Display inlay hints for label references

CHANGELOG.md

@@ -5,6 +5,13 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### Added
+
+- Add `texlab.inlayHints.labelDefinitions` and `texlab.inlayHints.labelReferences` options ([#753](https://github.com/latex-lsp/texlab/issues/753))
+- Display inlay hints for label references by default ([#753](https://github.com/latex-lsp/texlab/issues/753))
+
 ## [5.10.1] - 2023-10-10
 
 ### Fixed

crates/base-db/src/config.rs

@@ -14,6 +14,7 @@ pub struct Config {
     pub symbols: SymbolConfig,
     pub syntax: SyntaxConfig,
     pub completion: CompletionConfig,
+    pub inlay_hints: InlayHintConfig,
 }
 
 #[derive(Debug)]
@@ -77,6 +78,12 @@ pub struct SymbolConfig {
     pub ignored_patterns: Vec<Regex>,
 }
 
+#[derive(Debug)]
+pub struct InlayHintConfig {
+    pub label_definitions: bool,
+    pub label_references: bool,
+}
+
 #[derive(Debug)]
 pub struct CompletionConfig {
     pub matcher: MatchingAlgo,
@@ -101,6 +108,7 @@ impl Default for Config {
             symbols: SymbolConfig::default(),
             syntax: SyntaxConfig::default(),
             completion: CompletionConfig::default(),
+            inlay_hints: InlayHintConfig::default(),
         }
     }
 }
@@ -174,6 +182,15 @@ impl Default for SymbolConfig {
     }
 }
 
+impl Default for InlayHintConfig {
+    fn default() -> Self {
+        Self {
+            label_definitions: true,
+            label_references: true,
+        }
+    }
+}
+
 impl Default for CompletionConfig {
     fn default() -> Self {
         Self {

crates/inlay-hints/Cargo.toml

@@ -9,6 +9,7 @@ rust-version.workspace = true
 [dependencies]
 base-db = { path = "../base-db" }
 rowan = "0.15.11"
+rustc-hash = "1.1.0"
 syntax = { path = "../syntax" }
 
 [dev-dependencies]

crates/inlay-hints/src/label.rs

@@ -1,29 +1,59 @@
-use base_db::{semantics::tex::LabelKind, util::render_label};
+use base_db::{
+    semantics::tex::{Label, LabelKind},
+    util::{queries::Object, render_label},
+    FeatureParams,
+};
+use rustc_hash::FxHashMap;
 
-use crate::InlayHintData;
-
-use super::InlayHintBuilder;
+use crate::{InlayHint, InlayHintBuilder, InlayHintData};
 
 pub(super) fn find_hints(builder: &mut InlayHintBuilder) -> Option<()> {
+    let definitions = base_db::semantics::tex::Label::find_all(&builder.params.feature.project)
+        .into_iter()
+        .filter(|(_, label)| label.kind == LabelKind::Definition)
+        .map(|(_, label)| (label.name_text(), label))
+        .collect::<FxHashMap<_, _>>();
+
     let params = &builder.params.feature;
     let data = params.document.data.as_tex()?;
     let range = builder.params.range;
     for label in data
         .semantics
         .labels
         .iter()
-        .filter(|label| label.kind == LabelKind::Definition)
         .filter(|label| label.name.range.intersect(range).is_some())
     {
-        let Some(rendered) = render_label(params.workspace, &params.project, label) else {
-            continue;
-        };
-
-        builder.hints.push(crate::InlayHint {
-            offset: label.full_range.end(),
-            data: InlayHintData::LabelDefinition(rendered),
-        });
+        if let Some(hint) = process_label(params, &definitions, label) {
+            builder.hints.push(hint);
+        }
     }
 
     Some(())
 }
+
+fn process_label<'a>(
+    params: &FeatureParams<'a>,
+    definitions: &FxHashMap<&str, &'a Label>,
+    label: &'a Label,
+) -> Option<InlayHint<'a>> {
+    let config = &params.workspace.config().inlay_hints;
+    let offset = label.full_range.end();
+    let data = if label.kind == LabelKind::Definition {
+        if !config.label_definitions {
+            return None;
+        }
+
+        let label = render_label(params.workspace, &params.project, label)?;
+        InlayHintData::LabelDefinition(label)
+    } else {
+        if !config.label_references {
+            return None;
+        }
+
+        let label = definitions.get(label.name.text.as_str())?;
+        let label = render_label(params.workspace, &params.project, label)?;
+        InlayHintData::LabelReference(label)
+    };
+
+    Some(InlayHint { offset, data })
+}

crates/inlay-hints/src/lib.rs

@@ -17,6 +17,7 @@ pub struct InlayHint<'a> {
 #[derive(Debug, PartialEq, Eq)]
 pub enum InlayHintData<'a> {
     LabelDefinition(RenderedLabel<'a>),
+    LabelReference(RenderedLabel<'a>),
 }
 
 pub fn find_all<'a>(params: InlayHintParams<'a>) -> Option<Vec<InlayHint>> {

crates/texlab/src/features/inlay_hint.rs

@@ -1,5 +1,5 @@
 use base_db::{util::RenderedObject, FeatureParams, Workspace};
-use inlay_hints::InlayHintParams;
+use inlay_hints::{InlayHintData, InlayHintParams};
 
 use crate::util::line_index_ext::LineIndexExt;
 
@@ -18,7 +18,7 @@ pub fn find_all(
     let hints = hints.into_iter().filter_map(|hint| {
         let position = line_index.line_col_lsp(hint.offset);
         Some(match hint.data {
-            inlay_hints::InlayHintData::LabelDefinition(label) => {
+            InlayHintData::LabelDefinition(label) => {
                 let number = label.number?;
 
                 let text = match &label.object {
@@ -35,6 +35,20 @@ pub fn find_all(
                     RenderedObject::EnumItem => format!("Item {}", number),
                 };
 
+                lsp_types::InlayHint {
+                    position,
+                    label: lsp_types::InlayHintLabel::String(format!(" {text} ")),
+                    kind: None,
+                    text_edits: None,
+                    tooltip: None,
+                    padding_left: Some(true),
+                    padding_right: None,
+                    data: None,
+                }
+            }
+            InlayHintData::LabelReference(label) => {
+                let text = label.reference();
+
                 lsp_types::InlayHint {
                     position,
                     label: lsp_types::InlayHintLabel::String(format!(" {text} ")),

crates/texlab/src/server/options.rs

@@ -22,6 +22,7 @@ pub struct Options {
     pub latexindent: LatexindentOptions,
     pub forward_search: ForwardSearchOptions,
     pub completion: CompletionOptions,
+    pub inlay_hints: InlayHintOptions,
     pub experimental: ExperimentalOptions,
 }
 
@@ -100,6 +101,14 @@ pub struct DiagnosticsOptions {
     pub ignored_patterns: Vec<RegexPattern>,
 }
 
+#[derive(Debug, Clone, Default, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+#[serde(default)]
+pub struct InlayHintOptions {
+    pub label_definitions: Option<bool>,
+    pub label_references: Option<bool>,
+}
+
 #[derive(Debug, Clone, Default, Serialize, Deserialize)]
 #[serde(rename_all = "camelCase")]
 #[serde(default)]
@@ -243,6 +252,9 @@ impl From<Options> for Config {
             .map(|pattern| pattern.0)
             .collect();
 
+        config.inlay_hints.label_definitions = value.inlay_hints.label_definitions.unwrap_or(true);
+        config.inlay_hints.label_references = value.inlay_hints.label_references.unwrap_or(true);
+
         config.completion.matcher = match value.completion.matcher {
             CompletionMatcher::Fuzzy => base_db::MatchingAlgo::Skim,
             CompletionMatcher::FuzzyIgnoreCase => base_db::MatchingAlgo::SkimIgnoreCase,