diff --git a/CHANGELOG.md b/CHANGELOG.md
index 01163915a82..9284916aa5d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@ All PRs to the Wasmer repository must add to this file.
 Blocks of changes will separated by version increments.
 
 ## **[Unreleased]**
+- [#371](https://github.com/wasmerio/wasmer/pull/371) Add more Debug impl for WASI types
 - [#368](https://github.com/wasmerio/wasmer/pull/368) Fix issue with write buffering
 - [#343](https://github.com/wasmerio/wasmer/pull/343) Implement preopened files for WASI and fix aligment issue when accessing WASI memory
 - [#367](https://github.com/wasmerio/wasmer/pull/367) Add caching support to the LLVM backend.
diff --git a/lib/wasi/src/macros.rs b/lib/wasi/src/macros.rs
index 0e00e77b319..1420b8f2d25 100644
--- a/lib/wasi/src/macros.rs
+++ b/lib/wasi/src/macros.rs
@@ -2,8 +2,14 @@ macro_rules! wasi_try {
     ($expr:expr) => {{
         let res: Result<_, crate::syscalls::types::__wasi_errno_t> = $expr;
         match res {
-            Ok(val) => val,
-            Err(err) => return err,
+            Ok(val) => {
+                debug!("wasi::wasi_try::val: {:?}", val);
+                val
+            }
+            Err(err) => {
+                debug!("wasi::wasi_try::err: {:?}", err);
+                return err;
+            }
         }
     }};
     ($expr:expr; $e:expr) => {{
diff --git a/lib/wasi/src/state.rs b/lib/wasi/src/state.rs
index 65cc3e6a88e..813250c574d 100644
--- a/lib/wasi/src/state.rs
+++ b/lib/wasi/src/state.rs
@@ -171,6 +171,7 @@ pub struct Fd {
     pub inode: Inode,
 }
 
+#[derive(Debug)]
 pub struct WasiFs {
     //pub repo: Repo,
     pub name_map: HashMap<String, Inode>,
@@ -430,6 +431,7 @@ impl WasiFs {
     }
 }
 
+#[derive(Debug)]
 pub struct WasiState<'a> {
     pub fs: WasiFs,
     pub args: &'a [Vec<u8>],
diff --git a/lib/wasi/src/syscalls/types.rs b/lib/wasi/src/syscalls/types.rs
index 6e16e03c651..c030df3124b 100644
--- a/lib/wasi/src/syscalls/types.rs
+++ b/lib/wasi/src/syscalls/types.rs
@@ -2,6 +2,7 @@
 
 use crate::ptr::{Array, WasmPtr};
 use byteorder::{ReadBytesExt, WriteBytesExt, LE};
+use std::fmt;
 use std::mem;
 use wasmer_runtime_core::types::ValueType;
 
@@ -212,9 +213,15 @@ pub union __wasi_prestat_u {
     dir: __wasi_prestat_u_dir_t,
 }
 
+impl fmt::Debug for __wasi_prestat_u {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "__wasi_prestat_u")
+    }
+}
+
 unsafe impl ValueType for __wasi_prestat_u {}
 
-#[derive(Copy, Clone)]
+#[derive(Debug, Copy, Clone)]
 #[repr(C)]
 pub struct __wasi_prestat_t {
     pub pr_type: __wasi_preopentype_t,