fix: 对齐 counter/emitter 指令条数，修解构参数、数组赋值元素、解构catch、for-init 无初始化的跳转漂移

crates/oxide_vm/tests/compiler_alignment_binding_tests.rs

@@ -0,0 +1,63 @@
+use oxide_compiler::compiler::Compiler;
+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();
+    match vm.run(&module) {
+        Ok(result) => format!("{result}"),
+        Err(e) => format!("vm error: {e}"),
+    }
+}
+
+// Destructured parameter followed by a loop body: the counter must count the parameter
+// destructuring prologue or the loop's back-jump lands at the wrong PC.
+#[test]
+fn param_array_pattern_with_loop_body() {
+    assert_eq!(eval("function f([a]){var s=0; while(a>0){s=s+1;a=a-1;} return s;} f([3])"), "3");
+}
+
+#[test]
+fn param_array_pattern_default_element() {
+    assert_eq!(eval("function f([a=5]){return a;} f([])"), "5");
+}
+
+// Array assignment target with a default element followed by a loop.
+#[test]
+fn array_assignment_default_element_then_loop() {
+    assert_eq!(eval("var a,c=0; [a=5]=[]; while(c<a){c=c+1;} c"), "5");
+}
+
+// Nested array assignment target element.
+#[test]
+fn array_assignment_nested_element() {
+    assert_eq!(eval("var a,b; [[a],b]=[[1],2]; a*10+b"), "12");
+}
+
+// Destructuring catch param followed by a loop: the counter must not count a STORE_VAR the
+// emitter does not emit for a pattern catch binding.
+#[test]
+fn destructuring_catch_param_then_loop() {
+    assert_eq!(eval("var c=0; try{throw 1;}catch({e}){} while(c<3){c=c+1;} c"), "3");
+}
+
+// Regression: for-init declaration without an initializer followed by loop iterations.
+#[test]
+fn for_init_no_initializer_declarator() {
+    assert_eq!(eval("var c=0; for(var i; c<3; c=c+1){} c"), "3");
+}
+
+// Identifier element array assignment stays correct (simple path unchanged).
+#[test]
+fn array_assignment_identifier_elements() {
+    assert_eq!(eval("var a,b; [a,b]=[7,8]; a*10+b"), "78");
+}