Fixed taking an explicit reference to an enum

asn1_derive/src/lib.rs

@@ -90,6 +90,12 @@ pub fn derive_asn1_write(input: proc_macro::TokenStream) -> proc_macro::TokenStr
                         #write_block
                     }
                 }
+
+                impl #impl_generics asn1::Asn1Writable for &#name #ty_generics #where_clause {
+                    fn write(&self, w: &mut asn1::Writer) -> asn1::WriteResult {
+                        #name::write(self, w)
+                    }
+                }
             }
         }
         _ => unimplemented!("Not supported for unions"),

src/types.rs

@@ -145,6 +145,13 @@ impl Asn1Writable for Tlv<'_> {
     }
 }
 
+impl Asn1Writable for &Tlv<'_> {
+    #[inline]
+    fn write(&self, w: &mut Writer<'_>) -> WriteResult {
+        Tlv::write(self, w)
+    }
+}
+
 /// The ASN.1 NULL type, for use with `Parser.read_element` and
 /// `Writer.write_element`.
 pub type Null = ();
@@ -1809,13 +1816,6 @@ impl<T: Asn1Writable, const TAG: u32> SimpleAsn1Writable for Explicit<T, { TAG }
     }
 }
 
-impl<const TAG: u32> SimpleAsn1Writable for Explicit<&'_ Tlv<'_>, { TAG }> {
-    const TAG: Tag = crate::explicit_tag(TAG);
-    fn write_data(&self, dest: &mut WriteBuf) -> WriteResult {
-        self.inner.write(&mut Writer::new(dest))
-    }
-}
-
 impl<'a, T: Asn1Readable<'a>, U: Asn1DefinedByReadable<'a, T>, const TAG: u32>
     Asn1DefinedByReadable<'a, T> for Explicit<U, { TAG }>
 {

tests/derive_test.rs

@@ -441,6 +441,30 @@ fn test_enum_implicit() {
     ]);
 }
 
+#[test]
+fn test_enum_in_explicit() {
+    #[derive(asn1::Asn1Read, asn1::Asn1Write, PartialEq, Debug, Eq)]
+    enum BasicChoice {
+        A(u64),
+    }
+
+    #[derive(asn1::Asn1Read, asn1::Asn1Write, PartialEq, Debug, Eq)]
+    struct StructWithExplicitChoice {
+        #[explicit(0)]
+        c: Option<BasicChoice>,
+    }
+
+    assert_roundtrips(&[
+        (Ok(StructWithExplicitChoice { c: None }), b"\x30\x00"),
+        (
+            Ok(StructWithExplicitChoice {
+                c: Some(BasicChoice::A(3)),
+            }),
+            b"\x30\x05\xa0\x03\x02\x01\x03",
+        ),
+    ]);
+}
+
 #[test]
 fn test_error_parse_location() {
     #[derive(asn1::Asn1Read, asn1::Asn1Write, PartialEq, Debug, Eq)]