When working with an untyped const expression involving a division, if
the default type of the result should be an int (for example because the
default types of all the operands are ints as well), then we should make
sure that the operation that is applied is indeed an integer division,
and that the type of the result is not a float.
This is achieved by using the QUO_ASSIGN operator, instead of the QUO
operator.
This should fix several problems lurking around, and it notably fixes
one of the visible consequences, which is a systematic panic when using
the REPL as a "calculator".
This incidentally also allows us to revert what was done in
5dfc3b86dc since it now turns out it was
just a hack to fix one of the symptoms.
Fixes#864
16f5586a11