Policy/Assumptions on field_types in MultitypeBlockVector/Matrix?
I am trying to get rid of some warnings about shadowing variables/using directions. Some of them are due to using field_type = ... being reset in some methods (e.g. norms). I don't want to break anything, hence the question arises:
Do we insist on field_type being the same for each entry? Seems like the code at least insists that the field_types of all entries are convertible to the one of the very first entry.
For the template parameters, arbitrary different types are possible.
Our tests assume always use the same type.