Cannot read property 'heritageClauses' of undefined

[Fsss126]

TypeScript Version: 3.7.5

Code

When I add

import 'whatwg-fetch';

in my project with Webpack and run a command to build it or start watching for changes it fails with error

TypeError: Cannot read property 'heritageClauses' of undefined
    at getClassExtendsHeritageElement (/Users/alex/WebstormProjects/rete-tracker/node_modules/typescript/lib/typescript.js:12354:53)
    at Object.getEffectiveBaseTypeNode (/Users/alex/WebstormProjects/rete-tracker/node_modules/typescript/lib/typescript.js:12342:24)
    at getBaseConstructorTypeOfClass (/Users/alex/WebstormProjects/rete-tracker/node_modules/typescript/lib/typescript.js:40022:35)
    at serializeAsClass (/Users/alex/WebstormProjects/rete-tracker/node_modules/typescript/lib/typescript.js:38029:42)
    at serializeSymbolWorker (/Users/alex/WebstormProjects/rete-tracker/node_modules/typescript/lib/typescript.js:37763:29)
    at serializeSymbol (/Users/alex/WebstormProjects/rete-tracker/node_modules/typescript/lib/typescript.js:37704:38)
    at /Users/alex/WebstormProjects/rete-tracker/node_modules/typescript/lib/typescript.js:37679:25
    at Map.forEach (<anonymous>)
    at visitSymbolTable (/Users/alex/WebstormProjects/rete-tracker/node_modules/typescript/lib/typescript.js:37678:33)
    at symbolTableToDeclarationStatements (/Users/alex/WebstormProjects/rete-tracker/node_modules/typescript/lib/typescript.js:37549:17)
    at /Users/alex/WebstormProjects/rete-tracker/node_modules/typescript/lib/typescript.js:36346:106
    at withContext (/Users/alex/WebstormProjects/rete-tracker/node_modules/typescript/lib/typescript.js:36367:37)
    at Object.symbolTableToDeclarationStatements (/Users/alex/WebstormProjects/rete-tracker/node_modules/typescript/lib/typescript.js:36346:28)
    at Object.getDeclarationStatementsForSourceFile (/Users/alex/WebstormProjects/rete-tracker/node_modules/typescript/lib/typescript.js:64426:60)
    at transformDeclarationsForJS (/Users/alex/WebstormProjects/rete-tracker/node_modules/typescript/lib/typescript.js:88037:35)
    at transformRoot (/Users/alex/WebstormProjects/rete-tracker/node_modules/typescript/lib/typescript.js:88114:57)

But it compiles just fine if add this line later when Webpack is already watching for changes in files.

whatwg-fetch has the following in its package.json:

"main": "./dist/fetch.umd.js",
"module": "./fetch.js",

The problem occurs when the module export picked by default, when I point to the script exported as main with

import 'whatwg-fetch/dist/fetch.umd';

everything works fine.

I have the following tsconfig:

{
  "compilerOptions": {
    "target": "es2018",
    "lib": [
      "dom",
      "dom.iterable",
      "esnext"
    ],
    "outDir": "dist/core", 
    "noEmitOnError": true,
    "sourceMap": true,
    "baseUrl": "src",
    "strictNullChecks": true,
    "allowJs": true,
    "skipLibCheck": true,
    "esModuleInterop": true,
    "downlevelIteration": true,
    "allowSyntheticDefaultImports": true,
    "strict": true,
    "forceConsistentCasingInFileNames": true,
    "module": "commonjs",
    "moduleResolution": "node",
    "resolveJsonModule": true,
    "isolatedModules": true,
    "typeRoots": [
      "./node_modules/@types",
      "./src/declarations"
    ]
  },
  "include": [
    "src"
  ]
}

Related Issues: #10268

[rbuckton]

I do not yet have a consistent repro for this locally, but at first glance this might be due to inconsistent behavior between Webpack and TypeScript. TypeScript does not yet support "module" exports in package.json, so this could possibly be a conflict between what Webpack resolves for import 'whatwg-fetch' vs what TS resolves. This is by no means a definitive answer, so I will continue to investigate.

edit: sorry, I clicked close by mistake when posting the comment.