From 3ea2353194c9c7047c565fe13759fb2341f2c3ce Mon Sep 17 00:00:00 2001
From: pjh456 <147148383@qq.com>
Date: Tue, 23 Jun 2026 23:00:20 +0800
Subject: [PATCH] =?UTF-8?q?feat:=20=E5=AE=9E=E7=8E=B0=20SequenceExpression?=
 =?UTF-8?q?=20+=20=E5=B8=A6=E6=A0=87=E7=AD=BE=20break/continue=20+=20Empty?=
 =?UTF-8?q?Statement?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 crates/oxide_compiler/src/compiler.rs         | 71 +++++++++++++++++++
 .../oxide_compiler/src/counter/stmt/basic.rs  | 23 ++++++
 crates/oxide_compiler/src/counter/stmt/mod.rs |  1 +
 .../src/emitter/expr/literal.rs               | 13 ++++
 crates/oxide_compiler/src/emitter/mod.rs      |  7 +-
 .../oxide_compiler/src/emitter/stmt/basic.rs  | 62 ++++++++++++++--
 .../src/emitter/stmt/iteration.rs             | 10 +++
 crates/oxide_compiler/src/hash/expression.rs  |  6 ++
 crates/oxide_compiler/src/hash/statement.rs   | 16 ++++-
 .../tests/compile_stmt_tests.rs               | 15 ++++
 crates/oxide_vm/tests/control_flow_tests.rs   | 69 ++++++++++++++++++
 11 files changed, 284 insertions(+), 9 deletions(-)

diff --git a/crates/oxide_compiler/src/compiler.rs b/crates/oxide_compiler/src/compiler.rs
index ba246941..936e2e17 100644
--- a/crates/oxide_compiler/src/compiler.rs
+++ b/crates/oxide_compiler/src/compiler.rs
@@ -125,6 +125,17 @@ pub(crate) enum Label {
     CatchBody(u32),
     FinallyBody(u32),
     TryEnd(u32),
+    LabeledEnd(u32),
+}
+
+/// A labeled-statement scope active during emission. `break label` targets
+/// `break_label`; `continue label` targets `continue_label` (only set when the
+/// labeled statement directly wraps an iteration statement).
+#[derive(Debug, Clone)]
+pub(crate) struct LabelScope {
+    pub(crate) name: String,
+    pub(crate) break_label: Label,
+    pub(crate) continue_label: Option<Label>,
 }
 
 pub(crate) struct CompileCtx {
@@ -139,6 +150,10 @@ pub(crate) struct CompileCtx {
     pub(crate) loop_stack: Vec<(Label, Label)>,
     #[allow(dead_code)]
     pub(crate) switch_stack: Vec<Label>,
+    /// Active labeled-statement scopes (resolves `break label` / `continue label`).
+    pub(crate) label_scopes: Vec<LabelScope>,
+    /// Label names awaiting binding to the next emitted loop's continue target.
+    pub(crate) pending_loop_labels: Vec<String>,
     pub(crate) label_counter: u32,
     pub(crate) projected_pc: usize,
     pub(crate) builtin_reg_map: Vec<(String, u8)>,
@@ -210,6 +225,8 @@ impl CompileCtx {
             label_map: HashMap::new(),
             loop_stack: Vec::new(),
             switch_stack: Vec::new(),
+            label_scopes: Vec::new(),
+            pending_loop_labels: Vec::new(),
             label_counter: 0,
             projected_pc: 0,
             builtin_reg_map: Vec::new(),
@@ -468,6 +485,60 @@ impl CompileCtx {
         self.switch_stack.last()
     }
 
+    pub(crate) fn push_label_scope(
+        &mut self, name: &str, break_label: Label, continue_label: Option<Label>,
+    ) -> Result<(), String> {
+        if self.label_scopes.iter().any(|s| s.name == name) {
+            return Err(format!("SyntaxError: Label '{name}' has already been declared"));
+        }
+        self.label_scopes.push(LabelScope {
+            name: name.to_string(),
+            break_label,
+            continue_label,
+        });
+        Ok(())
+    }
+
+    pub(crate) fn pop_label_scope(&mut self) {
+        self.label_scopes.pop();
+    }
+
+    pub(crate) fn find_label(&self, name: &str) -> Option<&LabelScope> {
+        self.label_scopes.iter().rev().find(|s| s.name == name)
+    }
+
+    /// Queue a label name to be bound to the continue target of the next loop
+    /// emitted as the labeled statement's body. Rejects duplicates in the active
+    /// or pending sets.
+    pub(crate) fn queue_loop_label(&mut self, name: &str) -> Result<(), String> {
+        if self.label_scopes.iter().any(|s| s.name == name) || self.pending_loop_labels.iter().any(|n| n == name) {
+            return Err(format!("SyntaxError: Label '{name}' has already been declared"));
+        }
+        self.pending_loop_labels.push(name.to_string());
+        Ok(())
+    }
+
+    /// Drain queued loop labels into active scopes bound to this loop's break and
+    /// continue targets. Returns how many scopes were pushed (to pop after).
+    pub(crate) fn take_pending_loop_labels(&mut self, break_label: Label, continue_label: Label) -> usize {
+        let names = std::mem::take(&mut self.pending_loop_labels);
+        let count = names.len();
+        for name in names {
+            self.label_scopes.push(LabelScope {
+                name,
+                break_label,
+                continue_label: Some(continue_label),
+            });
+        }
+        count
+    }
+
+    pub(crate) fn pop_label_scopes(&mut self, n: usize) {
+        for _ in 0..n {
+            self.label_scopes.pop();
+        }
+    }
+
     pub(crate) fn is_builtin(&self, name: &str) -> bool {
         self.builtin_reg_map.iter().any(|(n, _)| n == name)
     }
diff --git a/crates/oxide_compiler/src/counter/stmt/basic.rs b/crates/oxide_compiler/src/counter/stmt/basic.rs
index 54129959..c0fd0369 100644
--- a/crates/oxide_compiler/src/counter/stmt/basic.rs
+++ b/crates/oxide_compiler/src/counter/stmt/basic.rs
@@ -23,4 +23,27 @@ impl Compiler {
     pub(in crate::counter) fn count_continue_statement(&self, ctx: &mut CompileCtx) {
         ctx.projected_pc += 1; // JMP
     }
+
+    pub(in crate::counter) fn count_labeled_statement(
+        &self, stmt: &oxide_parser::LabeledStatement<'_>, ctx: &mut CompileCtx,
+    ) {
+        let body_is_loop = matches!(
+            stmt.body,
+            Statement::WhileStatement(_)
+                | Statement::DoWhileStatement(_)
+                | Statement::ForStatement(_)
+                | Statement::ForInStatement(_)
+                | Statement::ForOfStatement(_)
+        );
+        if body_is_loop {
+            // Loop body owns its labels; labeled break/continue reuse them.
+            self.count_statement(&stmt.body, ctx);
+        } else {
+            // Non-loop label: consume one id (parity with emit) and place the
+            // LabeledEnd target right after the body for `break label`.
+            let id = ctx.next_label_id();
+            self.count_statement(&stmt.body, ctx);
+            ctx.label_map.insert(Label::LabeledEnd(id), ctx.projected_pc);
+        }
+    }
 }
diff --git a/crates/oxide_compiler/src/counter/stmt/mod.rs b/crates/oxide_compiler/src/counter/stmt/mod.rs
index 71b79ca4..66c0b7f2 100644
--- a/crates/oxide_compiler/src/counter/stmt/mod.rs
+++ b/crates/oxide_compiler/src/counter/stmt/mod.rs
@@ -28,6 +28,7 @@ impl Compiler {
             Statement::ClassDeclaration(class) => self.count_class_declaration(class, ctx),
             Statement::ThrowStatement(ts) => self.count_throw_statement(ts, ctx),
             Statement::TryStatement(ts) => self.count_try_statement(ts, ctx),
+            Statement::LabeledStatement(ls) => self.count_labeled_statement(ls, ctx),
             _ => {}
         }
     }
diff --git a/crates/oxide_compiler/src/emitter/expr/literal.rs b/crates/oxide_compiler/src/emitter/expr/literal.rs
index dba865c9..7d25b98d 100644
--- a/crates/oxide_compiler/src/emitter/expr/literal.rs
+++ b/crates/oxide_compiler/src/emitter/expr/literal.rs
@@ -82,6 +82,19 @@ impl Compiler {
         }
     }
 
+    pub(in crate::emitter) fn emit_sequence_expression(
+        &self, seq: &oxide_parser::SequenceExpression, ctx: &mut CompileCtx,
+    ) -> Result<u8, String> {
+        // Comma operator: evaluate each expression in order, value is the last.
+        // Emits exactly one expression per element (no extra instruction), so the
+        // projected-PC count in count_sequence_expression stays aligned.
+        let mut last = 0u8;
+        for e in &seq.expressions {
+            last = self.emit_expression(e, ctx)?;
+        }
+        Ok(last)
+    }
+
     pub(in crate::emitter) fn emit_unsupported_expression(
         &self, expr: &Expression, ctx: &mut CompileCtx,
     ) -> Result<u8, String> {
diff --git a/crates/oxide_compiler/src/emitter/mod.rs b/crates/oxide_compiler/src/emitter/mod.rs
index 8c8f84e1..02d200d0 100644
--- a/crates/oxide_compiler/src/emitter/mod.rs
+++ b/crates/oxide_compiler/src/emitter/mod.rs
@@ -967,12 +967,14 @@ impl Compiler {
             Statement::ForInStatement(_) => self.emit_for_in_statement(stmt, ctx),
             Statement::ForOfStatement(_) => self.emit_for_of_statement(stmt, ctx),
             Statement::SwitchStatement(_) => self.emit_switch_statement(stmt, ctx),
-            Statement::BreakStatement(_) => self.emit_break_statement(ctx),
-            Statement::ContinueStatement(_) => self.emit_continue_statement(ctx),
+            Statement::BreakStatement(b) => self.emit_break_statement(b, ctx),
+            Statement::ContinueStatement(c) => self.emit_continue_statement(c, ctx),
             Statement::FunctionDeclaration(_) => self.emit_function_declaration_statement(stmt, ctx),
             Statement::ClassDeclaration(_) => self.emit_class_declaration_statement(stmt, ctx),
             Statement::ThrowStatement(_) => self.emit_throw_statement(stmt, ctx),
             Statement::TryStatement(_) => self.emit_try_statement(stmt, ctx),
+            Statement::LabeledStatement(ls) => self.emit_labeled_statement(ls, ctx),
+            Statement::EmptyStatement(_) => Ok(None),
             _ => Ok(None),
         }
     }
@@ -1006,6 +1008,7 @@ impl Compiler {
             Expression::CallExpression(call) => self.emit_call_expression(call, ctx),
             Expression::ThisExpression(_) => self.emit_this_expression(ctx),
             Expression::RegExpLiteral(lit) => self.emit_reg_exp_literal_expression(lit, ctx),
+            Expression::SequenceExpression(seq) => self.emit_sequence_expression(seq, ctx),
             _ => self.emit_unsupported_expression(expr, ctx),
         }
     }
diff --git a/crates/oxide_compiler/src/emitter/stmt/basic.rs b/crates/oxide_compiler/src/emitter/stmt/basic.rs
index 042720c4..ce34b859 100644
--- a/crates/oxide_compiler/src/emitter/stmt/basic.rs
+++ b/crates/oxide_compiler/src/emitter/stmt/basic.rs
@@ -28,8 +28,16 @@ impl Compiler {
         Ok(None)
     }
 
-    pub(in crate::emitter) fn emit_break_statement(&self, ctx: &mut CompileCtx) -> Result<Option<u8>, String> {
-        let break_label = if let Some(sw_label) = ctx.current_switch() {
+    pub(in crate::emitter) fn emit_break_statement(
+        &self, stmt: &oxide_parser::BreakStatement, ctx: &mut CompileCtx,
+    ) -> Result<Option<u8>, String> {
+        let break_label = if let Some(label) = &stmt.label {
+            let name = label.name.as_str();
+            let scope = ctx
+                .find_label(name)
+                .ok_or_else(|| format!("SyntaxError: Undefined label '{name}'"))?;
+            scope.break_label
+        } else if let Some(sw_label) = ctx.current_switch() {
             *sw_label
         } else {
             let (bl, _) = ctx.current_loop().ok_or("break outside switch or loop".to_string())?;
@@ -42,12 +50,56 @@ impl Compiler {
         Ok(None)
     }
 
-    pub(in crate::emitter) fn emit_continue_statement(&self, ctx: &mut CompileCtx) -> Result<Option<u8>, String> {
-        let (_, continue_label) = ctx.current_loop().ok_or("continue outside loop".to_string())?;
-        let continue_pos = ctx.resolve_label(*continue_label)?;
+    pub(in crate::emitter) fn emit_continue_statement(
+        &self, stmt: &oxide_parser::ContinueStatement, ctx: &mut CompileCtx,
+    ) -> Result<Option<u8>, String> {
+        let continue_label = if let Some(label) = &stmt.label {
+            let name = label.name.as_str();
+            let scope = ctx
+                .find_label(name)
+                .ok_or_else(|| format!("SyntaxError: Undefined label '{name}'"))?;
+            scope.continue_label.ok_or_else(|| {
+                format!("SyntaxError: Illegal continue statement: '{name}' does not denote an iteration statement")
+            })?
+        } else {
+            let (_, cl) = ctx.current_loop().ok_or("continue outside loop".to_string())?;
+            *cl
+        };
+        let continue_pos = ctx.resolve_label(continue_label)?;
         let offset = (continue_pos as isize) - (ctx.bytecode.len() as isize);
         let offset = ctx.checked_jump_offset(offset);
         ctx.emit(opcode::encode_jmp(offset));
         Ok(None)
     }
+
+    pub(in crate::emitter) fn emit_labeled_statement(
+        &self, stmt: &oxide_parser::LabeledStatement, ctx: &mut CompileCtx,
+    ) -> Result<Option<u8>, String> {
+        let name = stmt.label.name.as_str();
+        if Self::is_iteration_statement(&stmt.body) {
+            // Bind the label to the loop's own continue/break targets (the loop
+            // drains the queue and pops the scope after its body).
+            ctx.queue_loop_label(name)?;
+            self.emit_statement(&stmt.body, ctx)?;
+        } else {
+            // Non-loop labeled statement: only `break label` is valid; it targets
+            // the LabeledEnd placed (by the count pass) right after the body.
+            let id = ctx.next_label_id();
+            ctx.push_label_scope(name, Label::LabeledEnd(id), None)?;
+            self.emit_statement(&stmt.body, ctx)?;
+            ctx.pop_label_scope();
+        }
+        Ok(None)
+    }
+
+    pub(in crate::emitter) fn is_iteration_statement(stmt: &Statement) -> bool {
+        matches!(
+            stmt,
+            Statement::WhileStatement(_)
+                | Statement::DoWhileStatement(_)
+                | Statement::ForStatement(_)
+                | Statement::ForInStatement(_)
+                | Statement::ForOfStatement(_)
+        )
+    }
 }
diff --git a/crates/oxide_compiler/src/emitter/stmt/iteration.rs b/crates/oxide_compiler/src/emitter/stmt/iteration.rs
index b574205f..4b6ee5b9 100644
--- a/crates/oxide_compiler/src/emitter/stmt/iteration.rs
+++ b/crates/oxide_compiler/src/emitter/stmt/iteration.rs
@@ -12,6 +12,7 @@ impl Compiler {
         let end_label = Label::WhileEnd(id);
 
         ctx.push_loop(end_label, start_label);
+        let n_labeled = ctx.take_pending_loop_labels(end_label, start_label);
 
         let test_reg = self.emit_expression(&wh.test, ctx)?;
         let end_pos = ctx.resolve_label(end_label)?;
@@ -26,6 +27,7 @@ impl Compiler {
         let offset = ctx.checked_jump_offset(offset);
         ctx.emit(opcode::encode_jmp(offset));
 
+        ctx.pop_label_scopes(n_labeled);
         ctx.pop_loop();
         Ok(None)
     }
@@ -41,6 +43,7 @@ impl Compiler {
         let end_label = Label::DoWhileEnd(id);
 
         ctx.push_loop(end_label, start_label);
+        let n_labeled = ctx.take_pending_loop_labels(end_label, start_label);
         self.emit_statement(&dw.body, ctx)?;
         let test_reg = self.emit_expression(&dw.test, ctx)?;
 
@@ -49,6 +52,7 @@ impl Compiler {
         let offset = ctx.checked_jump_offset(offset);
         ctx.emit(opcode::encode_jmp_if_true(test_reg, offset));
 
+        ctx.pop_label_scopes(n_labeled);
         ctx.pop_loop();
         Ok(None)
     }
@@ -65,6 +69,7 @@ impl Compiler {
         let end_label = Label::ForEnd(id);
 
         ctx.push_loop(end_label, update_label);
+        let n_labeled = ctx.take_pending_loop_labels(end_label, update_label);
 
         if let Some(init) = &fr.init {
             if let Some(expr) = init.as_expression() {
@@ -102,6 +107,7 @@ impl Compiler {
         let offset = ctx.checked_jump_offset(offset);
         ctx.emit(opcode::encode_jmp(offset));
 
+        ctx.pop_label_scopes(n_labeled);
         ctx.pop_loop();
 
         Ok(None)
@@ -121,6 +127,7 @@ impl Compiler {
         ctx.emit(opcode::encode(OpCode::FOR_IN_INIT, 0, obj_reg, 0));
 
         ctx.push_loop(end_label, start_label);
+        let n_labeled = ctx.take_pending_loop_labels(end_label, start_label);
 
         let done_reg = ctx.alloc_reg();
         ctx.emit(opcode::encode(OpCode::FOR_IN_DONE, done_reg, 0, 0));
@@ -164,6 +171,7 @@ impl Compiler {
 
         ctx.emit(opcode::encode(OpCode::FOR_IN_CLEANUP, 0, 0, 0));
 
+        ctx.pop_label_scopes(n_labeled);
         ctx.pop_loop();
         Ok(None)
     }
@@ -181,6 +189,7 @@ impl Compiler {
         let iter_src_reg = self.emit_expression(&fo.right, ctx)?;
         ctx.emit(opcode::encode(OpCode::FOR_OF_INIT, 0, iter_src_reg, 0));
         ctx.push_loop(end_label, start_label);
+        let n_labeled = ctx.take_pending_loop_labels(end_label, start_label);
 
         let has_reg = ctx.alloc_reg();
         ctx.emit(opcode::encode(OpCode::FOR_OF_DONE, has_reg, 0, 0));
@@ -217,6 +226,7 @@ impl Compiler {
         let offset = ctx.checked_jump_offset(offset);
         ctx.emit(opcode::encode_jmp(offset));
         ctx.emit(opcode::encode(OpCode::FOR_OF_CLOSE, 0, 0, 0));
+        ctx.pop_label_scopes(n_labeled);
         ctx.pop_loop();
         Ok(None)
     }
diff --git a/crates/oxide_compiler/src/hash/expression.rs b/crates/oxide_compiler/src/hash/expression.rs
index a22b5f96..b2524e66 100644
--- a/crates/oxide_compiler/src/hash/expression.rs
+++ b/crates/oxide_compiler/src/hash/expression.rs
@@ -34,6 +34,12 @@ pub(super) fn hash_expression(expr: &Expression, h: &mut rustc_hash::FxHasher, i
             pin.left.name.as_str().hash(h);
             hash_expression(&pin.right, h, include_binding_names);
         }
+        Expression::SequenceExpression(seq) => {
+            (seq.expressions.len() as u32).hash(h);
+            for e in &seq.expressions {
+                hash_expression(e, h, include_binding_names);
+            }
+        }
         Expression::Identifier(ident) => {
             if include_binding_names {
                 ident.name.as_str().hash(h);
diff --git a/crates/oxide_compiler/src/hash/statement.rs b/crates/oxide_compiler/src/hash/statement.rs
index 9f38c0ec..35643fa8 100644
--- a/crates/oxide_compiler/src/hash/statement.rs
+++ b/crates/oxide_compiler/src/hash/statement.rs
@@ -32,8 +32,20 @@ pub(super) fn hash_statement(stmt: &Statement, h: &mut rustc_hash::FxHasher, inc
                 hash_statement(s, h, include_binding_names);
             }
         }
-        Statement::BreakStatement(_) => {}
-        Statement::ContinueStatement(_) => {}
+        Statement::BreakStatement(b) => {
+            if let Some(label) = &b.label {
+                label.name.as_str().hash(h);
+            }
+        }
+        Statement::ContinueStatement(c) => {
+            if let Some(label) = &c.label {
+                label.name.as_str().hash(h);
+            }
+        }
+        Statement::LabeledStatement(ls) => {
+            ls.label.name.as_str().hash(h);
+            hash_statement(&ls.body, h, include_binding_names);
+        }
         Statement::DoWhileStatement(dw) => {
             hash_statement(&dw.body, h, include_binding_names);
             expression::hash_expression(&dw.test, h, include_binding_names);
diff --git a/crates/oxide_compiler/tests/compile_stmt_tests.rs b/crates/oxide_compiler/tests/compile_stmt_tests.rs
index 60733371..50138ba0 100644
--- a/crates/oxide_compiler/tests/compile_stmt_tests.rs
+++ b/crates/oxide_compiler/tests/compile_stmt_tests.rs
@@ -297,3 +297,18 @@ fn compile_class_static_setter_emits_define_accessor() {
         "static class setter should emit DEFINE_ACCESSOR"
     );
 }
+
+#[test]
+fn compile_labeled_loop_emits_body() {
+    let module = compile_source("outer: while (true) { break outer; }");
+    assert!(!module.bytecode.is_empty(), "labeled loop should produce bytecode");
+}
+
+#[test]
+fn compile_empty_statements_are_skipped() {
+    let module = compile_source("; ; var x = 1;");
+    assert!(
+        module.constants.iter().any(|c| matches!(c, Constant::Int(1))),
+        "var after empty statements should still compile"
+    );
+}
diff --git a/crates/oxide_vm/tests/control_flow_tests.rs b/crates/oxide_vm/tests/control_flow_tests.rs
index 01f5e999..672eb9ea 100644
--- a/crates/oxide_vm/tests/control_flow_tests.rs
+++ b/crates/oxide_vm/tests/control_flow_tests.rs
@@ -236,3 +236,72 @@ fn eval_large_adjacent_switches_do_not_collide_labels() {
     source.push_str("}switch(0){case 0:r=r+1;break;}r");
     assert_eq!(eval(&source), "2");
 }
+
+#[test]
+fn eval_sequence_expression_returns_last() {
+    assert_eq!(eval("var x = 0; (x = 1, x = x + 2, x)"), "3");
+    assert_eq!(eval("(1, 2, 3)"), "3");
+}
+
+#[test]
+fn eval_sequence_expression_in_for_clauses() {
+    assert_eq!(eval("for (var i = (0, 1); i < 3; i = (i + 1, i + 1)) {} i"), "3");
+}
+
+#[test]
+fn eval_empty_statement_is_noop() {
+    assert_eq!(eval("while (false); 1"), "1");
+    assert_eq!(eval("; ; var x = 1; x"), "1");
+}
+
+#[test]
+fn eval_labeled_break_exits_loop() {
+    assert_eq!(eval("outer: while (true) { break outer; } 7"), "7");
+}
+
+#[test]
+fn eval_labeled_break_exits_block() {
+    assert_eq!(eval("label: { break label; } 5"), "5");
+}
+
+#[test]
+fn eval_labeled_continue_loop() {
+    assert_eq!(eval("var i = 0; outer: while (i < 3) { i = i + 1; continue outer; } i"), "3");
+}
+
+#[test]
+fn eval_labeled_continue_outer_from_inner_loop() {
+    assert_eq!(
+        eval("var c = 0; outer: for (var i = 0; i < 3; i++) { for (var j = 0; j < 3; j++) { if (j == 1) continue outer; c = c + 1; } } c"),
+        "3"
+    );
+}
+
+#[test]
+fn eval_labeled_break_outer_from_inner_loop() {
+    assert_eq!(
+        eval("var c = 0; outer: for (var i = 0; i < 3; i++) { for (var j = 0; j < 3; j++) { if (i == 1 && j == 1) break outer; c = c + 1; } } c"),
+        "4"
+    );
+}
+
+#[test]
+fn eval_duplicate_label_is_compile_error() {
+    let r = eval("a: a: while (false) {}");
+    assert!(r.contains("compile error") && r.contains("already been declared"), "got: {r}");
+}
+
+#[test]
+fn eval_continue_to_non_loop_label_is_compile_error() {
+    let r = eval("label: { continue label; }");
+    assert!(
+        r.contains("compile error") && r.contains("does not denote an iteration statement"),
+        "got: {r}"
+    );
+}
+
+#[test]
+fn eval_break_to_undefined_label_is_compile_error() {
+    let r = eval("foo: while (false) {} break bar;");
+    assert!(r.contains("compile error") && r.contains("Undefined label"), "got: {r}");
+}