diff --git a/compiler/gen/src/llvm/build.rs b/compiler/gen/src/llvm/build.rs
index defff8359e..59c1dd428b 100644
--- a/compiler/gen/src/llvm/build.rs
+++ b/compiler/gen/src/llvm/build.rs
@@ -1806,7 +1806,8 @@ fn expose_function_to_host_help<'a, 'ctx, 'env>(
 
     // STEP 3: build a {} -> u64 function that gives the size of the return type
     let size_function_type = env.context.i64_type().fn_type(&[], false);
-    let size_function_name: String = format!("{}_size", roc_function.get_name().to_str().unwrap());
+    let size_function_name: String =
+        format!("roc_{}_size", roc_function.get_name().to_str().unwrap());
 
     let size_function = env.module.add_function(
         size_function_name.as_str(),
@@ -2119,8 +2120,9 @@ pub fn build_closure_caller<'a, 'ctx, 'env>(
 
     // STEP 1: build function header
 
+    // e.g. `roc__main_1_Fx_caller`
     let function_name = format!(
-        "{}_{}_caller",
+        "roc_{}_{}_caller",
         def_name,
         alias_symbol.ident_string(&env.interns)
     );
@@ -2200,7 +2202,7 @@ pub fn build_closure_caller<'a, 'ctx, 'env>(
     // STEP 3: build a {} -> u64 function that gives the size of the return type
     let size_function_type = env.context.i64_type().fn_type(&[], false);
     let size_function_name: String = format!(
-        "{}_{}_size",
+        "roc_{}_{}_size",
         def_name,
         alias_symbol.ident_string(&env.interns)
     );
diff --git a/examples/effect/Main.roc b/examples/effect/Main.roc
index c13c2afb63..2e37d4be5b 100644
--- a/examples/effect/Main.roc
+++ b/examples/effect/Main.roc
@@ -1,31 +1,11 @@
-app "effect-example" provides [ main ] imports [ Effect, RBTree ]
-
-toAndFro : Int
-toAndFro =
-    empty : RBTree.Dict Int {}
-    empty = RBTree.empty
-
-    empty
-        |> (\d -> RBTree.insert 1 {} d)
-        |> RBTree.toList
-        |> List.len
-
-
-
+app "effect-example" imports [ Effect, RBTree ] provides [ main ] to "./platform"
 
 main : Effect.Effect {} as Fx
 main =
-    # if RBTree.isEmpty empty then
-    if toAndFro == 2 then
+    if RBTree.isEmpty (RBTree.insert 1 2 Empty) then
         Effect.putLine "Yay"
             |> Effect.after (\{} -> Effect.getLine)
             |> Effect.after (\line -> Effect.putLine line)
     else
         Effect.putLine "Nay"
 
-
-#    Effect.always "Write a thing"
-#        |> Effect.map (\line -> Str.concat line "!")
-#        |> Effect.after (\line -> Effect.putLine line)
-#        |> Effect.after (\{} -> Effect.getLine)
-#        |> Effect.after (\line -> Effect.putLine line)
diff --git a/examples/effect/RBTree.roc b/examples/effect/RBTree.roc
index 6278d3eafd..1c792e5125 100644
--- a/examples/effect/RBTree.roc
+++ b/examples/effect/RBTree.roc
@@ -1,4 +1,4 @@
-interface RBTree exposes [ Dict, empty, size, singleton, isEmpty, insert, remove, update, fromList, toList ] imports []
+interface RBTree exposes [ Dict, empty, size, singleton, isEmpty, insert, remove, update, fromList, toList, balance ] imports []
 
 # The color of a node. Leaves are considered Black.
 NodeColor : [ Red, Black ]
diff --git a/examples/effect/platform/src/lib.rs b/examples/effect/platform/src/lib.rs
index 1e8554f4c3..ba517b18c8 100644
--- a/examples/effect/platform/src/lib.rs
+++ b/examples/effect/platform/src/lib.rs
@@ -7,16 +7,16 @@ use std::alloc::Layout;
 use std::time::SystemTime;
 
 extern "C" {
-    #[link_name = "Main_main_1_exposed"]
+    #[link_name = "roc__main_1_exposed"]
     fn roc_main(output: *mut u8) -> ();
 
-    #[link_name = "Main_main_1_size"]
+    #[link_name = "roc__main_1_size"]
     fn roc_main_size() -> i64;
 
-    #[link_name = "Main_main_1_Fx_caller"]
+    #[link_name = "roc__main_1_Fx_caller"]
     fn call_Fx(function_pointer: *const u8, closure_data: *const u8, output: *mut u8) -> ();
 
-    #[link_name = "Main_main_1_Fx_size"]
+    #[link_name = "roc__main_1_Fx_size"]
     fn size_Fx() -> i64;
 }
 
@@ -60,10 +60,10 @@ unsafe fn call_the_closure(function_pointer: *const u8, closure_data_ptr: *const
             buffer as *mut u8,
         );
 
-        let output = &*(buffer as *mut RocCallResult<i64>);
+        let output = &*(buffer as *mut RocCallResult<()>);
 
         match output.into() {
-            Ok(v) => v,
+            Ok(_) => 0,
             Err(e) => panic!("failed with {}", e),
         }
     })