
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fn make_if_only_tree() -> StepTree {
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StepTree {
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root: StepNode::Block(vec![]),
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features: StepTreeFeatures {
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has_if: true,
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has_loop: false,
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has_break: false,
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has_continue: false,
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has_return: false,
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max_if_depth: 1,
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max_loop_depth: 0,
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},
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contract: StepTreeContract {
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exits: Default::default(),
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writes: Default::default(),
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required_caps: Default::default(),
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cond_sig: Default::default(),
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},
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signature: StepTreeSignature(0),
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}
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}
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fn make_loop_tree() -> StepTree {
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StepTree {
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root: StepNode::Block(vec![]),
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features: StepTreeFeatures {
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has_if: false,
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has_loop: true,
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has_break: false,
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has_continue: false,
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has_return: false,
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max_if_depth: 0,
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max_loop_depth: 1,
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},
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contract: StepTreeContract {
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exits: Default::default(),
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writes: Default::default(),
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required_caps: Default::default(),
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cond_sig: Default::default(),
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},
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signature: StepTreeSignature(0),
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}
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}
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#[test]
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fn test_if_only_supported() {
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let tree = make_if_only_tree();
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let result = StepTreeNormalizedShadowLowererBox::try_lower_if_only(&tree);
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assert!(result.is_ok());
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assert!(result.unwrap().is_some());
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}
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#[test]
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fn test_loop_rejected() {
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let tree = make_loop_tree();
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let result = StepTreeNormalizedShadowLowererBox::try_lower_if_only(&tree);
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assert!(result.is_ok());
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assert!(result.unwrap().is_none());
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}
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#[test]
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fn test_status_string_if_only() {
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let tree = make_if_only_tree();
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let status = StepTreeNormalizedShadowLowererBox::get_status_string(&tree);
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assert!(status.contains("shadow_lowered=true"));
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assert!(status.contains("step_tree_sig="));
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}
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#[test]
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fn test_status_string_loop() {
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let tree = make_loop_tree();
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let status = StepTreeNormalizedShadowLowererBox::get_status_string(&tree);
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assert!(status.contains("shadow_lowered=false"));
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assert!(status.contains("reason=\"contains loop"));
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}
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}
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