tests for lack of Soundness bug

safe-discriminant-derive/Cargo.toml

@@ -6,7 +6,7 @@ readme = "../Readme.md"
 license = "BSD-3-Clause"
 keywords = ["no_std", "enums"]
 description = """A minimalistic, `no_std` compatible trait and procedural macro \
-                 for extracting discriminants from enums at zero cost.""""
+                 for extracting discriminants from enums at zero cost."""
 documentation = "https://docs.rs/safe_discriminant_derive"
 homepage = "https://docs.rs/safe_discriminant"
 repository = "https://github.com/oddcoder/safe-discriminant"

safe-discriminant-derive/src/lib.rs

@@ -155,3 +155,12 @@ pub fn repr(_: TokenStream, item: TokenStream) -> TokenStream {
 pub fn do_nothing(_: TokenStream, item: TokenStream) -> TokenStream {
     item
 }
+
+#[cfg(feature = "test-utils")]
+/// This macro will remove the discriminant of any enum field it is applied to
+#[proc_macro_attribute]
+pub fn remove_disc(_: TokenStream, item: TokenStream) -> TokenStream {
+    let mut variant = parse_macro_input!(item as Variant);
+    variant.discriminant = None;
+    quote!(#variant).into()
+}

safe-discriminant/tests/fail/remove_disc.rs

@@ -0,0 +1,11 @@
+use safe_discriminant::Discriminant;
+use safe_discriminant_derive::remove_disc;
+#[derive(Discriminant)]
+#[repr(u8)]
+pub enum Foo {
+    #[remove_disc]
+    A = 0,
+    B = 1,
+}
+
+fn main() {}

safe-discriminant/tests/fail/remove_disc.stderr

@@ -0,0 +1,5 @@
+error: expected non-macro attribute, found attribute macro `remove_disc`
+ --> tests/fail/remove_disc.rs:6:7
+  |
+6 |     #[remove_disc]
+  |       ^^^^^^^^^^^ not a non-macro attribute