Rustdoc-Json: Report discriminant on all kinds of enum variant.

src/librustdoc/clean/mod.rs

@@ -1949,40 +1949,52 @@ pub(crate) fn clean_field_with_def_id(
 }
 
 pub(crate) fn clean_variant_def<'tcx>(variant: &ty::VariantDef, cx: &mut DocContext<'tcx>) -> Item {
+    let discriminant = match variant.discr {
+        ty::VariantDiscr::Explicit(def_id) => Some(Discriminant { expr: None, value: def_id }),
+        ty::VariantDiscr::Relative(_) => None,
+    };
+
     let kind = match variant.ctor_kind() {
-        Some(CtorKind::Const) => Variant::CLike(match variant.discr {
-            ty::VariantDiscr::Explicit(def_id) => Some(Discriminant { expr: None, value: def_id }),
-            ty::VariantDiscr::Relative(_) => None,
-        }),
-        Some(CtorKind::Fn) => Variant::Tuple(
+        Some(CtorKind::Const) => VariantKind::CLike,
+        Some(CtorKind::Fn) => VariantKind::Tuple(
             variant.fields.iter().map(|field| clean_middle_field(field, cx)).collect(),
         ),
-        None => Variant::Struct(VariantStruct {
+        None => VariantKind::Struct(VariantStruct {
             ctor_kind: None,
             fields: variant.fields.iter().map(|field| clean_middle_field(field, cx)).collect(),
         }),
     };
-    Item::from_def_id_and_parts(variant.def_id, Some(variant.name), VariantItem(kind), cx)
+
+    Item::from_def_id_and_parts(
+        variant.def_id,
+        Some(variant.name),
+        VariantItem(Variant { kind, discriminant }),
+        cx,
+    )
 }
 
 fn clean_variant_data<'tcx>(
     variant: &hir::VariantData<'tcx>,
     disr_expr: &Option<hir::AnonConst>,
     cx: &mut DocContext<'tcx>,
 ) -> Variant {
-    match variant {
-        hir::VariantData::Struct(..) => Variant::Struct(VariantStruct {
+    let discriminant = disr_expr.map(|disr| Discriminant {
+        expr: Some(disr.body),
+        value: cx.tcx.hir().local_def_id(disr.hir_id).to_def_id(),
+    });
+
+    let kind = match variant {
+        hir::VariantData::Struct(..) => VariantKind::Struct(VariantStruct {
             ctor_kind: None,
             fields: variant.fields().iter().map(|x| clean_field(x, cx)).collect(),
         }),
         hir::VariantData::Tuple(..) => {
-            Variant::Tuple(variant.fields().iter().map(|x| clean_field(x, cx)).collect())
+            VariantKind::Tuple(variant.fields().iter().map(|x| clean_field(x, cx)).collect())
         }
-        hir::VariantData::Unit(..) => Variant::CLike(disr_expr.map(|disr| Discriminant {
-            expr: Some(disr.body),
-            value: cx.tcx.hir().local_def_id(disr.hir_id).to_def_id(),
-        })),
-    }
+        hir::VariantData::Unit(..) => VariantKind::CLike,
+    };
+
+    Variant { discriminant, kind }
 }
 
 fn clean_path<'tcx>(path: &hir::Path<'tcx>, cx: &mut DocContext<'tcx>) -> Path {

src/librustdoc/clean/types.rs

@@ -807,8 +807,11 @@ impl ItemKind {
         match self {
             StructItem(s) => s.fields.iter(),
             UnionItem(u) => u.fields.iter(),
-            VariantItem(Variant::Struct(v)) => v.fields.iter(),
-            VariantItem(Variant::Tuple(v)) => v.iter(),
+            VariantItem(v) => match &v.kind {
+                VariantKind::CLike => [].iter(),
+                VariantKind::Tuple(t) => t.iter(),
+                VariantKind::Struct(s) => s.fields.iter(),
+            },
             EnumItem(e) => e.variants.iter(),
             TraitItem(t) => t.items.iter(),
             ImplItem(i) => i.items.iter(),
@@ -824,7 +827,6 @@ impl ItemKind {
             | TyMethodItem(_)
             | MethodItem(_, _)
             | StructFieldItem(_)
-            | VariantItem(_)
             | ForeignFunctionItem(_)
             | ForeignStaticItem(_)
             | ForeignTypeItem
@@ -2136,17 +2138,23 @@ impl Enum {
 }
 
 #[derive(Clone, Debug)]
-pub(crate) enum Variant {
-    CLike(Option<Discriminant>),
+pub(crate) struct Variant {
+    pub kind: VariantKind,
+    pub discriminant: Option<Discriminant>,
+}
+
+#[derive(Clone, Debug)]
+pub(crate) enum VariantKind {
+    CLike,
     Tuple(Vec<Item>),
     Struct(VariantStruct),
 }
 
 impl Variant {
     pub(crate) fn has_stripped_entries(&self) -> Option<bool> {
-        match *self {
-            Self::Struct(ref struct_) => Some(struct_.has_stripped_entries()),
-            Self::CLike(..) | Self::Tuple(_) => None,
+        match &self.kind {
+            VariantKind::Struct(struct_) => Some(struct_.has_stripped_entries()),
+            VariantKind::CLike | VariantKind::Tuple(_) => None,
         }
     }
 }

src/librustdoc/fold.rs

@@ -37,17 +37,21 @@ pub(crate) trait DocFolder: Sized {
                 i.items = i.items.into_iter().filter_map(|x| self.fold_item(x)).collect();
                 ImplItem(i)
             }
-            VariantItem(i) => match i {
-                Variant::Struct(mut j) => {
-                    j.fields = j.fields.into_iter().filter_map(|x| self.fold_item(x)).collect();
-                    VariantItem(Variant::Struct(j))
-                }
-                Variant::Tuple(fields) => {
-                    let fields = fields.into_iter().filter_map(|x| self.fold_item(x)).collect();
-                    VariantItem(Variant::Tuple(fields))
-                }
-                Variant::CLike(disr) => VariantItem(Variant::CLike(disr)),
-            },
+            VariantItem(Variant { kind, discriminant }) => {
+                let kind = match kind {
+                    VariantKind::Struct(mut j) => {
+                        j.fields = j.fields.into_iter().filter_map(|x| self.fold_item(x)).collect();
+                        VariantKind::Struct(j)
+                    }
+                    VariantKind::Tuple(fields) => {
+                        let fields = fields.into_iter().filter_map(|x| self.fold_item(x)).collect();
+                        VariantKind::Tuple(fields)
+                    }
+                    VariantKind::CLike => VariantKind::CLike,
+                };
+
+                VariantItem(Variant { kind, discriminant })
+            }
             ExternCrateItem { src: _ }
             | ImportItem(_)
             | FunctionItem(_)

src/librustdoc/html/render/print_item.rs

@@ -1220,15 +1220,15 @@ fn item_enum(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, e: &clean::
                     w.write_str("    ");
                     let name = v.name.unwrap();
                     match *v.kind {
-                        clean::VariantItem(ref var) => match var {
-                            // FIXME(#101337): Show discriminant
-                            clean::Variant::CLike(..) => write!(w, "{}", name),
-                            clean::Variant::Tuple(ref s) => {
+                        // FIXME(#101337): Show discriminant
+                        clean::VariantItem(ref var) => match var.kind {
+                            clean::VariantKind::CLike => write!(w, "{}", name),
+                            clean::VariantKind::Tuple(ref s) => {
                                 write!(w, "{}(", name);
                                 print_tuple_struct_fields(w, cx, s);
                                 w.write_str(")");
                             }
-                            clean::Variant::Struct(ref s) => {
+                            clean::VariantKind::Struct(ref s) => {
                                 render_struct(
                                     w,
                                     v,
@@ -1286,25 +1286,28 @@ fn item_enum(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, e: &clean::
                 " rightside",
             );
             write!(w, "<h3 class=\"code-header\">{name}", name = variant.name.unwrap());
-            if let clean::VariantItem(clean::Variant::Tuple(ref s)) = *variant.kind {
+
+            let clean::VariantItem(variant_data) = &*variant.kind else { unreachable!() };
+
+            if let clean::VariantKind::Tuple(ref s) = variant_data.kind {
                 w.write_str("(");
                 print_tuple_struct_fields(w, cx, s);
                 w.write_str(")");
             }
             w.write_str("</h3></section>");
 
-            use crate::clean::Variant;
-
-            let heading_and_fields = match &*variant.kind {
-                clean::VariantItem(Variant::Struct(s)) => Some(("Fields", &s.fields)),
-                // Documentation on tuple variant fields is rare, so to reduce noise we only emit
-                // the section if at least one field is documented.
-                clean::VariantItem(Variant::Tuple(fields))
-                    if fields.iter().any(|f| f.doc_value().is_some()) =>
-                {
-                    Some(("Tuple Fields", fields))
+            let heading_and_fields = match &variant_data.kind {
+                clean::VariantKind::Struct(s) => Some(("Fields", &s.fields)),
+                clean::VariantKind::Tuple(fields) => {
+                    // Documentation on tuple variant fields is rare, so to reduce noise we only emit
+                    // the section if at least one field is documented.
+                    if fields.iter().any(|f| f.doc_value().is_some()) {
+                        Some(("Tuple Fields", fields))
+                    } else {
+                        None
+                    }
                 }
-                _ => None,
+                clean::VariantKind::CLike => None,
             };
 
             if let Some((heading, fields)) = heading_and_fields {

src/librustdoc/json/conversions.rs

@@ -646,15 +646,20 @@ impl FromWithTcx<clean::Enum> for Enum {
 
 impl FromWithTcx<clean::Variant> for Variant {
     fn from_tcx(variant: clean::Variant, tcx: TyCtxt<'_>) -> Self {
-        use clean::Variant::*;
-        match variant {
-            CLike(disr) => Variant::Plain(disr.map(|disr| disr.into_tcx(tcx))),
-            Tuple(fields) => Variant::Tuple(ids_keeping_stripped(fields, tcx)),
-            Struct(s) => Variant::Struct {
+        use clean::VariantKind::*;
+
+        let discriminant = variant.discriminant.map(|d| d.into_tcx(tcx));
+
+        let kind = match variant.kind {
+            CLike => VariantKind::Plain,
+            Tuple(fields) => VariantKind::Tuple(ids_keeping_stripped(fields, tcx)),
+            Struct(s) => VariantKind::Struct {
                 fields_stripped: s.has_stripped_entries(),
                 fields: ids(s.fields, tcx),
             },
-        }
+        };
+
+        Variant { kind, discriminant }
     }
 }
 

src/librustdoc/passes/stripper.rs

@@ -132,7 +132,10 @@ impl<'a, 'tcx> DocFolder for Stripper<'a, 'tcx> {
             // implementations of traits are always public.
             clean::ImplItem(ref imp) if imp.trait_.is_some() => true,
             // Variant fields have inherited visibility
-            clean::VariantItem(clean::Variant::Struct(..) | clean::Variant::Tuple(..)) => true,
+            clean::VariantItem(clean::Variant {
+                kind: clean::VariantKind::Struct(..) | clean::VariantKind::Tuple(..),
+                ..
+            }) => true,
             _ => false,
         };
 

src/librustdoc/visit.rs

@@ -17,10 +17,10 @@ pub(crate) trait DocVisitor: Sized {
             EnumItem(i) => i.variants.iter().for_each(|x| self.visit_item(x)),
             TraitItem(i) => i.items.iter().for_each(|x| self.visit_item(x)),
             ImplItem(i) => i.items.iter().for_each(|x| self.visit_item(x)),
-            VariantItem(i) => match i {
-                Variant::Struct(j) => j.fields.iter().for_each(|x| self.visit_item(x)),
-                Variant::Tuple(fields) => fields.iter().for_each(|x| self.visit_item(x)),
-                Variant::CLike(_) => {}
+            VariantItem(i) => match &i.kind {
+                VariantKind::Struct(j) => j.fields.iter().for_each(|x| self.visit_item(x)),
+                VariantKind::Tuple(fields) => fields.iter().for_each(|x| self.visit_item(x)),
+                VariantKind::CLike => {}
             },
             ExternCrateItem { src: _ }
             | ImportItem(_)

src/rustdoc-json-types/lib.rs

@@ -9,7 +9,7 @@ use std::path::PathBuf;
 use serde::{Deserialize, Serialize};
 
 /// rustdoc format-version.
-pub const FORMAT_VERSION: u32 = 23;
+pub const FORMAT_VERSION: u32 = 24;
 
 /// A `Crate` is the root of the emitted JSON blob. It contains all type/documentation information
 /// about the language items in the local crate, as well as info about external items to allow
@@ -333,19 +333,26 @@ pub struct Enum {
     pub impls: Vec<Id>,
 }
 
+#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
+pub struct Variant {
+    /// Whether the variant is plain, a tuple-like, or struct-like. Contains the fields.
+    pub kind: VariantKind,
+    /// The discriminant, if explicitly specified.
+    pub discriminant: Option<Discriminant>,
+}
+
 #[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
 #[serde(rename_all = "snake_case")]
-#[serde(tag = "variant_kind", content = "variant_inner")]
-pub enum Variant {
-    /// A variant with no parentheses, and possible discriminant.
+pub enum VariantKind {
+    /// A variant with no parentheses
     ///
     /// ```rust
     /// enum Demo {
     ///     PlainVariant,
     ///     PlainWithDiscriminant = 1,
     /// }
     /// ```
-    Plain(Option<Discriminant>),
+    Plain,
     /// A variant with unnamed fields.
     ///
     /// Unlike most of json, `#[doc(hidden)]` fields will be given as `None`

src/test/rustdoc-json/enums/discriminant/basic.rs

@@ -1,12 +1,12 @@
 #[repr(i8)]
 pub enum Ordering {
-    // @is "$.index[*][?(@.name=='Less')].inner.variant_inner.expr" '"-1"'
-    // @is "$.index[*][?(@.name=='Less')].inner.variant_inner.value" '"-1"'
+    // @is "$.index[*][?(@.name=='Less')].inner.discriminant.expr" '"-1"'
+    // @is "$.index[*][?(@.name=='Less')].inner.discriminant.value" '"-1"'
     Less = -1,
-    // @is "$.index[*][?(@.name=='Equal')].inner.variant_inner.expr" '"0"'
-    // @is "$.index[*][?(@.name=='Equal')].inner.variant_inner.value" '"0"'
+    // @is "$.index[*][?(@.name=='Equal')].inner.discriminant.expr" '"0"'
+    // @is "$.index[*][?(@.name=='Equal')].inner.discriminant.value" '"0"'
     Equal = 0,
-    // @is "$.index[*][?(@.name=='Greater')].inner.variant_inner.expr" '"1"'
-    // @is "$.index[*][?(@.name=='Greater')].inner.variant_inner.value" '"1"'
+    // @is "$.index[*][?(@.name=='Greater')].inner.discriminant.expr" '"1"'
+    // @is "$.index[*][?(@.name=='Greater')].inner.discriminant.value" '"1"'
     Greater = 1,
 }

src/test/rustdoc-json/enums/discriminant/expr.rs

@@ -1,30 +1,30 @@
 pub enum Foo {
-    // @is "$.index[*][?(@.name=='Addition')].inner.variant_inner.value" '"0"'
-    // @is "$.index[*][?(@.name=='Addition')].inner.variant_inner.expr" '"{ _ }"'
+    // @is "$.index[*][?(@.name=='Addition')].inner.discriminant.value" '"0"'
+    // @is "$.index[*][?(@.name=='Addition')].inner.discriminant.expr" '"{ _ }"'
     Addition = 0 + 0,
-    // @is "$.index[*][?(@.name=='Bin')].inner.variant_inner.value" '"1"'
-    // @is "$.index[*][?(@.name=='Bin')].inner.variant_inner.expr" '"0b1"'
+    // @is "$.index[*][?(@.name=='Bin')].inner.discriminant.value" '"1"'
+    // @is "$.index[*][?(@.name=='Bin')].inner.discriminant.expr" '"0b1"'
     Bin = 0b1,
-    // @is "$.index[*][?(@.name=='Oct')].inner.variant_inner.value" '"2"'
-    // @is "$.index[*][?(@.name=='Oct')].inner.variant_inner.expr" '"0o2"'
+    // @is "$.index[*][?(@.name=='Oct')].inner.discriminant.value" '"2"'
+    // @is "$.index[*][?(@.name=='Oct')].inner.discriminant.expr" '"0o2"'
     Oct = 0o2,
-    // @is "$.index[*][?(@.name=='PubConst')].inner.variant_inner.value" '"3"'
-    // @is "$.index[*][?(@.name=='PubConst')].inner.variant_inner.expr" '"THREE"'
+    // @is "$.index[*][?(@.name=='PubConst')].inner.discriminant.value" '"3"'
+    // @is "$.index[*][?(@.name=='PubConst')].inner.discriminant.expr" '"THREE"'
     PubConst = THREE,
-    // @is "$.index[*][?(@.name=='Hex')].inner.variant_inner.value" '"4"'
-    // @is "$.index[*][?(@.name=='Hex')].inner.variant_inner.expr" '"0x4"'
+    // @is "$.index[*][?(@.name=='Hex')].inner.discriminant.value" '"4"'
+    // @is "$.index[*][?(@.name=='Hex')].inner.discriminant.expr" '"0x4"'
     Hex = 0x4,
-    // @is "$.index[*][?(@.name=='Cast')].inner.variant_inner.value" '"5"'
-    // @is "$.index[*][?(@.name=='Cast')].inner.variant_inner.expr" '"{ _ }"'
+    // @is "$.index[*][?(@.name=='Cast')].inner.discriminant.value" '"5"'
+    // @is "$.index[*][?(@.name=='Cast')].inner.discriminant.expr" '"{ _ }"'
     Cast = 5 as isize,
-    // @is "$.index[*][?(@.name=='PubCall')].inner.variant_inner.value" '"6"'
-    // @is "$.index[*][?(@.name=='PubCall')].inner.variant_inner.expr" '"{ _ }"'
+    // @is "$.index[*][?(@.name=='PubCall')].inner.discriminant.value" '"6"'
+    // @is "$.index[*][?(@.name=='PubCall')].inner.discriminant.expr" '"{ _ }"'
     PubCall = six(),
-    // @is "$.index[*][?(@.name=='PrivCall')].inner.variant_inner.value" '"7"'
-    // @is "$.index[*][?(@.name=='PrivCall')].inner.variant_inner.expr" '"{ _ }"'
+    // @is "$.index[*][?(@.name=='PrivCall')].inner.discriminant.value" '"7"'
+    // @is "$.index[*][?(@.name=='PrivCall')].inner.discriminant.expr" '"{ _ }"'
     PrivCall = seven(),
-    // @is "$.index[*][?(@.name=='PrivConst')].inner.variant_inner.value" '"8"'
-    // @is "$.index[*][?(@.name=='PrivConst')].inner.variant_inner.expr" '"EIGHT"'
+    // @is "$.index[*][?(@.name=='PrivConst')].inner.discriminant.value" '"8"'
+    // @is "$.index[*][?(@.name=='PrivConst')].inner.discriminant.expr" '"EIGHT"'
     PrivConst = EIGHT,
 }