Error in re-building vignettes:
  ...
                                                   ^
In file included from filede9fca7e66c.cpp:8:
In file included from /Volumes/SSD-Data/Builds/R-dev-web/QA/Simon/packages/el-capitan-x86_64/Rlib/3.5/StanHeaders/include/stan/math.hpp:4:
In file included from /Volumes/SSD-Data/Builds/R-dev-web/QA/Simon/packages/el-capitan-x86_64/Rlib/3.5/StanHeaders/include/stan/math/rev/mat.hpp:4:
In file included from /Volumes/SSD-Data/Builds/R-dev-web/QA/Simon/packages/el-capitan-x86_64/Rlib/3.5/StanHeaders/include/stan/math/rev/core.hpp:44:
/Volumes/SSD-Data/Builds/R-dev-web/QA/Simon/packages/el-capitan-x86_64/Rlib/3.5/StanHeaders/include/stan/math/rev/core/set_zero_all_adjoints.hpp:14:17: warning: unused function 'set_zero_all_adjoints' [-Wunused-function]
    static void set_zero_all_adjoints() {
                ^
In file included from filede9fca7e66c.cpp:8:
In file included from /Volumes/SSD-Data/Builds/R-dev-web/QA/Simon/packages/el-capitan-x86_64/Rlib/3.5/StanHeaders/include/stan/math.hpp:4:
In file included from /Volumes/SSD-Data/Builds/R-dev-web/QA/Simon/packages/el-capitan-x86_64/Rlib/3.5/StanHeaders/include/stan/math/rev/mat.hpp:4:
In file included from /Volumes/SSD-Data/Builds/R-dev-web/QA/Simon/packages/el-capitan-x86_64/Rlib/3.5/StanHeaders/include/stan/math/rev/core.hpp:45:
/Volumes/SSD-Data/Builds/R-dev-web/QA/Simon/packages/el-capitan-x86_64/Rlib/3.5/StanHeaders/include/stan/math/rev/core/set_zero_all_adjoints_nested.hpp:17:17: warning: 'static' function 'set_zero_all_adjoints_nested' declared in header file should be declared 'static inline' [-Wunneeded-internal-declaration]
    static void set_zero_all_adjoints_nested() {
                ^
In file included from filede9fca7e66c.cpp:8:
In file included from /Volumes/SSD-Data/Builds/R-dev-web/QA/Simon/packages/el-capitan-x86_64/Rlib/3.5/StanHeaders/include/stan/math.hpp:4:
In file included from /Volumes/SSD-Data/Builds/R-dev-web/QA/Simon/packages/el-capitan-x86_64/Rlib/3.5/StanHeaders/include/stan/math/rev/mat.hpp:12:
In file included from /Volumes/SSD-Data/Builds/R-dev-web/QA/Simon/packages/el-capitan-x86_64/Rlib/3.5/StanHeaders/include/stan/math/prim/mat.hpp:58:
/Volumes/SSD-Data/Builds/R-dev-web/QA/Simon/packages/el-capitan-x86_64/Rlib/3.5/StanHeaders/include/stan/math/prim/mat/fun/autocorrelation.hpp:17:14: warning: function 'fft_next_good_size' is not needed and will not be emitted [-Wunneeded-internal-declaration]
      size_t fft_next_good_size(size_t N) {
             ^
22 warnings generated.

Execution halted