converter doesn't work for case statement branches with the .. operator

[sealmove]

The following code crushes the compiler

converter toInt(c: char): int = int(c)
var c: int = 5
case c
of 'a' .. 'c': discard
else: discard

bug.nim(5, 4) Error: internal error: genLiteral(nkHiddenCallConv)
No stack traceback available
To create a stacktrace, rerun compilation with ./koch temp c <file>

[kraptor]

related to #8984

[metagn]

semBranchRange calls fitNode after semConstExpr, probably just adapt #8336 to it