title: Can't use interfaces from another file when they import any dependencies
body: <p>I have a problem with interface import. When I have interface with non import dependencies in separate files like:</p>
  
  <p><code>/src/app/something/something.interface.ts</code></p>
  
  <pre><code>interface ISomething {
      a: String[];
  }
  </code></pre>
  
  <p>I can use it in another file in the same directory without import it, fo example:</p>
  
  <p><code>/src/app/someting/something.tsx</code></p>
  
  <pre><code>class Something extends React.Component&lt;ISomething, any&gt; {
  
  }
  </code></pre>
  
  <p>But when I have interface like this:</p>
  
  <pre><code>import Page from '../components/page';
  
  interface ISomething {
      a: String[];
      b: Page;
  }
  </code></pre>
  
  <p>I get an error from compilation process:
  <code>[2] ERROR in src/app/something/something.tsx(9,40): error TS2304: Cannot find name 'ISomething'.</code></p>
  
  <p>I try to use <code>export interface ISomething ...</code> and import them in <code>something.tsx</code> but this get an error </p>
  
  <pre><code>[2] ERROR in src/app/application/education/react/renderer/renderer.tsx(8,9): error TS2305: Module '"/Users/xxx/Projects/react/src/app/something/something.interface"' has no exported member 'ISomething'.
  </code></pre>
  
  <p>When I put my <code>ISomething</code> interface in <code>something.tsx</code> file it work, but I want to keep it clean in separate file.</p>
  
  <p>Do you have any idea why?</p>
  
  <p>EDIT:
  tsconfig.json</p>
  
  <pre><code>{
    "compileOnSave": false,
    "compilerOptions": {
      "baseUrl": "./",
      "outDir": "./dist/out-tsc",
      "sourceMap": true,
      "declaration": false,
      "moduleResolution": "node",
      "emitDecoratorMetadata": true,
      "experimentalDecorators": true,
      "target": "es5",
      "typeRoots": [
        "node_modules/@types"
      ],
      "lib": [
        "es2017",
        "dom"
      ]
    }
  }
  </code></pre>
  
  <p>tsconfig.app.json</p>
  
  <pre><code>{
    "extends": "../tsconfig.json",
    "compilerOptions": {
      "outDir": "../dist/out-tsc/app",
      "module": "es2015",
      "types": [
        "node"
      ]
    },
    "exclude": [
      "src/test.ts",
      "**/*.spec.ts"
    ],
      "angularCompilerOptions": {
          "preserveWhitespaces": true
      }
  }
  </code></pre>