title: Angular5 :polyfills.ts & \main.ts is missing from the TypeScript compilation
body: <p>This is my Angular5 project structure.</p>
  
  <p><a href="https://i.stack.imgur.com/tmbE7.png" rel="noreferrer"><img src="https://i.stack.imgur.com/tmbE7.png" alt="enter image description here"></a></p>
  
  <p>Both <code>tsconfig.app.json</code> and <code>package.json</code> contain this section  </p>
  
  <pre><code> "include": [
        "/src/main.ts",
        "/src/polyfills.ts"
      ]
  </code></pre>
  
  <p>But no matter what I try I still get this error:</p>
  
  <pre><code>    \polyfills.ts &amp; \main.ts is missing from the TypeScript compilation. 
  Please make sure it is in your tsconfig via the 'files' or 'include' property.
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/jEZPp.png" rel="noreferrer"><img src="https://i.stack.imgur.com/jEZPp.png" alt="enter image description here"></a>
  Anyone has idea what's missing here?</p>
  
  <pre><code>  tsconfig.json
          {
            "compileOnSave": false,
            "compilerOptions": {
              "outDir": "./dist/out-tsc",
              "sourceMap": true,
              "declaration": false,
              "moduleResolution": "node",
              "emitDecoratorMetadata": true,
              "experimentalDecorators": true,
              "target": "es5",
              "typeRoots": [
                "node_modules/@types"
              ],
              "lib": [
                "es2017",
                "dom"
              ]
            }
          }
  src/tsconfig.app.json
  {
    "extends": "../tsconfig.json",
    "compilerOptions": {
      "outDir": "../out-tsc/app",
      "baseUrl": "./",
      "module": "es2015",
      "types": []
    },
    "include": [
      "main.ts",
      "polyfills.ts"
    ],
    "exclude": [
      "test.ts",
      "**/*.spec.ts"
    ]
  }
  </code></pre>