Keep already computed inlay hint properties instead of late resolving them

crates/hir/src/lib.rs

@@ -45,7 +45,7 @@ use hir_def::{
     body::BodyDiagnostic,
     data::{adt::VariantData, TraitFlags},
     generics::{LifetimeParamData, TypeOrConstParamData, TypeParamProvenance},
-    hir::{BindingAnnotation, BindingId, ExprId, ExprOrPatId, LabelId, Pat},
+    hir::{BindingAnnotation, BindingId, Expr, ExprId, ExprOrPatId, LabelId, Pat},
     item_tree::{AttrOwner, FieldParent, ItemTreeFieldId, ItemTreeNode},
     lang_item::LangItemTarget,
     layout::{self, ReprOptions, TargetDataLayout},
@@ -2470,20 +2470,31 @@ impl Param {
     }
 
     pub fn as_local(&self, db: &dyn HirDatabase) -> Option<Local> {
-        let parent = match self.func {
-            Callee::Def(CallableDefId::FunctionId(it)) => DefWithBodyId::FunctionId(it),
-            Callee::Closure(closure, _) => db.lookup_intern_closure(closure.into()).0,
-            _ => return None,
-        };
-        let body = db.body(parent);
-        if let Some(self_param) = body.self_param.filter(|_| self.idx == 0) {
-            Some(Local { parent, binding_id: self_param })
-        } else if let Pat::Bind { id, .. } =
-            &body[body.params[self.idx - body.self_param.is_some() as usize]]
-        {
-            Some(Local { parent, binding_id: *id })
-        } else {
-            None
+        match self.func {
+            Callee::Def(CallableDefId::FunctionId(it)) => {
+                let parent = DefWithBodyId::FunctionId(it);
+                let body = db.body(parent);
+                if let Some(self_param) = body.self_param.filter(|_| self.idx == 0) {
+                    Some(Local { parent, binding_id: self_param })
+                } else if let Pat::Bind { id, .. } =
+                    &body[body.params[self.idx - body.self_param.is_some() as usize]]
+                {
+                    Some(Local { parent, binding_id: *id })
+                } else {
+                    None
+                }
+            }
+            Callee::Closure(closure, _) => {
+                let c = db.lookup_intern_closure(closure.into());
+                let body = db.body(c.0);
+                if let Expr::Closure { args, .. } = &body[c.1] {
+                    if let Pat::Bind { id, .. } = &body[args[self.idx]] {
+                        return Some(Local { parent: c.0, binding_id: *id });
+                    }
+                }
+                None
+            }
+            _ => None,
         }
     }
 

crates/ide/src/inlay_hints.rs

@@ -209,7 +209,7 @@ fn hints(
 ) {
     closing_brace::hints(hints, sema, config, file_id, node.clone());
     if let Some(any_has_generic_args) = ast::AnyHasGenericArgs::cast(node.clone()) {
-        generic_param::hints(hints, sema, config, any_has_generic_args);
+        generic_param::hints(hints, famous_defs, config, any_has_generic_args);
     }
 
     match_ast! {
@@ -300,22 +300,23 @@ pub struct InlayHintsConfig {
     pub closing_brace_hints_min_lines: Option<usize>,
     pub fields_to_resolve: InlayFieldsToResolve,
 }
+
 impl InlayHintsConfig {
-    fn lazy_text_edit(&self, finish: impl FnOnce() -> TextEdit) -> Lazy<TextEdit> {
+    fn lazy_text_edit(&self, finish: impl FnOnce() -> TextEdit) -> LazyProperty<TextEdit> {
         if self.fields_to_resolve.resolve_text_edits {
-            Lazy::Lazy
+            LazyProperty::Lazy
         } else {
             let edit = finish();
             never!(edit.is_empty(), "inlay hint produced an empty text edit");
-            Lazy::Computed(edit)
+            LazyProperty::Computed(edit)
         }
     }
 
-    fn lazy_tooltip(&self, finish: impl FnOnce() -> InlayTooltip) -> Lazy<InlayTooltip> {
+    fn lazy_tooltip(&self, finish: impl FnOnce() -> InlayTooltip) -> LazyProperty<InlayTooltip> {
         if self.fields_to_resolve.resolve_hint_tooltip
             && self.fields_to_resolve.resolve_label_tooltip
         {
-            Lazy::Lazy
+            LazyProperty::Lazy
         } else {
             let tooltip = finish();
             never!(
@@ -326,7 +327,20 @@ impl InlayHintsConfig {
                 .is_empty(),
                 "inlay hint produced an empty tooltip"
             );
-            Lazy::Computed(tooltip)
+            LazyProperty::Computed(tooltip)
+        }
+    }
+
+    /// This always reports a resolvable location, so only use this when it is very likely for a
+    /// location link to actually resolve but where computing `finish` would be costly.
+    fn lazy_location_opt(
+        &self,
+        finish: impl FnOnce() -> Option<FileRange>,
+    ) -> Option<LazyProperty<FileRange>> {
+        if self.fields_to_resolve.resolve_label_location {
+            Some(LazyProperty::Lazy)
+        } else {
+            finish().map(LazyProperty::Computed)
         }
     }
 }
@@ -441,23 +455,23 @@ pub struct InlayHint {
     /// The actual label to show in the inlay hint.
     pub label: InlayHintLabel,
     /// Text edit to apply when "accepting" this inlay hint.
-    pub text_edit: Option<Lazy<TextEdit>>,
+    pub text_edit: Option<LazyProperty<TextEdit>>,
     /// Range to recompute inlay hints when trying to resolve for this hint. If this is none, the
     /// hint does not support resolving.
     pub resolve_parent: Option<TextRange>,
 }
 
 /// A type signaling that a value is either computed, or is available for computation.
 #[derive(Clone, Debug)]
-pub enum Lazy<T> {
+pub enum LazyProperty<T> {
     Computed(T),
     Lazy,
 }
 
-impl<T> Lazy<T> {
+impl<T> LazyProperty<T> {
     pub fn computed(self) -> Option<T> {
         match self {
-            Lazy::Computed(it) => Some(it),
+            LazyProperty::Computed(it) => Some(it),
             _ => None,
         }
     }
@@ -508,8 +522,8 @@ pub struct InlayHintLabel {
 impl InlayHintLabel {
     pub fn simple(
         s: impl Into<String>,
-        tooltip: Option<Lazy<InlayTooltip>>,
-        linked_location: Option<FileRange>,
+        tooltip: Option<LazyProperty<InlayTooltip>>,
+        linked_location: Option<LazyProperty<FileRange>>,
     ) -> InlayHintLabel {
         InlayHintLabel {
             parts: smallvec![InlayHintLabelPart { text: s.into(), linked_location, tooltip }],
@@ -593,33 +607,37 @@ pub struct InlayHintLabelPart {
     /// refers to (not necessarily the location itself).
     /// When setting this, no tooltip must be set on the containing hint, or VS Code will display
     /// them both.
-    pub linked_location: Option<FileRange>,
+    pub linked_location: Option<LazyProperty<FileRange>>,
     /// The tooltip to show when hovering over the inlay hint, this may invoke other actions like
     /// hover requests to show.
-    pub tooltip: Option<Lazy<InlayTooltip>>,
+    pub tooltip: Option<LazyProperty<InlayTooltip>>,
 }
 
 impl std::hash::Hash for InlayHintLabelPart {
     fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
         self.text.hash(state);
-        self.linked_location.hash(state);
+        self.linked_location.is_some().hash(state);
         self.tooltip.is_some().hash(state);
     }
 }
 
 impl fmt::Debug for InlayHintLabelPart {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
-            Self { text, linked_location: None, tooltip: None | Some(Lazy::Lazy) } => text.fmt(f),
+            Self { text, linked_location: None, tooltip: None | Some(LazyProperty::Lazy) } => {
+                text.fmt(f)
+            }
             Self { text, linked_location, tooltip } => f
                 .debug_struct("InlayHintLabelPart")
                 .field("text", text)
                 .field("linked_location", linked_location)
                 .field(
                     "tooltip",
                     &tooltip.as_ref().map_or("", |it| match it {
-                        Lazy::Computed(InlayTooltip::String(it) | InlayTooltip::Markdown(it)) => it,
-                        Lazy::Lazy => "",
+                        LazyProperty::Computed(
+                            InlayTooltip::String(it) | InlayTooltip::Markdown(it),
+                        ) => it,
+                        LazyProperty::Lazy => "",
                     }),
                 )
                 .finish(),
@@ -632,7 +650,8 @@ struct InlayHintLabelBuilder<'a> {
     db: &'a RootDatabase,
     result: InlayHintLabel,
     last_part: String,
-    location: Option<FileRange>,
+    resolve: bool,
+    location: Option<LazyProperty<FileRange>>,
 }
 
 impl fmt::Write for InlayHintLabelBuilder<'_> {
@@ -645,11 +664,16 @@ impl HirWrite for InlayHintLabelBuilder<'_> {
     fn start_location_link(&mut self, def: ModuleDefId) {
         never!(self.location.is_some(), "location link is already started");
         self.make_new_part();
-        let Some(location) = ModuleDef::from(def).try_to_nav(self.db) else { return };
-        let location = location.call_site();
-        let location =
-            FileRange { file_id: location.file_id, range: location.focus_or_full_range() };
-        self.location = Some(location);
+
+        self.location = Some(if self.resolve {
+            LazyProperty::Lazy
+        } else {
+            LazyProperty::Computed({
+                let Some(location) = ModuleDef::from(def).try_to_nav(self.db) else { return };
+                let location = location.call_site();
+                FileRange { file_id: location.file_id, range: location.focus_or_full_range() }
+            })
+        });
     }
 
     fn end_location_link(&mut self) {
@@ -735,6 +759,7 @@ fn label_of_ty(
         last_part: String::new(),
         location: None,
         result: InlayHintLabel::default(),
+        resolve: config.fields_to_resolve.resolve_label_location,
     };
     let _ = rec(sema, famous_defs, config.max_length, ty, &mut label_builder, config, edition);
     let r = label_builder.finish();
@@ -783,7 +808,7 @@ fn ty_to_text_edit(
     ty: &hir::Type,
     offset_to_insert: TextSize,
     prefix: impl Into<String>,
-) -> Option<Lazy<TextEdit>> {
+) -> Option<LazyProperty<TextEdit>> {
     // FIXME: Limit the length and bail out on excess somehow?
     let rendered = sema
         .scope(node_for_hint)

crates/ide/src/inlay_hints/bounds.rs

@@ -22,11 +22,7 @@ pub(super) fn hints(
         return None;
     }
 
-    let linked_location =
-        famous_defs.core_marker_Sized().and_then(|it| it.try_to_nav(sema.db)).map(|it| {
-            let n = it.call_site();
-            FileRange { file_id: n.file_id, range: n.focus_or_full_range() }
-        });
+    let sized_trait = famous_defs.core_marker_Sized();
 
     for param in params.type_or_const_params() {
         match param {
@@ -48,7 +44,17 @@ pub(super) fn hints(
                         }
                         hint.parts.push(InlayHintLabelPart {
                             text: "Sized".to_owned(),
-                            linked_location,
+                            linked_location: sized_trait.and_then(|it| {
+                                config.lazy_location_opt(|| {
+                                    it.try_to_nav(sema.db).map(|it| {
+                                        let n = it.call_site();
+                                        FileRange {
+                                            file_id: n.file_id,
+                                            range: n.focus_or_full_range(),
+                                        }
+                                    })
+                                })
+                            }),
                             tooltip: None,
                         });
                         if has_bounds {
@@ -134,12 +140,14 @@ fn foo<T>() {}
                             InlayHintLabelPart {
                                 text: "Sized",
                                 linked_location: Some(
-                                    FileRangeWrapper {
-                                        file_id: FileId(
-                                            1,
-                                        ),
-                                        range: 135..140,
-                                    },
+                                    Computed(
+                                        FileRangeWrapper {
+                                            file_id: FileId(
+                                                1,
+                                            ),
+                                            range: 135..140,
+                                        },
+                                    ),
                                 ),
                                 tooltip: "",
                             },