KT-224 "Overload ambiguity" when calling toString() method

compiler/cli/src/org/jetbrains/jet/compiler/JetCoreEnvironment.java

@@ -22,6 +22,7 @@ import com.intellij.mock.MockApplication;
 import com.intellij.openapi.Disposable;
 import com.intellij.openapi.vfs.VirtualFile;
 import org.jetbrains.jet.lang.parsing.JetParserDefinition;
+import org.jetbrains.jet.lang.types.JetStandardLibrary;
 import org.jetbrains.jet.plugin.JetFileType;
 import org.jetbrains.jet.plugin.compiler.PathUtil;
 
@@ -47,6 +48,8 @@ public class JetCoreEnvironment extends JavaCoreEnvironment {
         for (VirtualFile root : PathUtil.getAltHeadersRoots()) {
             addLibraryRoot(root);
         }
+
+        JetStandardLibrary.initialize(getProject());
     }
 
     public MockApplication getApplication() {