diff --git a/cli/ops/dispatch_json.rs b/cli/ops/dispatch_json.rs
index 26ffc7d33a..30a3a44333 100644
--- a/cli/ops/dispatch_json.rs
+++ b/cli/ops/dispatch_json.rs
@@ -3,6 +3,7 @@ use crate::op_error::OpError;
 use deno_core::Buf;
 use deno_core::CoreIsolateState;
 use deno_core::Op;
+use deno_core::OpDispatcher;
 use deno_core::ZeroCopyBuf;
 use futures::future::FutureExt;
 pub use serde_derive::Deserialize;
@@ -44,9 +45,7 @@ struct AsyncArgs {
   promise_id: Option<u64>,
 }
 
-pub fn json_op<D>(
-  d: D,
-) -> impl Fn(&mut CoreIsolateState, &mut [ZeroCopyBuf]) -> Op
+pub fn json_op<D>(d: D) -> impl OpDispatcher
 where
   D: Fn(
     &mut CoreIsolateState,
diff --git a/cli/ops/dispatch_minimal.rs b/cli/ops/dispatch_minimal.rs
index 45b90ef81c..c37e57e45f 100644
--- a/cli/ops/dispatch_minimal.rs
+++ b/cli/ops/dispatch_minimal.rs
@@ -9,6 +9,7 @@ use byteorder::{LittleEndian, WriteBytesExt};
 use deno_core::Buf;
 use deno_core::CoreIsolateState;
 use deno_core::Op;
+use deno_core::OpDispatcher;
 use deno_core::ZeroCopyBuf;
 use futures::future::FutureExt;
 use std::future::Future;
@@ -114,9 +115,7 @@ fn test_parse_min_record() {
   assert_eq!(parse_min_record(&buf), None);
 }
 
-pub fn minimal_op<D>(
-  d: D,
-) -> impl Fn(&mut CoreIsolateState, &mut [ZeroCopyBuf]) -> Op
+pub fn minimal_op<D>(d: D) -> impl OpDispatcher
 where
   D: Fn(&mut CoreIsolateState, bool, i32, &mut [ZeroCopyBuf]) -> MinimalOp,
 {
diff --git a/cli/ops/plugin.rs b/cli/ops/plugin.rs
index 16debac50a..ba105cff8f 100644
--- a/cli/ops/plugin.rs
+++ b/cli/ops/plugin.rs
@@ -110,7 +110,8 @@ impl<'a> plugin_api::Interface for PluginInterface<'a> {
     let plugin_lib = self.plugin_lib.clone();
     self.isolate_state.op_registry.register(
       name,
-      move |isolate_state, zero_copy| {
+      move |isolate_state: &mut CoreIsolateState,
+            zero_copy: &mut [ZeroCopyBuf]| {
         let mut interface = PluginInterface::new(isolate_state, &plugin_lib);
         let op = dispatch_op_fn(&mut interface, zero_copy);
         match op {
diff --git a/cli/state.rs b/cli/state.rs
index 5f3873510f..2d871d74d0 100644
--- a/cli/state.rs
+++ b/cli/state.rs
@@ -16,6 +16,7 @@ use deno_core::ModuleLoadId;
 use deno_core::ModuleLoader;
 use deno_core::ModuleSpecifier;
 use deno_core::Op;
+use deno_core::OpDispatcher;
 use deno_core::ZeroCopyBuf;
 use futures::future::FutureExt;
 use futures::Future;
@@ -62,10 +63,7 @@ pub struct StateInner {
 }
 
 impl State {
-  pub fn stateful_json_op<D>(
-    &self,
-    dispatcher: D,
-  ) -> impl Fn(&mut deno_core::CoreIsolateState, &mut [ZeroCopyBuf]) -> Op
+  pub fn stateful_json_op<D>(&self, dispatcher: D) -> impl OpDispatcher
   where
     D: Fn(&State, Value, &mut [ZeroCopyBuf]) -> Result<JsonOp, OpError>,
   {
@@ -73,10 +71,7 @@ impl State {
     self.core_op(json_op(self.stateful_op(dispatcher)))
   }
 
-  pub fn stateful_json_op2<D>(
-    &self,
-    dispatcher: D,
-  ) -> impl Fn(&mut deno_core::CoreIsolateState, &mut [ZeroCopyBuf]) -> Op
+  pub fn stateful_json_op2<D>(&self, dispatcher: D) -> impl OpDispatcher
   where
     D: Fn(
       &mut deno_core::CoreIsolateState,
@@ -92,13 +87,7 @@ impl State {
   /// Wrap core `OpDispatcher` to collect metrics.
   // TODO(ry) this should be private. Is called by stateful_json_op or
   // stateful_minimal_op
-  pub fn core_op<D>(
-    &self,
-    dispatcher: D,
-  ) -> impl Fn(&mut deno_core::CoreIsolateState, &mut [ZeroCopyBuf]) -> Op
-  where
-    D: Fn(&mut deno_core::CoreIsolateState, &mut [ZeroCopyBuf]) -> Op,
-  {
+  pub fn core_op(&self, dispatcher: impl OpDispatcher) -> impl OpDispatcher {
     let state = self.clone();
 
     move |isolate_state: &mut deno_core::CoreIsolateState,
@@ -109,7 +98,7 @@ impl State {
       let bytes_sent_zero_copy =
         zero_copy[1..].iter().map(|b| b.len()).sum::<usize>() as u64;
 
-      let op = dispatcher(isolate_state, zero_copy);
+      let op = dispatcher.dispatch(isolate_state, zero_copy);
 
       match op {
         Op::Sync(buf) => {
@@ -152,10 +141,7 @@ impl State {
     }
   }
 
-  pub fn stateful_minimal_op2<D>(
-    &self,
-    dispatcher: D,
-  ) -> impl Fn(&mut deno_core::CoreIsolateState, &mut [ZeroCopyBuf]) -> Op
+  pub fn stateful_minimal_op2<D>(&self, dispatcher: D) -> impl OpDispatcher
   where
     D: Fn(
       &mut deno_core::CoreIsolateState,
diff --git a/core/core_isolate.rs b/core/core_isolate.rs
index ffe75c00c5..c9e718d2db 100644
--- a/core/core_isolate.rs
+++ b/core/core_isolate.rs
@@ -348,10 +348,11 @@ impl CoreIsolate {
   /// corresponds to the second argument of Deno.core.dispatch().
   ///
   /// Requires runtime to explicitly ask for op ids before using any of the ops.
-  pub fn register_op<F>(&mut self, name: &str, op: F) -> OpId
-  where
-    F: Fn(&mut CoreIsolateState, &mut [ZeroCopyBuf]) -> Op + 'static,
-  {
+  pub fn register_op(
+    &mut self,
+    name: &str,
+    op: impl OpDispatcher + 'static,
+  ) -> OpId {
     let state_rc = Self::state(self);
     let mut state = state_rc.borrow_mut();
     state.op_registry.register(name, op)
@@ -466,7 +467,7 @@ impl CoreIsolateState {
   /// Requires runtime to explicitly ask for op ids before using any of the ops.
   pub fn register_op<F>(&mut self, name: &str, op: F) -> OpId
   where
-    F: Fn(&mut CoreIsolateState, &mut [ZeroCopyBuf]) -> Op + 'static,
+    F: OpDispatcher + 'static,
   {
     self.op_registry.register(name, op)
   }
@@ -488,7 +489,7 @@ impl CoreIsolateState {
     zero_copy_bufs: &mut [ZeroCopyBuf],
   ) -> Option<(OpId, Box<[u8]>)> {
     let op = if let Some(dispatcher) = self.op_registry.get(op_id) {
-      dispatcher(self, zero_copy_bufs)
+      dispatcher.dispatch(self, zero_copy_bufs)
     } else {
       let message =
         v8::String::new(scope, &format!("Unknown op id: {}", op_id)).unwrap();
diff --git a/core/lib.rs b/core/lib.rs
index 7358af1c43..f348ed6cf4 100644
--- a/core/lib.rs
+++ b/core/lib.rs
@@ -46,6 +46,7 @@ pub use crate::modules::RecursiveModuleLoad;
 pub use crate::ops::Buf;
 pub use crate::ops::Op;
 pub use crate::ops::OpAsyncFuture;
+pub use crate::ops::OpDispatcher;
 pub use crate::ops::OpId;
 pub use crate::resources::ResourceTable;
 pub use crate::zero_copy_buf::ZeroCopyBuf;
diff --git a/core/ops.rs b/core/ops.rs
index 65a0f325b1..8aa13936b4 100644
--- a/core/ops.rs
+++ b/core/ops.rs
@@ -20,31 +20,52 @@ pub enum Op {
   AsyncUnref(OpAsyncFuture),
 }
 
-/// Main type describing op
-pub type OpDispatcher =
-  dyn Fn(&mut CoreIsolateState, &mut [ZeroCopyBuf]) -> Op + 'static;
+pub trait OpDispatcher {
+  fn dispatch(
+    &self,
+    isolate: &mut CoreIsolateState,
+    buf: &mut [ZeroCopyBuf],
+  ) -> Op;
+}
+
+impl<F> OpDispatcher for F
+where
+  F: Fn(&mut CoreIsolateState, &mut [ZeroCopyBuf]) -> Op,
+{
+  fn dispatch(
+    &self,
+    isolate: &mut CoreIsolateState,
+    buf: &mut [ZeroCopyBuf],
+  ) -> Op {
+    self(isolate, buf)
+  }
+}
 
 #[derive(Default)]
 pub struct OpRegistry {
-  dispatchers: Vec<Rc<OpDispatcher>>,
+  dispatchers: Vec<Rc<dyn OpDispatcher>>,
   name_to_id: HashMap<String, OpId>,
 }
 
 impl OpRegistry {
   pub fn new() -> Self {
     let mut registry = Self::default();
-    let op_id = registry.register("ops", |state, _| {
-      let buf = state.op_registry.json_map();
-      Op::Sync(buf)
-    });
+    let op_id = registry.register(
+      "ops",
+      |state: &mut CoreIsolateState, _: &mut [ZeroCopyBuf]| {
+        let buf = state.op_registry.json_map();
+        Op::Sync(buf)
+      },
+    );
     assert_eq!(op_id, 0);
     registry
   }
 
-  pub fn register<F>(&mut self, name: &str, op: F) -> OpId
-  where
-    F: Fn(&mut CoreIsolateState, &mut [ZeroCopyBuf]) -> Op + 'static,
-  {
+  pub fn register(
+    &mut self,
+    name: &str,
+    op: impl OpDispatcher + 'static,
+  ) -> OpId {
     let op_id = self.dispatchers.len() as u32;
 
     let existing = self.name_to_id.insert(name.to_string(), op_id);
@@ -61,8 +82,8 @@ impl OpRegistry {
     op_map_json.as_bytes().to_owned().into_boxed_slice()
   }
 
-  pub fn get(&self, op_id: OpId) -> Option<Rc<OpDispatcher>> {
-    self.dispatchers.get(op_id as usize).map(Rc::clone)
+  pub fn get(&self, op_id: OpId) -> Option<Rc<dyn OpDispatcher>> {
+    self.dispatchers.get(op_id as usize).cloned()
   }
 
   pub fn unregister_op(&mut self, name: &str) {
@@ -81,10 +102,13 @@ fn test_op_registry() {
   let c = Arc::new(atomic::AtomicUsize::new(0));
   let c_ = c.clone();
 
-  let test_id = op_registry.register("test", move |_, _| {
-    c_.fetch_add(1, atomic::Ordering::SeqCst);
-    Op::Sync(Box::new([]))
-  });
+  let test_id = op_registry.register(
+    "test",
+    move |_: &mut CoreIsolateState, _: &mut [ZeroCopyBuf]| {
+      c_.fetch_add(1, atomic::Ordering::SeqCst);
+      Op::Sync(Box::new([]))
+    },
+  );
   assert!(test_id != 0);
 
   let mut expected = HashMap::new();
@@ -97,7 +121,7 @@ fn test_op_registry() {
   let dispatch = op_registry.get(test_id).unwrap();
   let state_rc = CoreIsolate::state(&isolate);
   let mut state = state_rc.borrow_mut();
-  let res = dispatch(&mut state, &mut []);
+  let res = dispatch.dispatch(&mut state, &mut []);
   if let Op::Sync(buf) = res {
     assert_eq!(buf.len(), 0);
   } else {
@@ -127,15 +151,21 @@ fn register_op_during_call() {
 
   let test_id = {
     let mut g = op_registry.lock().unwrap();
-    g.register("dynamic_register_op", move |_, _| {
-      let c__ = c_.clone();
-      let mut g = op_registry_.lock().unwrap();
-      g.register("test", move |_, _| {
-        c__.fetch_add(1, atomic::Ordering::SeqCst);
+    g.register(
+      "dynamic_register_op",
+      move |_: &mut CoreIsolateState, _: &mut [ZeroCopyBuf]| {
+        let c__ = c_.clone();
+        let mut g = op_registry_.lock().unwrap();
+        g.register(
+          "test",
+          move |_: &mut CoreIsolateState, _: &mut [ZeroCopyBuf]| {
+            c__.fetch_add(1, atomic::Ordering::SeqCst);
+            Op::Sync(Box::new([]))
+          },
+        );
         Op::Sync(Box::new([]))
-      });
-      Op::Sync(Box::new([]))
-    })
+      },
+    )
   };
   assert!(test_id != 0);
 
@@ -148,7 +178,7 @@ fn register_op_during_call() {
   {
     let state_rc = CoreIsolate::state(&isolate);
     let mut state = state_rc.borrow_mut();
-    dispatcher1(&mut state, &mut []);
+    dispatcher1.dispatch(&mut state, &mut []);
   }
 
   let mut expected = HashMap::new();
@@ -166,7 +196,7 @@ fn register_op_during_call() {
   };
   let state_rc = CoreIsolate::state(&isolate);
   let mut state = state_rc.borrow_mut();
-  let res = dispatcher2(&mut state, &mut []);
+  let res = dispatcher2.dispatch(&mut state, &mut []);
   if let Op::Sync(buf) = res {
     assert_eq!(buf.len(), 0);
   } else {
diff --git a/deno_typescript/lib.rs b/deno_typescript/lib.rs
index 70d6d42d0b..f64959e0d7 100644
--- a/deno_typescript/lib.rs
+++ b/deno_typescript/lib.rs
@@ -13,6 +13,7 @@ use deno_core::CoreIsolateState;
 use deno_core::ErrBox;
 use deno_core::ModuleSpecifier;
 use deno_core::Op;
+use deno_core::OpDispatcher;
 use deno_core::StartupData;
 use deno_core::ZeroCopyBuf;
 pub use ops::EmitResult;
@@ -50,7 +51,7 @@ pub struct TSState {
 fn compiler_op<D>(
   ts_state: Arc<Mutex<TSState>>,
   dispatcher: D,
-) -> impl Fn(&mut CoreIsolateState, &mut [ZeroCopyBuf]) -> Op
+) -> impl OpDispatcher
 where
   D: Fn(&mut TSState, &[u8]) -> Op,
 {
@@ -337,7 +338,7 @@ pub fn trace_serializer() {
 /// CoreIsolate.
 pub fn op_fetch_asset<S: ::std::hash::BuildHasher>(
   custom_assets: HashMap<String, PathBuf, S>,
-) -> impl Fn(&mut CoreIsolateState, &mut [ZeroCopyBuf]) -> Op {
+) -> impl OpDispatcher {
   for (_, path) in custom_assets.iter() {
     println!("cargo:rerun-if-changed={}", path.display());
   }