6 files changed, 479 insertions, 152 deletions

diff --git a/rust/qemu-api-macros/Cargo.toml b/rust/qemu-api-macros/Cargo.toml
index 89dee1c..0cd40c8 100644
--- a/rust/qemu-api-macros/Cargo.toml
+++ b/rust/qemu-api-macros/Cargo.toml
@@ -1,15 +1,16 @@
 [package]
 name = "qemu_api_macros"
 version = "0.1.0"
-edition = "2021"
 authors = ["Manos Pitsidianakis <manos.pitsidianakis@linaro.org>"]
-license = "GPL-2.0-or-later"
 description = "Rust bindings for QEMU - Utility macros"
 resolver = "2"
 publish = false
-keywords = []
-categories = []
-rust-version = "1.63.0"
+
+edition.workspace = true
+homepage.workspace = true
+license.workspace = true
+repository.workspace = true
+rust-version.workspace = true
 
 [lib]
 proc-macro = true
diff --git a/rust/qemu-api-macros/meson.build b/rust/qemu-api-macros/meson.build
index 6f94a4b..2152bcb 100644
--- a/rust/qemu-api-macros/meson.build
+++ b/rust/qemu-api-macros/meson.build
@@ -1,11 +1,3 @@
-subproject('proc-macro2-1-rs', required: true)
-subproject('quote-1-rs', required: true)
-subproject('syn-2-rs', required: true)
-
-quote_dep = dependency('quote-1-rs', native: true)
-syn_dep = dependency('syn-2-rs', native: true)
-proc_macro2_dep = dependency('proc-macro2-1-rs', native: true)
-
 _qemu_api_macros_rs = rust.proc_macro(
   'qemu_api_macros',
   files('src/lib.rs'),
@@ -16,12 +8,15 @@ _qemu_api_macros_rs = rust.proc_macro(
     '--cfg', 'feature="proc-macro"',
   ],
   dependencies: [
-    proc_macro2_dep,
-    quote_dep,
-    syn_dep,
+    proc_macro2_rs_native,
+    quote_rs_native,
+    syn_rs_native,
   ],
 )
 
 qemu_api_macros = declare_dependency(
   link_with: _qemu_api_macros_rs,
 )
+
+rust.test('rust-qemu-api-macros-tests', _qemu_api_macros_rs,
+          suite: ['unit', 'rust'])
diff --git a/rust/qemu-api-macros/src/bits.rs b/rust/qemu-api-macros/src/bits.rs
new file mode 100644
index 0000000..a80a3b9
--- /dev/null
+++ b/rust/qemu-api-macros/src/bits.rs
@@ -0,0 +1,213 @@
+// SPDX-License-Identifier: MIT or Apache-2.0 or GPL-2.0-or-later
+
+// shadowing is useful together with "if let"
+#![allow(clippy::shadow_unrelated)]
+
+use proc_macro2::{
+    Delimiter, Group, Ident, Punct, Spacing, Span, TokenStream, TokenTree, TokenTree as TT,
+};
+use syn::Error;
+
+pub struct BitsConstInternal {
+    typ: TokenTree,
+}
+
+fn paren(ts: TokenStream) -> TokenTree {
+    TT::Group(Group::new(Delimiter::Parenthesis, ts))
+}
+
+fn ident(s: &'static str) -> TokenTree {
+    TT::Ident(Ident::new(s, Span::call_site()))
+}
+
+fn punct(ch: char) -> TokenTree {
+    TT::Punct(Punct::new(ch, Spacing::Alone))
+}
+
+/// Implements a recursive-descent parser that translates Boolean expressions on
+/// bitmasks to invocations of `const` functions defined by the `bits!` macro.
+impl BitsConstInternal {
+    // primary ::= '(' or ')'
+    //           | ident
+    //           | '!' ident
+    fn parse_primary(
+        &self,
+        tok: TokenTree,
+        it: &mut dyn Iterator<Item = TokenTree>,
+        out: &mut TokenStream,
+    ) -> Result<Option<TokenTree>, Error> {
+        let next = match tok {
+            TT::Group(ref g) => {
+                if g.delimiter() != Delimiter::Parenthesis && g.delimiter() != Delimiter::None {
+                    return Err(Error::new(g.span(), "expected parenthesis"));
+                }
+                let mut stream = g.stream().into_iter();
+                let Some(first_tok) = stream.next() else {
+                    return Err(Error::new(g.span(), "expected operand, found ')'"));
+                };
+                let mut output = TokenStream::new();
+                // start from the lowest precedence
+                let next = self.parse_or(first_tok, &mut stream, &mut output)?;
+                if let Some(tok) = next {
+                    return Err(Error::new(tok.span(), format!("unexpected token {tok}")));
+                }
+                out.extend(Some(paren(output)));
+                it.next()
+            }
+            TT::Ident(_) => {
+                let mut output = TokenStream::new();
+                output.extend([
+                    self.typ.clone(),
+                    TT::Punct(Punct::new(':', Spacing::Joint)),
+                    TT::Punct(Punct::new(':', Spacing::Joint)),
+                    tok,
+                ]);
+                out.extend(Some(paren(output)));
+                it.next()
+            }
+            TT::Punct(ref p) => {
+                if p.as_char() != '!' {
+                    return Err(Error::new(p.span(), "expected operand"));
+                }
+                let Some(rhs_tok) = it.next() else {
+                    return Err(Error::new(p.span(), "expected operand at end of input"));
+                };
+                let next = self.parse_primary(rhs_tok, it, out)?;
+                out.extend([punct('.'), ident("invert"), paren(TokenStream::new())]);
+                next
+            }
+            _ => {
+                return Err(Error::new(tok.span(), "unexpected literal"));
+            }
+        };
+        Ok(next)
+    }
+
+    fn parse_binop<
+        F: Fn(
+            &Self,
+            TokenTree,
+            &mut dyn Iterator<Item = TokenTree>,
+            &mut TokenStream,
+        ) -> Result<Option<TokenTree>, Error>,
+    >(
+        &self,
+        tok: TokenTree,
+        it: &mut dyn Iterator<Item = TokenTree>,
+        out: &mut TokenStream,
+        ch: char,
+        f: F,
+        method: &'static str,
+    ) -> Result<Option<TokenTree>, Error> {
+        let mut next = f(self, tok, it, out)?;
+        while next.is_some() {
+            let op = next.as_ref().unwrap();
+            let TT::Punct(ref p) = op else { break };
+            if p.as_char() != ch {
+                break;
+            }
+
+            let Some(rhs_tok) = it.next() else {
+                return Err(Error::new(p.span(), "expected operand at end of input"));
+            };
+            let mut rhs = TokenStream::new();
+            next = f(self, rhs_tok, it, &mut rhs)?;
+            out.extend([punct('.'), ident(method), paren(rhs)]);
+        }
+        Ok(next)
+    }
+
+    // sub ::= primary ('-' primary)*
+    pub fn parse_sub(
+        &self,
+        tok: TokenTree,
+        it: &mut dyn Iterator<Item = TokenTree>,
+        out: &mut TokenStream,
+    ) -> Result<Option<TokenTree>, Error> {
+        self.parse_binop(tok, it, out, '-', Self::parse_primary, "difference")
+    }
+
+    // and ::= sub ('&' sub)*
+    fn parse_and(
+        &self,
+        tok: TokenTree,
+        it: &mut dyn Iterator<Item = TokenTree>,
+        out: &mut TokenStream,
+    ) -> Result<Option<TokenTree>, Error> {
+        self.parse_binop(tok, it, out, '&', Self::parse_sub, "intersection")
+    }
+
+    // xor ::= and ('&' and)*
+    fn parse_xor(
+        &self,
+        tok: TokenTree,
+        it: &mut dyn Iterator<Item = TokenTree>,
+        out: &mut TokenStream,
+    ) -> Result<Option<TokenTree>, Error> {
+        self.parse_binop(tok, it, out, '^', Self::parse_and, "symmetric_difference")
+    }
+
+    // or ::= xor ('|' xor)*
+    pub fn parse_or(
+        &self,
+        tok: TokenTree,
+        it: &mut dyn Iterator<Item = TokenTree>,
+        out: &mut TokenStream,
+    ) -> Result<Option<TokenTree>, Error> {
+        self.parse_binop(tok, it, out, '|', Self::parse_xor, "union")
+    }
+
+    pub fn parse(
+        it: &mut dyn Iterator<Item = TokenTree>,
+    ) -> Result<proc_macro2::TokenStream, Error> {
+        let mut pos = Span::call_site();
+        let mut typ = proc_macro2::TokenStream::new();
+
+        // Gobble everything up to an `@` sign, which is followed by a
+        // parenthesized expression; that is, all token trees except the
+        // last two form the type.
+        let next = loop {
+            let tok = it.next();
+            if let Some(ref t) = tok {
+                pos = t.span();
+            }
+            match tok {
+                None => break None,
+                Some(TT::Punct(ref p)) if p.as_char() == '@' => {
+                    let tok = it.next();
+                    if let Some(ref t) = tok {
+                        pos = t.span();
+                    }
+                    break tok;
+                }
+                Some(x) => typ.extend(Some(x)),
+            }
+        };
+
+        let Some(tok) = next else {
+            return Err(Error::new(
+                pos,
+                "expected expression, do not call this macro directly",
+            ));
+        };
+        let TT::Group(ref _group) = tok else {
+            return Err(Error::new(
+                tok.span(),
+                "expected parenthesis, do not call this macro directly",
+            ));
+        };
+        let mut out = TokenStream::new();
+        let state = Self {
+            typ: TT::Group(Group::new(Delimiter::None, typ)),
+        };
+
+        let next = state.parse_primary(tok, it, &mut out)?;
+
+        // A parenthesized expression is a single production of the grammar,
+        // so the input must have reached the last token.
+        if let Some(tok) = next {
+            return Err(Error::new(tok.span(), format!("unexpected token {tok}")));
+        }
+        Ok(out)
+    }
+}
diff --git a/rust/qemu-api-macros/src/lib.rs b/rust/qemu-api-macros/src/lib.rs
index eda0d46..b525d89 100644
--- a/rust/qemu-api-macros/src/lib.rs
+++ b/rust/qemu-api-macros/src/lib.rs
@@ -6,89 +6,82 @@ use proc_macro::TokenStream;
 use quote::quote;
 use syn::{
     parse_macro_input, parse_quote, punctuated::Punctuated, spanned::Spanned, token::Comma, Data,
-    DeriveInput, Field, Fields, FieldsUnnamed, Ident, Meta, Path, Token, Type, Variant, Visibility,
+    DeriveInput, Error, Field, Fields, FieldsUnnamed, Ident, Meta, Path, Token, Variant,
 };
+mod bits;
+use bits::BitsConstInternal;
 
-mod utils;
-use utils::MacroError;
+#[cfg(test)]
+mod tests;
 
 fn get_fields<'a>(
     input: &'a DeriveInput,
     msg: &str,
-) -> Result<&'a Punctuated<Field, Comma>, MacroError> {
-    if let Data::Struct(s) = &input.data {
-        if let Fields::Named(fs) = &s.fields {
-            Ok(&fs.named)
-        } else {
-            Err(MacroError::Message(
-                format!("Named fields required for {}", msg),
-                input.ident.span(),
-            ))
-        }
-    } else {
-        Err(MacroError::Message(
-            format!("Struct required for {}", msg),
+) -> Result<&'a Punctuated<Field, Comma>, Error> {
+    let Data::Struct(ref s) = &input.data else {
+        return Err(Error::new(
             input.ident.span(),
-        ))
-    }
+            format!("Struct required for {msg}"),
+        ));
+    };
+    let Fields::Named(ref fs) = &s.fields else {
+        return Err(Error::new(
+            input.ident.span(),
+            format!("Named fields required for {msg}"),
+        ));
+    };
+    Ok(&fs.named)
 }
 
-fn get_unnamed_field<'a>(input: &'a DeriveInput, msg: &str) -> Result<&'a Field, MacroError> {
-    if let Data::Struct(s) = &input.data {
-        let unnamed = match &s.fields {
-            Fields::Unnamed(FieldsUnnamed {
-                unnamed: ref fields,
-                ..
-            }) => fields,
-            _ => {
-                return Err(MacroError::Message(
-                    format!("Tuple struct required for {}", msg),
-                    s.fields.span(),
-                ))
-            }
-        };
-        if unnamed.len() != 1 {
-            return Err(MacroError::Message(
-                format!("A single field is required for {}", msg),
-                s.fields.span(),
-            ));
-        }
-        Ok(&unnamed[0])
-    } else {
-        Err(MacroError::Message(
-            format!("Struct required for {}", msg),
+fn get_unnamed_field<'a>(input: &'a DeriveInput, msg: &str) -> Result<&'a Field, Error> {
+    let Data::Struct(ref s) = &input.data else {
+        return Err(Error::new(
             input.ident.span(),
-        ))
+            format!("Struct required for {msg}"),
+        ));
+    };
+    let Fields::Unnamed(FieldsUnnamed { ref unnamed, .. }) = &s.fields else {
+        return Err(Error::new(
+            s.fields.span(),
+            format!("Tuple struct required for {msg}"),
+        ));
+    };
+    if unnamed.len() != 1 {
+        return Err(Error::new(
+            s.fields.span(),
+            format!("A single field is required for {msg}"),
+        ));
     }
+    Ok(&unnamed[0])
 }
 
-fn is_c_repr(input: &DeriveInput, msg: &str) -> Result<(), MacroError> {
+fn is_c_repr(input: &DeriveInput, msg: &str) -> Result<(), Error> {
     let expected = parse_quote! { #[repr(C)] };
 
     if input.attrs.iter().any(|attr| attr == &expected) {
         Ok(())
     } else {
-        Err(MacroError::Message(
-            format!("#[repr(C)] required for {}", msg),
+        Err(Error::new(
             input.ident.span(),
+            format!("#[repr(C)] required for {msg}"),
         ))
     }
 }
 
-fn is_transparent_repr(input: &DeriveInput, msg: &str) -> Result<(), MacroError> {
+fn is_transparent_repr(input: &DeriveInput, msg: &str) -> Result<(), Error> {
     let expected = parse_quote! { #[repr(transparent)] };
 
     if input.attrs.iter().any(|attr| attr == &expected) {
         Ok(())
     } else {
-        Err(MacroError::Message(
-            format!("#[repr(transparent)] required for {}", msg),
+        Err(Error::new(
             input.ident.span(),
+            format!("#[repr(transparent)] required for {msg}"),
         ))
     }
 }
 
-fn derive_object_or_error(input: DeriveInput) -> Result<proc_macro2::TokenStream, MacroError> {
+fn derive_object_or_error(input: DeriveInput) -> Result<proc_macro2::TokenStream, Error> {
     is_c_repr(&input, "#[derive(Object)]")?;
 
     let name = &input.ident;
@@ -109,12 +102,13 @@ fn derive_object_or_error(input: DeriveInput) -> Result<proc_macro2::TokenStream
 #[proc_macro_derive(Object)]
 pub fn derive_object(input: TokenStream) -> TokenStream {
     let input = parse_macro_input!(input as DeriveInput);
-    let expanded = derive_object_or_error(input).unwrap_or_else(Into::into);
 
-    TokenStream::from(expanded)
+    derive_object_or_error(input)
+        .unwrap_or_else(syn::Error::into_compile_error)
+        .into()
 }
 
-fn derive_opaque_or_error(input: DeriveInput) -> Result<proc_macro2::TokenStream, MacroError> {
+fn derive_opaque_or_error(input: DeriveInput) -> Result<proc_macro2::TokenStream, Error> {
     is_transparent_repr(&input, "#[derive(Wrapper)]")?;
 
     let name = &input.ident;
@@ -155,40 +149,14 @@ fn derive_opaque_or_error(input: DeriveInput) -> Result<proc_macro2::TokenStream
 #[proc_macro_derive(Wrapper)]
 pub fn derive_opaque(input: TokenStream) -> TokenStream {
     let input = parse_macro_input!(input as DeriveInput);
-    let expanded = derive_opaque_or_error(input).unwrap_or_else(Into::into);
-
-    TokenStream::from(expanded)
-}
-
-#[rustfmt::skip::macros(quote)]
-fn derive_offsets_or_error(input: DeriveInput) -> Result<proc_macro2::TokenStream, MacroError> {
-    is_c_repr(&input, "#[derive(offsets)]")?;
-
-    let name = &input.ident;
-    let fields = get_fields(&input, "#[derive(offsets)]")?;
-    let field_names: Vec<&Ident> = fields.iter().map(|f| f.ident.as_ref().unwrap()).collect();
-    let field_types: Vec<&Type> = fields.iter().map(|f| &f.ty).collect();
-    let field_vis: Vec<&Visibility> = fields.iter().map(|f| &f.vis).collect();
-
-    Ok(quote! {
-	::qemu_api::with_offsets! {
-	    struct #name {
-		#(#field_vis #field_names: #field_types,)*
-	    }
-	}
-    })
-}
-
-#[proc_macro_derive(offsets)]
-pub fn derive_offsets(input: TokenStream) -> TokenStream {
-    let input = parse_macro_input!(input as DeriveInput);
-    let expanded = derive_offsets_or_error(input).unwrap_or_else(Into::into);
 
-    TokenStream::from(expanded)
+    derive_opaque_or_error(input)
+        .unwrap_or_else(syn::Error::into_compile_error)
+        .into()
 }
 
 #[allow(non_snake_case)]
-fn get_repr_uN(input: &DeriveInput, msg: &str) -> Result<Path, MacroError> {
+fn get_repr_uN(input: &DeriveInput, msg: &str) -> Result<Path, Error> {
     let repr = input.attrs.iter().find(|attr| attr.path().is_ident("repr"));
     if let Some(repr) = repr {
         let nested = repr.parse_args_with(Punctuated::<Meta, Token![,]>::parse_terminated)?;
@@ -203,47 +171,75 @@ fn get_repr_uN(input: &DeriveInput, msg: &str) -> Result<Path, MacroError> {
         }
     }
 
-    Err(MacroError::Message(
-        format!("#[repr(u8/u16/u32/u64) required for {}", msg),
+    Err(Error::new(
         input.ident.span(),
+        format!("#[repr(u8/u16/u32/u64) required for {msg}"),
     ))
 }
 
-fn get_variants(input: &DeriveInput) -> Result<&Punctuated<Variant, Comma>, MacroError> {
-    if let Data::Enum(e) = &input.data {
-        if let Some(v) = e.variants.iter().find(|v| v.fields != Fields::Unit) {
-            return Err(MacroError::Message(
-                "Cannot derive TryInto for enum with non-unit variants.".to_string(),
-                v.fields.span(),
-            ));
-        }
-        Ok(&e.variants)
-    } else {
-        Err(MacroError::Message(
-            "Cannot derive TryInto for union or struct.".to_string(),
+fn get_variants(input: &DeriveInput) -> Result<&Punctuated<Variant, Comma>, Error> {
+    let Data::Enum(ref e) = &input.data else {
+        return Err(Error::new(
             input.ident.span(),
-        ))
+            "Cannot derive TryInto for union or struct.",
+        ));
+    };
+    if let Some(v) = e.variants.iter().find(|v| v.fields != Fields::Unit) {
+        return Err(Error::new(
+            v.fields.span(),
+            "Cannot derive TryInto for enum with non-unit variants.",
+        ));
     }
+    Ok(&e.variants)
 }
 
 #[rustfmt::skip::macros(quote)]
-fn derive_tryinto_or_error(input: DeriveInput) -> Result<proc_macro2::TokenStream, MacroError> {
-    let repr = get_repr_uN(&input, "#[derive(TryInto)]")?;
+fn derive_tryinto_body(
+    name: &Ident,
+    variants: &Punctuated<Variant, Comma>,
+    repr: &Path,
+) -> Result<proc_macro2::TokenStream, Error> {
+    let discriminants: Vec<&Ident> = variants.iter().map(|f| &f.ident).collect();
 
+    Ok(quote! {
+        #(const #discriminants: #repr = #name::#discriminants as #repr;)*
+        match value {
+            #(#discriminants => core::result::Result::Ok(#name::#discriminants),)*
+            _ => core::result::Result::Err(value),
+        }
+    })
+}
+
+#[rustfmt::skip::macros(quote)]
+fn derive_tryinto_or_error(input: DeriveInput) -> Result<proc_macro2::TokenStream, Error> {
+    let repr = get_repr_uN(&input, "#[derive(TryInto)]")?;
     let name = &input.ident;
-    let variants = get_variants(&input)?;
-    let discriminants: Vec<&Ident> = variants.iter().map(|f| &f.ident).collect();
+    let body = derive_tryinto_body(name, get_variants(&input)?, &repr)?;
+    let errmsg = format!("invalid value for {name}");
 
     Ok(quote! {
+        impl #name {
+            #[allow(dead_code)]
+            pub const fn into_bits(self) -> #repr {
+                self as #repr
+            }
+
+            #[allow(dead_code)]
+            pub const fn from_bits(value: #repr) -> Self {
+                match ({
+                    #body
+                }) {
+                    Ok(x) => x,
+                    Err(_) => panic!(#errmsg),
+                }
+            }
+        }
         impl core::convert::TryFrom<#repr> for #name {
             type Error = #repr;
 
-            fn try_from(value: #repr) -> Result<Self, Self::Error> {
-                #(const #discriminants: #repr = #name::#discriminants as #repr;)*;
-                match value {
-                    #(#discriminants => Ok(Self::#discriminants),)*
-                    _ => Err(value),
-                }
+            #[allow(ambiguous_associated_items)]
+            fn try_from(value: #repr) -> Result<Self, #repr> {
+                #body
             }
         }
     })
@@ -252,7 +248,18 @@ fn derive_tryinto_or_error(input: DeriveInput) -> Result<proc_macro2::TokenStrea
 #[proc_macro_derive(TryInto)]
 pub fn derive_tryinto(input: TokenStream) -> TokenStream {
     let input = parse_macro_input!(input as DeriveInput);
-    let expanded = derive_tryinto_or_error(input).unwrap_or_else(Into::into);
 
-    TokenStream::from(expanded)
+    derive_tryinto_or_error(input)
+        .unwrap_or_else(syn::Error::into_compile_error)
+        .into()
+}
+
+#[proc_macro]
+pub fn bits_const_internal(ts: TokenStream) -> TokenStream {
+    let ts = proc_macro2::TokenStream::from(ts);
+    let mut it = ts.into_iter();
+
+    BitsConstInternal::parse(&mut it)
+        .unwrap_or_else(syn::Error::into_compile_error)
+        .into()
 }
diff --git a/rust/qemu-api-macros/src/tests.rs b/rust/qemu-api-macros/src/tests.rs
new file mode 100644
index 0000000..d6dcd62
--- /dev/null
+++ b/rust/qemu-api-macros/src/tests.rs
@@ -0,0 +1,137 @@
+// Copyright 2025, Linaro Limited
+// Author(s): Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+use quote::quote;
+
+use super::*;
+
+macro_rules! derive_compile_fail {
+    ($derive_fn:ident, $input:expr, $error_msg:expr) => {{
+        let input: proc_macro2::TokenStream = $input;
+        let error_msg: &str = $error_msg;
+        let derive_fn: fn(input: syn::DeriveInput) -> Result<proc_macro2::TokenStream, syn::Error> =
+            $derive_fn;
+
+        let input: syn::DeriveInput = syn::parse2(input).unwrap();
+        let result = derive_fn(input);
+        let err = result.unwrap_err().into_compile_error();
+        assert_eq!(
+            err.to_string(),
+            quote! { ::core::compile_error! { #error_msg } }.to_string()
+        );
+    }};
+}
+
+macro_rules! derive_compile {
+    ($derive_fn:ident, $input:expr, $($expected:tt)*) => {{
+        let input: proc_macro2::TokenStream = $input;
+        let expected: proc_macro2::TokenStream = $($expected)*;
+        let derive_fn: fn(input: syn::DeriveInput) -> Result<proc_macro2::TokenStream, syn::Error> =
+            $derive_fn;
+
+        let input: syn::DeriveInput = syn::parse2(input).unwrap();
+        let result = derive_fn(input).unwrap();
+        assert_eq!(result.to_string(), expected.to_string());
+    }};
+}
+
+#[test]
+fn test_derive_object() {
+    derive_compile_fail!(
+        derive_object_or_error,
+        quote! {
+            #[derive(Object)]
+            struct Foo {
+                _unused: [u8; 0],
+            }
+        },
+        "#[repr(C)] required for #[derive(Object)]"
+    );
+    derive_compile!(
+        derive_object_or_error,
+        quote! {
+            #[derive(Object)]
+            #[repr(C)]
+            struct Foo {
+                _unused: [u8; 0],
+            }
+        },
+        quote! {
+            ::qemu_api::assert_field_type!(
+                Foo,
+                _unused,
+                ::qemu_api::qom::ParentField<<Foo as ::qemu_api::qom::ObjectImpl>::ParentType>
+            );
+            ::qemu_api::module_init! {
+                MODULE_INIT_QOM => unsafe {
+                    ::qemu_api::bindings::type_register_static(&<Foo as ::qemu_api::qom::ObjectImpl>::TYPE_INFO);
+                }
+            }
+        }
+    );
+}
+
+#[test]
+fn test_derive_tryinto() {
+    derive_compile_fail!(
+        derive_tryinto_or_error,
+        quote! {
+            #[derive(TryInto)]
+            struct Foo {
+                _unused: [u8; 0],
+            }
+        },
+        "#[repr(u8/u16/u32/u64) required for #[derive(TryInto)]"
+    );
+    derive_compile!(
+        derive_tryinto_or_error,
+        quote! {
+            #[derive(TryInto)]
+            #[repr(u8)]
+            enum Foo {
+                First = 0,
+                Second,
+            }
+        },
+        quote! {
+            impl Foo {
+                #[allow(dead_code)]
+                pub const fn into_bits(self) -> u8 {
+                    self as u8
+                }
+
+                #[allow(dead_code)]
+                pub const fn from_bits(value: u8) -> Self {
+                    match ({
+                        const First: u8 = Foo::First as u8;
+                        const Second: u8 = Foo::Second as u8;
+                        match value {
+                            First => core::result::Result::Ok(Foo::First),
+                            Second => core::result::Result::Ok(Foo::Second),
+                            _ => core::result::Result::Err(value),
+                        }
+                    }) {
+                        Ok(x) => x,
+                        Err(_) => panic!("invalid value for Foo"),
+                    }
+                }
+            }
+
+            impl core::convert::TryFrom<u8> for Foo {
+                type Error = u8;
+
+                #[allow(ambiguous_associated_items)]
+                fn try_from(value: u8) -> Result<Self, u8> {
+                    const First: u8 = Foo::First as u8;
+                    const Second: u8 = Foo::Second as u8;
+                    match value {
+                        First => core::result::Result::Ok(Foo::First),
+                        Second => core::result::Result::Ok(Foo::Second),
+                        _ => core::result::Result::Err(value),
+                    }
+                }
+            }
+        }
+    );
+}
diff --git a/rust/qemu-api-macros/src/utils.rs b/rust/qemu-api-macros/src/utils.rs
deleted file mode 100644
index 02c91ae..0000000
--- a/rust/qemu-api-macros/src/utils.rs
+++ /dev/null
@@ -1,26 +0,0 @@
-// Procedural macro utilities.
-// Author(s): Paolo Bonzini <pbonzini@redhat.com>
-// SPDX-License-Identifier: GPL-2.0-or-later
-
-use proc_macro2::Span;
-use quote::quote_spanned;
-
-pub enum MacroError {
-    Message(String, Span),
-    ParseError(syn::Error),
-}
-
-impl From<syn::Error> for MacroError {
-    fn from(err: syn::Error) -> Self {
-        MacroError::ParseError(err)
-    }
-}
-
-impl From<MacroError> for proc_macro2::TokenStream {
-    fn from(err: MacroError) -> Self {
-        match err {
-            MacroError::Message(msg, span) => quote_spanned! { span => compile_error!(#msg); },
-            MacroError::ParseError(err) => err.into_compile_error(),
-        }
-    }
-}