<p dir="auto">Hi, i'am running webpack 1.13.1</p>
<div class="highlight highlight-source-js notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="//works
import {SuperClass} from '../super_class';
class SubClass extends SuperClass () {}

//doesn't work
//TypeError: Super expression must either be null or a function, not undefined
import {SuperClass} from '../main';
class SubClass extends SuperClass () {}"><pre class="notranslate"><span class="pl-c">//works</span>
<span class="pl-k">import</span> <span class="pl-kos">{</span><span class="pl-v">SuperClass</span><span class="pl-kos">}</span> <span class="pl-k">from</span> <span class="pl-s">'../super_class'</span><span class="pl-kos">;</span>
<span class="pl-k">class</span> <span class="pl-v">SubClass</span> <span class="pl-k">extends</span> <span class="pl-v">SuperClass</span> <span class="pl-kos">(</span><span class="pl-kos">)</span> <span class="pl-kos">{</span><span class="pl-kos">}</span>

<span class="pl-c">//doesn't work</span>
<span class="pl-c">//TypeError: Super expression must either be null or a function, not undefined</span>
<span class="pl-k">import</span> <span class="pl-kos">{</span><span class="pl-v">SuperClass</span><span class="pl-kos">}</span> <span class="pl-k">from</span> <span class="pl-s">'../main'</span><span class="pl-kos">;</span>
<span class="pl-k">class</span> <span class="pl-v">SubClass</span> <span class="pl-k">extends</span> <span class="pl-v">SuperClass</span> <span class="pl-kos">(</span><span class="pl-kos">)</span> <span class="pl-kos">{</span><span class="pl-kos">}</span></pre></div>
<p dir="auto"><strong>Do you want to request a <em>feature</em> or report a <em>bug</em>?</strong><br>
report a bug<br>
<strong>What is the current behavior?</strong></p>
<p dir="auto">For web targets when the process global is encountered the  process/browser.js module is included in the bundle.  The problem is the drive letter is sometimes not in sync with the drive letter as specified by process.cwd().</p>
<p dir="auto">This is a problem creating duplicate copies of this internal module when the path differs only by the case of the drive letter.  We have no control over how internal modules are expanded.</p>
<p dir="auto">Our practice is to observe process.cwd() and return config after checking the case of the drive letter with entry points and aliases matching the drive letter case.  This has eliminated 99% of duplicate module warnings.  However the internal modules if they expand out to paths where the drive letter casing is different than the process.cwd() casing we get duplicates of internal modules in our bundle.</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content=" �[1m�[33mWARNING in ./node_modules/process/browser.js
    There are multiple modules with names that only differ in casing.
    This can lead to unexpected behavior when compiling on a filesystem with other case-semantic.
    Use equal casing. Compare these module identifiers:
    * C:\WebClientToolkit\node_modules\process\browser.js
        Used by 3 module(s), i. e.
        C:\WebClientToolkit\packages\core\wct-http\source\index.js
    * c:\WebClientToolkit\node_modules\process\browser.js
        Used by 1 module(s), i. e.
        c:\WebClientToolkit\node_modules\path-browserify\index.js�[39m�[22m"><pre class="notranslate"><code class="notranslate"> �[1m�[33mWARNING in ./node_modules/process/browser.js
    There are multiple modules with names that only differ in casing.
    This can lead to unexpected behavior when compiling on a filesystem with other case-semantic.
    Use equal casing. Compare these module identifiers:
    * C:\WebClientToolkit\node_modules\process\browser.js
        Used by 3 module(s), i. e.
        C:\WebClientToolkit\packages\core\wct-http\source\index.js
    * c:\WebClientToolkit\node_modules\process\browser.js
        Used by 1 module(s), i. e.
        c:\WebClientToolkit\node_modules\path-browserify\index.js�[39m�[22m
</code></pre></div>
<p dir="auto"><strong>If the current behavior is a bug, please provide the steps to reproduce.</strong><br>
I can provide our config, however it's going to happen when bundling web targets on windows unless you get 'lucky' and the expansion for the internal process module happens to match process.cwd().</p>
<p dir="auto"><strong>What is the expected behavior?</strong><br>
There should not be duplicates of internal modules.</p>
<p dir="auto"><strong>If this is a feature request, what is motivation or use case for changing the behavior?</strong><br>
When the path is expanded for internal modules check process.cwd() and match the drive letter case.</p>
<p dir="auto"><strong>Please mention other relevant information such as the browser version, Node.js version, webpack version and Operating System.</strong><br>
We're on webpack 3.6.0 and Node 6.10.3.</p>