It used to only work without the debugger.
--- /dev/null
+#!/usr/bin/perl
+
+use FindBin qw/ $Bin /;
+
+BEGIN {
+#line 1
+#!/usr/bin/perl -d
+
+ push @DB::typeahead, "c", "q";
+
+ # try to shut it up at least a little bit
+ open my $out, ">", \my $out_buf;
+ $DB::OUT = $out;
+ open my $in, "<", \my $in_buf;
+ $DB::IN = $in;
+}
+
+require "$Bin/type_constraints/duck_types.t";