Relax enum default case expansion rules

o2o-impl/src/expand.rs

@@ -406,10 +406,10 @@ fn enum_init_block(input: &Enum, ctx: &ImplContext) -> TokenStream {
         .flat_map(|x| &x.attr.ghost_data)
         .map(VariantData::GhostData));
 
-    enum_init_block_inner(&mut fields.iter().peekable(), input, ctx)
+    enum_init_block_inner(&mut fields.iter().peekable(), ctx)
 }
 
-fn enum_init_block_inner(members: &mut Peekable<Iter<VariantData>>, input: &Enum, ctx: &ImplContext) -> TokenStream {
+fn enum_init_block_inner(members: &mut Peekable<Iter<VariantData>>, ctx: &ImplContext) -> TokenStream {
     let mut fragments: Vec<TokenStream> = vec![];
 
     while let Some(member_data) = members.peek() {
@@ -443,12 +443,8 @@ fn enum_init_block_inner(members: &mut Peekable<Iter<VariantData>>, input: &Enum
     }
 
     if let Some(default_case) = &ctx.struct_attr.default_case {
-        if ctx.kind.is_from() && (input.variants.iter().any(|v| v.attrs.lit(&ctx.struct_attr.ty).is_some() || v.attrs.pat(&ctx.struct_attr.ty).is_some()) || input.attrs.ghosts_attr(&ctx.struct_attr.ty, &ctx.kind).is_some())
-            || !ctx.kind.is_from() && input.variants.iter().any(|v| v.attrs.ghost(&ctx.struct_attr.ty, &ctx.kind).is_some())
-        {
-            let g = quote_action(default_case, None, ctx);
-            fragments.push(quote!(_ #g))
-        }
+        let g = quote_action(default_case, None, ctx);
+        fragments.push(quote!(_ #g))
     }
 
     quote!({#(#fragments)*})

o2o-tests/Cargo.toml

@@ -15,5 +15,6 @@ anyhow = "1.0.86"
 test-case = "3"
 
 [features]
+default = ["syn1"]
 syn1 = ["o2o/syn1"]
 syn2 = ["o2o/syn2"]

o2o-tests/tests/48_enum_default_case_tests.rs

@@ -0,0 +1,53 @@
+use test_case::test_case;
+
+#[derive(Debug, PartialEq, Clone)]
+pub enum Enum {
+    Opt1,
+    Opt2,
+    Opt3
+}
+
+#[derive(Debug, PartialEq, o2o::o2o)]
+#[map_owned(Enum| _ => todo!("unknown"))]
+enum EnumDto {
+    Opt1,
+    Opt2,
+}
+
+#[derive(Debug, PartialEq, Clone)]
+pub enum Enum2 {
+    Opt1,
+    Opt2,
+    Opt3
+}
+
+#[derive(Debug, PartialEq, o2o::o2o)]
+#[from_owned(Enum2| _ => EnumDto2::Opt1)]
+enum EnumDto2 {
+    Opt1,
+    Opt2,
+}
+
+#[test_case(Enum::Opt1, EnumDto::Opt1)]
+#[test_case(Enum::Opt2, EnumDto::Opt2)]
+fn legit_options(l: Enum, r: EnumDto) {
+    let e: EnumDto = l.clone().into();
+    assert_eq!(r, e);
+
+    let e: Enum = r.into();
+    assert_eq!(l, e);
+}
+
+#[test]
+#[should_panic(expected = "unknown")]
+fn default_case() {
+    let _: EnumDto = Enum::Opt3.into();
+}
+
+#[test_case(Enum2::Opt1, EnumDto2::Opt1)]
+#[test_case(Enum2::Opt2, EnumDto2::Opt2)]
+#[test_case(Enum2::Opt3, EnumDto2::Opt1)]
+fn legit_options_2(l: Enum2, r: EnumDto2) {
+    let e: EnumDto2 = l.clone().into();
+    assert_eq!(r, e);
+}

o2o-tests/tests/48_enum_default_case_tests_fallible.rs

@@ -0,0 +1,53 @@
+use test_case::test_case;
+
+#[derive(Debug, PartialEq, Clone)]
+pub enum Enum {
+    Opt1,
+    Opt2,
+    Opt3
+}
+
+#[derive(Debug, PartialEq, o2o::o2o)]
+#[try_map_owned(Enum, String| _ => todo!("unknown"))]
+enum EnumDto {
+    Opt1,
+    Opt2,
+}
+
+#[derive(Debug, PartialEq, Clone)]
+pub enum Enum2 {
+    Opt1,
+    Opt2,
+    Opt3
+}
+
+#[derive(Debug, PartialEq, o2o::o2o)]
+#[try_from_owned(Enum2, String| _ => EnumDto2::Opt1)]
+enum EnumDto2 {
+    Opt1,
+    Opt2,
+}
+
+#[test_case(Enum::Opt1, EnumDto::Opt1)]
+#[test_case(Enum::Opt2, EnumDto::Opt2)]
+fn legit_options(l: Enum, r: EnumDto) {
+    let e: EnumDto = l.clone().try_into().unwrap();
+    assert_eq!(r, e);
+
+    let e: Enum = r.try_into().unwrap();
+    assert_eq!(l, e);
+}
+
+#[test]
+#[should_panic(expected = "unknown")]
+fn default_case() {
+    let _: EnumDto = Enum::Opt3.try_into().unwrap();
+}
+
+#[test_case(Enum2::Opt1, EnumDto2::Opt1)]
+#[test_case(Enum2::Opt2, EnumDto2::Opt2)]
+#[test_case(Enum2::Opt3, EnumDto2::Opt1)]
+fn legit_options_2(l: Enum2, r: EnumDto2) {
+    let e: EnumDto2 = l.clone().try_into().unwrap();
+    assert_eq!(r, e);
+}

tests.sh

@@ -1,7 +1,7 @@
 cargo test -q -p o2o
 cargo test -q -p o2o --no-default-features --features syn1
 cargo test -q -p o2o --no-default-features --features syn2
-cargo test -q -p o2o-tests --features syn1
-cargo test -q -p o2o-tests --features syn2
+cargo test -q -p o2o-tests --no-default-features --features syn1
+cargo test -q -p o2o-tests --no-default-features --features syn2
 cargo test -q -p o2o-impl --features syn
 cargo test -q -p o2o-impl --features syn2