delete GuestErrorConversion from docs, tests

crates/wiggle/tests/atoms.rs

@@ -6,7 +6,7 @@ wiggle::from_witx!({
     witx: ["$CARGO_MANIFEST_DIR/tests/atoms.witx"],
 });
 
-impl_errno!(types::Errno, types::GuestErrorConversion);
+impl_errno!(types::Errno);
 
 impl<'a> atoms::Atoms for WasiCtx<'a> {
     fn int_float_args(&self, an_int: u32, an_float: f32) -> Result<(), types::Errno> {

crates/wiggle/tests/atoms_async.rs

@@ -12,7 +12,7 @@ wiggle::from_witx!({
     }
 });
 
-impl_errno!(types::Errno, types::GuestErrorConversion);
+impl_errno!(types::Errno);
 
 #[wiggle::async_trait(?Send)]
 impl<'a> atoms::Atoms for WasiCtx<'a> {

crates/wiggle/tests/errors.rs

@@ -26,9 +26,7 @@ mod convert_just_errno {
         errors: { errno => RichError },
     });
 
-    // The impl of GuestErrorConversion works just like in every other test where
-    // we have a single error type with witx `$errno` with the success called `$ok`
-    impl_errno!(types::Errno, types::GuestErrorConversion);
+    impl_errno!(types::Errno);
 
     /// When the `errors` mapping in witx is non-empty, we need to impl the
     /// types::UserErrorConversion trait that wiggle generates from that mapping.
@@ -104,7 +102,7 @@ mod convert_just_errno {
 /// we use two distinct error types.
 mod convert_multiple_error_types {
     pub use super::convert_just_errno::RichError;
-    use wiggle_test::WasiCtx;
+    use wiggle_test::{impl_errno, WasiCtx};
 
     /// Test that we can map multiple types of errors.
     #[derive(Debug, thiserror::Error)]
@@ -135,27 +133,8 @@ mod convert_multiple_error_types {
         errors: { errno => RichError, errno2 => AnotherRichError },
     });
 
-    // Can't use the impl_errno! macro as usual here because the conversion
-    // trait ends up having two methods.
-    // We aren't going to execute this code, so the bodies are elided.
-    impl<'a> types::GuestErrorConversion for WasiCtx<'a> {
-        fn into_errno(&self, _e: wiggle::GuestError) -> types::Errno {
-            unimplemented!()
-        }
-        fn into_errno2(&self, _e: wiggle::GuestError) -> types::Errno2 {
-            unimplemented!()
-        }
-    }
-    impl wiggle::GuestErrorType for types::Errno {
-        fn success() -> types::Errno {
-            <types::Errno>::Ok
-        }
-    }
-    impl wiggle::GuestErrorType for types::Errno2 {
-        fn success() -> types::Errno2 {
-            <types::Errno2>::Ok
-        }
-    }
+    impl_errno!(types::Errno);
+    impl_errno!(types::Errno2);
 
     // The UserErrorConversion trait will also have two methods for this test. They correspond to
     // each member of the `errors` mapping.

crates/wiggle/tests/flags.rs

@@ -7,7 +7,7 @@ wiggle::from_witx!({
     witx: ["$CARGO_MANIFEST_DIR/tests/flags.witx"],
 });
 
-impl_errno!(types::Errno, types::GuestErrorConversion);
+impl_errno!(types::Errno);
 
 impl<'a> flags::Flags for WasiCtx<'a> {
     fn configure_car(

crates/wiggle/tests/handles.rs

@@ -8,7 +8,7 @@ wiggle::from_witx!({
     witx: ["$CARGO_MANIFEST_DIR/tests/handles.witx"],
 });
 
-impl_errno!(types::Errno, types::GuestErrorConversion);
+impl_errno!(types::Errno);
 
 impl<'a> handle_examples::HandleExamples for WasiCtx<'a> {
     fn fd_create(&self) -> Result<types::Fd, types::Errno> {

crates/wiggle/tests/ints.rs

@@ -7,7 +7,7 @@ wiggle::from_witx!({
     witx: ["$CARGO_MANIFEST_DIR/tests/ints.witx"],
 });
 
-impl_errno!(types::Errno, types::GuestErrorConversion);
+impl_errno!(types::Errno);
 
 impl<'a> ints::Ints for WasiCtx<'a> {
     fn cookie_cutter(&self, init_cookie: types::Cookie) -> Result<types::Bool, types::Errno> {

crates/wiggle/tests/lists.rs

@@ -6,7 +6,7 @@ wiggle::from_witx!({
     witx: ["$CARGO_MANIFEST_DIR/tests/lists.witx"],
 });
 
-impl_errno!(types::Errno, types::GuestErrorConversion);
+impl_errno!(types::Errno);
 
 impl<'a> lists::Lists for WasiCtx<'a> {
     fn reduce_excuses(

crates/wiggle/tests/pointers.rs

@@ -6,7 +6,7 @@ wiggle::from_witx!({
     witx: ["$CARGO_MANIFEST_DIR/tests/pointers.witx"],
 });
 
-impl_errno!(types::Errno, types::GuestErrorConversion);
+impl_errno!(types::Errno);
 
 impl<'a> pointers::Pointers for WasiCtx<'a> {
     fn pointers_and_enums<'b>(

crates/wiggle/tests/records.rs

@@ -6,7 +6,7 @@ wiggle::from_witx!({
     witx: ["$CARGO_MANIFEST_DIR/tests/records.witx"],
 });
 
-impl_errno!(types::Errno, types::GuestErrorConversion);
+impl_errno!(types::Errno);
 
 impl<'a> records::Records for WasiCtx<'a> {
     fn sum_of_pair(&self, an_pair: &types::PairInts) -> Result<i64, types::Errno> {

crates/wiggle/tests/strings.rs

@@ -6,7 +6,7 @@ wiggle::from_witx!({
     witx: ["$CARGO_MANIFEST_DIR/tests/strings.witx"],
 });
 
-impl_errno!(types::Errno, types::GuestErrorConversion);
+impl_errno!(types::Errno);
 
 impl<'a> strings::Strings for WasiCtx<'a> {
     fn hello_string(&self, a_string: &GuestPtr<str>) -> Result<u32, types::Errno> {

crates/wiggle/tests/variant.rs

@@ -6,7 +6,7 @@ wiggle::from_witx!({
     witx: ["$CARGO_MANIFEST_DIR/tests/variant.witx"],
 });
 
-impl_errno!(types::Errno, types::GuestErrorConversion);
+impl_errno!(types::Errno);
 
 // Avoid panics on overflow
 fn mult_lose_overflow(a: i32, b: u32) -> i32 {

crates/wiggle/tests/wasi.rs

@@ -1,4 +1,4 @@
-use wiggle::{GuestError, GuestErrorType, GuestPtr, GuestSlice};
+use wiggle::{GuestErrorType, GuestPtr, GuestSlice};
 use wiggle_test::WasiCtx;
 
 // This test file exists to make sure that the entire `wasi.witx` file can be
@@ -31,13 +31,6 @@ impl GuestErrorType for types::Errno {
     }
 }
 
-impl<'a> types::GuestErrorConversion for WasiCtx<'a> {
-    fn into_errno(&self, e: GuestError) -> types::Errno {
-        eprintln!("GuestError {:?}", e);
-        types::Errno::Badf
-    }
-}
-
 impl<'a> crate::wasi_snapshot_preview1::WasiSnapshotPreview1 for WasiCtx<'a> {
     fn args_get(&self, _argv: &GuestPtr<GuestPtr<u8>>, _argv_buf: &GuestPtr<u8>) -> Result<()> {
         unimplemented!("args_get")