Rollup merge of #33839 - kamalmarhubi:codemape-get-filemap-option, r=…

…nmatsakis

 This is more idiomatic, putting the caller in charge of whether or not
to panic.

src/librustc_driver/pretty.rs

@@ -757,6 +757,7 @@ fn get_source(input: &Input, sess: &Session) -> (Vec<u8>, String) {
  let src_name = driver::source_name(input);
  let src = sess.codemap()
  .get_filemap(&src_name)
+ .unwrap()
  .src
  .as_ref()
  .unwrap()

src/libsyntax/codemap.rs

@@ -1191,13 +1191,13 @@ impl CodeMap {
  }
  }
 
- pub fn get_filemap(&self, filename: &str) -> Rc<FileMap> {
+ pub fn get_filemap(&self, filename: &str) -> Option<Rc<FileMap>> {
  for fm in self.files.borrow().iter() {
  if filename == fm.name {
- return fm.clone();
+ return Some(fm.clone());
  }
  }
- panic!("asking for {} which we don't know about", filename);
+ None
  }
 
  /// For a global BytePos compute the local offset within the containing FileMap