Take a riskier approach to removing host.fileExists

Author: AlexMarkUSDS

src/compiler/moduleSpecifiers.ts

@@ -996,7 +996,7 @@ function tryGetModuleNameFromRootDirs(rootDirs: readonly string[], moduleFileNam
 }
 
 function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCanonicalFileName, canonicalSourceDirectory }: Info, importingSourceFile: SourceFile, host: ModuleSpecifierResolutionHost, options: CompilerOptions, userPreferences: UserPreferences, packageNameOnly?: boolean, overrideMode?: ResolutionMode): string | undefined {
-    if (host.fileExists === undefined || !host.readFile) {
+    if (!host.readFile) {
         return undefined;
     }
     const parts: NodeModulePathParts = getNodeModulePathParts(path)!;
@@ -1145,7 +1145,6 @@ function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCan
 }
 
 function tryGetAnyFileFromPath(host: ModuleSpecifierResolutionHost, path: string) {
-    if (host.fileExists === undefined) return;
     // We check all js, `node` and `json` extensions in addition to TS, since node module resolution would also choose those over the directory
     const extensions = flatten(getSupportedExtensions({ allowJs: true }, [{ extension: "node", isMixedContent: false }, { extension: "json", isMixedContent: false, scriptKind: ScriptKind.JSON }]));
     for (const e of extensions) {

src/services/stringCompletions.ts

@@ -1182,8 +1182,6 @@ function getCompletionEntriesFromTypings(host: LanguageServiceHost, options: Com
 }
 
 function enumerateNodeModulesVisibleToScript(host: LanguageServiceHost, scriptPath: string): readonly string[] {
-    if (!host.readFile || !host.fileExists) return emptyArray;
-
     const result: string[] = [];
     for (const packageJson of findPackageJsons(scriptPath, host)) {
         const contents = readJson(packageJson, host as { readFile: (filename: string) => string | undefined; }); // Cast to assert that readFile is defined

src/services/utilities.ts

@@ -3670,10 +3670,6 @@ export function findPackageJson(directory: string, host: LanguageServiceHost): s
 
 /** @internal */
 export function getPackageJsonsVisibleToFile(fileName: string, host: LanguageServiceHost): readonly ProjectPackageJsonInfo[] {
-    if (!host.fileExists) {
-        return [];
-    }
-
     const packageJsons: ProjectPackageJsonInfo[] = [];
     forEachAncestorDirectory(getDirectoryPath(fileName), ancestor => {
         const packageJsonFileName = combinePaths(ancestor, "package.json");