diff --git a/crates/cli-support/Cargo.toml b/crates/cli-support/Cargo.toml
index 81479563..85c56055 100644
--- a/crates/cli-support/Cargo.toml
+++ b/crates/cli-support/Cargo.toml
@@ -14,6 +14,7 @@ edition = '2018'
 [dependencies]
 base64 = "0.9"
 failure = "0.1.2"
+log = "0.4"
 rustc-demangle = "0.1.13"
 tempfile = "3.0"
 walrus = "0.2.1"
diff --git a/crates/cli-support/src/js/closures.rs b/crates/cli-support/src/js/closures.rs
index 8cc8c138..92575307 100644
--- a/crates/cli-support/src/js/closures.rs
+++ b/crates/cli-support/src/js/closures.rs
@@ -13,7 +13,7 @@ use crate::descriptor::Descriptor;
 use crate::js::js2rust::Js2Rust;
 use crate::js::Context;
 use failure::Error;
-use std::collections::BTreeMap;
+use std::collections::{BTreeMap, HashSet};
 use std::mem;
 use walrus::ir::{Expr, ExprId};
 use walrus::{FunctionId, LocalFunction};
@@ -21,12 +21,6 @@ use walrus::{FunctionId, LocalFunction};
 pub fn rewrite(input: &mut Context) -> Result<(), Error> {
     let info = ClosureDescriptors::new(input);
 
-    // Sanity check to make sure things look ok and skip everything below if
-    // there's not calls to `Closure::new`.
-    assert_eq!(
-        info.element_removal_list.len(),
-        info.func_to_descriptor.len(),
-    );
     if info.element_removal_list.len() == 0 {
         return Ok(());
     }
@@ -41,7 +35,7 @@ struct ClosureDescriptors {
     /// A list of elements to remove from the function table. The first element
     /// of the pair is the index of the entry in the element section, and the
     /// second element of the pair is the index within that entry to remove.
-    element_removal_list: Vec<usize>,
+    element_removal_list: HashSet<usize>,
 
     /// A map from local functions which contain calls to
     /// `__wbindgen_describe_closure` to the information about the closure
@@ -150,6 +144,7 @@ impl ClosureDescriptors {
             walrus::TableKind::Function(f) => f,
         };
         for idx in self.element_removal_list.iter().cloned() {
+            log::trace!("delete element {}", idx);
             assert!(table.elements[idx].is_some());
             table.elements[idx] = None;
         }
diff --git a/crates/wasm-interpreter/src/lib.rs b/crates/wasm-interpreter/src/lib.rs
index 55a2165c..645de6fb 100644
--- a/crates/wasm-interpreter/src/lib.rs
+++ b/crates/wasm-interpreter/src/lib.rs
@@ -18,7 +18,7 @@
 
 #![deny(missing_docs)]
 
-use std::collections::{BTreeMap, HashMap};
+use std::collections::{BTreeMap, HashMap, HashSet};
 use walrus::ir::ExprId;
 use walrus::{FunctionId, LocalFunction, LocalId, Module, TableId};
 
@@ -168,7 +168,7 @@ impl Interpreter {
         &mut self,
         id: FunctionId,
         module: &Module,
-        entry_removal_list: &mut Vec<usize>,
+        entry_removal_list: &mut HashSet<usize>,
     ) -> Option<&[u32]> {
         // Call the `id` function. This is an internal `#[inline(never)]`
         // whose code is completely controlled by the `wasm-bindgen` crate, so
@@ -213,7 +213,7 @@ impl Interpreter {
 
         // This is used later to actually remove the entry from the table, but
         // we don't do the removal just yet
-        entry_removal_list.push(descriptor_table_idx);
+        entry_removal_list.insert(descriptor_table_idx);
 
         // And now execute the descriptor!
         self.interpret_descriptor_id(descriptor_id, module)