Proposed expandable hover API

src/compiler/types.ts

@@ -5042,6 +5042,11 @@ export interface TypeCheckerHost extends ModuleSpecifierResolutionHost, SourceFi
     packageBundlesTypes(packageName: string): boolean;
 }
 
+/** @internal */
+export interface WriterContextOut {
+    couldUnfoldMore: boolean;
+}
+
 export interface TypeChecker {
     getTypeOfSymbolAtLocation(symbol: Symbol, node: Node): Type;
     getTypeOfSymbol(symbol: Symbol): Type;
@@ -5128,6 +5133,7 @@ export interface TypeChecker {
     symbolToParameterDeclaration(symbol: Symbol, enclosingDeclaration: Node | undefined, flags: NodeBuilderFlags | undefined): ParameterDeclaration | undefined;
     /** Note that the resulting nodes cannot be checked. */
     typeParameterToDeclaration(parameter: TypeParameter, enclosingDeclaration: Node | undefined, flags: NodeBuilderFlags | undefined): TypeParameterDeclaration | undefined;
+    /** @internal */ typeParameterToDeclaration(parameter: TypeParameter, enclosingDeclaration: Node | undefined, flags: NodeBuilderFlags | undefined, internalFlags?: InternalNodeBuilderFlags, tracker?: SymbolTracker, verbosityLevel?: number): TypeParameterDeclaration | undefined; // eslint-disable-line @typescript-eslint/unified-signatures
 
     getSymbolsInScope(location: Node, meaning: SymbolFlags): Symbol[];
     getSymbolAtLocation(node: Node): Symbol | undefined;
@@ -5160,7 +5166,7 @@ export interface TypeChecker {
     typePredicateToString(predicate: TypePredicate, enclosingDeclaration?: Node, flags?: TypeFormatFlags): string;
 
     /** @internal */ writeSignature(signature: Signature, enclosingDeclaration?: Node, flags?: TypeFormatFlags, kind?: SignatureKind, writer?: EmitTextWriter): string;
-    /** @internal */ writeType(type: Type, enclosingDeclaration?: Node, flags?: TypeFormatFlags, writer?: EmitTextWriter): string;
+    /** @internal */ writeType(type: Type, enclosingDeclaration?: Node, flags?: TypeFormatFlags, writer?: EmitTextWriter, verbosityLevel?: number, out?: WriterContextOut): string;
     /** @internal */ writeSymbol(symbol: Symbol, enclosingDeclaration?: Node, meaning?: SymbolFlags, flags?: SymbolFormatFlags, writer?: EmitTextWriter): string;
     /** @internal */ writeTypePredicate(predicate: TypePredicate, enclosingDeclaration?: Node, flags?: TypeFormatFlags, writer?: EmitTextWriter): string;
 

src/harness/client.ts

@@ -254,8 +254,8 @@ export class SessionClient implements LanguageService {
         return { line, character: offset };
     }
 
-    getQuickInfoAtPosition(fileName: string, position: number): QuickInfo {
-        const args = this.createFileLocationRequestArgs(fileName, position);
+    getQuickInfoAtPosition(fileName: string, position: number, verbosityLevel?: number | undefined): QuickInfo {
+        const args = { ...this.createFileLocationRequestArgs(fileName, position), verbosityLevel };
 
         const request = this.processRequest<protocol.QuickInfoRequest>(protocol.CommandTypes.Quickinfo, args);
         const response = this.processResponse<protocol.QuickInfoResponse>(request);
@@ -268,6 +268,7 @@ export class SessionClient implements LanguageService {
             displayParts: [{ kind: "text", text: body.displayString }],
             documentation: typeof body.documentation === "string" ? [{ kind: "text", text: body.documentation }] : body.documentation,
             tags: this.decodeLinkDisplayParts(body.tags),
+            canIncreaseVerbosityLevel: body.canIncreaseVerbosityLevel,
         };
     }
 

src/harness/fourslashImpl.ts

@@ -86,6 +86,10 @@ export interface TextSpan {
     end: number;
 }
 
+export interface VerbosityLevels {
+    [markerName: string]: number | number[] | undefined;
+}
+
 // Name of testcase metadata including ts.CompilerOptions properties that will be used by globalOptions
 // To add additional option, add property into the testOptMetadataNames, refer the property in either globalMetadataNames or fileMetadataNames
 // Add cases into convertGlobalOptionsToCompilationsSettings function for the compiler to acknowledge such option from meta data
@@ -2451,19 +2455,28 @@ export class TestState {
         return result;
     }
 
-    public baselineQuickInfo(): void {
-        const result = ts.arrayFrom(this.testData.markerPositions.entries(), ([name, marker]) => ({
-            marker: { ...marker, name },
-            item: this.languageService.getQuickInfoAtPosition(marker.fileName, marker.position),
-        }));
+    public baselineQuickInfo(verbosityLevels?: VerbosityLevels): void {
+        const result = ts.arrayFrom(this.testData.markerPositions.entries(), ([name, marker]) => {
+            const verbosityLevel = toArray(verbosityLevels?.[name]);
+            const items = verbosityLevel.map(verbosityLevel => {
+                const item: ts.QuickInfo & { verbosityLevel?: number; } | undefined = this.languageService.getQuickInfoAtPosition(marker.fileName, marker.position, verbosityLevel);
+                if (item) item.verbosityLevel = verbosityLevel;
+                return {
+                    marker: { ...marker, name },
+                    item,
+                };
+            });
+            return items;
+        }).flat();
         const annotations = this.annotateContentWithTooltips(
             result,
             "quickinfo",
             item => item.textSpan,
-            ({ displayParts, documentation, tags }) => [
+            ({ displayParts, documentation, tags, verbosityLevel }) => [
                 ...(displayParts ? displayParts.map(p => p.text).join("").split("\n") : []),
                 ...(documentation?.length ? documentation.map(p => p.text).join("").split("\n") : []),
                 ...(tags?.length ? tags.map(p => `@${p.name} ${p.text?.map(dp => dp.text).join("") ?? ""}`).join("\n").split("\n") : []),
+                ...(verbosityLevel !== undefined ? [`(verbosity level: ${verbosityLevel})`] : []),
             ],
         );
         this.baseline("QuickInfo", annotations + "\n\n" + stringify(result));

src/harness/fourslashInterfaceImpl.ts

@@ -453,8 +453,8 @@ export class Verify extends VerifyNegatable {
         this.state.baselineGetEmitOutput();
     }
 
-    public baselineQuickInfo(): void {
-        this.state.baselineQuickInfo();
+    public baselineQuickInfo(verbosityLevels?: FourSlash.VerbosityLevels): void {
+        this.state.baselineQuickInfo(verbosityLevels);
     }
 
     public baselineSignatureHelp(): void {

src/server/protocol.ts

@@ -2004,6 +2004,11 @@ export interface QuickInfoRequest extends FileLocationRequest {
     arguments: FileLocationRequestArgs;
 }
 
+export interface QuickInfoRequestArgs extends FileLocationRequestArgs {
+    /** TODO */
+    verbosityLevel?: number;
+}
+
 /**
  * Body of QuickInfoResponse.
  */
@@ -2043,6 +2048,11 @@ export interface QuickInfoResponseBody {
      * JSDoc tags associated with symbol.
      */
     tags: JSDocTagInfo[];
+
+    /**
+     * TODO
+     */
+    canIncreaseVerbosityLevel?: boolean;
 }
 
 /**

src/server/session.ts

@@ -2394,10 +2394,10 @@ export class Session<TMessage = string> implements EventSender {
         return languageService.isValidBraceCompletionAtPosition(file, position, args.openingBrace.charCodeAt(0));
     }
 
-    private getQuickInfoWorker(args: protocol.FileLocationRequestArgs, simplifiedResult: boolean): protocol.QuickInfoResponseBody | QuickInfo | undefined {
+    private getQuickInfoWorker(args: protocol.QuickInfoRequestArgs, simplifiedResult: boolean): protocol.QuickInfoResponseBody | QuickInfo | undefined {
         const { file, project } = this.getFileAndProject(args);
         const scriptInfo = this.projectService.getScriptInfoForNormalizedPath(file)!;
-        const quickInfo = project.getLanguageService().getQuickInfoAtPosition(file, this.getPosition(args, scriptInfo));
+        const quickInfo = project.getLanguageService().getQuickInfoAtPosition(file, this.getPosition(args, scriptInfo), args.verbosityLevel);
         if (!quickInfo) {
             return undefined;
         }
@@ -2413,6 +2413,7 @@ export class Session<TMessage = string> implements EventSender {
                 displayString,
                 documentation: useDisplayParts ? this.mapDisplayParts(quickInfo.documentation, project) : displayPartsToString(quickInfo.documentation),
                 tags: this.mapJSDocTagInfo(quickInfo.tags, project, useDisplayParts),
+                canIncreaseVerbosityLevel: quickInfo.canIncreaseVerbosityLevel,
             };
         }
         else {

src/services/services.ts

@@ -2277,7 +2277,7 @@ export function createLanguageService(
         return Completions.getCompletionEntrySymbol(program, log, getValidSourceFile(fileName), position, { name, source }, host, preferences);
     }
 
-    function getQuickInfoAtPosition(fileName: string, position: number): QuickInfo | undefined {
+    function getQuickInfoAtPosition(fileName: string, position: number, verbosityLevel?: number): QuickInfo | undefined {
         synchronizeHostData();
 
         const sourceFile = getValidSourceFile(fileName);
@@ -2296,20 +2296,34 @@ export function createLanguageService(
                 kind: ScriptElementKind.unknown,
                 kindModifiers: ScriptElementKindModifier.none,
                 textSpan: createTextSpanFromNode(nodeForQuickInfo, sourceFile),
-                displayParts: typeChecker.runWithCancellationToken(cancellationToken, typeChecker => typeToDisplayParts(typeChecker, type, getContainerNode(nodeForQuickInfo))),
+                displayParts: typeChecker.runWithCancellationToken(cancellationToken, typeChecker => typeToDisplayParts(typeChecker, type, getContainerNode(nodeForQuickInfo), /*flags*/ undefined, verbosityLevel)),
                 documentation: type.symbol ? type.symbol.getDocumentationComment(typeChecker) : undefined,
                 tags: type.symbol ? type.symbol.getJsDocTags(typeChecker) : undefined,
             };
         }
 
-        const { symbolKind, displayParts, documentation, tags } = typeChecker.runWithCancellationToken(cancellationToken, typeChecker => SymbolDisplay.getSymbolDisplayPartsDocumentationAndSymbolKind(typeChecker, symbol, sourceFile, getContainerNode(nodeForQuickInfo), nodeForQuickInfo));
+        const { symbolKind, displayParts, documentation, tags, canIncreaseVerbosityLevel } = typeChecker.runWithCancellationToken(
+            cancellationToken,
+            typeChecker =>
+                SymbolDisplay.getSymbolDisplayPartsDocumentationAndSymbolKind(
+                    typeChecker,
+                    symbol,
+                    sourceFile,
+                    getContainerNode(nodeForQuickInfo),
+                    nodeForQuickInfo,
+                    /*semanticMeaning*/ undefined,
+                    /*alias*/ undefined,
+                    verbosityLevel,
+                ),
+        );
         return {
             kind: symbolKind,
             kindModifiers: SymbolDisplay.getSymbolModifiers(typeChecker, symbol),
             textSpan: createTextSpanFromNode(nodeForQuickInfo, sourceFile),
             displayParts,
             documentation,
             tags,
+            canIncreaseVerbosityLevel,
         };
     }
 

src/services/symbolDisplay.ts

@@ -108,6 +108,7 @@ import {
     TypeParameter,
     typeToDisplayParts,
     VariableDeclaration,
+    WriterContextOut,
 } from "./_namespaces/ts.js";
 
 const symbolDisplayNodeBuilderFlags = NodeBuilderFlags.OmitParameterModifiers | NodeBuilderFlags.IgnoreErrors | NodeBuilderFlags.UseAliasDefinedOutsideCurrentScope;
@@ -254,9 +255,20 @@ export interface SymbolDisplayPartsDocumentationAndSymbolKind {
     documentation: SymbolDisplayPart[];
     symbolKind: ScriptElementKind;
     tags: JSDocTagInfo[] | undefined;
+    canIncreaseVerbosityLevel?: boolean;
 }
 
-function getSymbolDisplayPartsDocumentationAndSymbolKindWorker(typeChecker: TypeChecker, symbol: Symbol, sourceFile: SourceFile, enclosingDeclaration: Node | undefined, location: Node, type: Type | undefined, semanticMeaning: SemanticMeaning, alias?: Symbol): SymbolDisplayPartsDocumentationAndSymbolKind {
+function getSymbolDisplayPartsDocumentationAndSymbolKindWorker(
+    typeChecker: TypeChecker,
+    symbol: Symbol,
+    sourceFile: SourceFile,
+    enclosingDeclaration: Node | undefined,
+    location: Node,
+    type: Type | undefined,
+    semanticMeaning: SemanticMeaning,
+    alias?: Symbol,
+    verbosityLevel?: number,
+): SymbolDisplayPartsDocumentationAndSymbolKind {
     const displayParts: SymbolDisplayPart[] = [];
     let documentation: SymbolDisplayPart[] = [];
     let tags: JSDocTagInfo[] = [];
@@ -267,6 +279,7 @@ function getSymbolDisplayPartsDocumentationAndSymbolKindWorker(typeChecker: Type
     let documentationFromAlias: SymbolDisplayPart[] | undefined;
     let tagsFromAlias: JSDocTagInfo[] | undefined;
     let hasMultipleSignatures = false;
+    const typeWriterOut: WriterContextOut | undefined = verbosityLevel !== undefined ? { couldUnfoldMore: false } : undefined;
 
     if (location.kind === SyntaxKind.ThisKeyword && !isThisExpression) {
         return { displayParts: [keywordPart(SyntaxKind.ThisKeyword)], documentation: [], symbolKind: ScriptElementKind.primitiveType, tags: undefined };
@@ -462,7 +475,17 @@ function getSymbolDisplayPartsDocumentationAndSymbolKindWorker(typeChecker: Type
         displayParts.push(spacePart());
         displayParts.push(operatorPart(SyntaxKind.EqualsToken));
         displayParts.push(spacePart());
-        addRange(displayParts, typeToDisplayParts(typeChecker, location.parent && isConstTypeReference(location.parent) ? typeChecker.getTypeAtLocation(location.parent) : typeChecker.getDeclaredTypeOfSymbol(symbol), enclosingDeclaration, TypeFormatFlags.InTypeAlias));
+        addRange(
+            displayParts,
+            typeToDisplayParts(
+                typeChecker,
+                location.parent && isConstTypeReference(location.parent) ? typeChecker.getTypeAtLocation(location.parent) : typeChecker.getDeclaredTypeOfSymbol(symbol),
+                enclosingDeclaration,
+                TypeFormatFlags.InTypeAlias,
+                verbosityLevel,
+                typeWriterOut,
+            ),
+        );
     }
     if (symbolFlags & SymbolFlags.Enum) {
         prefixNextMeaning();
@@ -650,13 +673,30 @@ function getSymbolDisplayPartsDocumentationAndSymbolKindWorker(typeChecker: Type
                     // If the type is type parameter, format it specially
                     if (type.symbol && type.symbol.flags & SymbolFlags.TypeParameter && symbolKind !== ScriptElementKind.indexSignatureElement) {
                         const typeParameterParts = mapToDisplayParts(writer => {
-                            const param = typeChecker.typeParameterToDeclaration(type as TypeParameter, enclosingDeclaration, symbolDisplayNodeBuilderFlags)!;
+                            const param = typeChecker.typeParameterToDeclaration(
+                                type as TypeParameter,
+                                enclosingDeclaration,
+                                symbolDisplayNodeBuilderFlags,
+                                /*internalFlags*/ undefined,
+                                /*tracker*/ undefined,
+                                verbosityLevel,
+                            )!;
                             getPrinter().writeNode(EmitHint.Unspecified, param, getSourceFileOfNode(getParseTreeNode(enclosingDeclaration)), writer);
                         });
                         addRange(displayParts, typeParameterParts);
                     }
                     else {
-                        addRange(displayParts, typeToDisplayParts(typeChecker, type, enclosingDeclaration));
+                        addRange(
+                            displayParts,
+                            typeToDisplayParts(
+                                typeChecker,
+                                type,
+                                enclosingDeclaration,
+                                /*flags*/ undefined,
+                                verbosityLevel,
+                                typeWriterOut,
+                            ),
+                        );
                     }
                     if (isTransientSymbol(symbol) && symbol.links.target && isTransientSymbol(symbol.links.target) && symbol.links.target.links.tupleLabelDeclaration) {
                         const labelDecl = symbol.links.target.links.tupleLabelDeclaration;
@@ -742,7 +782,13 @@ function getSymbolDisplayPartsDocumentationAndSymbolKindWorker(typeChecker: Type
         tags = tagsFromAlias;
     }
 
-    return { displayParts, documentation, symbolKind, tags: tags.length === 0 ? undefined : tags };
+    return {
+        displayParts,
+        documentation,
+        symbolKind,
+        tags: tags.length === 0 ? undefined : tags,
+        canIncreaseVerbosityLevel: typeWriterOut?.couldUnfoldMore,
+    };
 
     function getPrinter() {
         return createPrinterWithRemoveComments();
@@ -874,8 +920,9 @@ export function getSymbolDisplayPartsDocumentationAndSymbolKind(
     location: Node,
     semanticMeaning: SemanticMeaning = getMeaningFromLocation(location),
     alias?: Symbol,
+    verbosityLevel?: number,
 ): SymbolDisplayPartsDocumentationAndSymbolKind {
-    return getSymbolDisplayPartsDocumentationAndSymbolKindWorker(typeChecker, symbol, sourceFile, enclosingDeclaration, location, /*type*/ undefined, semanticMeaning, alias);
+    return getSymbolDisplayPartsDocumentationAndSymbolKindWorker(typeChecker, symbol, sourceFile, enclosingDeclaration, location, /*type*/ undefined, semanticMeaning, alias, verbosityLevel);
 }
 
 function isLocalVariableOrFunction(symbol: Symbol) {

src/services/types.ts

@@ -583,6 +583,8 @@ export interface LanguageService {
      * @param position A zero-based index of the character where you want the quick info
      */
     getQuickInfoAtPosition(fileName: string, position: number): QuickInfo | undefined;
+    /** @internal */
+    getQuickInfoAtPosition(fileName: string, position: number, verbosityLevel: number | undefined): QuickInfo | undefined; // eslint-disable-line @typescript-eslint/unified-signatures
 
     getNameOrDottedNameSpan(fileName: string, startPos: number, endPos: number): TextSpan | undefined;
 
@@ -1325,6 +1327,7 @@ export interface QuickInfo {
     displayParts?: SymbolDisplayPart[];
     documentation?: SymbolDisplayPart[];
     tags?: JSDocTagInfo[];
+    canIncreaseVerbosityLevel?: boolean;
 }
 
 export type RenameInfo = RenameInfoSuccess | RenameInfoFailure;

src/services/utilities.ts

@@ -390,6 +390,7 @@ import {
     visitEachChild,
     VoidExpression,
     walkUpParenthesizedExpressions,
+    WriterContextOut,
     YieldExpression,
 } from "./_namespaces/ts.js";
 
@@ -3055,9 +3056,9 @@ export function mapToDisplayParts(writeDisplayParts: (writer: DisplayPartsSymbol
 }
 
 /** @internal */
-export function typeToDisplayParts(typechecker: TypeChecker, type: Type, enclosingDeclaration?: Node, flags: TypeFormatFlags = TypeFormatFlags.None): SymbolDisplayPart[] {
+export function typeToDisplayParts(typechecker: TypeChecker, type: Type, enclosingDeclaration?: Node, flags: TypeFormatFlags = TypeFormatFlags.None, verbosityLevel?: number, out?: WriterContextOut): SymbolDisplayPart[] {
     return mapToDisplayParts(writer => {
-        typechecker.writeType(type, enclosingDeclaration, flags | TypeFormatFlags.MultilineObjectLiterals | TypeFormatFlags.UseAliasDefinedOutsideCurrentScope, writer);
+        typechecker.writeType(type, enclosingDeclaration, flags | TypeFormatFlags.MultilineObjectLiterals | TypeFormatFlags.UseAliasDefinedOutsideCurrentScope, writer, verbosityLevel, out);
     });
 }