diff --git a/repl_test/src/wasm.rs b/repl_test/src/wasm.rs
index 64df3a5d7c..f3722cd2ed 100644
--- a/repl_test/src/wasm.rs
+++ b/repl_test/src/wasm.rs
@@ -6,10 +6,12 @@ use std::{
     sync::Mutex,
     thread_local,
 };
-use wasmer::{imports, Function, Instance, Module, Store, Value};
+use wasmer::{
+    imports, ChainableNamedResolver, Function, ImportObject, Instance, Module, Store, Value,
+};
 use wasmer_wasi::WasiState;
 
-const WASM_REPL_COMPILER_PATH: &str = "../target/wasm32-unknown-unknown/release/roc_repl_wasm.wasm";
+const WASM_REPL_COMPILER_PATH: &str = "../target/wasm32-wasi/release/roc_repl_wasm.wasm";
 
 thread_local! {
     static REPL_STATE: RefCell<Option<ReplState>> = RefCell::new(None)
@@ -40,7 +42,13 @@ fn init_compiler() -> Instance {
     let wasmer_module =
         unsafe { Module::from_binary_unchecked(&store, &wasm_module_bytes).unwrap() };
 
-    let import_object = imports! {
+    // Specify the external functions the Wasm module needs to link to
+    // We only use WASI so that we can debug test failures more easily with println!(), dbg!(), etc.
+    let mut wasi_env = WasiState::new("compiler").finalize().unwrap();
+    let wasi_import_obj = wasi_env
+        .import_object(&wasmer_module)
+        .unwrap_or_else(|_| ImportObject::new());
+    let repl_import_obj = imports! {
         "env" => {
             "wasmer_create_app" => Function::new_native(&store, wasmer_create_app),
             "wasmer_run_app" => Function::new_native(&store, wasmer_run_app),
@@ -50,7 +58,10 @@ fn init_compiler() -> Instance {
             "now" => Function::new_native(&store, dummy_system_time_now),
         }
     };
+    // "Chain" the import objects together. Wasmer will look up the REPL object first, then the WASI object
+    let import_object = wasi_import_obj.chain_front(repl_import_obj);
 
+    // Make a fully-linked instance with its own block of memory
     Instance::new(&wasmer_module, &import_object).unwrap()
 }
 
@@ -87,7 +98,7 @@ fn wasmer_create_app(app_bytes_ptr: u32, app_bytes_len: u32) -> u32 {
         };
 
         // Get the WASI imports for the app
-        let mut wasi_env = WasiState::new("hello").finalize().unwrap();
+        let mut wasi_env = WasiState::new("app").finalize().unwrap();
         let import_object = wasi_env
             .import_object(&wasmer_module)
             .unwrap_or_else(|_| imports!());
diff --git a/repl_test/test_wasm.sh b/repl_test/test_wasm.sh
index 41ded30ab4..08a49a8d31 100755
--- a/repl_test/test_wasm.sh
+++ b/repl_test/test_wasm.sh
@@ -2,9 +2,11 @@ set -eux
 
 # Build the compiler for WebAssembly target
 # We *could* write a build.rs to do this but we'd have nested cargo processes with different targets.
-# That can be solved using two separate target direcories with --target-dir but there isn't a huge win.
+# If we ever decide to do that, one of the cargo processes will need to use the `--target-dir` option.
+
 # We need to clear RUSTFLAGS for this command, as CI sets normally some flags that are specific to CPU targets.
-RUSTFLAGS="" cargo build --target wasm32-unknown-unknown -p roc_repl_wasm --no-default-features --features wasmer --release
+# Tests target wasm32-wasi instead of wasm32-unknown-unknown, so that we can debug with println! and dbg!
+RUSTFLAGS="" cargo build --target wasm32-wasi -p roc_repl_wasm --no-default-features --features wasmer --release
 
 # Build & run the test code on *native* target, not WebAssembly
 cargo test -p repl_test --features wasm -- --test-threads=1