chore(joinir): Phase 286C-5 Step 3 - Remove unused imports

Ran `cargo fix --allow-dirty --lib` to automatically remove unused imports
across the codebase. This cleanup is standard maintenance and improves code
hygiene.

**Files Modified**:
- instruction_rewriter.rs: Removed 6 unused imports
  - block_remapper::remap_block_id
  - LoweringDecision
  - ParameterBindingBox
  - propagate_value_type_for_inst (2 occurrences)
  - apply_remapped_terminator
  - PhiAdjustment, ParameterBinding from scan_box
- Other files: Minor unused import cleanup (12 files total)

**No Functional Changes**: Pure cleanup, all tests expected to pass.

Phase 286C-5 progress: 3/4 steps complete

Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/mir/builder/control_flow/joinir/merge/instruction_rewriter.rs

@@ -49,12 +49,12 @@
 //! - **Main function**: `merge_and_rewrite` (lines 63-1400)
 //! - **Target**: Reduce to ~600 lines by extracting 4 boxes (InstructionFilterBox, ReturnConverterBox, TailCallDetectorBox, ParameterBindingBox)
 
-use super::block_remapper::remap_block_id; // Phase 284 P1: SSOT
+ // Phase 284 P1: SSOT
 use super::exit_args_collector::ExitArgsCollectorBox;
 use super::loop_header_phi_info::LoopHeaderPhiInfo;
 use super::merge_result::MergeResult;
 use super::tail_call_classifier::{classify_tail_call, TailCallKind};
-use super::tail_call_lowering_policy::{LoweringDecision, TailCallLoweringPolicyBox};
+use super::tail_call_lowering_policy::TailCallLoweringPolicyBox;
 use super::super::trace;
 use crate::mir::builder::joinir_id_remapper::JoinIrIdRemapper;
 use crate::mir::join_ir::lowering::error_tags;
@@ -69,15 +69,13 @@ use super::rewriter::helpers::is_skippable_continuation;
 // Phase 286C-2 Step 2: Import from instruction_filter_box module
 use super::rewriter::instruction_filter_box::InstructionFilterBox;
 // Phase 286C-2 Step 2: Import from parameter_binding_box module
-use super::rewriter::parameter_binding_box::ParameterBindingBox;
 // Phase 286C-2 Step 2: Import from return_converter_box module
 use super::rewriter::return_converter_box::ReturnConverterBox;
 // Phase 286C-3: Import RewriteContext for state consolidation
 use super::rewriter::rewrite_context::RewriteContext;
 // Phase 260 P0.1 Step 4: Import from type_propagation module
-use super::rewriter::type_propagation::propagate_value_type_for_inst;
 // Phase 260 P0.1 Step 5: Import from terminator module
-use super::rewriter::terminator::{apply_remapped_terminator, remap_branch, remap_jump};
+use super::rewriter::terminator::{remap_branch, remap_jump};
 // Phase 260 P0.1 Step 6: exit_collection module available
 // TODO: Migrate inline Return→Jump conversion to use exit_collection functions:
 // - collect_exit_values_from_edge_args()
@@ -88,7 +86,7 @@ use super::rewriter::terminator::{apply_remapped_terminator, remap_branch, remap
 // requires careful refactoring due to logging context and flow control.
 
 // Phase 286C-2.1: Import scaffolding data structures for 3-stage pipeline
-use super::rewriter::scan_box::{RewritePlan, TailCallRewrite, ReturnConversion, PhiAdjustment, ParameterBinding};
+use super::rewriter::scan_box::{RewritePlan, TailCallRewrite, ReturnConversion};
 use super::rewriter::plan_box::RewrittenBlocks;
 // Phase 286C-5 Step 1: Import CarrierInputsCollector for DRY
 use super::rewriter::carrier_inputs_collector::CarrierInputsCollector;
@@ -236,7 +234,7 @@ fn plan_rewrites(
     debug: bool,
 ) -> Result<RewrittenBlocks, String> {
     use super::rewriter::plan_helpers::{build_local_block_map, sync_spans};
-    use super::rewriter::type_propagation::propagate_value_type_for_inst;
+    
     use super::phi_block_remapper::remap_phi_instruction;
     use super::block_remapper::remap_block_id;
 

src/mir/builder/control_flow/joinir/merge/rewriter/apply_box.rs

@@ -4,7 +4,6 @@
 //! Adds/replaces blocks in MirBuilder WITHOUT reading/analyzing.
 
 use crate::mir::builder::MirBuilder;
-use crate::mir::{BasicBlock, BasicBlockId};
 
 use super::plan_box::RewrittenBlocks;
 

src/mir/builder/control_flow/joinir/merge/rewriter/plan_helpers.rs

@@ -4,7 +4,7 @@
 //! These are pure helper functions that both the current monolithic code and the
 //! new plan_rewrites() function can use.
 
-use crate::mir::{BasicBlock, BasicBlockId, MirFunction, MirInstruction, ValueId};
+use crate::mir::{BasicBlock, BasicBlockId, MirFunction, MirInstruction};
 use crate::mir::builder::joinir_id_remapper::JoinIrIdRemapper;
 use std::collections::BTreeMap;
 

src/mir/builder/control_flow/joinir/merge/rewriter/scan_box.rs

@@ -3,7 +3,7 @@
 //! Phase 286C-2.1: First stage of 3-stage pipeline (Scan → Plan → Apply)
 //! Identifies what needs to be rewritten WITHOUT mutating any state.
 
-use crate::mir::{BasicBlock, BasicBlockId, MirFunction, MirInstruction, ValueId};
+use crate::mir::{BasicBlock, BasicBlockId, MirInstruction, ValueId};
 use std::collections::BTreeSet;
 
 /// Rewrite plan: Describes WHAT to do (doesn't touch instructions yet)
@@ -108,7 +108,7 @@ impl ScanBox {
         block_id: BasicBlockId,
         _func_name: &str,
     ) -> BlockScanResult {
-        let mut skip_instructions = BTreeSet::new();
+        let skip_instructions = BTreeSet::new();
         let mut found_tail_call = false;
 
         // Scan instructions for tail calls, returns, etc.

src/mir/builder/control_flow/joinir/merge/rewriter/tail_call_detector_box.rs

@@ -3,7 +3,6 @@
 //! Phase 286C-2: Extracted from instruction_rewriter.rs
 //! Helper functions related to tail call detection and classification.
 
-use crate::mir::ValueId;
 
 /// TailCallDetectorBox: Tail call detection helpers
 ///

src/mir/builder/control_flow/joinir/patterns/pattern7_split_scan.rs

@@ -27,9 +27,7 @@
 //! - Side effects: result.push() in both loop and post-loop
 //! - P0 restriction: 1-char separator only
 
-use super::super::trace;
 use crate::ast::ASTNode;
-use crate::mir::builder::MirBuilder;
 
 /// Phase 256 P0: Split/Scan pattern parts extractor
 ///

src/mir/join_ir/normalized.rs

@@ -3,11 +3,11 @@
 //! テスト専用の極小サブセット。Pattern1 の while だけを Structured → Normalized に
 //! 変換して遊ぶための足場だよ。本線の Structured→MIR 経路には影響しない。
 
-use std::collections::{BTreeMap, HashSet};
+use std::collections::BTreeMap;
 
 use crate::mir::join_ir::{
-    BinOpKind, CompareOp, ConstValue, JoinContId, JoinFuncId, JoinFunction, JoinInst, JoinIrPhase,
-    JoinModule, MirLikeInst, UnaryOp,
+    BinOpKind, CompareOp, ConstValue, JoinIrPhase,
+    JoinModule, UnaryOp,
 };
 use crate::mir::ValueId;
 #[cfg(feature = "normalized_dev")]

src/mir/join_ir/normalized/env_layout_builder.rs

@@ -7,7 +7,6 @@
 //! - Create default env layouts
 //! - Manage env field construction
 
-use crate::mir::ValueId;
 use crate::mir::join_ir::JoinFunction;
 
 use super::{EnvField, EnvLayout};

src/mir/join_ir/normalized/pattern1_normalizer.rs

@@ -11,8 +11,8 @@
 use std::collections::{BTreeMap, HashSet};
 
 use crate::mir::join_ir::{
-    BinOpKind, CompareOp, ConstValue, JoinContId, JoinFuncId, JoinFunction, JoinInst, JoinIrPhase,
-    JoinModule, MirLikeInst, UnaryOp,
+    JoinContId, JoinFuncId, JoinFunction, JoinInst, JoinIrPhase,
+    JoinModule, MirLikeInst,
 };
 use crate::mir::ValueId;
 

src/mir/join_ir/normalized/pattern2_normalizer.rs

@@ -8,11 +8,11 @@
 //! - Convert Normalized JoinIR → Structured JoinIR (reverse)
 //! - Verify normalized module invariants
 
-use std::collections::{BTreeMap, HashMap};
+use std::collections::BTreeMap;
 
 use crate::mir::join_ir::{
-    BinOpKind, CompareOp, ConstValue, JoinContId, JoinFuncId, JoinFunction, JoinInst, JoinIrPhase,
-    JoinModule, MirLikeInst, UnaryOp,
+    JoinContId, JoinFuncId, JoinFunction, JoinInst, JoinIrPhase,
+    JoinModule, MirLikeInst,
 };
 use crate::mir::ValueId;
 

src/parser/items/functions.rs

@@ -3,7 +3,6 @@
  */
 
 use crate::ast::{ASTNode, Span};
-use crate::must_advance;
 use crate::parser::common::ParserUtils;
 use crate::parser::{NyashParser, ParseError};
 use crate::tokenizer::TokenType;

src/parser/items/static_items.rs

@@ -4,7 +4,6 @@
  */
 
 use crate::ast::{ASTNode, Span};
-use crate::must_advance;
 use crate::parser::common::ParserUtils;
 use crate::parser::{NyashParser, ParseError};
 use crate::tokenizer::TokenType;

src/runtime/weak_handles.rs

@@ -14,8 +14,7 @@
 use once_cell::sync::OnceCell;
 use std::collections::HashMap;
 use std::sync::{
-    atomic::{AtomicU64, Ordering},
-    Arc, RwLock, Weak,
+    atomic::{AtomicU64, Ordering}, RwLock, Weak,
 };
 
 use crate::box_trait::NyashBox;