feat: with 回退未声明名写落隐式全局

crates/oxide_vm/tests/with_fallback_implicit_global_tests.rs

@@ -0,0 +1,70 @@
+use std::sync::Arc;
+
+use oxide_compiler::compiler::Compiler;
+use oxide_compiler::DefaultCompilerService;
+use oxide_parser::Allocator;
+use oxide_vm::vm::Vm;
+
+fn eval(source: &str) -> String {
+    let allocator = Allocator::default();
+    let program = match oxide_parser::parse(&allocator, source) {
+        Ok(p) => p,
+        Err(e) => return format!("parse error: {}", e[0].message),
+    };
+    let module = match Compiler::new().compile(&program) {
+        Ok(m) => m,
+        Err(e) => return format!("compile error: {e}"),
+    };
+    let mut vm = Vm::new();
+    vm.set_compiler_service(Arc::new(DefaultCompilerService));
+    match vm.run(&Arc::new(module)) {
+        Ok(result) => format!("{result}"),
+        Err(e) => format!("vm error: {e}"),
+    }
+}
+
+// 规范（ECMA-262 `with` 写解析）：with 对象无该属性且名字未在静态作用域
+// 声明时，写落隐式全局——sloppy 物化全局属性；对象命中臂与已声明绑定的
+// 回退分支行为不变。严格模式禁止 `with` 语句（解析期 SyntaxError），
+// 故回退臂的 strict 抛错分支仅经静态写路径可达。
+
+#[test]
+fn with_fallback_undeclared_write_goes_to_implicit_global() {
+    assert_eq!(
+        eval("var o={}; with(o){x=42;} globalThis.x===42"),
+        "true",
+        "sloppy with 回退未声明名写物化隐式全局属性"
+    );
+}
+
+#[test]
+fn with_hit_write_stays_on_object() {
+    assert_eq!(
+        eval("var o={x:1}; with(o){x=42;} o.x===42 && globalThis.x===undefined"),
+        "true",
+        "with 对象命中臂写对象属性，不落全局"
+    );
+}
+
+#[test]
+fn with_fallback_declared_var_writes_outer_binding() {
+    assert_eq!(
+        eval(
+            "(function(){var o={}, y=0; with(o){y=1;} \
+             return y===1 && globalThis.y===undefined;})()"
+        ),
+        "true",
+        "with 回退已声明 var 写外层绑定，不落全局"
+    );
+}
+
+#[test]
+fn with_fallback_compound_undeclared_write_keeps_existing_behavior() {
+    // 复合赋值回退臂走静态复合路径：未声明名旧值按 undefined 读
+    // （GetBaseValue 语义不抛），复合运算结果落隐式全局。
+    assert_eq!(
+        eval("var o={}; with(o){x+=1;} isNaN(globalThis.x)"),
+        "true",
+        "with 回退未声明名复合赋值保持既有读 undefined 行为"
+    );
+}