From 2ea9247391be9c5a3e78d6d60d930c4c3baf4f28 Mon Sep 17 00:00:00 2001
From: Pat Hickey <phickey@fastly.com>
Date: Tue, 15 Nov 2022 16:47:12 -0800
Subject: [PATCH] mention in macro docs

---
 crates/wiggle/macro/src/lib.rs | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/crates/wiggle/macro/src/lib.rs b/crates/wiggle/macro/src/lib.rs
index 1b5cfb9d6f2a..9ea2cf104857 100644
--- a/crates/wiggle/macro/src/lib.rs
+++ b/crates/wiggle/macro/src/lib.rs
@@ -39,6 +39,10 @@ use syn::parse_macro_input;
 ///   `{ errno => YourErrnoType }`. This allows you to use the `UserErrorConversion`
 ///   trait to map these rich errors into the flat witx type, or to terminate
 ///   WebAssembly execution by trapping.
+///     * Instead of requiring the user to define an error type, wiggle can
+///       generate an error type for the user which has conversions to/from
+///       the base type, and permits trapping, using the syntax
+///       `errno => trappable AnErrorType`.
 /// * Optional: `async` takes a set of witx modules and functions which are
 ///   made Rust `async` functions in the module trait.
 ///