refactor: change to use peekable

rust-lang · Dylan-DPC · Mar 16, 2022 · Mar 18, 2022 · Feb 28, 2022 · Mar 8, 2022
commit 1b7008dc77e25049b04e5c3e31aecf4de00803e7
diff --git a/compiler/rustc_parse/src/lexer/mod.rs b/compiler/rustc_parse/src/lexer/mod.rs
@@ -557,39 557,36 @@ impl<'a> StringReader<'a> {
  );
  let mut nested_block_comment_open_idxs = vec![];
  let mut last_nested_block_comment_idxs = None;
- let mut content_chars = self.str_from(start).char_indices();
  let mut content_chars = self.str_from(start).char_indices().peekable();
 
- if let Some((_, mut last_char)) = content_chars.next() {
- while let Some((idx, c)) = content_chars.next() {
- match c {
- '*' if last_char == '/' => {
- nested_block_comment_open_idxs.push(idx);
- }
- '/' if last_char == '*' => {
- last_nested_block_comment_idxs =
- nested_block_comment_open_idxs.pop().map(|open_idx| (open_idx, idx));
- }
- _ => {}
- };
- last_char = c;
- }
  while let Some((idx, current_char)) = content_chars.next() {
  match content_chars.peek() {
  Some((_, '*')) if current_char == '/' => {
  nested_block_comment_open_idxs.push(idx);
  }
  Some((_, '/')) if current_char == '*' => {
  last_nested_block_comment_idxs =
  nested_block_comment_open_idxs.pop().map(|open_idx| (open_idx, idx));
  }
  _ => {}
  };
  }
 
  if let Some((nested_open_idx, nested_close_idx)) = last_nested_block_comment_idxs {
  err.span_label(self.mk_sp(start, start BytePos(2)), msg)
  .span_label(
  self.mk_sp(
- start BytePos(nested_open_idx as u32 - 1),
- start BytePos(nested_open_idx as u32 1),
  start BytePos(nested_open_idx as u32),
  start BytePos(nested_open_idx as u32 2),
  ),
  "...as last nested comment starts here, maybe you want to close this instead?",
  )
  .span_label(
  self.mk_sp(
- start BytePos(nested_close_idx as u32 - 1),
- start BytePos(nested_close_idx as u32 1),
  start BytePos(nested_close_idx as u32),
  start BytePos(nested_close_idx as u32 2),
  ),
- "...and last nested comment terminates here",
  "...and last nested comment terminates here.",
  );
  }
 

diff --git a/src/test/ui/unterminated-nested-comment.stderr b/src/test/ui/unterminated-nested-comment.stderr
@@ -14,7 14,7 @@ LL | | /*
 LL | | */
  | |_--^
  | |
- | ...and last nested comment terminates here
  | ...and last nested comment terminates here.
 
 error: aborting due to previous error