Enable method signature completion for object literals (#48168)

* skeleton of new feature

* working prototype

* refactor print and format code into its own function

* minor changes; don't support overloads

* have two completion entries

* get rid of accessor support

* add snippet support

* add formatting

* add trailing comma

* add sourcedisplay

* support auto-imports via completion details

* add user preference option and fix ordering of entries

* cleanup

* don't return code actions for no import fixes

* make sortText lower priority for snippets

* get rid of flag

* use optional member sort text

* update baselines

* don't collect method symbols if insert text is not supported

* remove comment

* return undefined if type is not function type

* only slice if needed

* use union reduction; more test cases

* WIP: modify sort text system

* Improve new sort text system

* add signature and union type check

* re-add flag

* fix tests

* rename sort text helper

* fix test and code for union case

* add new flag to protocol type

* fix spaces

* CR: minor fixes

* CR: more fixes

* CR: restructure main flow

* minor fix

src/compiler/types.ts

@@ -8752,6 +8752,7 @@ namespace ts {
         readonly includeAutomaticOptionalChainCompletions?: boolean;
         readonly includeCompletionsWithInsertText?: boolean;
         readonly includeCompletionsWithClassMemberSnippets?: boolean;
+        readonly includeCompletionsWithObjectLiteralMethodSnippets?: boolean;
         readonly allowIncompleteCompletions?: boolean;
         readonly importModuleSpecifierPreference?: "shortest" | "project-relative" | "relative" | "non-relative";
         /** Determines whether we import `foo/index.ts` as "foo", "foo/index", or "foo/index.js" */

src/harness/fourslashImpl.ts

@@ -960,36 +960,36 @@ namespace FourSlash {
             expected = typeof expected === "string" ? { name: expected } : expected;
 
             if (actual.insertText !== expected.insertText) {
-                this.raiseError(`Completion insert text did not match: ${showTextDiff(expected.insertText || "", actual.insertText || "")}`);
+                this.raiseError(`At entry ${actual.name}: Completion insert text did not match: ${showTextDiff(expected.insertText || "", actual.insertText || "")}`);
             }
             const convertedReplacementSpan = expected.replacementSpan && ts.createTextSpanFromRange(expected.replacementSpan);
             if (convertedReplacementSpan?.length) {
                 try {
                     assert.deepEqual(actual.replacementSpan, convertedReplacementSpan);
                 }
                 catch {
-                    this.raiseError(`Expected completion replacementSpan to be ${stringify(convertedReplacementSpan)}, got ${stringify(actual.replacementSpan)}`);
+                    this.raiseError(`At entry ${actual.name}: Expected completion replacementSpan to be ${stringify(convertedReplacementSpan)}, got ${stringify(actual.replacementSpan)}`);
                 }
             }
 
             if (expected.kind !== undefined || expected.kindModifiers !== undefined) {
-                assert.equal(actual.kind, expected.kind, `Expected 'kind' for ${actual.name} to match`);
-                assert.equal(actual.kindModifiers, expected.kindModifiers || "", `Expected 'kindModifiers' for ${actual.name} to match`);
+                assert.equal(actual.kind, expected.kind, `At entry ${actual.name}: Expected 'kind' for ${actual.name} to match`);
+                assert.equal(actual.kindModifiers, expected.kindModifiers || "", `At entry ${actual.name}:  Expected 'kindModifiers' for ${actual.name} to match`);
             }
             if (expected.isFromUncheckedFile !== undefined) {
-                assert.equal<boolean | undefined>(actual.isFromUncheckedFile, expected.isFromUncheckedFile, "Expected 'isFromUncheckedFile' properties to match");
+                assert.equal<boolean | undefined>(actual.isFromUncheckedFile, expected.isFromUncheckedFile, `At entry ${actual.name}: Expected 'isFromUncheckedFile' properties to match`);
             }
             if (expected.isPackageJsonImport !== undefined) {
-                assert.equal<boolean | undefined>(actual.isPackageJsonImport, expected.isPackageJsonImport, "Expected 'isPackageJsonImport' properties to match");
+                assert.equal<boolean | undefined>(actual.isPackageJsonImport, expected.isPackageJsonImport, `At entry ${actual.name}: Expected 'isPackageJsonImport' properties to match`);
             }
 
-            assert.equal(actual.hasAction, expected.hasAction, `Expected 'hasAction' properties to match`);
-            assert.equal(actual.isRecommended, expected.isRecommended, `Expected 'isRecommended' properties to match'`);
-            assert.equal(actual.isSnippet, expected.isSnippet, `Expected 'isSnippet' properties to match`);
-            assert.equal(actual.source, expected.source, `Expected 'source' values to match`);
-            assert.equal(actual.sortText, expected.sortText || ts.Completions.SortText.LocationPriority, `Expected 'sortText' properties to match`);
+            assert.equal(actual.hasAction, expected.hasAction, `At entry ${actual.name}: Expected 'hasAction' properties to match`);
+            assert.equal(actual.isRecommended, expected.isRecommended, `At entry ${actual.name}: Expected 'isRecommended' properties to match'`);
+            assert.equal(actual.isSnippet, expected.isSnippet, `At entry ${actual.name}: Expected 'isSnippet' properties to match`);
+            assert.equal(actual.source, expected.source, `At entry ${actual.name}: Expected 'source' values to match`);
+            assert.equal(actual.sortText, expected.sortText || ts.Completions.SortText.LocationPriority, `At entry ${actual.name}: Expected 'sortText' properties to match`);
             if (expected.sourceDisplay && actual.sourceDisplay) {
-                assert.equal(ts.displayPartsToString(actual.sourceDisplay), expected.sourceDisplay, `Expected 'sourceDisplay' properties to match`);
+                assert.equal(ts.displayPartsToString(actual.sourceDisplay), expected.sourceDisplay, `At entry ${actual.name}: Expected 'sourceDisplay' properties to match`);
             }
 
             if (expected.text !== undefined) {

src/harness/fourslashInterfaceImpl.ts

@@ -950,9 +950,36 @@ namespace FourSlashInterface {
     }
 
     export namespace Completion {
-        export import SortText = ts.Completions.SortText;
+        import SortTextType = ts.Completions.SortText;
+        export type SortText = SortTextType;
         export import CompletionSource = ts.Completions.CompletionSource;
 
+        export const SortText = {
+            // Presets
+            LocalDeclarationPriority: "10" as SortText,
+            LocationPriority: "11" as SortText,
+            OptionalMember: "12" as SortText,
+            MemberDeclaredBySpreadAssignment: "13" as SortText,
+            SuggestedClassMembers: "14" as SortText,
+            GlobalsOrKeywords: "15" as SortText,
+            AutoImportSuggestions: "16" as SortText,
+            ClassMemberSnippets: "17" as SortText,
+            JavascriptIdentifiers: "18" as SortText,
+
+            // Transformations
+            Deprecated(sortText: SortText): SortText {
+                return "z" + sortText as SortText;
+            },
+
+            ObjectLiteralProperty(presetSortText: SortText, symbolDisplayName: string): SortText {
+                return `${presetSortText}\0${symbolDisplayName}\0` as SortText;
+            },
+
+            SortBelow(sortText: SortText): SortText {
+                return sortText + "1" as SortText;
+            },
+        };
+
         const functionEntry = (name: string): ExpectedCompletionEntryObject => ({
             name,
             kind: "function",
@@ -963,7 +990,7 @@ namespace FourSlashInterface {
             name,
             kind: "function",
             kindModifiers: "deprecated,declare",
-            sortText: SortText.DeprecatedGlobalsOrKeywords
+            sortText: "z15" as SortText,
         });
         const varEntry = (name: string): ExpectedCompletionEntryObject => ({
             name,
@@ -992,7 +1019,7 @@ namespace FourSlashInterface {
             name,
             kind: "method",
             kindModifiers: "deprecated,declare",
-            sortText: SortText.DeprecatedLocationPriority
+            sortText: "z11" as SortText,
         });
         const propertyEntry = (name: string): ExpectedCompletionEntryObject => ({
             name,

src/server/protocol.ts

@@ -3406,6 +3406,13 @@ namespace ts.server.protocol {
          * `class A { foo }`.
          */
         readonly includeCompletionsWithClassMemberSnippets?: boolean;
+        /**
+         * If enabled, object literal methods will have a method declaration completion entry in addition
+         * to the regular completion entry containing just the method name.
+         * E.g., `const objectLiteral: T = { f| }` could be completed to `const objectLiteral: T = { foo(): void {} }`,
+         * in addition to `const objectLiteral: T = { foo }`.
+         */
+        readonly includeCompletionsWithObjectLiteralMethodSnippets?: boolean;
         readonly allowIncompleteCompletions?: boolean;
         readonly importModuleSpecifierPreference?: "shortest" | "project-relative" | "relative" | "non-relative";
         /** Determines whether we import `foo/index.ts` as "foo", "foo/index", or "foo/index.js" */