Make InlayHint::linked_location computation lazy

Author: Veykril

src/tools/rust-analyzer/crates/ide/src/inlay_hints.rs

@@ -300,6 +300,7 @@ 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> {
         if self.fields_to_resolve.resolve_text_edits {
@@ -329,6 +330,19 @@ impl InlayHintsConfig {
             Lazy::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<Lazy<FileRange>> {
+        if self.fields_to_resolve.resolve_label_location {
+            Some(Lazy::Lazy)
+        } else {
+            finish().map(Lazy::Computed)
+        }
+    }
 }
 
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
@@ -509,7 +523,7 @@ impl InlayHintLabel {
     pub fn simple(
         s: impl Into<String>,
         tooltip: Option<Lazy<InlayTooltip>>,
-        linked_location: Option<FileRange>,
+        linked_location: Option<Lazy<FileRange>>,
     ) -> InlayHintLabel {
         InlayHintLabel {
             parts: smallvec![InlayHintLabelPart { text: s.into(), linked_location, tooltip }],
@@ -593,7 +607,7 @@ 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<Lazy<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>>,
@@ -602,7 +616,7 @@ pub struct InlayHintLabelPart {
 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);
     }
 }
@@ -663,7 +677,7 @@ impl InlayHintLabelBuilder<'_> {
         if !text.is_empty() {
             self.result.parts.push(InlayHintLabelPart {
                 text,
-                linked_location: self.location.take(),
+                linked_location: self.location.take().map(Lazy::Computed),
                 tooltip: None,
             });
         }

src/tools/rust-analyzer/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: "",
                             },