stage3: unify to cleanup; MIR return-defer; docs+smokes updated; LLVM(harness): finalize_phis ownership, ret.py simplified, uses-predeclare; cleanup return override green; method-postfix cleanup return WIP (PHI head)

src/archive/interpreter_legacy/async_ops.rs

@@ -0,0 +1,40 @@
+/*!
+ * Async Operations Module
+ * 
+ * Extracted from expressions.rs lines 1020-1031 (~11 lines)
+ * Handles await expression processing for asynchronous operations
+ * Core philosophy: "Everything is Box" with async support
+ */
+
+use super::*;
+use crate::boxes::result::NyashResultBox;
+use crate::box_trait::StringBox;
+
+impl NyashInterpreter {
+    /// await式を実行 - 非同期操作の結果を待機
+    pub(super) fn execute_await(&mut self, expression: &ASTNode) -> Result<Box<dyn NyashBox>, RuntimeError> {
+        let value = self.execute_expression(expression)?;
+        
+        // FutureBoxなら協調待機して Result.Ok/Err を返す
+        if let Some(future) = value.as_any().downcast_ref::<FutureBox>() {
+            let max_ms: u64 = crate::config::env::await_max_ms();
+            let start = std::time::Instant::now();
+            let mut spins = 0usize;
+            while !future.ready() {
+                crate::runtime::global_hooks::safepoint_and_poll();
+                std::thread::yield_now();
+                spins += 1;
+                if spins % 1024 == 0 { std::thread::sleep(std::time::Duration::from_millis(1)); }
+                if start.elapsed() >= std::time::Duration::from_millis(max_ms) {
+                    let err = Box::new(StringBox::new("Timeout"));
+                    return Ok(Box::new(NyashResultBox::new_err(err)));
+                }
+            }
+            let v = future.get();
+            Ok(Box::new(NyashResultBox::new_ok(v)))
+        } else {
+            // FutureBoxでなければ Ok(value) で返す
+            Ok(Box::new(NyashResultBox::new_ok(value)))
+        }
+    }
+}