diff --git a/compiler/gen/src/llvm/build.rs b/compiler/gen/src/llvm/build.rs
index da7812491a..197ede8e3c 100644
--- a/compiler/gen/src/llvm/build.rs
+++ b/compiler/gen/src/llvm/build.rs
@@ -15,7 +15,6 @@ use crate::llvm::refcounting::{
 };
 use bumpalo::collections::Vec;
 use bumpalo::Bump;
-use either;
 use inkwell::basic_block::BasicBlock;
 use inkwell::builder::Builder;
 use inkwell::context::Context;
@@ -1941,7 +1940,7 @@ where
     let catch_block = context.append_basic_block(parent, "catch_block");
     let cont_block = context.append_basic_block(parent, "cont_block");
 
-    let result_alloca = builder.build_alloca(call_result_type.clone(), "result");
+    let result_alloca = builder.build_alloca(call_result_type, "result");
 
     // invoke instead of call, so that we can catch any exeptions thrown in Roc code
     let call_result = {
@@ -2147,6 +2146,11 @@ pub fn build_proc_header<'a, 'ctx, 'env>(
                     Layout::Closure(arguments, closure, result) => {
                         build_closure_caller(env, &fn_name, *name, arguments, closure, result)
                     }
+                    Layout::FunctionPointer(_arguments, _result) => {
+                        // TODO should this be considered a closure of size 0?
+                        // or do we let the host call it directly?
+                        // then we have no RocCallResult wrapping though
+                    }
                     _ => {
                         // TODO
                     }
@@ -2215,12 +2219,11 @@ pub fn build_closure_caller<'a, 'ctx, 'env>(
     let function_pointer_type = {
         let function_layout =
             ClosureLayout::extend_function_layout(arena, arguments, closure.clone(), result);
-        let basic_type = basic_type_from_layout(arena, context, &function_layout, env.ptr_bytes);
 
         // this is already a (function) pointer type
-        basic_type
+        basic_type_from_layout(arena, context, &function_layout, env.ptr_bytes)
     };
-    argument_types.push(function_pointer_type.into());
+    argument_types.push(function_pointer_type);
 
     let closure_argument_type = {
         let basic_type = basic_type_from_layout(
diff --git a/compiler/mono/src/ir.rs b/compiler/mono/src/ir.rs
index 3ff462ff8f..af4fce5653 100644
--- a/compiler/mono/src/ir.rs
+++ b/compiler/mono/src/ir.rs
@@ -1793,9 +1793,7 @@ fn introduce_solved_type_to_subs<'a>(env: &mut Env<'a, '_>, solved_type: &Solved
 
     env.subs.extend_by(variables_introduced as usize);
 
-    let result = insert_type_into_subs(env.subs, &normal_type);
-
-    result
+    insert_type_into_subs(env.subs, &normal_type)
 }
 
 fn specialize_solved_type<'a>(
diff --git a/examples/closure/platform/src/lib.rs b/examples/closure/platform/src/lib.rs
index 11002134c0..4d23d9522c 100644
--- a/examples/closure/platform/src/lib.rs
+++ b/examples/closure/platform/src/lib.rs
@@ -1,9 +1,7 @@
 use roc_std::alloca;
+use roc_std::RocCallResult;
 use std::alloc::Layout;
-use std::ffi::CString;
-use std::os::raw::c_char;
 use std::time::SystemTime;
-use RocCallResult::*;
 
 extern "C" {
     #[link_name = "makeClosure_1_exposed"]
@@ -53,10 +51,10 @@ pub fn rust_main() -> isize {
 
         make_closure(buffer);
 
-        let output = &*(buffer as *mut RocCallResult<((), ())>);
+        let output = &*(buffer as *mut RocCallResult<()>);
 
         match output.into() {
-            Ok((_, _)) => {
+            Ok(()) => {
                 let function_pointer = {
                     // this is a pointer to the location where the function pointer is stored
                     // we pass just the function pointer
@@ -89,45 +87,3 @@ pub fn rust_main() -> isize {
     // Exit code
     0
 }
-
-#[repr(u64)]
-pub enum RocCallResult<T> {
-    Success(T),
-    Failure(*mut c_char),
-}
-
-impl<T: Sized> Into<Result<T, String>> for RocCallResult<T> {
-    fn into(self) -> Result<T, String> {
-        match self {
-            Success(value) => Ok(value),
-            Failure(failure) => Err({
-                let raw = unsafe { CString::from_raw(failure) };
-
-                let result = format!("{:?}", raw);
-
-                // make sure rust does not try to free the Roc string
-                std::mem::forget(raw);
-
-                result
-            }),
-        }
-    }
-}
-
-impl<T: Sized + Copy> Into<Result<T, String>> for &RocCallResult<T> {
-    fn into(self) -> Result<T, String> {
-        match self {
-            Success(value) => Ok(*value),
-            Failure(failure) => Err({
-                let raw = unsafe { CString::from_raw(*failure) };
-
-                let result = format!("{:?}", raw);
-
-                // make sure rust does not try to free the Roc string
-                std::mem::forget(raw);
-
-                result
-            }),
-        }
-    }
-}
diff --git a/roc_std/src/lib.rs b/roc_std/src/lib.rs
index 10e93386de..a501f7f26c 100644
--- a/roc_std/src/lib.rs
+++ b/roc_std/src/lib.rs
@@ -464,3 +464,30 @@ impl<T: Sized> Into<Result<T, &'static str>> for RocCallResult<T> {
         }
     }
 }
+
+impl<'a, T: Sized + Copy> Into<Result<T, &'a str>> for &'a RocCallResult<T> {
+    fn into(self) -> Result<T, &'a str> {
+        use RocCallResult::*;
+
+        match self {
+            Success(value) => Ok(*value),
+            Failure(failure) => Err({
+                let msg = unsafe {
+                    let mut null_byte_index = 0;
+                    loop {
+                        if *failure.offset(null_byte_index) == 0 {
+                            break;
+                        }
+                        null_byte_index += 1;
+                    }
+
+                    let bytes = core::slice::from_raw_parts(*failure, null_byte_index as usize);
+
+                    core::str::from_utf8_unchecked(bytes)
+                };
+
+                msg
+            }),
+        }
+    }
+}