syntax: Avoid span arithmetics for delimiter tokens

Author: petrochenkov

src/libsyntax/parse/parser.rs

@@ -210,12 +210,12 @@ 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

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)
     }
 }
 

src/libsyntax_expand/mbe.rs

@@ -13,7 +13,7 @@ use syntax::ast;
 use syntax::parse::token::{self, Token, TokenKind};
 use syntax::tokenstream::{DelimSpan};
 
-use syntax_pos::{BytePos, Span};
+use syntax_pos::Span;
 
 use rustc_data_structures::sync::Lrc;
 
@@ -27,23 +27,13 @@ struct Delimited {
 
 impl Delimited {
     /// Returns a `self::TokenTree` with a `Span` corresponding to the opening delimiter.
-    fn open_tt(&self, span: Span) -> TokenTree {
-        let open_span = if span.is_dummy() {
-            span
-        } else {
-            span.with_hi(span.lo() + BytePos(self.delim.len() as u32))
-        };
-        TokenTree::token(token::OpenDelim(self.delim), open_span)
+    fn open_tt(&self, span: DelimSpan) -> TokenTree {
+        TokenTree::token(token::OpenDelim(self.delim), span.open)
     }
 
     /// Returns a `self::TokenTree` with a `Span` corresponding to the closing delimiter.
-    fn close_tt(&self, span: Span) -> TokenTree {
-        let close_span = if span.is_dummy() {
-            span
-        } else {
-            span.with_lo(span.hi() - BytePos(self.delim.len() as u32))
-        };
-        TokenTree::token(token::CloseDelim(self.delim), close_span)
+    fn close_tt(&self, span: DelimSpan) -> TokenTree {
+        TokenTree::token(token::CloseDelim(self.delim), span.close)
     }
 }
 
@@ -138,10 +128,10 @@ impl TokenTree {
             }
             (&TokenTree::Delimited(span, ref delimed), _) => {
                 if index == 0 {
-                    return delimed.open_tt(span.open);
+                    return delimed.open_tt(span);
                 }
                 if index == delimed.tts.len() + 1 {
-                    return delimed.close_tt(span.close);
+                    return delimed.close_tt(span);
                 }
                 delimed.tts[index - 1].clone()
             }

src/libsyntax_expand/mbe/macro_rules.rs

@@ -566,7 +566,7 @@ impl FirstSets {
                     }
                     TokenTree::Delimited(span, ref delimited) => {
                         build_recur(sets, &delimited.tts[..]);
-                        first.replace_with(delimited.open_tt(span.open));
+                        first.replace_with(delimited.open_tt(span));
                     }
                     TokenTree::Sequence(sp, ref seq_rep) => {
                         let subfirst = build_recur(sets, &seq_rep.tts[..]);
@@ -628,7 +628,7 @@ impl FirstSets {
                     return first;
                 }
                 TokenTree::Delimited(span, ref delimited) => {
-                    first.add_one(delimited.open_tt(span.open));
+                    first.add_one(delimited.open_tt(span));
                     return first;
                 }
                 TokenTree::Sequence(sp, ref seq_rep) => {
@@ -826,7 +826,7 @@ fn check_matcher_core(
                 }
             }
             TokenTree::Delimited(span, ref d) => {
-                let my_suffix = TokenSet::singleton(d.close_tt(span.close));
+                let my_suffix = TokenSet::singleton(d.close_tt(span));
                 check_matcher_core(sess, features, attrs, first_sets, &d.tts, &my_suffix);
                 // don't track non NT tokens
                 last.replace_with_irrelevant();

src/test/ui/imports/import-prefix-macro-1.stderr

@@ -2,7 +2,7 @@ error: expected one of `::`, `;`, or `as`, found `{`
   --> $DIR/import-prefix-macro-1.rs:11:27
    |
 LL |     ($p: path) => (use $p {S, Z});
-   |                           ^ expected one of `::`, `;`, or `as` here
+   |                           ^^^^^^ expected one of `::`, `;`, or `as` here
 ...
 LL | import! { a::b::c }
    | ------------------- in this macro invocation

src/test/ui/issues/issue-39848.stderr

@@ -2,7 +2,7 @@ error: expected `{`, found `foo`
   --> $DIR/issue-39848.rs:8:19
    |
 LL |         if $tgt.has_$field() {}
-   |         --                 - help: try placing this code inside a block: `{ ) }`
+   |         --                -- help: try placing this code inside a block: `{ () }`
    |         |
    |         this `if` statement has a condition, but no block
 ...

src/test/ui/parser/issue-62973.stderr

@@ -34,13 +34,13 @@ LL | )
    |
 
 error: expected one of `.`, `?`, `{`, or an operator, found `}`
-  --> $DIR/issue-62973.rs:8:1
+  --> $DIR/issue-62973.rs:8:2
    |
 LL | fn p() { match s { v, E { [) {) }
    |          ----- while parsing this match expression
 LL | 
 LL | 
-   | ^ expected one of `.`, `?`, `{`, or an operator here
+   |  ^ expected one of `.`, `?`, `{`, or an operator here
 
 error: incorrect close delimiter: `)`
   --> $DIR/issue-62973.rs:6:28

src/test/ui/parser/issue-63135.stderr

@@ -23,16 +23,16 @@ LL | fn i(n{...,f #
    |        `..` must be at the end and cannot have a trailing comma
 
 error: expected `[`, found `}`
-  --> $DIR/issue-63135.rs:3:15
+  --> $DIR/issue-63135.rs:3:16
    |
 LL | fn i(n{...,f #
-   |               ^ expected `[`
+   |                ^ expected `[`
 
 error: expected one of `:` or `|`, found `)`
-  --> $DIR/issue-63135.rs:3:15
+  --> $DIR/issue-63135.rs:3:16
    |
 LL | fn i(n{...,f #
-   |               ^ expected one of `:` or `|` here
+   |                ^ expected one of `:` or `|` here
 
 error: aborting due to 5 previous errors
 

src/test/ui/parser/macro/macro-doc-comments-2.stderr

@@ -5,7 +5,7 @@ LL | macro_rules! inner {
    | ------------------ when calling this macro
 ...
 LL |     /// Outer
-   |     ^ no rules expected this token in macro call
+   |     ^^^^^^^^^ no rules expected this token in macro call
 
 error: aborting due to previous error
 

src/test/ui/parser/missing_right_paren.rs

@@ -0,0 +1,3 @@
+// ignore-tidy-trailing-newlines
+// error-pattern: aborting due to 2 previous errors
+fn main((ؼ