tentative example of ParamTypeCheck use

check-param.p6

use QAST:from<NQP>;
use nqp;

my $ast := QAST::Block.new(
    QAST::Op.new(:op<call>,
      QAST::Block.new(
        QAST::Var.new(:name<$a>, :scope<param>, :decl<var>,
          QAST::ParamTypeCheck.new(
            QAST::Op.new(:op<istrue>, QAST::Var.new(:name<$a>, :scope<param>)))),
        QAST::Op.new(:op<say>,
          QAST::Op.new(:op<callmethod>, :name<Str>,QAST::Var.new(:name<$a>, :scope<param>))
        )
      ),
      QAST::Ival(:value(42))
    )
);

say($ast.dump());
say(exec_qast($ast));

sub exec_qast($qast) {
    my $*QAST_BLOCK_NO_CLOSE := 1;
    my $code := nqp::getcomp('nqp').compile($qast, :from('ast'));
    $code();
}