6 files changed, 34 insertions, 2 deletions
diff --git a/cli/diagnostics.rs b/cli/diagnostics.rs
index d49916f2d..8181c5fa0 100644
--- a/cli/diagnostics.rs
+++ b/cli/diagnostics.rs
@@ -15,6 +15,7 @@ use std::fmt;
 const MAX_SOURCE_LINE_LENGTH: usize = 150;
 
 const UNSTABLE_DENO_PROPS: &[&str] = &[
+  "BenchDefinition",
   "CompilerOptions",
   "CreateHttpClientOptions",
   "DatagramConn",
@@ -39,6 +40,7 @@ const UNSTABLE_DENO_PROPS: &[&str] = &[
   "UnixListenOptions",
   "addSignalListener",
   "applySourceMap",
+  "bench",
   "connect",
   "consoleSize",
   "createHttpClient",
diff --git a/cli/ops/bench.rs b/cli/ops/bench.rs
index 4b7d6743f..ea040b4a5 100644
--- a/cli/ops/bench.rs
+++ b/cli/ops/bench.rs
@@ -12,7 +12,7 @@ use std::time;
 use tokio::sync::mpsc::UnboundedSender;
 use uuid::Uuid;
 
-pub fn init(sender: UnboundedSender<BenchEvent>) -> Extension {
+pub fn init(sender: UnboundedSender<BenchEvent>, unstable: bool) -> Extension {
   Extension::builder()
     .ops(vec![
       op_pledge_test_permissions::decl(),
@@ -20,14 +20,36 @@ pub fn init(sender: UnboundedSender<BenchEvent>) -> Extension {
       op_get_bench_origin::decl(),
       op_dispatch_bench_event::decl(),
       op_bench_now::decl(),
+      op_bench_check_unstable::decl(),
     ])
     .state(move |state| {
       state.put(sender.clone());
+      state.put(Unstable(unstable));
       Ok(())
     })
     .build()
 }
 
+pub struct Unstable(pub bool);
+
+fn check_unstable(state: &OpState, api_name: &str) {
+  let unstable = state.borrow::<Unstable>();
+
+  if !unstable.0 {
+    eprintln!(
+      "Unstable API '{}'. The --unstable flag must be provided.",
+      api_name
+    );
+    std::process::exit(70);
+  }
+}
+
+#[op]
+fn op_bench_check_unstable(state: &mut OpState) -> Result<(), AnyError> {
+  check_unstable(state, "Deno.bench");
+  Ok(())
+}
+
 #[derive(Clone)]
 struct PermissionsHolder(Uuid, Permissions);
 
diff --git a/cli/tests/integration/bench_tests.rs b/cli/tests/integration/bench_tests.rs
index 06806c0b7..2df08bdb5 100644
--- a/cli/tests/integration/bench_tests.rs
+++ b/cli/tests/integration/bench_tests.rs
@@ -2,6 +2,12 @@
 
 use crate::itest;
 
+itest!(requires_unstable {
+  args: "bench bench/requires_unstable.js",
+  exit_code: 70,
+  output: "bench/requires_unstable.out",
+});
+
 itest!(overloads {
   args: "bench --unstable bench/overloads.ts",
   exit_code: 0,
diff --git a/cli/tests/testdata/bench/requires_unstable.js b/cli/tests/testdata/bench/requires_unstable.js
new file mode 100644
index 000000000..06a07bb38
--- /dev/null
+++ b/cli/tests/testdata/bench/requires_unstable.js
@@ -0,0 +1 @@
+Deno.bench("bench0", () => {});
diff --git a/cli/tests/testdata/bench/requires_unstable.out b/cli/tests/testdata/bench/requires_unstable.out
new file mode 100644
index 000000000..574fb07e1
--- /dev/null
+++ b/cli/tests/testdata/bench/requires_unstable.out
@@ -0,0 +1 @@
+Unstable API 'Deno.bench'. The --unstable flag must be provided.
diff --git a/cli/tools/bench.rs b/cli/tools/bench.rs
index 8c3b67943..7a1e260ac 100644
--- a/cli/tools/bench.rs
+++ b/cli/tools/bench.rs
@@ -295,7 +295,7 @@ async fn bench_specifier(
     &ps,
     specifier.clone(),
     permissions,
-    vec![ops::bench::init(channel.clone())],
+    vec![ops::bench::init(channel.clone(), ps.flags.unstable)],
   );
 
   if options.compat_mode {