diff --git a/core/isolate.rs b/core/isolate.rs
index 5df5b4d3c15670..0f693ff92dba1d 100644
--- a/core/isolate.rs
+++ b/core/isolate.rs
@@ -269,34 +269,14 @@ impl Isolate {
     zero_copy_buf: deno_pinned_buf,
   ) {
     let isolate = unsafe { Isolate::from_raw_ptr(user_data) };
-    let control_shared = isolate.shared.shift();
 
-    let op = if control_argv0.len() > 0 {
-      // The user called Deno.core.send(control)
-      if let Some(ref f) = isolate.dispatch {
-        f(control_argv0.as_ref(), PinnedBuf::new(zero_copy_buf))
-      } else {
-        panic!("isolate.dispatch not set")
-      }
-    } else if let Some(c) = control_shared {
-      // The user called Deno.sharedQueue.push(control)
-      if let Some(ref f) = isolate.dispatch {
-        f(&c, PinnedBuf::new(zero_copy_buf))
-      } else {
-        panic!("isolate.dispatch not set")
-      }
+    let op = if let Some(ref f) = isolate.dispatch {
+      f(control_argv0.as_ref(), PinnedBuf::new(zero_copy_buf))
     } else {
-      // The sharedQueue is empty. The shouldn't happen usually, but it's also
-      // not technically a failure.
-      #[cfg(test)]
-      unreachable!();
-      #[cfg(not(test))]
-      return;
+      panic!("isolate.dispatch not set")
     };
 
-    // At this point the SharedQueue should be empty.
-    assert_eq!(isolate.shared.size(), 0);
-
+    debug_assert_eq!(isolate.shared.size(), 0);
     match op {
       Op::Sync(buf) => {
         // For sync messages, we always return the response via Deno.core.send's
@@ -871,43 +851,6 @@ pub mod tests {
     });
   }
 
-  #[test]
-  fn test_shared() {
-    run_in_task(|| {
-      let (mut isolate, dispatch_count) = setup(Mode::AsyncImmediate);
-
-      js_check(isolate.execute(
-        "setup2.js",
-        r#"
-        let nrecv = 0;
-        Deno.core.setAsyncHandler((buf) => {
-          assert(buf.byteLength === 1);
-          assert(buf[0] === 43);
-          nrecv++;
-        });
-        "#,
-      ));
-      assert_eq!(dispatch_count.load(Ordering::Relaxed), 0);
-
-      js_check(isolate.execute(
-        "send1.js",
-        r#"
-        let control = new Uint8Array([42]);
-        Deno.core.sharedQueue.push(control);
-        Deno.core.send();
-        assert(nrecv === 0);
-
-        Deno.core.sharedQueue.push(control);
-        Deno.core.send();
-        assert(nrecv === 0);
-        "#,
-      ));
-      assert_eq!(dispatch_count.load(Ordering::Relaxed), 2);
-      assert_eq!(Async::Ready(()), isolate.poll().unwrap());
-      js_check(isolate.execute("send1.js", "assert(nrecv === 2);"));
-    });
-  }
-
   #[test]
   fn dyn_import_err() {
     // Test an erroneous dynamic import where the specified module isn't found.
diff --git a/core/shared_queue.js b/core/shared_queue.js
index d7ab382d6e9317..1b338b052715b4 100644
--- a/core/shared_queue.js
+++ b/core/shared_queue.js
@@ -165,11 +165,7 @@ SharedQueue Binary Layout
 
   function dispatch(control, zeroCopy = null) {
     maybeInit();
-    // First try to push control to shared.
-    const success = push(control);
-    // If successful, don't use first argument of core.send.
-    const arg0 = success ? null : control;
-    return Deno.core.send(arg0, zeroCopy);
+    return Deno.core.send(control, zeroCopy);
   }
 
   const denoCore = {
diff --git a/core/shared_queue.rs b/core/shared_queue.rs
index c33a37b90a9c79..616272f8d90e36 100644
--- a/core/shared_queue.rs
+++ b/core/shared_queue.rs
@@ -103,6 +103,7 @@ impl SharedQueue {
     s[INDEX_OFFSETS + index] = end as u32;
   }
 
+  #[cfg(test)]
   fn get_end(&self, index: usize) -> Option<usize> {
     if index < self.num_records() {
       let s = self.as_u32_slice();
@@ -112,6 +113,7 @@ impl SharedQueue {
     }
   }
 
+  #[cfg(test)]
   fn get_offset(&self, index: usize) -> Option<usize> {
     if index < self.num_records() {
       Some(if index == 0 {
@@ -126,6 +128,7 @@ impl SharedQueue {
   }
 
   /// Returns none if empty.
+  #[cfg(test)]
   pub fn shift(&mut self) -> Option<&[u8]> {
     let u32_slice = self.as_u32_slice();
     let i = u32_slice[INDEX_NUM_SHIFTED_OFF] as usize;