[zerocopy-derive] Fix panic with raw identifiers

Release 0.8.33.

Applies the same approach as in #2788, but to new lines of code (that
should have used this technique to begin with). Introduces a macro that
makes this pattern less verbose, and also hopefully encourages future
uses to use the correct pattern.

gherrit-pr-id: Gc07a814b14897f1beb00786c47a1343e65c9b884

Author: joshlf

Cargo.toml

@@ -15,7 +15,7 @@
 [package]
 edition = "2021"
 name = "zerocopy"
-version = "0.8.32"
+version = "0.8.33"
 authors = [
     "Joshua Liebow-Feeser <joshlf@google.com>",
     "Jack Wrenn <jswrenn@amazon.com>",
@@ -112,13 +112,13 @@ __internal_use_only_features_that_work_on_stable = [
 ]
 
 [dependencies]
-zerocopy-derive = { version = "=0.8.32", path = "zerocopy-derive", optional = true }
+zerocopy-derive = { version = "=0.8.33", path = "zerocopy-derive", optional = true }
 
 # The "associated proc macro pattern" ensures that the versions of zerocopy and
 # zerocopy-derive remain equal, even if the 'derive' feature isn't used.
 # See: https://github.com/matklad/macro-dep-test
 [target.'cfg(any())'.dependencies]
-zerocopy-derive = { version = "=0.8.32", path = "zerocopy-derive" }
+zerocopy-derive = { version = "=0.8.33", path = "zerocopy-derive" }
 
 [dev-dependencies]
 # More recent versions of `either` have an MSRV higher than ours.
@@ -142,4 +142,4 @@ testutil = { path = "testutil" }
 # CI test failures.
 trybuild = { version = "=1.0.89", features = ["diff"] }
 # In tests, unlike in production, zerocopy-derive is not optional
-zerocopy-derive = { version = "=0.8.32", path = "zerocopy-derive" }
+zerocopy-derive = { version = "=0.8.33", path = "zerocopy-derive" }

zerocopy-derive/Cargo.toml

@@ -9,7 +9,7 @@
 [package]
 edition = "2021"
 name = "zerocopy-derive"
-version = "0.8.32"
+version = "0.8.33"
 authors = ["Joshua Liebow-Feeser <joshlf@google.com>", "Jack Wrenn <jswrenn@amazon.com>"]
 description = "Custom derive for traits from the zerocopy crate"
 license = "BSD-2-Clause OR Apache-2.0 OR MIT"

zerocopy-derive/src/enum.rs

@@ -55,8 +55,7 @@ pub(crate) fn generate_tag_enum(repr: &EnumRepr, data: &DataEnum) -> TokenStream
 }
 
 fn tag_ident(variant_ident: &Ident) -> Ident {
-    let variant_ident_str = crate::ext::to_ident_str(variant_ident);
-    Ident::new(&format!("___ZEROCOPY_TAG_{}", variant_ident_str), variant_ident.span())
+    ident!(("___ZEROCOPY_TAG_{}", variant_ident), variant_ident.span())
 }
 
 /// Generates a constant for the tag associated with each variant of the enum.
@@ -103,8 +102,7 @@ fn generate_tag_consts(data: &DataEnum) -> TokenStream {
 }
 
 fn variant_struct_ident(variant_ident: &Ident) -> Ident {
-    let variant_ident_str = crate::ext::to_ident_str(variant_ident);
-    Ident::new(&format!("___ZerocopyVariantStruct_{}", variant_ident_str), variant_ident.span())
+    ident!(("___ZerocopyVariantStruct_{}", variant_ident), variant_ident.span())
 }
 
 /// Generates variant structs for the given enum variant.
@@ -171,10 +169,9 @@ fn generate_variant_structs(
 }
 
 fn variants_union_field_ident(ident: &Ident) -> Ident {
-    let variant_ident_str = crate::ext::to_ident_str(ident);
     // Field names are prefixed with `__field_` to prevent name collision
     // with the `__nonempty` field.
-    Ident::new(&format!("__field_{}", variant_ident_str), ident.span())
+    ident!(("__field_{}", ident), ident.span())
 }
 
 fn generate_variants_union(

zerocopy-derive/src/lib.rs

@@ -37,6 +37,12 @@
 )]
 #![recursion_limit = "128"]
 
+macro_rules! ident {
+    (($fmt:literal $(, $arg:expr)*), $span:expr) => {
+        syn::Ident::new(&format!($fmt $(, crate::ext::to_ident_str($arg))*), $span)
+    };
+}
+
 mod r#enum;
 mod ext;
 #[cfg(test)]
@@ -322,10 +328,8 @@ fn derive_known_layout_inner(
 
             // Generate a valid ident for a type-level handle to a field of a
             // given `name`.
-            let field_index = |name: &TokenStream| {
-                let name = to_ident_str(name);
-                Ident::new(&format!("__Zerocopy_Field_{}", name), ident.span())
-            };
+            let field_index =
+                |name: &TokenStream| ident!(("__Zerocopy_Field_{}", name), ident.span());
 
             let field_indices: Vec<_> =
                 fields.iter().map(|(_vis, name, _ty)| field_index(name)).collect();
@@ -764,7 +768,7 @@ fn derive_has_field_struct_union(
     }
 
     let field_tokens = fields.iter().map(|(vis, ident, _)| {
-        let ident = Ident::new(&format!("ẕ{}", ident), ident.span());
+        let ident = ident!(("ẕ{}", ident), ident.span());
         quote!(
             #vis enum #ident {}
         )
@@ -783,7 +787,7 @@ fn derive_has_field_struct_union(
         Data::Enum(..) | Data::Struct(..) => false,
     };
     let has_fields = fields.iter().map(move |(_, ident, ty)| {
-        let field_token = Ident::new(&format!("ẕ{}", ident), ident.span());
+        let field_token = ident!(("ẕ{}", ident), ident.span());
         let field: Box<Type> = parse_quote!(#field_token);
         let field_id: Box<Expr> = parse_quote!({ #zerocopy_crate::ident_id!(#ident) });
         ImplBlockBuilder::new(

zerocopy-derive/tests/struct_try_from_bytes.rs

@@ -249,3 +249,11 @@ struct A;
 struct B {
     a: A,
 }
+
+#[derive(imp::TryFromBytes)]
+#[repr(C)]
+struct RawType {
+    r#type: u8,
+}
+
+util_assert_impl_all!(RawType: imp::TryFromBytes);