Invert is_top_level to avoid negation.

Author: nnethercote

compiler/rustc_parse/src/lexer/tokentrees.rs

@@ -40,26 +40,26 @@ impl<'a> TokenTreesReader<'a> {
             last_delim_empty_block_spans: FxHashMap::default(),
             matching_block_spans: Vec::new(),
         };
-        let res = tt_reader.parse_token_trees(/* is_top_level */ true);
+        let res = tt_reader.parse_token_trees(/* is_delimited */ false);
         (res, tt_reader.unmatched_braces)
     }
 
     // Parse a stream of tokens into a list of `TokenTree`s.
-    fn parse_token_trees(&mut self, is_top_level: bool) -> PResult<'a, TokenStream> {
+    fn parse_token_trees(&mut self, is_delimited: bool) -> PResult<'a, TokenStream> {
         self.token = self.string_reader.next_token().0;
         let mut buf = Vec::new();
         loop {
             match self.token.kind {
                 token::OpenDelim(delim) => buf.push(self.parse_token_tree_open_delim(delim)),
                 token::CloseDelim(delim) => {
-                    return if !is_top_level {
+                    return if is_delimited {
                         Ok(TokenStream::new(buf))
                     } else {
                         Err(self.close_delim_err(delim))
                     };
                 }
                 token::Eof => {
-                    if !is_top_level {
+                    if is_delimited {
                         self.eof_err().emit();
                     }
                     return Ok(TokenStream::new(buf));
@@ -133,7 +133,7 @@ impl<'a> TokenTreesReader<'a> {
         // Parse the token trees within the delimiters.
         // We stop at any delimiter so we can try to recover if the user
         // uses an incorrect delimiter.
-        let tts = self.parse_token_trees(/* is_top_level */ false).unwrap();
+        let tts = self.parse_token_trees(/* is_delimited */ true).unwrap();
 
         // Expand to cover the entire delimited token tree
         let delim_span = DelimSpan::from_pair(pre_span, self.token.span);