Add undefined to Symbol.valueDeclaration (#43033)

* About halfway through the checker

I'm going to merge with master to avoid clashing with the declaration
fix.

* Add undefined to Symbol.valueDeclaration

Also add undefined to a number of utility functions that have always
accepted it, but never added it to their type.

* Fix lint from code review

Co-authored-by: Daniel Rosenwasser <[email protected]>

* remove obsoleted fix from inferFromUsage

Co-authored-by: Daniel Rosenwasser <[email protected]>

Author: sandersn

src/compiler/binder.ts

@@ -3187,7 +3187,7 @@ namespace ts {
                 undefined;
             init = init && getRightMostAssignedExpression(init);
             if (init) {
-                const isPrototypeAssignment = isPrototypeAccess(isVariableDeclaration(node) ? node.name : isBinaryExpression(node) ? node.left : node);
+                const isPrototypeAssignment = isPrototypeAccess(isVariableDeclaration(node!) ? node.name : isBinaryExpression(node!) ? node.left : node!);
                 return !!getExpandoInitializer(isBinaryExpression(init) && (init.operatorToken.kind === SyntaxKind.BarBarToken || init.operatorToken.kind === SyntaxKind.QuestionQuestionToken) ? init.right : init, isPrototypeAssignment);
             }
             return false;

src/compiler/checker.ts

@@ -5507,7 +5507,7 @@ namespace ts {
                 : reduceLeft(expressions, factory.createComma)!;
         }
 
-        function getName(node: Declaration, allowComments?: boolean, allowSourceMaps?: boolean, emitFlags: EmitFlags = 0) {
+        function getName(node: Declaration | undefined, allowComments?: boolean, allowSourceMaps?: boolean, emitFlags: EmitFlags = 0) {
             const nodeName = getNameOfDeclaration(node);
             if (nodeName && isIdentifier(nodeName) && !isGeneratedIdentifier(nodeName)) {
                 // TODO(rbuckton): Does this need to be parented?
@@ -5571,7 +5571,7 @@ namespace ts {
          * @param allowComments A value indicating whether comments may be emitted for the name.
          * @param allowSourceMaps A value indicating whether source maps may be emitted for the name.
          */
-        function getDeclarationName(node: Declaration, allowComments?: boolean, allowSourceMaps?: boolean) {
+        function getDeclarationName(node: Declaration | undefined, allowComments?: boolean, allowSourceMaps?: boolean) {
             return getName(node, allowComments, allowSourceMaps);
         }
 

src/compiler/factory/nodeFactory.ts

@@ -103,6 +103,9 @@ namespace ts.moduleSpecifiers {
 
         const info = getInfo(importingSourceFile.path, host);
         const moduleSourceFile = getSourceFileOfNode(moduleSymbol.valueDeclaration || getNonAugmentationDeclaration(moduleSymbol));
+        if (!moduleSourceFile) {
+            return [];
+        }
         const modulePaths = getAllModulePaths(importingSourceFile.path, moduleSourceFile.originalFileName, host);
         const preferences = getPreferences(userPreferences, compilerOptions, importingSourceFile);
 

src/compiler/moduleSpecifiers.ts

@@ -1202,7 +1202,7 @@ namespace ts {
                         fakespace.symbol = props[0].parent!;
                         const exportMappings: [Identifier, string][] = [];
                         let declarations: (VariableStatement | ExportDeclaration)[] = mapDefined(props, p => {
-                            if (!isPropertyAccessExpression(p.valueDeclaration)) {
+                            if (!p.valueDeclaration || !isPropertyAccessExpression(p.valueDeclaration)) {
                                 return undefined; // TODO GH#33569: Handle element access expressions that created late bound names (rather than silently omitting them)
                             }
                             getSymbolAccessibilityDiagnostic = createGetSymbolAccessibilityDiagnosticForNode(p.valueDeclaration);

src/compiler/transformers/declarations.ts

@@ -4046,7 +4046,7 @@ namespace ts {
          * The function returns the value (local variable) symbol of an identifier in the short-hand property assignment.
          * This is necessary as an identifier in short-hand property assignment can contains two meaning: property name and property value.
          */
-        getShorthandAssignmentValueSymbol(location: Node): Symbol | undefined;
+        getShorthandAssignmentValueSymbol(location: Node | undefined): Symbol | undefined;
 
         getExportSpecifierLocalTargetSymbol(location: ExportSpecifier | Identifier): Symbol | undefined;
         /**
@@ -4715,7 +4715,7 @@ namespace ts {
         flags: SymbolFlags;                     // Symbol flags
         escapedName: __String;                  // Name of symbol
         declarations?: Declaration[];           // Declarations associated with this symbol
-        valueDeclaration: Declaration;          // First value declaration of the symbol
+        valueDeclaration?: Declaration;         // First value declaration of the symbol
         members?: SymbolTable;                  // Class, interface or object literal instance members
         exports?: SymbolTable;                  // Module exports
         globalExports?: SymbolTable;            // Conditional global UMD exports
@@ -7394,7 +7394,7 @@ namespace ts {
          * @param allowComments A value indicating whether comments may be emitted for the name.
          * @param allowSourceMaps A value indicating whether source maps may be emitted for the name.
          */
-        /* @internal */ getDeclarationName(node: Declaration, allowComments?: boolean, allowSourceMaps?: boolean): Identifier;
+        /* @internal */ getDeclarationName(node: Declaration | undefined, allowComments?: boolean, allowSourceMaps?: boolean): Identifier;
         /**
          * Gets a namespace-qualified name for use in expressions.
          *

src/compiler/types.ts

@@ -734,9 +734,9 @@ namespace ts {
         return isShorthandAmbientModule(moduleSymbol.valueDeclaration);
     }
 
-    function isShorthandAmbientModule(node: Node): boolean {
+    function isShorthandAmbientModule(node: Node | undefined): boolean {
         // The only kind of module that can be missing a body is a shorthand ambient module.
-        return node && node.kind === SyntaxKind.ModuleDeclaration && (!(<ModuleDeclaration>node).body);
+        return !!node && node.kind === SyntaxKind.ModuleDeclaration && (!(<ModuleDeclaration>node).body);
     }
 
     export function isBlockScopedContainerTopLevel(node: Node): boolean {

src/compiler/utilities.ts

@@ -614,7 +614,7 @@ namespace ts {
         return (declaration as NamedDeclaration).name;
     }
 
-    export function getNameOfDeclaration(declaration: Declaration | Expression): DeclarationName | undefined {
+    export function getNameOfDeclaration(declaration: Declaration | Expression | undefined): DeclarationName | undefined {
         if (declaration === undefined) return undefined;
         return getNonAssignedNameOfDeclaration(declaration) ||
             (isFunctionExpression(declaration) || isClassExpression(declaration) ? getAssignedName(declaration) : undefined);
@@ -1208,8 +1208,8 @@ namespace ts {
 
     // Functions
 
-    export function isFunctionLike(node: Node): node is SignatureDeclaration {
-        return node && isFunctionLikeKind(node.kind);
+    export function isFunctionLike(node: Node | undefined): node is SignatureDeclaration {
+        return !!node && isFunctionLikeKind(node.kind);
     }
 
     /* @internal */

src/compiler/utilitiesPublic.ts

@@ -18,7 +18,7 @@ namespace ts.codefix {
         const token = getTokenAtPosition(sourceFile, pos);
         const checker = program.getTypeChecker();
         const symbol = checker.getSymbolAtLocation(token);
-        if (symbol) {
+        if (symbol?.valueDeclaration) {
             return symbol.valueDeclaration.parent.parent as VariableStatement;
         }
     }

src/services/codefixes/convertConstToLet.ts

@@ -16,7 +16,7 @@ namespace ts.codefix {
 
     function doChange(changes: textChanges.ChangeTracker, sourceFile: SourceFile, position: number, checker: TypeChecker, preferences: UserPreferences, compilerOptions: CompilerOptions): void {
         const ctorSymbol = checker.getSymbolAtLocation(getTokenAtPosition(sourceFile, position))!;
-        if (!ctorSymbol || !(ctorSymbol.flags & (SymbolFlags.Function | SymbolFlags.Variable))) {
+        if (!ctorSymbol || !ctorSymbol.valueDeclaration || !(ctorSymbol.flags & (SymbolFlags.Function | SymbolFlags.Variable))) {
             // Bad input
             return undefined;
         }
@@ -46,7 +46,7 @@ namespace ts.codefix {
             // all instance members are stored in the "member" array of symbol
             if (symbol.members) {
                 symbol.members.forEach((member, key) => {
-                    if (key === "constructor") {
+                    if (key === "constructor" && member.valueDeclaration) {
                         // fn.prototype.constructor = fn
                         changes.delete(sourceFile, member.valueDeclaration.parent);
                         return;