RustPython
diff --git a/‎crates/codegen/src/compile.rs‎
Lines changed: 16 additions & 3 deletions b/‎crates/codegen/src/compile.rs‎
Lines changed: 16 additions & 3 deletions
@@ -1811,8 +1811,7 @@ impl Compiler {
         if has_module_cond_ann {
             let ncells = self.code_stack.last().unwrap().metadata.cellvars.len();
             for i in 0..ncells {
-                let i_varnum: oparg::VarNum =
-                    u32::try_from(i).expect("too many cellvars").into();
+                let i_varnum: oparg::VarNum = u32::try_from(i).expect("too many cellvars").into();
                 emit!(self, Instruction::MakeCell { i: i_varnum });
             }
         }
@@ -5458,7 +5457,21 @@ impl Compiler {
         let mut end_async_for_target = BlockIdx::NULL;
 
         // The thing iterated:
-        self.compile_expression(iter)?;
+        // Optimize: `for x in [a, b, c]` → use tuple instead of list
+        // (list creation is wasteful for iteration)
+        if let ast::Expr::List(ast::ExprList { elts, .. }) = iter {
+            for elt in elts {
+                self.compile_expression(elt)?;
+            }
+            emit!(
+                self,
+                Instruction::BuildTuple {
+                    count: u32::try_from(elts.len()).expect("too many elements"),
+                }
+            );
+        } else {
+            self.compile_expression(iter)?;
+        }
 
         if is_async {
             if self.ctx.func != FunctionContext::AsyncFunction {