explicit reference to error
explicit reference to error

Former-commit-id: bb244baaaca9b4bb03e42fba8887c4b5cc72ae9b
danielhers/dynet,xunzhang/dynet,clab/cnn,xunzhang/dynet,chunyang-wen/dynet,danielhers/dynet,shuheik/dynet,clab/dynet,shuheik/dynet,chunyang-wen/dynet,xunzhang/dynet,clab/dynet,shuheik/dynet,clab/cnn,clab/dynet,clab/dynet,chunyang-wen/dynet,shuheik/dynet,clab/dynet,chunyang-wen/dynet,xunzhang/dynet,shuheik/dynet,clab/dynet,danielhers/dynet,clab/cnn,clab/dynet,danielhers/dynet,shuheik/dynet,shuheik/dynet,danielhers/dynet,danielhers/dynet,danielhers/dynet