1 files changed, 78 insertions, 30 deletions

diff --git a/src/tools/rust-analyzer/crates/ide/src/inlay_hints/discriminant.rs b/src/tools/rust-analyzer/crates/ide/src/inlay_hints/discriminant.rs
index f32c4bdf2..5dd51ad11 100644
--- a/src/tools/rust-analyzer/crates/ide/src/inlay_hints/discriminant.rs
+++ b/src/tools/rust-analyzer/crates/ide/src/inlay_hints/discriminant.rs
@@ -4,27 +4,43 @@
 //!    Bar/* = 0*/,
 //! }
 //! ```
-use ide_db::{base_db::FileId, famous_defs::FamousDefs};
+use hir::Semantics;
+use ide_db::{base_db::FileId, famous_defs::FamousDefs, RootDatabase};
 use syntax::ast::{self, AstNode, HasName};
 
-use crate::{DiscriminantHints, InlayHint, InlayHintsConfig, InlayKind, InlayTooltip};
+use crate::{
+    DiscriminantHints, InlayHint, InlayHintLabel, InlayHintsConfig, InlayKind, InlayTooltip,
+};
 
-pub(super) fn hints(
+pub(super) fn enum_hints(
     acc: &mut Vec<InlayHint>,
     FamousDefs(sema, _): &FamousDefs<'_, '_>,
     config: &InlayHintsConfig,
     _: FileId,
-    variant: &ast::Variant,
+    enum_: ast::Enum,
 ) -> Option<()> {
-    let field_list = match config.discriminant_hints {
-        DiscriminantHints::Always => variant.field_list(),
-        DiscriminantHints::Fieldless => match variant.field_list() {
-            Some(_) => return None,
-            None => None,
-        },
-        DiscriminantHints::Never => return None,
+    let enabled = match config.discriminant_hints {
+        DiscriminantHints::Always => true,
+        DiscriminantHints::Fieldless => {
+            !sema.to_def(&enum_)?.is_data_carrying(sema.db)
+                || enum_.variant_list()?.variants().any(|v| v.expr().is_some())
+        }
+        DiscriminantHints::Never => false,
     };
+    if !enabled {
+        return None;
+    }
+    for variant in enum_.variant_list()?.variants() {
+        variant_hints(acc, sema, &variant);
+    }
+    None
+}
 
+fn variant_hints(
+    acc: &mut Vec<InlayHint>,
+    sema: &Semantics<'_, RootDatabase>,
+    variant: &ast::Variant,
+) -> Option<()> {
     if variant.eq_token().is_some() {
         return None;
     }
@@ -37,19 +53,22 @@ pub(super) fn hints(
     let d = v.eval(sema.db);
 
     acc.push(InlayHint {
-        range: match field_list {
+        range: match variant.field_list() {
             Some(field_list) => name.syntax().text_range().cover(field_list.syntax().text_range()),
             None => name.syntax().text_range(),
         },
-        kind: InlayKind::DiscriminantHint,
-        label: match &d {
-            Ok(v) => format!("{}", v).into(),
-            Err(_) => "?".into(),
-        },
-        tooltip: Some(InlayTooltip::String(match &d {
-            Ok(_) => "enum variant discriminant".into(),
-            Err(e) => format!("{e:?}").into(),
-        })),
+        kind: InlayKind::Discriminant,
+        label: InlayHintLabel::simple(
+            match &d {
+                Ok(v) => format!("{}", v),
+                Err(_) => "?".into(),
+            },
+            Some(InlayTooltip::String(match &d {
+                Ok(_) => "enum variant discriminant".into(),
+                Err(e) => format!("{e:?}").into(),
+            })),
+            None,
+        ),
     });
 
     Some(())
@@ -86,15 +105,30 @@ mod tests {
         check_discriminants(
             r#"
 enum Enum {
-    Variant,
-  //^^^^^^^0
-    Variant1,
-  //^^^^^^^^1
-    Variant2,
-  //^^^^^^^^2
-    Variant5 = 5,
-    Variant6,
-  //^^^^^^^^6
+  Variant,
+//^^^^^^^0
+  Variant1,
+//^^^^^^^^1
+  Variant2,
+//^^^^^^^^2
+  Variant5 = 5,
+  Variant6,
+//^^^^^^^^6
+}
+"#,
+        );
+        check_discriminants_fieldless(
+            r#"
+enum Enum {
+  Variant,
+//^^^^^^^0
+  Variant1,
+//^^^^^^^^1
+  Variant2,
+//^^^^^^^^2
+  Variant5 = 5,
+  Variant6,
+//^^^^^^^^6
 }
 "#,
         );
@@ -128,8 +162,22 @@ enum Enum {
 enum Enum {
     Variant(),
     Variant1,
+    Variant2 {},
+    Variant3,
+    Variant5,
+    Variant6,
+}
+"#,
+        );
+        check_discriminants_fieldless(
+            r#"
+enum Enum {
+    Variant(),
+  //^^^^^^^^^0
+    Variant1,
   //^^^^^^^^1
     Variant2 {},
+  //^^^^^^^^^^^2
     Variant3,
   //^^^^^^^^3
     Variant5 = 5,