Partial fix for #4363
Partial fix for #4363

Fixes the my @a[1]; my @b[1]; @a = @b case.

labster/rakudo,tbrowder/rakudo,tony-o/rakudo,MasterDuke17/rakudo,rakudo/rakudo,salortiz/rakudo,salortiz/rakudo,labster/rakudo,MasterDuke17/rakudo,tony-o/rakudo,tony-o/rakudo,tbrowder/rakudo,MasterDuke17/rakudo,MasterDuke17/rakudo,labster/rakudo,labster/rakudo,tbrowder/rakudo,labster/rakudo,tony-o/rakudo,rakudo/rakudo,rakudo/rakudo,tony-o/rakudo,labster/rakudo,salortiz/rakudo,salortiz/rakudo,MasterDuke17/rakudo,rakudo/rakudo,tbrowder/rakudo,MasterDuke17/rakudo,tbrowder/rakudo,salortiz/rakudo,rakudo/rakudo,salortiz/rakudo,tony-o/rakudo,rakudo/rakudo,tbrowder/rakudo