diff --git a/src/compile-cache.js b/src/compile-cache.js
index e15674a2e..9b1966fc8 100644
--- a/src/compile-cache.js
+++ b/src/compile-cache.js
@@ -221,5 +221,5 @@ exports.install = function (nodeRequire) {
   })
 }
 
-
+exports.supportedExtensions = Object.keys(COMPILERS)
 exports.resetCacheStats()
diff --git a/src/package.coffee b/src/package.coffee
index dea9c0e58..ed0f7aa87 100644
--- a/src/package.coffee
+++ b/src/package.coffee
@@ -503,7 +503,7 @@ class Package
           path.join(@path, @metadata.main)
         else
           path.join(@path, 'index')
-      @mainModulePath = fs.resolveExtension(mainModulePath, ["", _.keys(require.extensions)...])
+      @mainModulePath = fs.resolveExtension(mainModulePath, ["", CompileCache.supportedExtensions...])
 
   activationShouldBeDeferred: ->
     @hasActivationCommands() or @hasActivationHooks()