diff --git a/compiler/backend/src/org/jetbrains/jet/compiler/CompileEnvironment.java b/compiler/backend/src/org/jetbrains/jet/compiler/CompileEnvironment.java
index 7a98b234052..a6a2c41fd8e 100644
--- a/compiler/backend/src/org/jetbrains/jet/compiler/CompileEnvironment.java
+++ b/compiler/backend/src/org/jetbrains/jet/compiler/CompileEnvironment.java
@@ -22,7 +22,6 @@ import java.io.*;
 import java.lang.reflect.Field;
 import java.net.URL;
 import java.net.URLClassLoader;
-import java.util.Arrays;
 import java.util.List;
 import java.util.jar.*;
 
@@ -189,7 +188,7 @@ public class CompileEnvironment {
     public IModuleSetBuilder loadModuleScript(String moduleFile) {
         CompileSession scriptCompileSession = new CompileSession(myEnvironment);
         scriptCompileSession.addSources(moduleFile);
-        scriptCompileSession.addStdLibSources();
+        scriptCompileSession.addStdLibSources(true);
 
         if (!scriptCompileSession.analyze(myErrorStream)) {
             return null;
@@ -228,7 +227,7 @@ public class CompileEnvironment {
 
     public ClassFileFactory compileModule(IModuleBuilder moduleBuilder, String directory) {
         CompileSession moduleCompileSession = new CompileSession(myEnvironment);
-        moduleCompileSession.addStdLibSources();
+        moduleCompileSession.addStdLibSources(false);
         for (String sourceFile : moduleBuilder.getSourceFiles()) {
             File source = new File(sourceFile);
             if (!source.isAbsolute()) {
@@ -250,17 +249,6 @@ public class CompileEnvironment {
        return new File(PathManager.getResourceRoot(CompileEnvironment.class, "/org/jetbrains/jet/compiler/CompileEnvironment.class")).getParentFile().getParentFile().getParent();
     }
 
-    private static final List<String> sanitized = Arrays.asList("kotlin/", "std/");
-    public static boolean skipFile(String name) {
-        boolean skip = false;
-        for (String prefix : sanitized) {
-            if(name.startsWith(prefix)) {
-                return true;
-            }
-        }
-        return false;
-    }
-
     public static void writeToJar(ClassFileFactory factory, final OutputStream fos, @Nullable String mainClass, boolean includeRuntime) {
         try {
             Manifest manifest = new Manifest();
@@ -273,10 +261,8 @@ public class CompileEnvironment {
             JarOutputStream stream = new JarOutputStream(fos, manifest);
             try {
                 for (String file : factory.files()) {
-                    if(!skipFile(file)) {
-                        stream.putNextEntry(new JarEntry(file));
-                        stream.write(factory.asBytes(file));
-                    }
+                    stream.putNextEntry(new JarEntry(file));
+                    stream.write(factory.asBytes(file));
                 }
                 if (includeRuntime) {
                     writeRuntimeToJar(stream);
@@ -343,7 +329,7 @@ public class CompileEnvironment {
     public void compileBunchOfSources(String sourceFileOrDir, String jar, String outputDir, boolean includeRuntime) {
         CompileSession session = new CompileSession(myEnvironment);
         session.addSources(sourceFileOrDir);
-        session.addStdLibSources();
+        session.addStdLibSources(false);
 
         String mainClass = null;
         for (JetFile file : session.getSourceFileNamespaces()) {
@@ -375,13 +361,11 @@ public class CompileEnvironment {
     public static void writeToOutputDirectory(ClassFileFactory factory, final String outputDir) {
         List<String> files = factory.files();
         for (String file : files) {
-            if(!skipFile(file)) {
-                File target = new File(outputDir, file);
-                try {
-                    FileUtil.writeToFile(target, factory.asBytes(file));
-                } catch (IOException e) {
-                    throw new CompileEnvironmentException(e);
-                }
+            File target = new File(outputDir, file);
+            try {
+                FileUtil.writeToFile(target, factory.asBytes(file));
+            } catch (IOException e) {
+                throw new CompileEnvironmentException(e);
             }
         }
     }
diff --git a/compiler/backend/src/org/jetbrains/jet/compiler/CompileSession.java b/compiler/backend/src/org/jetbrains/jet/compiler/CompileSession.java
index dffab3f4c06..494291f1d52 100644
--- a/compiler/backend/src/org/jetbrains/jet/compiler/CompileSession.java
+++ b/compiler/backend/src/org/jetbrains/jet/compiler/CompileSession.java
@@ -49,35 +49,39 @@ public class CompileSession {
             return;
         }
 
-        addSources(new File(path));
+        addSources(new File(path), false);
     }
 
-    private void addSources(File file) {
+    private void addSources(File file, boolean library) {
         if(file.isDirectory()) {
             for (File child : file.listFiles()) {
-                addSources(child);
+                addSources(child, library);
             }
         }
         else {
             VirtualFile fileByPath = myEnvironment.getLocalFileSystem().findFileByPath(file.getAbsolutePath());
             PsiFile psiFile = PsiManager.getInstance(myEnvironment.getProject()).findFile(fileByPath);
             if(psiFile instanceof JetFile) {
-                mySourceFiles.add((JetFile) psiFile);
+                (library ? myLibrarySourceFiles : mySourceFiles).add((JetFile) psiFile);
             }
         }
     }
 
     public void addSources(VirtualFile vFile) {
+        addSources(vFile, false);
+    }
+
+    private void addSources(VirtualFile vFile, boolean library) {
         if  (vFile.isDirectory())  {
             for (VirtualFile virtualFile : vFile.getChildren()) {
-                addSources(virtualFile);
+                addSources(virtualFile, library);
             }
         }
         else {
             if (vFile.getFileType() == JetFileType.INSTANCE) {
                 PsiFile psiFile = PsiManager.getInstance(myEnvironment.getProject()).findFile(vFile);
                 if (psiFile instanceof JetFile) {
-                    mySourceFiles.add((JetFile) psiFile);
+                    (library ? myLibrarySourceFiles : mySourceFiles).add((JetFile) psiFile);
                 }
             }
         }
@@ -115,17 +119,17 @@ public class CompileSession {
         return generationState.createText();
     }
 
-    public boolean addStdLibSources() {
+    public boolean addStdLibSources(boolean toModuleSources) {
         final File unpackedRuntimePath = CompileEnvironment.getUnpackedRuntimePath();
         if (unpackedRuntimePath != null) {
-            addSources(new File(unpackedRuntimePath, "../../../stdlib/ktSrc").getAbsoluteFile());
+            addSources(new File(unpackedRuntimePath, "../../../stdlib/ktSrc").getAbsoluteFile(), !toModuleSources);
         }
         else {
             final File runtimeJarPath = CompileEnvironment.getRuntimeJarPath();
             if (runtimeJarPath != null && runtimeJarPath.exists()) {
                 VirtualFile runtimeJar = myEnvironment.getLocalFileSystem().findFileByPath(runtimeJarPath.getAbsolutePath());
                 VirtualFile jarRoot = myEnvironment.getJarFileSystem().findFileByPath(runtimeJar.getPath() + "!/stdlib/ktSrc");
-                addSources(jarRoot);
+                addSources(jarRoot, !toModuleSources);
             }
             else {
                 return false;
diff --git a/compiler/tests/org/jetbrains/jet/codegen/StdlibTest.java b/compiler/tests/org/jetbrains/jet/codegen/StdlibTest.java
index 875cfee5ee0..50e8f8b2e20 100644
--- a/compiler/tests/org/jetbrains/jet/codegen/StdlibTest.java
+++ b/compiler/tests/org/jetbrains/jet/codegen/StdlibTest.java
@@ -18,7 +18,7 @@ public class StdlibTest extends CodegenTestCase {
 
         session.addSources(myFile.getVirtualFile());
         try {
-            session.addStdLibSources();
+            session.addStdLibSources(true);
         } catch (Throwable e) {
             throw new RuntimeException(e);
         }
@@ -35,7 +35,7 @@ public class StdlibTest extends CodegenTestCase {
             CompileSession session = new CompileSession(myEnvironment);
             CompileEnvironment.initializeKotlinRuntime(myEnvironment);
             session.addSources(myFile.getVirtualFile());
-            session.addStdLibSources();
+            session.addStdLibSources(true);
 
             if (!session.analyze(System.out)) {
                 return null;