feat: support inlay hints (#16287)

Closes: #11853

11 files changed, 628 insertions, 2 deletions

diff --git a/cli/lsp/capabilities.rs b/cli/lsp/capabilities.rs
index 0e9c93e63..03192f597 100644
--- a/cli/lsp/capabilities.rs
+++ b/cli/lsp/capabilities.rs
@@ -141,6 +141,6 @@ pub fn server_capabilities(
       "denoConfigTasks": true,
       "testingApi":true,
     })),
-    inlay_hint_provider: None,
+    inlay_hint_provider: Some(OneOf::Left(true)),
   }
 }
diff --git a/cli/lsp/config.rs b/cli/lsp/config.rs
index 98ba5afb5..3c44ebe05 100644
--- a/cli/lsp/config.rs
+++ b/cli/lsp/config.rs
@@ -106,6 +106,101 @@ impl Default for CompletionSettings {
   }
 }
 
+#[derive(Debug, Default, Clone, Deserialize, Serialize, PartialEq, Eq)]
+#[serde(rename_all = "camelCase")]
+pub struct InlayHintsSettings {
+  #[serde(default)]
+  pub parameter_names: InlayHintsParamNamesOptions,
+  #[serde(default)]
+  pub parameter_types: InlayHintsParamTypesOptions,
+  #[serde(default)]
+  pub variable_types: InlayHintsVarTypesOptions,
+  #[serde(default)]
+  pub property_declaration_types: InlayHintsPropDeclTypesOptions,
+  #[serde(default)]
+  pub function_like_return_types: InlayHintsFuncLikeReturnTypesOptions,
+  #[serde(default)]
+  pub enum_member_values: InlayHintsEnumMemberValuesOptions,
+}
+
+#[derive(Debug, Clone, Deserialize, Serialize, PartialEq, Eq)]
+#[serde(rename_all = "camelCase")]
+pub struct InlayHintsParamNamesOptions {
+  #[serde(default)]
+  pub enabled: InlayHintsParamNamesEnabled,
+  #[serde(default = "is_true")]
+  pub suppress_when_argument_matches_name: bool,
+}
+
+impl Default for InlayHintsParamNamesOptions {
+  fn default() -> Self {
+    Self {
+      enabled: InlayHintsParamNamesEnabled::None,
+      suppress_when_argument_matches_name: true,
+    }
+  }
+}
+
+#[derive(Debug, Clone, Deserialize, Serialize, PartialEq, Eq)]
+#[serde(rename_all = "camelCase")]
+pub enum InlayHintsParamNamesEnabled {
+  None,
+  Literals,
+  All,
+}
+
+impl Default for InlayHintsParamNamesEnabled {
+  fn default() -> Self {
+    Self::None
+  }
+}
+
+#[derive(Debug, Default, Clone, Deserialize, Serialize, PartialEq, Eq)]
+#[serde(rename_all = "camelCase")]
+pub struct InlayHintsParamTypesOptions {
+  #[serde(default)]
+  pub enabled: bool,
+}
+
+#[derive(Debug, Clone, Deserialize, Serialize, PartialEq, Eq)]
+#[serde(rename_all = "camelCase")]
+pub struct InlayHintsVarTypesOptions {
+  #[serde(default)]
+  pub enabled: bool,
+  #[serde(default = "is_true")]
+  pub suppress_when_argument_matches_name: bool,
+}
+
+impl Default for InlayHintsVarTypesOptions {
+  fn default() -> Self {
+    Self {
+      enabled: false,
+      suppress_when_argument_matches_name: true,
+    }
+  }
+}
+
+#[derive(Debug, Default, Clone, Deserialize, Serialize, PartialEq, Eq)]
+#[serde(rename_all = "camelCase")]
+pub struct InlayHintsPropDeclTypesOptions {
+  #[serde(default)]
+  pub enabled: bool,
+}
+
+#[derive(Debug, Default, Clone, Deserialize, Serialize, PartialEq, Eq)]
+#[serde(rename_all = "camelCase")]
+pub struct InlayHintsFuncLikeReturnTypesOptions {
+  #[serde(default)]
+  pub enabled: bool,
+}
+
+#[derive(Debug, Default, Clone, Deserialize, Serialize, PartialEq, Eq)]
+#[serde(rename_all = "camelCase")]
+pub struct InlayHintsEnumMemberValuesOptions {
+  #[serde(default)]
+  pub enabled: bool,
+}
+
 #[derive(Debug, Clone, Deserialize, Serialize, PartialEq, Eq)]
 #[serde(rename_all = "camelCase")]
 pub struct ImportCompletionSettings {
@@ -202,6 +297,9 @@ pub struct WorkspaceSettings {
   #[serde(default)]
   pub code_lens: CodeLensSettings,
 
+  #[serde(default)]
+  pub inlay_hints: InlayHintsSettings,
+
   /// A flag that indicates if internal debug logging should be made available.
   #[serde(default)]
   pub internal_debug: bool,
@@ -238,6 +336,19 @@ impl WorkspaceSettings {
   pub fn enabled_code_lens(&self) -> bool {
     self.code_lens.implementations || self.code_lens.references
   }
+
+  /// Determine if any inlay hints are enabled. This allows short circuiting
+  /// when there are no inlay hints enabled.
+  pub fn enabled_inlay_hints(&self) -> bool {
+    !matches!(
+      self.inlay_hints.parameter_names.enabled,
+      InlayHintsParamNamesEnabled::None
+    ) || self.inlay_hints.parameter_types.enabled
+      || self.inlay_hints.variable_types.enabled
+      || self.inlay_hints.property_declaration_types.enabled
+      || self.inlay_hints.function_like_return_types.enabled
+      || self.inlay_hints.enum_member_values.enabled
+  }
 }
 
 #[derive(Debug, Clone, Default)]
@@ -566,6 +677,26 @@ mod tests {
           references_all_functions: false,
           test: true,
         },
+        inlay_hints: InlayHintsSettings {
+          parameter_names: InlayHintsParamNamesOptions {
+            enabled: InlayHintsParamNamesEnabled::None,
+            suppress_when_argument_matches_name: true
+          },
+          parameter_types: InlayHintsParamTypesOptions { enabled: false },
+          variable_types: InlayHintsVarTypesOptions {
+            enabled: false,
+            suppress_when_argument_matches_name: true
+          },
+          property_declaration_types: InlayHintsPropDeclTypesOptions {
+            enabled: false
+          },
+          function_like_return_types: InlayHintsFuncLikeReturnTypesOptions {
+            enabled: false
+          },
+          enum_member_values: InlayHintsEnumMemberValuesOptions {
+            enabled: false
+          },
+        },
         internal_debug: false,
         lint: true,
         suggest: CompletionSettings {
diff --git a/cli/lsp/language_server.rs b/cli/lsp/language_server.rs
index 64c7adeb6..c4617df9f 100644
--- a/cli/lsp/language_server.rs
+++ b/cli/lsp/language_server.rs
@@ -196,6 +196,13 @@ impl LanguageServer {
     }
   }
 
+  pub async fn inlay_hint(
+    &self,
+    params: InlayHintParams,
+  ) -> LspResult<Option<Vec<InlayHint>>> {
+    self.0.lock().await.inlay_hint(params).await
+  }
+
   pub async fn virtual_text_document(
     &self,
     params: Option<Value>,
@@ -2896,6 +2903,50 @@ impl Inner {
     )
   }
 
+  async fn inlay_hint(
+    &self,
+    params: InlayHintParams,
+  ) -> LspResult<Option<Vec<InlayHint>>> {
+    let specifier = self.url_map.normalize_url(&params.text_document.uri);
+    let workspace_settings = self.config.get_workspace_settings();
+    if !self.is_diagnosable(&specifier)
+      || !self.config.specifier_enabled(&specifier)
+      || !workspace_settings.enabled_inlay_hints()
+    {
+      return Ok(None);
+    }
+
+    let mark = self.performance.mark("inlay_hint", Some(&params));
+    let asset_or_doc = self.get_asset_or_document(&specifier)?;
+    let line_index = asset_or_doc.line_index();
+    let range = tsc::TextSpan::from_range(&params.range, line_index.clone())
+      .map_err(|err| {
+        error!("Failed to convert range to text_span: {}", err);
+        LspError::internal_error()
+      })?;
+    let req = tsc::RequestMethod::ProvideInlayHints((
+      specifier.clone(),
+      range,
+      (&workspace_settings).into(),
+    ));
+    let maybe_inlay_hints: Option<Vec<tsc::InlayHint>> = self
+      .ts_server
+      .request(self.snapshot(), req)
+      .await
+      .map_err(|err| {
+        error!("Unable to get inlay hints: {}", err);
+        LspError::internal_error()
+      })?;
+    let maybe_inlay_hints = maybe_inlay_hints.map(|hints| {
+      hints
+        .iter()
+        .map(|hint| hint.to_lsp(line_index.clone()))
+        .collect()
+    });
+    self.performance.measure(mark);
+    Ok(maybe_inlay_hints)
+  }
+
   async fn reload_import_registries(&mut self) -> LspResult<Option<Value>> {
     fs_util::remove_dir_all_if_exists(&self.module_registries_location)
       .await
diff --git a/cli/lsp/lsp_custom.rs b/cli/lsp/lsp_custom.rs
index 49c06e15c..b154234c7 100644
--- a/cli/lsp/lsp_custom.rs
+++ b/cli/lsp/lsp_custom.rs
@@ -11,6 +11,9 @@ pub const RELOAD_IMPORT_REGISTRIES_REQUEST: &str =
   "deno/reloadImportRegistries";
 pub const VIRTUAL_TEXT_DOCUMENT: &str = "deno/virtualTextDocument";
 
+// While lsp_types supports inlay hints currently, tower_lsp does not.
+pub const INLAY_HINT: &str = "textDocument/inlayHint";
+
 #[derive(Debug, Deserialize, Serialize)]
 #[serde(rename_all = "camelCase")]
 pub struct CacheParams {
diff --git a/cli/lsp/mod.rs b/cli/lsp/mod.rs
index 2ee22510f..7161c5209 100644
--- a/cli/lsp/mod.rs
+++ b/cli/lsp/mod.rs
@@ -58,6 +58,7 @@ pub async fn start() -> Result<(), AnyError> {
     lsp_custom::VIRTUAL_TEXT_DOCUMENT,
     LanguageServer::virtual_text_document,
   )
+  .custom_method(lsp_custom::INLAY_HINT, LanguageServer::inlay_hint)
   .finish();
 
   Server::new(stdin, stdout, socket).serve(service).await;
diff --git a/cli/lsp/repl.rs b/cli/lsp/repl.rs
index b6329205a..60354f2d0 100644
--- a/cli/lsp/repl.rs
+++ b/cli/lsp/repl.rs
@@ -288,6 +288,7 @@ pub fn get_repl_workspace_settings() -> WorkspaceSettings {
     cache: None,
     import_map: None,
     code_lens: Default::default(),
+    inlay_hints: Default::default(),
     internal_debug: false,
     lint: false,
     tls_certificate: None,
diff --git a/cli/lsp/tsc.rs b/cli/lsp/tsc.rs
index 51dd74240..6c2136990 100644
--- a/cli/lsp/tsc.rs
+++ b/cli/lsp/tsc.rs
@@ -618,6 +618,15 @@ pub struct TextSpan {
 }
 
 impl TextSpan {
+  pub fn from_range(
+    range: &lsp::Range,
+    line_index: Arc<LineIndex>,
+  ) -> Result<Self, AnyError> {
+    let start = line_index.offset_tsc(range.start)?;
+    let length = line_index.offset_tsc(range.end)? - start;
+    Ok(Self { start, length })
+  }
+
   pub fn to_range(&self, line_index: Arc<LineIndex>) -> lsp::Range {
     lsp::Range {
       start: line_index.position_tsc(self.start.into()),
@@ -933,6 +942,48 @@ impl NavigateToItem {
 }
 
 #[derive(Debug, Clone, Deserialize)]
+pub enum InlayHintKind {
+  Type,
+  Parameter,
+  Enum,
+}
+
+impl InlayHintKind {
+  pub fn to_lsp(&self) -> Option<lsp::InlayHintKind> {
+    match self {
+      Self::Enum => None,
+      Self::Parameter => Some(lsp::InlayHintKind::PARAMETER),
+      Self::Type => Some(lsp::InlayHintKind::TYPE),
+    }
+  }
+}
+
+#[derive(Debug, Clone, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct InlayHint {
+  pub text: String,
+  pub position: u32,
+  pub kind: InlayHintKind,
+  pub whitespace_before: Option<bool>,
+  pub whitespace_after: Option<bool>,
+}
+
+impl InlayHint {
+  pub fn to_lsp(&self, line_index: Arc<LineIndex>) -> lsp::InlayHint {
+    lsp::InlayHint {
+      position: line_index.position_tsc(self.position.into()),
+      label: lsp::InlayHintLabel::String(self.text.clone()),
+      kind: self.kind.to_lsp(),
+      padding_left: self.whitespace_before,
+      padding_right: self.whitespace_after,
+      text_edits: None,
+      tooltip: None,
+      data: None,
+    }
+  }
+}
+
+#[derive(Debug, Clone, Deserialize)]
 #[serde(rename_all = "camelCase")]
 pub struct NavigationTree {
   pub text: String,
@@ -2830,6 +2881,18 @@ pub enum IncludeInlayParameterNameHints {
   All,
 }
 
+impl From<&config::InlayHintsParamNamesEnabled>
+  for IncludeInlayParameterNameHints
+{
+  fn from(setting: &config::InlayHintsParamNamesEnabled) -> Self {
+    match setting {
+      config::InlayHintsParamNamesEnabled::All => Self::All,
+      config::InlayHintsParamNamesEnabled::Literals => Self::Literals,
+      config::InlayHintsParamNamesEnabled::None => Self::None,
+    }
+  }
+}
+
 #[derive(Debug, Serialize)]
 #[serde(rename_all = "kebab-case")]
 #[allow(dead_code)]
@@ -2910,6 +2973,8 @@ pub struct UserPreferences {
   #[serde(skip_serializing_if = "Option::is_none")]
   pub include_inlay_variable_type_hints: Option<bool>,
   #[serde(skip_serializing_if = "Option::is_none")]
+  pub include_inlay_variable_type_hints_when_type_matches_name: Option<bool>,
+  #[serde(skip_serializing_if = "Option::is_none")]
   pub include_inlay_property_declaration_type_hints: Option<bool>,
   #[serde(skip_serializing_if = "Option::is_none")]
   pub include_inlay_function_like_return_type_hints: Option<bool>,
@@ -2921,6 +2986,43 @@ pub struct UserPreferences {
   pub auto_import_file_exclude_patterns: Option<Vec<String>>,
 }
 
+impl From<&config::WorkspaceSettings> for UserPreferences {
+  fn from(workspace_settings: &config::WorkspaceSettings) -> Self {
+    let inlay_hints = &workspace_settings.inlay_hints;
+    Self {
+      include_inlay_parameter_name_hints: Some(
+        (&inlay_hints.parameter_names.enabled).into(),
+      ),
+      include_inlay_parameter_name_hints_when_argument_matches_name: Some(
+        inlay_hints
+          .parameter_names
+          .suppress_when_argument_matches_name,
+      ),
+      include_inlay_function_parameter_type_hints: Some(
+        inlay_hints.parameter_types.enabled,
+      ),
+      include_inlay_variable_type_hints: Some(
+        inlay_hints.variable_types.enabled,
+      ),
+      include_inlay_variable_type_hints_when_type_matches_name: Some(
+        inlay_hints
+          .variable_types
+          .suppress_when_argument_matches_name,
+      ),
+      include_inlay_property_declaration_type_hints: Some(
+        inlay_hints.property_declaration_types.enabled,
+      ),
+      include_inlay_function_like_return_type_hints: Some(
+        inlay_hints.function_like_return_types.enabled,
+      ),
+      include_inlay_enum_member_value_hints: Some(
+        inlay_hints.enum_member_values.enabled,
+      ),
+      ..Default::default()
+    }
+  }
+}
+
 #[derive(Debug, Serialize)]
 #[serde(rename_all = "camelCase")]
 pub struct SignatureHelpItemsOptions {
@@ -3053,6 +3155,8 @@ pub enum RequestMethod {
   ProvideCallHierarchyIncomingCalls((ModuleSpecifier, u32)),
   /// Resolve outgoing call hierarchy items for a specific position.
   ProvideCallHierarchyOutgoingCalls((ModuleSpecifier, u32)),
+  /// Resolve inlay hints for a specific text span
+  ProvideInlayHints((ModuleSpecifier, TextSpan, UserPreferences)),
 
   // Special request, used only internally by the LSP
   Restart,
@@ -3269,6 +3373,15 @@ impl RequestMethod {
           "position": position
         })
       }
+      RequestMethod::ProvideInlayHints((specifier, span, preferences)) => {
+        json!({
+          "id": id,
+          "method": "provideInlayHints",
+          "specifier": state.denormalize_specifier(specifier),
+          "span": span,
+          "preferences": preferences,
+        })
+      }
       RequestMethod::Restart => json!({
         "id": id,
         "method": "restart",
diff --git a/cli/tests/integration/lsp_tests.rs b/cli/tests/integration/lsp_tests.rs
index cc8625476..7dc5ff02d 100644
--- a/cli/tests/integration/lsp_tests.rs
+++ b/cli/tests/integration/lsp_tests.rs
@@ -1072,6 +1072,213 @@ fn lsp_hover_disabled() {
 }
 
 #[test]
+fn lsp_inlay_hints() {
+  let mut client = init("initialize_params_hints.json");
+  did_open(
+    &mut client,
+    json!({
+      "textDocument": {
+        "uri": "file:///a/file.ts",
+        "languageId": "typescript",
+        "version": 1,
+        "text": r#"function a(b: string) {
+          return b;
+        }
+        
+        a("foo");
+        
+        enum C {
+          A,
+        }
+        
+        parseInt("123", 8);
+        
+        const d = Date.now();
+        
+        class E {
+          f = Date.now();
+        }
+        
+        ["a"].map((v) => v + v);
+        "#
+      }
+    }),
+  );
+  let (maybe_res, maybe_err) = client
+    .write_request::<_, _, Value>(
+      "textDocument/inlayHint",
+      json!({
+        "textDocument": {
+          "uri": "file:///a/file.ts",
+        },
+        "range": {
+          "start": {
+            "line": 0,
+            "character": 0
+          },
+          "end": {
+            "line": 19,
+            "character": 0,
+          }
+        }
+      }),
+    )
+    .unwrap();
+  assert!(maybe_err.is_none());
+  assert_eq!(
+    json!(maybe_res),
+    json!([
+      {
+        "position": {
+          "line": 0,
+          "character": 21
+        },
+        "label": ": string",
+        "kind": 1,
+        "paddingLeft": true
+      },
+      {
+        "position": {
+          "line": 4,
+          "character": 10
+        },
+        "label": "b:",
+        "kind": 2,
+        "paddingRight": true
+      },
+      {
+        "position": {
+          "line": 7,
+          "character": 11
+        },
+        "label": "= 0",
+        "paddingLeft": true
+      },
+      {
+        "position": {
+          "line": 10,
+          "character": 17
+        },
+        "label": "string:",
+        "kind": 2,
+        "paddingRight": true
+      },
+      {
+        "position": {
+          "line": 10,
+          "character": 24
+        },
+        "label": "radix:",
+        "kind": 2,
+        "paddingRight": true
+      },
+      {
+        "position": {
+          "line": 12,
+          "character": 15
+        },
+        "label": ": number",
+        "kind": 1,
+        "paddingLeft": true
+      },
+      {
+        "position": {
+          "line": 15,
+          "character": 11
+        },
+        "label": ": number",
+        "kind": 1,
+        "paddingLeft": true
+      },
+      {
+        "position": {
+          "line": 18,
+          "character": 18
+        },
+        "label": "callbackfn:",
+        "kind": 2,
+        "paddingRight": true
+      },
+      {
+        "position": {
+          "line": 18,
+          "character": 20
+        },
+        "label": ": string",
+        "kind": 1,
+        "paddingLeft": true
+      },
+      {
+        "position": {
+          "line": 18,
+          "character": 21
+        },
+        "label": ": string",
+        "kind": 1,
+        "paddingLeft": true
+      }
+    ])
+  );
+}
+
+#[test]
+fn lsp_inlay_hints_not_enabled() {
+  let mut client = init("initialize_params.json");
+  did_open(
+    &mut client,
+    json!({
+      "textDocument": {
+        "uri": "file:///a/file.ts",
+        "languageId": "typescript",
+        "version": 1,
+        "text": r#"function a(b: string) {
+          return b;
+        }
+        
+        a("foo");
+        
+        enum C {
+          A,
+        }
+        
+        parseInt("123", 8);
+        
+        const d = Date.now();
+        
+        class E {
+          f = Date.now();
+        }
+        
+        ["a"].map((v) => v + v);
+        "#
+      }
+    }),
+  );
+  let (maybe_res, maybe_err) = client
+    .write_request::<_, _, Value>(
+      "textDocument/inlayHint",
+      json!({
+        "textDocument": {
+          "uri": "file:///a/file.ts",
+        },
+        "range": {
+          "start": {
+            "line": 0,
+            "character": 0
+          },
+          "end": {
+            "line": 19,
+            "character": 0,
+          }
+        }
+      }),
+    )
+    .unwrap();
+  assert!(maybe_err.is_none());
+  assert_eq!(json!(maybe_res), json!(null));
+}
+
+#[test]
 fn lsp_workspace_enable_paths() {
   let mut params: lsp::InitializeParams = serde_json::from_value(load_fixture(
     "initialize_params_workspace_enable_paths.json",
diff --git a/cli/tests/testdata/lsp/initialize_params_hints.json b/cli/tests/testdata/lsp/initialize_params_hints.json
new file mode 100644
index 000000000..1bab6e86d
--- /dev/null
+++ b/cli/tests/testdata/lsp/initialize_params_hints.json
@@ -0,0 +1,102 @@
+{
+  "processId": 0,
+  "clientInfo": {
+    "name": "test-harness",
+    "version": "1.0.0"
+  },
+  "rootUri": null,
+  "initializationOptions": {
+    "enable": true,
+    "cache": null,
+    "certificateStores": null,
+    "codeLens": {
+      "implementations": true,
+      "references": true,
+      "test": true
+    },
+    "config": null,
+    "importMap": null,
+    "inlayHints": {
+      "parameterNames": {
+        "enabled": "all"
+      },
+      "parameterTypes": {
+        "enabled": true
+      },
+      "variableTypes": {
+        "enabled": true
+      },
+      "propertyDeclarationTypes": {
+        "enabled": true
+      },
+      "functionLikeReturnTypes": {
+        "enabled": true
+      },
+      "enumMemberValues": {
+        "enabled": true
+      }
+    },
+    "lint": true,
+    "suggest": {
+      "autoImports": true,
+      "completeFunctionCalls": false,
+      "names": true,
+      "paths": true,
+      "imports": {
+        "hosts": {}
+      }
+    },
+    "testing": {
+      "args": [
+        "--allow-all"
+      ],
+      "enable": true
+    },
+    "tlsCertificate": null,
+    "unsafelyIgnoreCertificateErrors": null,
+    "unstable": false
+  },
+  "capabilities": {
+    "textDocument": {
+      "codeAction": {
+        "codeActionLiteralSupport": {
+          "codeActionKind": {
+            "valueSet": [
+              "quickfix",
+              "refactor"
+            ]
+          }
+        },
+        "isPreferredSupport": true,
+        "dataSupport": true,
+        "disabledSupport": true,
+        "resolveSupport": {
+          "properties": [
+            "edit"
+          ]
+        }
+      },
+      "completion": {
+        "completionItem": {
+          "snippetSupport": true
+        }
+      },
+      "foldingRange": {
+        "lineFoldingOnly": true
+      },
+      "synchronization": {
+        "dynamicRegistration": true,
+        "willSave": true,
+        "willSaveWaitUntil": true,
+        "didSave": true
+      }
+    },
+    "workspace": {
+      "configuration": true,
+      "workspaceFolders": true
+    },
+    "experimental": {
+      "testingApi": true
+    }
+  }
+}
diff --git a/cli/tsc/99_main_compiler.js b/cli/tsc/99_main_compiler.js
index ab43af38d..b39f56cf6 100644
--- a/cli/tsc/99_main_compiler.js
+++ b/cli/tsc/99_main_compiler.js
@@ -898,6 +898,15 @@ delete Object.prototype.__proto__;
           ),
         );
       }
+      case "provideInlayHints":
+        return respond(
+          id,
+          languageService.provideInlayHints(
+            request.specifier,
+            request.span,
+            request.preferences,
+          ),
+        );
       default:
         throw new TypeError(
           // @ts-ignore exhausted case statement sets type to never
diff --git a/cli/tsc/compiler.d.ts b/cli/tsc/compiler.d.ts
index 31c8b8c64..ffd4695ae 100644
--- a/cli/tsc/compiler.d.ts
+++ b/cli/tsc/compiler.d.ts
@@ -77,7 +77,8 @@ declare global {
     | GetTypeDefinitionRequest
     | PrepareCallHierarchy
     | ProvideCallHierarchyIncomingCalls
-    | ProvideCallHierarchyOutgoingCalls;
+    | ProvideCallHierarchyOutgoingCalls
+    | ProvideInlayHints;
 
   interface BaseLanguageServerRequest {
     id: number;
@@ -255,6 +256,13 @@ declare global {
     position: number;
   }
 
+  interface ProvideInlayHints extends BaseLanguageServerRequest {
+    method: "provideInlayHints";
+    specifier: string;
+    span: ts.TextSpan;
+    preferences?: ts.UserPreferences;
+  }
+
   interface Restart extends BaseLanguageServerRequest {
     method: "restart";
   }