* Error -> Defect for defects
The distinction between Error and Defect is subjective,
context-dependent and somewhat arbitrary, so when looking at an
exception, it's hard to guess what it is - this happens often when
looking at a `raises` list _without_ opening the corresponding
definition and digging through layers of inheritance.
With the help of a little consistency in naming, it's at least possible
to start disentangling the two error types and the standard lib can set
a good example here.
* fixes#13102
* closes#13149
* ARC: fixes a move optimizer bug (there are more left regarding array and tuple indexing)
* proper fix; fixes#12957
* fixes yet another case object '=' code generation problem