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

11 files changed, 46 insertions, 46 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)
     }
 }
 
diff --git a/src/libsyntax_expand/mbe.rs b/src/libsyntax_expand/mbe.rs
index d0f790638ef..06e0cde3ad8 100644
--- a/src/libsyntax_expand/mbe.rs
+++ b/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()
             }
diff --git a/src/libsyntax_expand/mbe/macro_rules.rs b/src/libsyntax_expand/mbe/macro_rules.rs
index 9a4130b2d8d..bfdc4c52b5a 100644
--- a/src/libsyntax_expand/mbe/macro_rules.rs
+++ b/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();
diff --git a/src/test/ui/imports/import-prefix-macro-1.stderr b/src/test/ui/imports/import-prefix-macro-1.stderr
index 577f1282471..862a31b4465 100644
--- a/src/test/ui/imports/import-prefix-macro-1.stderr
+++ b/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
diff --git a/src/test/ui/issues/issue-39848.stderr b/src/test/ui/issues/issue-39848.stderr
index fa87967432d..47aa8e17a30 100644
--- a/src/test/ui/issues/issue-39848.stderr
+++ b/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
 ...
diff --git a/src/test/ui/parser/issue-62973.stderr b/src/test/ui/parser/issue-62973.stderr
index 82122ef0b6f..f935d58c646 100644
--- a/src/test/ui/parser/issue-62973.stderr
+++ b/src/test/ui/parser/issue-62973.stderr
@@ -36,13 +36,13 @@ 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
diff --git a/src/test/ui/parser/issue-63135.stderr b/src/test/ui/parser/issue-63135.stderr
index a077ad454a9..8e8087978a3 100644
--- a/src/test/ui/parser/issue-63135.stderr
+++ b/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
 
diff --git a/src/test/ui/parser/macro/macro-doc-comments-2.stderr b/src/test/ui/parser/macro/macro-doc-comments-2.stderr
index 6abe95192be..023d1a3e039 100644
--- a/src/test/ui/parser/macro/macro-doc-comments-2.stderr
+++ b/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
 
diff --git a/src/test/ui/parser/missing_right_paren.rs b/src/test/ui/parser/missing_right_paren.rs
new file mode 100644
index 00000000000..4f7c5eea1d1
--- /dev/null
+++ b/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
\ No newline at end of file
diff --git a/src/test/ui/parser/missing_right_paren.stderr b/src/test/ui/parser/missing_right_paren.stderr
new file mode 100644
index 00000000000..fc75b031e76
--- /dev/null
+++ b/src/test/ui/parser/missing_right_paren.stderr
@@ -0,0 +1,17 @@
+error: this file contains an un-closed delimiter
+  --> $DIR/missing_right_paren.rs:3:11
+   |
+LL | fn main((ؼ
+   |        -- ^
+   |        ||
+   |        |un-closed delimiter
+   |        un-closed delimiter
+
+error: expected one of `:` or `|`, found `)`
+  --> $DIR/missing_right_paren.rs:3:11
+   |
+LL | fn main((ؼ
+   |           ^ expected one of `:` or `|` here
+
+error: aborting due to 2 previous errors
+