chore: 消除所有编译器警告

- 移除unused方法: frame(), get_constant(), emit_i16_placeholder
- 移除LoopContext未使用字段: start_ip, scope_depth
- Vm字段改为私有: frames, open_upvalues
- is_const字段添加#[allow(dead_code)]
- 测试: 327/327 通过 | 0 warnings

aster-core/src/vm/compiler.rs

@@ -77,6 +77,7 @@ struct Local {
     name: String,
     depth: u8,       // scope depth where declared; 0 = uninitialized
     is_captured: bool,
+    #[allow(dead_code)]
     is_const: bool,
 }
 
@@ -88,10 +89,8 @@ struct Upvalue {
 }
 
 struct LoopContext {
-    start_ip: usize,             // bytecode offset of loop condition
-    break_patches: Vec<usize>,   // jump instruction offsets that need break dest
-    continue_patches: Vec<usize>,// jump instruction offsets that need continue dest
-    scope_depth: u8,             // scope depth when loop started
+    break_patches: Vec<usize>,
+    continue_patches: Vec<usize>,
 }
 
 pub struct Compiler {
@@ -241,10 +240,8 @@ impl Compiler {
         let exit_jump = self.emit_jump(OpCode::JumpIfFalse);
 
         self.loop_stack.push(LoopContext {
-            start_ip,
             break_patches: Vec::new(),
             continue_patches: Vec::new(),
-            scope_depth: self.scope_depth,
         });
 
         self.compile_stmt(body)?;
@@ -279,10 +276,8 @@ impl Compiler {
         let exit_jump = self.emit_jump(OpCode::JumpIfFalse);
 
         self.loop_stack.push(LoopContext {
-            start_ip,
             break_patches: Vec::new(),
             continue_patches: Vec::new(),
-            scope_depth: self.scope_depth,
         });
 
         self.compile_stmt(body)?;
@@ -355,10 +350,8 @@ impl Compiler {
 
         // 7. Loop body (can resolve var_name to loop_var_slot)
         self.loop_stack.push(LoopContext {
-            start_ip: forin_loc,
             break_patches: Vec::new(),
             continue_patches: Vec::new(),
-            scope_depth: self.scope_depth,
         });
 
         self.compile_stmt(body)?;
@@ -993,9 +986,3 @@ fn assign_op_to_compound(op: &AssignOp) -> CompoundOp {
         AssignOp::Equal => unreachable!(),
     }
 }
-
-fn emit_i16_placeholder(code: &mut Vec<u8>, op: OpCode) -> usize {
-    let loc = code.len();
-    emit_i16(code, op, 0x7FFF);
-    loc
-}