wiggle: delete GuestErrorConversion, improve some error reporting

crates/wiggle/generate/src/funcs.rs

@@ -139,10 +139,12 @@ impl witx::Bindgen for Rust<'_> {
     ) {
         let rt = self.rt;
         let wrap_err = |location: &str| {
+            let modulename = self.module.name.as_str();
             let funcname = self.funcname;
             quote! {
                 |e| {
                     #rt::GuestError::InFunc {
+                        modulename: #modulename,
                         funcname: #funcname,
                         location: #location,
                         err: Box::new(#rt::GuestError::from(e)),

crates/wiggle/generate/src/lib.rs

@@ -38,17 +38,6 @@ pub fn generate(doc: &witx::Document, names: &Names, settings: &CodegenSettings)
         }
     });
 
-    let guest_error_methods = doc.error_types().map(|t| {
-        let typename = names.type_ref(&t, anon_lifetime());
-        let err_method = names.guest_error_conversion_method(&t);
-        quote!(fn #err_method(&self, e: #rt::GuestError) -> #typename;)
-    });
-    let guest_error_conversion = quote! {
-        pub trait GuestErrorConversion {
-            #(#guest_error_methods)*
-        }
-    };
-
     let user_error_methods = settings.errors.iter().map(|errtype| {
         let abi_typename = names.type_ref(&errtype.abi_type(), anon_lifetime());
         let user_typename = errtype.typename();
@@ -82,7 +71,6 @@ pub fn generate(doc: &witx::Document, names: &Names, settings: &CodegenSettings)
 
             #(#types)*
             #(#constants)*
-            #guest_error_conversion
             #user_error_conversion
         }
         #(#modules)*

crates/wiggle/generate/src/names.rs

@@ -196,11 +196,6 @@ impl Names {
         }
     }
 
-    pub fn guest_error_conversion_method(&self, tref: &TypeRef) -> Ident {
-        let suffix = Self::snake_typename(tref);
-        format_ident!("into_{}", suffix)
-    }
-
     pub fn user_error_conversion_method(&self, user_type: &UserErrorType) -> Ident {
         let abi_type = Self::snake_typename(&user_type.abi_type());
         format_ident!(

crates/wiggle/macro/src/lib.rs

@@ -113,17 +113,6 @@ use syn::parse_macro_input;
 ///     }
 /// }
 ///
-/// /// The `types::GuestErrorConversion` trait is also generated with a method for
-/// /// each type used in the `error` position. This trait allows wiggle-generated
-/// /// code to convert a `wiggle::GuestError` into the right error type. The trait
-/// /// must be implemented for the user's ctx type.
-///
-/// impl types::GuestErrorConversion for YourCtxType {
-///     fn into_errno(&self, _e: wiggle::GuestError) -> types::Errno {
-///         unimplemented!()
-///     }
-/// }
-///
 /// /// If you specify a `error` mapping to the macro, you must implement the
 /// /// `types::UserErrorConversion` for your ctx type as well. This trait gives
 /// /// you an opportunity to store or log your rich error type, while returning

crates/wiggle/src/error.rs

@@ -19,20 +19,14 @@ pub enum GuestError {
     BorrowCheckerOutOfHandles,
     #[error("Slice length mismatch")]
     SliceLengthsDiffer,
-    #[error("In func {funcname}:{location}:")]
+    #[error("In func {modulename}::{funcname} at {location}: {err}")]
     InFunc {
+        modulename: &'static str,
         funcname: &'static str,
         location: &'static str,
         #[source]
         err: Box<GuestError>,
     },
-    #[error("In data {typename}.{field}:")]
-    InDataField {
-        typename: String,
-        field: String,
-        #[source]
-        err: Box<GuestError>,
-    },
     #[error("Invalid UTF-8 encountered: {0:?}")]
     InvalidUtf8(#[from] ::std::str::Utf8Error),
     #[error("Int conversion error: {0:?}")]

crates/wiggle/test-helpers/examples/tracing.rs

@@ -27,10 +27,6 @@ witx_literal: "
     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);
-
 /// When the `errors` mapping in witx is non-empty, we need to impl the
 /// types::UserErrorConversion trait that wiggle generates from that mapping.
 impl<'a> types::UserErrorConversion for WasiCtx<'a> {

crates/wiggle/test-helpers/src/lib.rs

@@ -347,18 +347,11 @@ impl<'a> WasiCtx<'a> {
 // with these errors. We just push them to vecs.
 #[macro_export]
 macro_rules! impl_errno {
-    ( $errno:ty, $convert:path ) => {
+    ( $errno:ty ) => {
         impl wiggle::GuestErrorType for $errno {
             fn success() -> $errno {
                 <$errno>::Ok
             }
         }
-        impl<'a> $convert for WasiCtx<'a> {
-            fn into_errno(&self, e: wiggle::GuestError) -> $errno {
-                eprintln!("GuestError: {:?}", e);
-                self.guest_errors.borrow_mut().push(e);
-                <$errno>::InvalidArg
-            }
-        }
     };
 }

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")