title: Android Studio keeps generating Eclipse-like files
body: <p>I'm using Android Studio 3.0.1 and I have noticed that for one of my projects (only this one) it generates <code>.project</code> files and a <code>bin</code> directory like Eclipse does (I suppose).</p>
  
  <p>The project was created in AS 3.0.1 and it was not migrated from Eclipse or anything like this. It also doesn't use any fancy Gradle plugins or dependencies - just the generated ones (AppCompat + Kotlin).</p>
  
  <p>Do you have any idea why it does so?</p>
  
  <p><a href="https://i.stack.imgur.com/KoVAI.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/KoVAI.png" alt="project file structure"></a></p>
  
  <p>Also, when I was trying to prepare a minimal project for reproduction, I noticed that the problem disappears just by copy-pasting the whole project directory so there's probably no point in sharing it with you.</p>
  
  <p>Using two project copies (let's call them <code>original</code> and <code>copy</code>) I was able to find out that when I close Android Studio and clean both copies using <code>git clean -xfd</code></p>
  
  <ul>
  <li><code>copy</code> has no issues when opened - no Eclipse-like files</li>
  <li><code>original</code> still has the issue when opened (files get generated)</li>
  <li><p><code>diff -r</code> before opening them (so just after <code>git clean</code>) gives only this:</p>
  
  <blockquote>
    <p>Binary files ../PWTA_Proj2/.git/index and ./.git/index differ</p>
  </blockquote></li>
  <li><p>both of them make Android Studio show an error like this when opened:</p>
  
  <blockquote>
    <p>Unsupported Modules Detected: Compilation is not supported for following modules: PWTA_Proj2. Unfortunately you can't have non-Gradle Java modules and Android-Gradle modules in one project.</p>
  </blockquote></li>
  </ul>
  
  <p>Despite of the error I can build the project normally. Also I don't have any non-Gradle modules - the project is very simple and generated by AS. The only less common thing is that the project contains a few AIDL files.</p>
  
  <p><em><strong>Edit #1: Gradle files:</strong></em></p>
  
  <p>top-level <code>build.gradle</code>:</p>
  
  <pre><code>// Top-level build file where you can add configuration options common to all sub-projects/modules.
  
  buildscript {
      ext.kotlin_version = '1.2.0'
      repositories {
          google()
          jcenter()
      }
      dependencies {
          classpath 'com.android.tools.build:gradle:3.0.1'
          classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
  
          // NOTE: Do not place your application dependencies here; they belong
          // in the individual module build.gradle files
      }
  }
  
  allprojects {
      repositories {
          google()
          jcenter()
      }
  }
  
  task clean(type: Delete) {
      delete rootProject.buildDir
  }
  </code></pre>
  
  <p>top-level <code>settings.gradle</code>:</p>
  
  <pre><code>include ':app'
  </code></pre>
  
  <p><code>app</code> module <code>build.gradle</code>:</p>
  
  <pre><code>apply plugin: 'com.android.application'
  
  apply plugin: 'kotlin-android'
  
  apply plugin: 'kotlin-android-extensions'
  
  android {
      compileSdkVersion 27
      buildToolsVersion '27.0.3'
      defaultConfig {
          final appId = "com.azabost.pwta.proj2"
          applicationId appId
          minSdkVersion 25
          targetSdkVersion 27
          versionCode 1
          versionName "1.0"
          testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
          manifestPlaceholders.tspProcessName = appId + ".tsp"
      }
      buildTypes {
          release {
              minifyEnabled false
              proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
          }
      }
  }
  
  dependencies {
      implementation fileTree(dir: 'libs', include: ['*.jar'])
      implementation"org.jetbrains.kotlin:kotlin-stdlib-jre7:$kotlin_version"
      implementation 'com.android.support:appcompat-v7:27.0.2'
      testImplementation 'junit:junit:4.12'
      androidTestImplementation 'com.android.support.test:runner:1.0.1'
      androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'
  }
  </code></pre>