boolean (PsiFileSystemItem file) { VirtualFile vFile = PsiUtilCore.getVirtualFile(file); vFile = vFile == null ? null : BackedVirtualFile.getOriginFileIfBacked(vFile); if (vFile == null || !vFile.isValid()) return false; ProjectFileIndex fileIndex = ProjectRootManager.getInstance(myProject).getFileIndex(); return fileIndex.isInSourceContent(vFile) || isInLibraryContentOnly(vFile); }