diff --git a/src/bin/thin_shrink.rs b/src/bin/thin_shrink.rs
index 55632c5..7c533be 100644
--- a/src/bin/thin_shrink.rs
+++ b/src/bin/thin_shrink.rs
@@ -26,7 +26,6 @@ fn main() {
 
     // FIXME: check these look like xml
     let input_file = matches.value_of("INPUT").unwrap();
-    let map_file = matches.value_of("MAP").unwrap();
     let output_file = matches.value_of("OUTPUT").unwrap();
 
     if !file_utils::file_exists(input_file) {
diff --git a/src/shrink/toplevel.rs b/src/shrink/toplevel.rs
index 0a647c2..53dfbe1 100644
--- a/src/shrink/toplevel.rs
+++ b/src/shrink/toplevel.rs
@@ -6,14 +6,15 @@ use crate::shrink::xml;
 
 //---------------------------------------
 
-pub fn shrink(input_file: &str, _output_file: &str, _map_file: &str) -> Result<()> {
+pub fn shrink(input_file: &str, _output_file: &str) -> Result<()> {
     let input = OpenOptions::new()
         .read(true)
         .write(false)
         .custom_flags(libc::O_EXCL)
         .open(input_file)?;
 
-    let mut visitor = xml::XmlWriter::new(std::io::stdout());
+    // let mut visitor = xml::XmlWriter::new(std::io::stdout());
+    let mut visitor = xml::NoopVisitor::new();
     xml::read(input, &mut visitor)?;
 
     Ok(())
diff --git a/src/shrink/xml.rs b/src/shrink/xml.rs
index 60cd3c4..f060016 100644
--- a/src/shrink/xml.rs
+++ b/src/shrink/xml.rs
@@ -51,6 +51,25 @@ pub trait MetadataVisitor {
     fn eof(&mut self) -> Result<()>;
 }
 
+pub struct NoopVisitor {
+}
+
+impl NoopVisitor {
+    pub fn new() -> NoopVisitor { NoopVisitor {} }
+}
+
+impl MetadataVisitor for NoopVisitor {
+    fn superblock_b(&mut self, _sb: &Superblock) -> Result<()> {Ok(())}
+    fn superblock_e(&mut self) -> Result<()> {Ok(())}
+
+    fn device_b(&mut self, _d: &Device) -> Result<()> {Ok(())}
+    fn device_e(&mut self) -> Result<()> {Ok(())}
+
+    fn map(&mut self, _m: Map) -> Result<()> {Ok(())}
+
+    fn eof(&mut self) -> Result<()> {Ok(())}
+}
+
 pub struct XmlWriter<W: Write> {
     w: Writer<W>,
 }