my $var4;
# This generates "Modification of a read-only value attempted at";
eval {
  # Still dies, even when in list context.
  # $var4 = map { s/\r?\n\Z/(munched)/; $_ } <<EOT
  ($var4) = map { s/\r?\n\Z/(munched)/; $_ } <<EOT
var4 has _NO_ interpolated var,
and will generate a runtime error
EOT
};

if ($@){
  ($var4 = $@) =~ s/\r?\n\Z//;
  $@ = undef;
  print map {s/\r?\n\Z//;$_ }(${^__} =<<EOT);
The error generated by
\$var4 = map { s/\\r?\\n\\Z/(munched)/; \$_ } <<EOT;
is: $var4

EOT
}