I’m having trouble getting adding some function signatures to Stan.

I added the function signature to the function signatures header file and made a test model (all the changes are here https://github.com/bbbales2/stan/commit/f31370ca2eac2c56a88ac8391721e3da47d719c8 – I’ll move the stuff to a regular Stan repo when it’s time for the pull req.)

When I go to run the model tests (`./runTests.py src/test/unit/lang/parser/matrix_functions_test.cpp`

), I get this in the output:

```
[==========] Running 90 tests from 1 test case.
[----------] Global test environment set-up.
[----------] 90 tests from lang_parser
...
[ RUN ] lang_parser.append_array_matrix_function_signatures
unknown file: Failure
C++ exception with description "" thrown in the test body.
[ FAILED ] lang_parser.append_array_matrix_function_signatures (49 ms)
[ RUN ] lang_parser.append_col_matrix_function_signatures
...
[----------] Global test environment tear-down
[==========] 90 tests from 1 test case ran. (5586 ms total)
[ PASSED ] 89 tests.
[ FAILED ] 1 test, listed below:
[ FAILED ] lang_parser.append_array_matrix_function_signatures
```

Any clue what’s blowing up here or what I might have done wrong? I’m following the directions here: https://github.com/stan-dev/stan/wiki/Contributing-New-Functions-to-Stan . I’m probably missing something obvious.

Roughly the function I’m adding is (with specializations so it works with int/real/vector/row_vector/matrix types):

```
/**
* Return the concatenation of two specified vectors in the order of
* the arguments.
*
* @tparam T1 Scalar type of first vector
* @tparam T2 Scalar type of second vector
* @param x First vector
* @param y Second vector
* @return A vector of x and y concatenated together (in that order)
*/
template <typename T1, typename T2>
inline typename std::vector<typename return_type<T1, T2>::type>
append_array(const std::vector<T1>& x, const std::vector<T2>& y) {
std::vector<typename return_type<T1, T2>::type> z;
z.reserve(x.size() + y.size());
z.insert(z.end(), x.begin(), x.end());
z.insert(z.end(), y.begin(), y.end());
return z;
}
```

Thanks!