fix: Make inlay hint resolving work better for inlays targetting the same position

crates/ide/src/inlay_hints.rs

@@ -1,5 +1,6 @@
 use std::{
     fmt::{self, Write},
+    hash::{BuildHasher, BuildHasherDefault},
     mem::take,
 };
 
@@ -8,7 +9,7 @@ use hir::{
     known, ClosureStyle, HasVisibility, HirDisplay, HirDisplayError, HirWrite, ModuleDef,
     ModuleDefId, Semantics,
 };
-use ide_db::{base_db::FileRange, famous_defs::FamousDefs, RootDatabase};
+use ide_db::{base_db::FileRange, famous_defs::FamousDefs, FxHasher, RootDatabase};
 use itertools::Itertools;
 use smallvec::{smallvec, SmallVec};
 use stdx::never;
@@ -116,7 +117,7 @@ pub enum AdjustmentHintsMode {
     PreferPostfix,
 }
 
-#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
 pub enum InlayKind {
     Adjustment,
     BindingMode,
@@ -132,7 +133,7 @@ pub enum InlayKind {
     RangeExclusive,
 }
 
-#[derive(Debug)]
+#[derive(Debug, Hash)]
 pub enum InlayHintPosition {
     Before,
     After,
@@ -151,13 +152,23 @@ pub struct InlayHint {
     pub label: InlayHintLabel,
     /// Text edit to apply when "accepting" this inlay hint.
     pub text_edit: Option<TextEdit>,
-    pub needs_resolve: bool,
+}
+
+impl std::hash::Hash for InlayHint {
+    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
+        self.range.hash(state);
+        self.position.hash(state);
+        self.pad_left.hash(state);
+        self.pad_right.hash(state);
+        self.kind.hash(state);
+        self.label.hash(state);
+        self.text_edit.is_some().hash(state);
+    }
 }
 
 impl InlayHint {
     fn closing_paren_after(kind: InlayKind, range: TextRange) -> InlayHint {
         InlayHint {
-            needs_resolve: false,
             range,
             kind,
             label: InlayHintLabel::from(")"),
@@ -167,9 +178,9 @@ impl InlayHint {
             pad_right: false,
         }
     }
+
     fn opening_paren_before(kind: InlayKind, range: TextRange) -> InlayHint {
         InlayHint {
-            needs_resolve: false,
             range,
             kind,
             label: InlayHintLabel::from("("),
@@ -179,15 +190,19 @@ impl InlayHint {
             pad_right: false,
         }
     }
+
+    pub fn needs_resolve(&self) -> bool {
+        self.text_edit.is_some() || self.label.needs_resolve()
+    }
 }
 
-#[derive(Debug)]
+#[derive(Debug, Hash)]
 pub enum InlayTooltip {
     String(String),
     Markdown(String),
 }
 
-#[derive(Default)]
+#[derive(Default, Hash)]
 pub struct InlayHintLabel {
     pub parts: SmallVec<[InlayHintLabelPart; 1]>,
 }
@@ -265,6 +280,7 @@ impl fmt::Debug for InlayHintLabel {
     }
 }
 
+#[derive(Hash)]
 pub struct InlayHintLabelPart {
     pub text: String,
     /// Source location represented by this label part. The client will use this to fetch the part's
@@ -313,9 +329,7 @@ impl fmt::Write for InlayHintLabelBuilder<'_> {
 
 impl HirWrite for InlayHintLabelBuilder<'_> {
     fn start_location_link(&mut self, def: ModuleDefId) {
-        if self.location.is_some() {
-            never!("location link is already started");
-        }
+        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();
@@ -425,11 +439,6 @@ fn ty_to_text_edit(
     Some(builder.finish())
 }
 
-pub enum RangeLimit {
-    Fixed(TextRange),
-    NearestParent(TextSize),
-}
-
 // Feature: Inlay Hints
 //
 // rust-analyzer shows additional information inline with the source code.
@@ -451,7 +460,7 @@ pub enum RangeLimit {
 pub(crate) fn inlay_hints(
     db: &RootDatabase,
     file_id: FileId,
-    range_limit: Option<RangeLimit>,
+    range_limit: Option<TextRange>,
     config: &InlayHintsConfig,
 ) -> Vec<InlayHint> {
     let _p = tracing::span!(tracing::Level::INFO, "inlay_hints").entered();
@@ -466,38 +475,53 @@ pub(crate) fn inlay_hints(
 
         let hints = |node| hints(&mut acc, &famous_defs, config, file_id, node);
         match range_limit {
-            Some(RangeLimit::Fixed(range)) => match file.covering_element(range) {
+            Some(range) => match file.covering_element(range) {
                 NodeOrToken::Token(_) => return acc,
                 NodeOrToken::Node(n) => n
                     .descendants()
                     .filter(|descendant| range.intersect(descendant.text_range()).is_some())
                     .for_each(hints),
             },
-            Some(RangeLimit::NearestParent(position)) => {
-                match file.token_at_offset(position).left_biased() {
-                    Some(token) => {
-                        if let Some(parent_block) =
-                            token.parent_ancestors().find_map(ast::BlockExpr::cast)
-                        {
-                            parent_block.syntax().descendants().for_each(hints)
-                        } else if let Some(parent_item) =
-                            token.parent_ancestors().find_map(ast::Item::cast)
-                        {
-                            parent_item.syntax().descendants().for_each(hints)
-                        } else {
-                            return acc;
-                        }
-                    }
-                    None => return acc,
-                }
-            }
             None => file.descendants().for_each(hints),
         };
     }
 
     acc
 }
 
+pub(crate) fn inlay_hints_resolve(
+    db: &RootDatabase,
+    file_id: FileId,
+    position: TextSize,
+    hash: u64,
+    config: &InlayHintsConfig,
+) -> Option<InlayHint> {
+    let _p = tracing::span!(tracing::Level::INFO, "inlay_hints").entered();
+    let sema = Semantics::new(db);
+    let file = sema.parse(file_id);
+    let file = file.syntax();
+
+    let scope = sema.scope(file)?;
+    let famous_defs = FamousDefs(&sema, scope.krate());
+    let mut acc = Vec::new();
+
+    let hints = |node| hints(&mut acc, &famous_defs, config, file_id, node);
+    match file.token_at_offset(position).left_biased() {
+        Some(token) => {
+            if let Some(parent_block) = token.parent_ancestors().find_map(ast::BlockExpr::cast) {
+                parent_block.syntax().descendants().for_each(hints)
+            } else if let Some(parent_item) = token.parent_ancestors().find_map(ast::Item::cast) {
+                parent_item.syntax().descendants().for_each(hints)
+            } else {
+                return None;
+            }
+        }
+        None => return None,
+    }
+
+    acc.into_iter().find(|hint| BuildHasherDefault::<FxHasher>::default().hash_one(hint) == hash)
+}
+
 fn hints(
     hints: &mut Vec<InlayHint>,
     famous_defs @ FamousDefs(sema, _): &FamousDefs<'_, '_>,

crates/ide/src/inlay_hints/adjustment.rs

@@ -147,7 +147,6 @@ pub(super) fn hints(
             None,
         );
         acc.push(InlayHint {
-            needs_resolve: label.needs_resolve(),
             range: expr.syntax().text_range(),
             pad_left: false,
             pad_right: false,

crates/ide/src/inlay_hints/bind_pat.rs

@@ -99,7 +99,6 @@ pub(super) fn hints(
         None => pat.syntax().text_range(),
     };
     acc.push(InlayHint {
-        needs_resolve: label.needs_resolve() || text_edit.is_some(),
         range: match type_ascriptable {
             Some(Some(t)) => text_range.cover(t.text_range()),
             _ => text_range,
@@ -177,11 +176,7 @@ mod tests {
     use syntax::{TextRange, TextSize};
     use test_utils::extract_annotations;
 
-    use crate::{
-        fixture,
-        inlay_hints::{InlayHintsConfig, RangeLimit},
-        ClosureReturnTypeHints,
-    };
+    use crate::{fixture, inlay_hints::InlayHintsConfig, ClosureReturnTypeHints};
 
     use crate::inlay_hints::tests::{
         check, check_edit, check_no_edit, check_with_config, DISABLED_CONFIG, TEST_CONFIG,
@@ -404,7 +399,7 @@ fn main() {
             .inlay_hints(
                 &InlayHintsConfig { type_hints: true, ..DISABLED_CONFIG },
                 file_id,
-                Some(RangeLimit::Fixed(TextRange::new(TextSize::from(500), TextSize::from(600)))),
+                Some(TextRange::new(TextSize::from(500), TextSize::from(600))),
             )
             .unwrap();
         let actual =

crates/ide/src/inlay_hints/binding_mode.rs

@@ -50,7 +50,6 @@ pub(super) fn hints(
             _ => return,
         };
         acc.push(InlayHint {
-            needs_resolve: false,
             range,
             kind: InlayKind::BindingMode,
             label: r.into(),
@@ -69,7 +68,6 @@ pub(super) fn hints(
                 hir::BindingMode::Ref(Mutability::Shared) => "ref",
             };
             acc.push(InlayHint {
-                needs_resolve: false,
                 range: pat.syntax().text_range(),
                 kind: InlayKind::BindingMode,
                 label: bm.into(),

crates/ide/src/inlay_hints/chaining.rs

@@ -59,7 +59,6 @@ pub(super) fn hints(
             }
             let label = label_of_ty(famous_defs, config, &ty)?;
             acc.push(InlayHint {
-                needs_resolve: label.needs_resolve(),
                 range: expr.syntax().text_range(),
                 kind: InlayKind::Chaining,
                 label,

crates/ide/src/inlay_hints/closing_brace.rs

@@ -109,7 +109,6 @@ pub(super) fn hints(
 
     let linked_location = name_range.map(|range| FileRange { file_id, range });
     acc.push(InlayHint {
-        needs_resolve: linked_location.is_some(),
         range: closing_token.text_range(),
         kind: InlayKind::ClosingBrace,
         label: InlayHintLabel::simple(label, None, linked_location),

crates/ide/src/inlay_hints/closure_captures.rs

@@ -32,7 +32,6 @@ pub(super) fn hints(
             let range = closure.syntax().first_token()?.prev_token()?.text_range();
             let range = TextRange::new(range.end() - TextSize::from(1), range.end());
             acc.push(InlayHint {
-                needs_resolve: false,
                 range,
                 kind: InlayKind::ClosureCapture,
                 label: InlayHintLabel::from("move"),
@@ -45,7 +44,6 @@ pub(super) fn hints(
         }
     };
     acc.push(InlayHint {
-        needs_resolve: false,
         range: move_kw_range,
         kind: InlayKind::ClosureCapture,
         label: InlayHintLabel::from("("),
@@ -79,7 +77,6 @@ pub(super) fn hints(
             }),
         );
         acc.push(InlayHint {
-            needs_resolve: label.needs_resolve(),
             range: move_kw_range,
             kind: InlayKind::ClosureCapture,
             label,
@@ -91,7 +88,6 @@ pub(super) fn hints(
 
         if idx != last {
             acc.push(InlayHint {
-                needs_resolve: false,
                 range: move_kw_range,
                 kind: InlayKind::ClosureCapture,
                 label: InlayHintLabel::from(", "),
@@ -103,7 +99,6 @@ pub(super) fn hints(
         }
     }
     acc.push(InlayHint {
-        needs_resolve: false,
         range: move_kw_range,
         kind: InlayKind::ClosureCapture,
         label: InlayHintLabel::from(")"),

crates/ide/src/inlay_hints/closure_ret.rs

@@ -64,7 +64,6 @@ pub(super) fn hints(
     };
 
     acc.push(InlayHint {
-        needs_resolve: label.needs_resolve() || text_edit.is_some(),
         range: param_list.syntax().text_range(),
         kind: InlayKind::Type,
         label,

crates/ide/src/inlay_hints/discriminant.rs

@@ -79,7 +79,6 @@ fn variant_hints(
         None,
     );
     acc.push(InlayHint {
-        needs_resolve: label.needs_resolve(),
         range: match eq_token {
             Some(t) => range.cover(t.text_range()),
             _ => range,

crates/ide/src/inlay_hints/fn_lifetime_fn.rs

@@ -22,7 +22,6 @@ pub(super) fn hints(
     }
 
     let mk_lt_hint = |t: SyntaxToken, label: String| InlayHint {
-        needs_resolve: false,
         range: t.text_range(),
         kind: InlayKind::Lifetime,
         label: label.into(),
@@ -184,7 +183,6 @@ pub(super) fn hints(
             let angle_tok = gpl.l_angle_token()?;
             let is_empty = gpl.generic_params().next().is_none();
             acc.push(InlayHint {
-                needs_resolve: false,
                 range: angle_tok.text_range(),
                 kind: InlayKind::Lifetime,
                 label: format!(
@@ -200,7 +198,6 @@ pub(super) fn hints(
             });
         }
         (None, allocated_lifetimes) => acc.push(InlayHint {
-            needs_resolve: false,
             range: func.name()?.syntax().text_range(),
             kind: InlayKind::GenericParamList,
             label: format!("<{}>", allocated_lifetimes.iter().format(", "),).into(),

crates/ide/src/inlay_hints/implicit_drop.rs

@@ -105,7 +105,6 @@ pub(super) fn hints(
                 pad_left: true,
                 pad_right: true,
                 kind: InlayKind::Drop,
-                needs_resolve: label.needs_resolve(),
                 label,
                 text_edit: None,
             })

crates/ide/src/inlay_hints/implicit_static.rs

@@ -31,7 +31,6 @@ pub(super) fn hints(
         if ty.lifetime().is_none() {
             let t = ty.amp_token()?;
             acc.push(InlayHint {
-                needs_resolve: false,
                 range: t.text_range(),
                 kind: InlayKind::Lifetime,
                 label: "'static".into(),

crates/ide/src/inlay_hints/param_name.rs

@@ -57,7 +57,6 @@ pub(super) fn hints(
             let label =
                 InlayHintLabel::simple(format!("{param_name}{colon}"), None, linked_location);
             InlayHint {
-                needs_resolve: label.needs_resolve(),
                 range,
                 kind: InlayKind::Parameter,
                 label,

crates/ide/src/inlay_hints/range_exclusive.rs

@@ -30,7 +30,6 @@ fn inlay_hint(token: SyntaxToken) -> InlayHint {
         kind: crate::InlayKind::RangeExclusive,
         label: crate::InlayHintLabel::from("<"),
         text_edit: None,
-        needs_resolve: false,
     }
 }