Manual fix required for Typescript bug that's not fixed in stable

[AlecDusheck]

If you're using Typescript v3.5.2 and are attempting to automatically generate type guards and getting this error:

(node:24782) UnhandledPromiseRejectionWarning: TypeError: realpath is not a function
    at visitDirectory (/home/simplyalec/WebstormProjects/SSManagerV3/node_modules/typescript/lib/typescript.js:16032:45)
    at Object.matchFiles (/home/simplyalec/WebstormProjects/SSManagerV3/node_modules/typescript/lib/typescript.js:16028:13)
    at Object.matchFiles (/home/simplyalec/WebstormProjects/SSManagerV3/node_modules/ts-simple-ast/dist/typescript/tsInternal.js:7:35)
    at Object.readDirectory (/home/simplyalec/WebstormProjects/SSManagerV3/node_modules/ts-simple-ast/dist/utils/compiler/readDirectory.js:16:27)
    at Object.readDirectory (/home/simplyalec/WebstormProjects/SSManagerV3/node_modules/ts-simple-ast/dist/utils/tsconfig/getTsParseConfigHost.js:11:37)
    at getFileNamesFromConfigSpecs (/home/simplyalec/WebstormProjects/SSManagerV3/node_modules/typescript/lib/typescript.js:26140:40)
    at matchFileNames (/home/simplyalec/WebstormProjects/SSManagerV3/node_modules/typescript/lib/typescript.js:26060:16)
    at getFileNames (/home/simplyalec/WebstormProjects/SSManagerV3/node_modules/typescript/lib/typescript.js:25628:26)
    at parseJsonConfigFileContentWorker (/home/simplyalec/WebstormProjects/SSManagerV3/node_modules/typescript/lib/typescript.js:25561:18)
    at Object.parseJsonConfigFileContent (/home/simplyalec/WebstormProjects/SSManagerV3/node_modules/typescript/lib/typescript.js:25510:16)
(node:24782) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 2)
(node:24782) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
s

apply this patch file to your ./node_modules/typescript/lib/typescript.ts file:

@@ -16029,7 +16029,7 @@ var ts;
         }
         return ts.flatten(results);
         function visitDirectory(path, absolutePath, depth) {
-            var canonicalPath = toCanonical(realpath(absolutePath));
+            var canonicalPath = toCanonical(absolutePath);
             if (visited.has(canonicalPath))
                 return;
             visited.set(canonicalPath, true);

[AlecDusheck]

Sorta a jank workaround but this is probably the smallest fix and won't break much in terms of what this project is using