Rollup merge of #66054 - petrochenkov:delspan, r=estebank

syntax: Avoid span arithmetic for delimiter tokens

The +/-1 logic is from the time where the whole group had a single span and the delimiter spans had to be calculated from it.
Now the delimiters have their own spans which are constructed by lexer or proc macro API and can be used directly.
If those spans are not perfect, then it should be fixed by tweaking the corresponding lexer logic rather than by trying to add or substract `1` from the span boundaries.

Fixes https://github.com/rust-lang/rust/issues/62524
r? @estebank

2 files changed, 7 insertions, 17 deletions

diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index e81d4573b73..7652c730e51 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -209,12 +209,12 @@ impl TokenCursor {
         loop {
             let tree = if !self.frame.open_delim {
                 self.frame.open_delim = true;
-                TokenTree::open_tt(self.frame.span.open, self.frame.delim)
+                TokenTree::open_tt(self.frame.span, self.frame.delim)
             } else if let Some(tree) = self.frame.tree_cursor.next() {
                 tree
             } else if !self.frame.close_delim {
                 self.frame.close_delim = true;
-                TokenTree::close_tt(self.frame.span.close, self.frame.delim)
+                TokenTree::close_tt(self.frame.span, self.frame.delim)
             } else if let Some(frame) = self.stack.pop() {
                 self.frame = frame;
                 continue
diff --git a/src/libsyntax/tokenstream.rs b/src/libsyntax/tokenstream.rs
index 0559f224f1f..7e0582797c7 100644
--- a/src/libsyntax/tokenstream.rs
+++ b/src/libsyntax/tokenstream.rs
@@ -15,7 +15,7 @@
 
 use crate::parse::token::{self, DelimToken, Token, TokenKind};
 
-use syntax_pos::{BytePos, Span, DUMMY_SP};
+use syntax_pos::{Span, DUMMY_SP};
 #[cfg(target_arch = "x86_64")]
 use rustc_data_structures::static_assert_size;
 use rustc_data_structures::sync::Lrc;
@@ -110,23 +110,13 @@ impl TokenTree {
     }
 
     /// Returns the opening delimiter as a token tree.
-    pub fn open_tt(span: Span, delim: DelimToken) -> TokenTree {
-        let open_span = if span.is_dummy() {
-            span
-        } else {
-            span.with_hi(span.lo() + BytePos(delim.len() as u32))
-        };
-        TokenTree::token(token::OpenDelim(delim), open_span)
+    pub fn open_tt(span: DelimSpan, delim: DelimToken) -> TokenTree {
+        TokenTree::token(token::OpenDelim(delim), span.open)
     }
 
     /// Returns the closing delimiter as a token tree.
-    pub fn close_tt(span: Span, delim: DelimToken) -> TokenTree {
-        let close_span = if span.is_dummy() {
-            span
-        } else {
-            span.with_lo(span.hi() - BytePos(delim.len() as u32))
-        };
-        TokenTree::token(token::CloseDelim(delim), close_span)
+    pub fn close_tt(span: DelimSpan, delim: DelimToken) -> TokenTree {
+        TokenTree::token(token::CloseDelim(delim), span.close)
     }
 }