From 3358cf712eb7d0d18f68335e9d17411cd07275b8 Mon Sep 17 00:00:00 2001
From: pjh456 <147148383@qq.com>
Date: Sat, 15 Aug 2026 23:20:36 +0800
Subject: [PATCH] =?UTF-8?q?fix:=20=E9=9D=9E=E5=B8=B8=E9=87=8F=E9=94=AE?=
 =?UTF-8?q?=E6=88=90=E5=91=98=20**=3D=20=E5=A4=8D=E5=90=88=E8=B5=8B?=
 =?UTF-8?q?=E5=80=BC=20rhs=20=E7=94=9F=E6=95=88?=
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---
 crates/oxide_emit/src/expr/assignment.rs |  4 +++-
 crates/oxide_vm/tests/object_tests.rs    | 18 ++++++++++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/crates/oxide_emit/src/expr/assignment.rs b/crates/oxide_emit/src/expr/assignment.rs
index 8db3528..b6e1f6d 100644
--- a/crates/oxide_emit/src/expr/assignment.rs
+++ b/crates/oxide_emit/src/expr/assignment.rs
@@ -501,7 +501,9 @@ impl Emitter {
                 AssignmentOperator::Multiplication => OpCode::MUL,
                 AssignmentOperator::Division => OpCode::DIV,
                 AssignmentOperator::Remainder => OpCode::MOD,
-                AssignmentOperator::Exponential => OpCode::COMPOUND_EXP,
+                // 指数无 COMPOUND_* 对应（COMPOUND_EXP 只读 [Rd,A] 会忽略 rhs）：
+                // 走三寄存器 EXP，旧值在 a 槽（val_reg 兼 rd/a）、rhs 在 b 槽。
+                AssignmentOperator::Exponential => OpCode::EXP,
                 AssignmentOperator::BitwiseAnd => OpCode::BIT_AND,
                 AssignmentOperator::BitwiseOR => OpCode::BIT_OR,
                 AssignmentOperator::BitwiseXOR => OpCode::BIT_XOR,
diff --git a/crates/oxide_vm/tests/object_tests.rs b/crates/oxide_vm/tests/object_tests.rs
index 5b6f761..e8bb194 100644
--- a/crates/oxide_vm/tests/object_tests.rs
+++ b/crates/oxide_vm/tests/object_tests.rs
@@ -91,6 +91,24 @@ fn eval_computed_compound_assign_preserves_read_before_rhs() {
     assert_eq!(eval("var o={a:5}; o.a += 1, o.a"), "6");
 }
 
+#[test]
+fn eval_dynamic_key_compound_exp_uses_rhs() {
+    // 非常量键走 DYNAMIC 路径：`**=` 的指数取 RHS（EXP 读 [A,B]，旧值 a 槽、rhs b 槽）。
+    assert_eq!(eval("var o={a:5}; var k='a'; o[k]**=2, o.a"), "25");
+    assert_eq!(eval("var o={a:5}; var k='a'; o[k]**=2"), "25");
+    // 负 number 指数：5 ** -1 = 0.2。
+    assert_eq!(eval("var o={a:5}; var k='a'; o[k]**=-1, o.a"), "0.2");
+    // BigInt：结果保持 BigInt。
+    assert_eq!(eval("var o={a:5n}; var k='a'; o[k]**=3n, o.a"), "BigInt(125)");
+    // 负 BigInt 指数抛 RangeError；BigInt/Number 混合抛 TypeError。
+    let err = eval("var o={a:5n}; var k='a'; o[k]**=-1n");
+    assert!(err.contains("RangeError"), "expected RangeError, got: {err}");
+    let err2 = eval("var o={a:5}; var k='a'; o[k]**=2n");
+    assert!(err2.contains("TypeError"), "expected TypeError, got: {err2}");
+    // 求值序：先读旧值再求值 RHS——RHS 副作用改写属性不影响被求幂的旧值。
+    assert_eq!(eval("var o={a:5}; var k='a'; function f(){o.a=100; return 2;} o[k]**=f(), o.a"), "25");
+}
+
 #[test]
 fn eval_computed_compound_assign_getter_order() {
     // getter 场景：先触发 getter 读取，再求值 RHS。