Update typescript-eslint to latest (#43381)

package.json

@@ -53,9 +53,9 @@
         "@types/source-map-support": "latest",
         "@types/through2": "latest",
         "@types/xml2js": "^0.4.0",
-        "@typescript-eslint/eslint-plugin": "4.5.0",
+        "@typescript-eslint/eslint-plugin": "^4.19.0",
-        "@typescript-eslint/experimental-utils": "4.5.0",
+        "@typescript-eslint/experimental-utils": "^4.19.0",
-        "@typescript-eslint/parser": "4.5.0",
+        "@typescript-eslint/parser": "^4.19.0",
         "async": "latest",
         "azure-devops-node-api": "^10.1.0",
         "browser-resolve": "^1.11.2",
@@ -94,7 +94,7 @@
         "remove-internal": "^2.9.2",
         "source-map-support": "latest",
         "through2": "latest",
-        "typescript": "^4.0.0-dev.20200624",
+        "typescript": "^4.2.3",
         "vinyl": "latest",
         "vinyl-sourcemaps-apply": "latest",
         "xml2js": "^0.4.19"
@@ -129,6 +129,5 @@
     },
     "volta": {
         "node": "14.15.5"
-    },
+    }
-    "dependencies": {}
 }

src/compiler/checker.ts

@@ -11616,7 +11616,7 @@ namespace ts {
                 }
             }
 
-            result.declarations = declarations!;
+            result.declarations = declarations;
             result.nameType = nameType;
             if (propTypes.length > 2) {
                 // When `propTypes` has the potential to explode in size when normalized, defer normalization until absolutely needed

src/compiler/emitter.ts

@@ -1166,8 +1166,8 @@ namespace ts {
             tempFlagsStack = [];
             tempFlags = TempFlags.Auto;
             reservedNamesStack = [];
-            currentSourceFile = undefined!;
+            currentSourceFile = undefined;
-            currentLineMap = undefined!;
+            currentLineMap = undefined;
             detachedCommentsInfo = undefined;
             setWriter(/*output*/ undefined, /*_sourceMapGenerator*/ undefined);
         }
@@ -3153,10 +3153,10 @@ namespace ts {
 
             let body = node.body;
             if (!body) return writeTrailingSemicolon();
-            while (body.kind === SyntaxKind.ModuleDeclaration) {
+            while (body && isModuleDeclaration(body)) {
                 writePunctuation(".");
-                emit((<ModuleDeclaration>body).name);
+                emit(body.name);
-                body = (<ModuleDeclaration>body).body!;
+                body = body.body;
             }
 
             writeSpace();

src/compiler/factory/nodeFactory.ts

@@ -555,9 +555,9 @@ namespace ts {
             // NOTE: The following properties are commonly set by the binder and are added here to
             // ensure declarations have a stable shape.
             node.symbol = undefined!; // initialized by binder
-            node.localSymbol = undefined!; // initialized by binder
+            node.localSymbol = undefined; // initialized by binder
-            node.locals = undefined!; // initialized by binder
+            node.locals = undefined; // initialized by binder
-            node.nextContainer = undefined!; // initialized by binder
+            node.nextContainer = undefined; // initialized by binder
             return node;
         }
 

src/compiler/parser.ts

@@ -1014,7 +1014,7 @@ namespace ts {
             jsDocDiagnostics = undefined!;
             parsingContext = 0;
             identifiers = undefined!;
-            notParenthesizedArrow = undefined!;
+            notParenthesizedArrow = undefined;
             topLevel = true;
         }
 

src/compiler/transformers/classFields.ts

@@ -534,7 +534,7 @@ namespace ts {
             if (shouldTransformPrivateElements) {
                 if (isDestructuringAssignment(node)) {
                     const savedPendingExpressions = pendingExpressions;
-                    pendingExpressions = undefined!;
+                    pendingExpressions = undefined;
                     node = factory.updateBinaryExpression(
                         node,
                         visitNode(node.left, visitorDestructuringTarget),

src/compiler/transformers/module/system.ts

@@ -133,7 +133,7 @@ namespace ts {
             moduleInfo = undefined!;
             exportFunction = undefined!;
             contextObject = undefined!;
-            hoistedStatements = undefined!;
+            hoistedStatements = undefined;
             enclosingBlockScopedContainer = undefined!;
             return updated;
         }

src/compiler/utilities.ts

@@ -5628,8 +5628,8 @@ namespace ts {
     function Symbol(this: Symbol, flags: SymbolFlags, name: __String) {
         this.flags = flags;
         this.escapedName = name;
-        this.declarations = undefined!;
+        this.declarations = undefined;
-        this.valueDeclaration = undefined!;
+        this.valueDeclaration = undefined;
         this.id = undefined;
         this.mergeId = undefined;
         this.parent = undefined;

src/harness/fourslashImpl.ts

@@ -962,12 +962,14 @@ namespace FourSlash {
         }
 
         /** Use `getProgram` instead of accessing this directly. */
-        private _program: ts.Program | undefined;
+        private _program: ts.Program | undefined | "missing";
         /** Use `getChecker` instead of accessing this directly. */
         private _checker: ts.TypeChecker | undefined;
 
         private getProgram(): ts.Program {
-            return this._program || (this._program = this.languageService.getProgram()!); // TODO: GH#18217
+            if (!this._program) this._program = this.languageService.getProgram() || "missing";
+            if (this._program === "missing") ts.Debug.fail("Could not retrieve program from language service");
+            return this._program;
         }
 
         private getChecker() {

src/server/project.ts

@@ -772,9 +772,9 @@ namespace ts.server {
 
             this.rootFiles = undefined!;
             this.rootFilesMap = undefined!;
-            this.externalFiles = undefined!;
+            this.externalFiles = undefined;
-            this.program = undefined!;
+            this.program = undefined;
-            this.builderState = undefined!;
+            this.builderState = undefined;
             this.resolutionCache.clear();
             this.resolutionCache = undefined!;
             this.cachedUnresolvedImportsPerFile = undefined!;
@@ -784,7 +784,7 @@ namespace ts.server {
             // Clean up file watchers waiting for missing files
             if (this.missingFilesMap) {
                 clearMap(this.missingFilesMap, closeFileWatcher);
-                this.missingFilesMap = undefined!;
+                this.missingFilesMap = undefined;
             }
             this.clearGeneratedFileWatch();
             this.clearInvalidateResolutionOfFailedLookupTimer();
@@ -1087,7 +1087,7 @@ namespace ts.server {
             const start = timestamp();
             this.hasInvalidatedResolution = this.resolutionCache.createHasInvalidatedResolution();
             this.resolutionCache.startCachingPerDirectoryResolution();
-            this.program = this.languageService.getProgram()!; // TODO: GH#18217
+            this.program = this.languageService.getProgram(); // TODO: GH#18217
             this.dirty = false;
             this.resolutionCache.finishCachingPerDirectoryResolution();
 
@@ -1096,8 +1096,9 @@ namespace ts.server {
             // bump up the version if
             // - oldProgram is not set - this is a first time updateGraph is called
             // - newProgram is different from the old program and structure of the old program was not reused.
-            const hasNewProgram = this.program && (!oldProgram || (this.program !== oldProgram && !(this.program.structureIsReused & StructureIsReused.Completely)));
+            let hasNewProgram = false;
-            if (hasNewProgram) {
+            if (this.program && (!oldProgram || (this.program !== oldProgram && !(this.program.structureIsReused & StructureIsReused.Completely)))) {
+                hasNewProgram = true;
                 if (oldProgram) {
                     for (const f of oldProgram.getSourceFiles()) {
                         const newFile = this.program.getSourceFileByPath(f.resolvedPath);
@@ -1163,7 +1164,7 @@ namespace ts.server {
             }
 
             if (!this.importSuggestionsCache.isEmpty()) {
-                if (this.hasAddedorRemovedFiles || oldProgram && !this.program.structureIsReused) {
+                if (this.hasAddedorRemovedFiles || oldProgram && !this.program!.structureIsReused) {
                     this.importSuggestionsCache.clear();
                 }
                 else if (this.dirtyFilesForSuggestions && oldProgram && this.program) {
@@ -1204,7 +1205,7 @@ namespace ts.server {
                 this.print(/*writeProjectFileNames*/ true);
             }
             else if (this.program !== oldProgram) {
-                this.writeLog(`Different program with same set of files:: structureIsReused:: ${this.program.structureIsReused}`);
+                this.writeLog(`Different program with same set of files:: structureIsReused:: ${this.program?.structureIsReused}`);
             }
             return hasNewProgram;
         }

src/services/shims.ts

@@ -1326,7 +1326,7 @@ namespace ts {
         public close(): void {
             // Forget all the registered shims
             clear(this._shims);
-            this.documentRegistry = undefined!;
+            this.documentRegistry = undefined;
         }
 
         public registerShim(shim: Shim): void {

src/services/symbolDisplay.ts

@@ -197,13 +197,13 @@ namespace ts.SymbolDisplay {
             }
 
             if (callExpressionLike) {
-                signature = typeChecker.getResolvedSignature(callExpressionLike)!; // TODO: GH#18217
+                signature = typeChecker.getResolvedSignature(callExpressionLike); // TODO: GH#18217
 
                 const useConstructSignatures = callExpressionLike.kind === SyntaxKind.NewExpression || (isCallExpression(callExpressionLike) && callExpressionLike.expression.kind === SyntaxKind.SuperKeyword);
 
                 const allSignatures = useConstructSignatures ? type.getConstructSignatures() : type.getCallSignatures();
 
-                if (!contains(allSignatures, signature.target) && !contains(allSignatures, signature)) {
+                if (signature && !contains(allSignatures, signature.target) && !contains(allSignatures, signature)) {
                     // Get the first signature if there is one -- allSignatures may contain
                     // either the original signature or its target, so check for either
                     signature = allSignatures.length ? allSignatures[0] : undefined;
@@ -278,7 +278,7 @@ namespace ts.SymbolDisplay {
                 if (locationIsSymbolDeclaration) {
                     const allSignatures = functionDeclaration.kind === SyntaxKind.Constructor ? type.getNonNullableType().getConstructSignatures() : type.getNonNullableType().getCallSignatures();
                     if (!typeChecker.isImplementationOfOverload(functionDeclaration)) {
-                        signature = typeChecker.getSignatureFromDeclaration(functionDeclaration)!; // TODO: GH#18217
+                        signature = typeChecker.getSignatureFromDeclaration(functionDeclaration); // TODO: GH#18217
                     }
                     else {
                         signature = allSignatures[0];
@@ -294,8 +294,9 @@ namespace ts.SymbolDisplay {
                         addPrefixForAnyFunctionOrVar(functionDeclaration.kind === SyntaxKind.CallSignature &&
                             !(type.symbol.flags & SymbolFlags.TypeLiteral || type.symbol.flags & SymbolFlags.ObjectLiteral) ? type.symbol : symbol, symbolKind);
                     }
-
+                    if (signature) {
-                    addSignatureDisplayParts(signature, allSignatures);
+                        addSignatureDisplayParts(signature, allSignatures);
+                    }
                     hasAddedSymbolInfo = true;
                     hasMultipleSignatures = allSignatures.length > 1;
                 }