* 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.
* Field checks for JS backend
* Clean nkCall nodes with no arguments
Generating a nkEmpty in place of no arguments makes no sense form the
AST point of view and also trips up the VM codegen.
* Field checks for VM backend
* Test case for #6612
This patchset fixes#6612
* Add test case for LHS double evaluation
* Prevent LHS double-eval for JS backend
* Prevent double evaluation in VM backend
