feat(language-service): add support for inline values

packages/language-core/lib/editorFeatures.ts

@@ -16,6 +16,10 @@ export function isMonikerEnabled(info: CodeInformation): boolean {
 	return !!info.semantic;
 }
 
+export function isInlineValueEnabled(info: CodeInformation): boolean {
+	return !!info.semantic;
+}
+
 export function isSemanticTokensEnabled(info: CodeInformation): boolean {
 	return typeof info.semantic === 'object'
 		? info.semantic.shouldHighlight?.() ?? true

packages/language-server/lib/features/languageFeatures.ts

@@ -493,6 +493,24 @@ export function register(
 			});
 		}
 
+		if (languageServicePlugins.some(({ capabilities }) => capabilities.inlineValueProvider)) {
+			serverCapabilities.inlineValueProvider = true;
+			server.connection.languages.inlineValue.on(async (params, token) => {
+				const uri = URI.parse(params.textDocument.uri);
+				return await worker(uri, token, languageService => {
+					return languageService.getInlineValue(uri, params.range, params.context, token);
+				});
+			});
+			if (initializeParams.capabilities.workspace?.inlineValue?.refreshSupport) {
+				refreshHandlers.push(() => {
+					server.connection.languages.inlineValue.refresh();
+				});
+			}
+			else {
+				console.warn('Inline value refresh is not supported by the client.');
+			}
+		}
+
 		if (languageServicePlugins.some(({ capabilities }) => capabilities.autoInsertionProvider)) {
 			const triggerCharacterToConfigurationSections = new Map<string, Set<string>>();
 			const tryAdd = (char: string, section?: string) => {

packages/language-service/lib/features/provideInlineValue.ts

@@ -0,0 +1,40 @@
+import { isInlineValueEnabled } from '@volar/language-core';
+import type * as vscode from 'vscode-languageserver-protocol';
+import { URI } from 'vscode-uri';
+import type { LanguageServiceContext } from '../types';
+import { NoneCancellationToken } from '../utils/cancellation';
+import { getGeneratedRanges, getSourceRange, languageFeatureWorker } from '../utils/featureWorkers';
+
+export function register(context: LanguageServiceContext) {
+
+	return (uri: URI, range: vscode.Range, ivContext: vscode.InlineValueContext, token = NoneCancellationToken) => {
+
+		return languageFeatureWorker(
+			context,
+			uri,
+			() => range,
+			docs => getGeneratedRanges(docs, range, isInlineValueEnabled),
+			(plugin, document, range) => {
+				if (token.isCancellationRequested) {
+					return;
+				}
+				return plugin[1].provideInlineValues?.(document, range, ivContext, token);
+			},
+			(items, docs) => {
+				if (!docs) {
+					return items;
+				}
+				return items
+					.map(item => {
+						const mappedRange = getSourceRange(docs, item.range, isInlineValueEnabled);
+						if (mappedRange) {
+							item.range = mappedRange;
+							return item;
+						}
+					})
+					.filter(item => !!item);
+			},
+			results => results.flat()
+		);
+	};
+}

packages/language-service/lib/languageService.ts

@@ -24,6 +24,7 @@ import * as foldingRanges from './features/provideFoldingRanges';
 import * as hover from './features/provideHover';
 import * as inlayHints from './features/provideInlayHints';
 import * as moniker from './features/provideMoniker';
+import * as inlineValue from './features/provideInlineValue';
 import * as linkedEditing from './features/provideLinkedEditingRanges';
 import * as references from './features/provideReferences';
 import * as rename from './features/provideRenameEdits';
@@ -239,6 +240,7 @@ function createLanguageServiceBase(
 		getDocumentDropEdits: documentDrop.register(context),
 		getInlayHints: inlayHints.register(context),
 		getMoniker: moniker.register(context),
+		getInlineValue: inlineValue.register(context),
 
 		resolveCodeAction: codeActionResolve.register(context),
 		resolveCompletionItem: completionResolve.register(context),

packages/language-service/lib/types.ts

@@ -105,6 +105,7 @@ export interface LanguageServicePlugin<P = any> {
 		hoverProvider?: boolean;
 		documentHighlightProvider?: boolean;
 		monikerProvider?: boolean;
+		inlineValueProvider?: boolean;
 		workspaceSymbolProvider?: {
 			resolveProvider?: boolean;
 		};
@@ -185,6 +186,7 @@ export interface LanguageServicePluginInstance<P = any> {
 	provideReferences?(document: TextDocument, position: vscode.Position, context: vscode.ReferenceContext, token: vscode.CancellationToken): NullableProviderResult<vscode.Location[]>;
 	provideSelectionRanges?(document: TextDocument, positions: vscode.Position[], token: vscode.CancellationToken): NullableProviderResult<vscode.SelectionRange[]>;
 	provideInlayHints?(document: TextDocument, range: vscode.Range, token: vscode.CancellationToken): NullableProviderResult<vscode.InlayHint[]>;
+	provideInlineValues?(document: TextDocument, range: vscode.Range, context: vscode.InlineValueContext, token: vscode.CancellationToken): NullableProviderResult<vscode.InlineValue[]>;
 	provideCallHierarchyItems?(document: TextDocument, position: vscode.Position, token: vscode.CancellationToken): NullableProviderResult<vscode.CallHierarchyItem[]>;
 	provideCallHierarchyIncomingCalls?(item: vscode.CallHierarchyItem, token: vscode.CancellationToken): ProviderResult<vscode.CallHierarchyIncomingCall[]>;
 	provideCallHierarchyOutgoingCalls?(item: vscode.CallHierarchyItem, token: vscode.CancellationToken): ProviderResult<vscode.CallHierarchyOutgoingCall[]>;