Trilinos: Sacado compiler warnings in 12.12.1

[davydden]

would be good to fix a minor compiler warning.

/Users/davydden/spack/opt/spack/darwin-highsierra-x86_64/clang-9.0.0-apple/trilinos-12.12.1-mdvzw5gcpvymi6lsy2e4xinrpeekhqhh/include/Sacado_Fad_Expression.hpp:83:5: warning: 'Expr' defined as a struct template here but previously declared as a class template
      [-Wmismatched-tags]
    struct Expr {
    ^
/Users/davydden/spack/opt/spack/darwin-highsierra-x86_64/clang-9.0.0-apple/trilinos-12.12.1-mdvzw5gcpvymi6lsy2e4xinrpeekhqhh/include/Sacado_Fad_ExpressionFwd.hpp:62:64: note: did you mean struct here?
              typename Spec = typename ExprSpec<ExprT>::type > class Expr;
                                                               ^~~~~
                                                               struct

I am not fixing it myself as I am not sure if you want to use struct or class.

[lucbv]

@trilinos/sacado

[etphipp]

Thanks for reporting. I'll fix Sacado_Fad_ExpressionFwd.hpp to be consistent with Sacado_Fad_Expression.hpp.

[etphipp]

This was fixed in develop (likes like by @mhoemmen, thanks Mark!). Thanks for reporting!