fix: 对齐 ?? 与静态成员复合赋值的 counter/emitter 计数，并加 projected_pc 断言

crates/oxide_vm/tests/compiler_alignment_expr_tests.rs

@@ -0,0 +1,90 @@
+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}"),
+    }
+}
+
+// Non-simple `??` (side-effecting operands) followed by a label-bearing construct must not
+// shift the downstream label id (which produced `Label ... not found` at emit time).
+
+#[test]
+fn coalesce_nonsimple_then_if() {
+    assert_eq!(
+        eval("function a(){return null;} function b(){return 2;} var v=a()??b(); if(v>0){v=v+10;} v"),
+        "12"
+    );
+}
+
+#[test]
+fn coalesce_nonsimple_then_while() {
+    assert_eq!(
+        eval("function a(){return null;} function b(){return 3;} var v=a()??b(); var c=0; while(c<v){c=c+1;} c"),
+        "3"
+    );
+}
+
+#[test]
+fn coalesce_nonsimple_then_for() {
+    assert_eq!(
+        eval("function a(){return null;} var v=a()??4; var s=0; for(var i=0;i<v;i=i+1){s=s+i;} s"),
+        "6"
+    );
+}
+
+#[test]
+fn coalesce_nonsimple_short_circuits_on_value() {
+    // 0 is not nullish, so `a() ?? b()` is 0 and the loop never runs.
+    assert_eq!(
+        eval("function a(){return 0;} function b(){return 9;} var v=a()??b(); var c=0; while(c<v){c=c+1;} c"),
+        "0"
+    );
+}
+
+// Static member compound assignment must not over-count vs the emitter (the extra +1 drifted
+// the following loop's jump target).
+
+#[test]
+fn static_member_compound_assign_then_loop() {
+    assert_eq!(eval("var o={x:1}; o.x+=2; var c=0; while(c<3){c=c+1;} c"), "3");
+}
+
+#[test]
+fn static_member_compound_assign_in_loop() {
+    assert_eq!(eval("var o={x:0}; var c=0; while(o.x<3){o.x+=1; c=c+1;} c"), "3");
+}
+
+// Regressions: simple coalesce, nested coalesce, And/Or, compound member value, plain assign.
+#[test]
+fn simple_coalesce_regression() {
+    assert_eq!(eval("var x = null ?? 5; x"), "5");
+}
+
+#[test]
+fn nested_coalesce_regression() {
+    assert_eq!(eval("function a(){return null;} var v = a() ?? a() ?? 7; v"), "7");
+}
+
+#[test]
+fn logical_and_nonsimple_regression() {
+    assert_eq!(eval("function a(){return 1;} function b(){return 2;} var v=a()&&b(); if(v>0){} v"), "2");
+}
+
+#[test]
+fn compound_member_value_regression() {
+    assert_eq!(eval("var o={x:10}; o.x-=3; o.x"), "7");
+}