commit fe89fccd0b6965593adc1b1ea3c14e77e808771a
author David Tolnay <dtolnay@gmail.com> Sat Sep 08 17:56:31 2018 -0700
committer David Tolnay <dtolnay@gmail.com> Sat Jan 05 13:33:54 2019 -0800
tree 82d5f57499107c5d8d76431a3541352d3e29d041
parent 9015b4128859163ffa77cc780b40be753226abb7

Use Group::span_open and span_close in error spans

Macro 1:

    input.parse::<Ident>()?;

Before:

    error: expected identifier
     --> src/main.rs:3:4
      |
    3 | m!([a]);
      |    ^^^

After:

    error: expected identifier
     --> src/main.rs:3:4
      |
    3 | m!([a]);
      |    ^

Macro 2:

    let content;
    bracketed!(content in input);
    content.parse::<Ident>()?;
    content.parse::<Ident>()?;

Before:

    error: unexpected end of input, expected identifier
     --> src/main.rs:3:4
      |
    3 | m!([a]);
      |    ^^^

After:

    error: unexpected end of input, expected identifier
     --> src/main.rs:3:6
      |
    3 | m!([a]);
      |      ^

src/buffer.rs

diff --git a/src/buffer.rs b/src/buffer.rs
index 1d0ffe0..8c32645 100644
--- a/src/buffer.rs
+++ b/src/buffer.rs
@@ -17,6 +17,7 @@
 use std::marker::PhantomData;
 use std::ptr;
 
+use private;
 use Lifetime;
 
 /// Internal type which is used instead of `TokenTree` to represent a token tree
@@ -345,3 +346,21 @@
         }
     }
 }
+
+impl private {
+    #[cfg(procmacro2_semver_exempt)]
+    pub fn open_span_of_group(cursor: Cursor) -> Span {
+        match *cursor.entry() {
+            Entry::Group(ref group, _) => group.span_open(),
+            _ => cursor.span(),
+        }
+    }
+
+    #[cfg(procmacro2_semver_exempt)]
+    pub fn close_span_of_group(cursor: Cursor) -> Span {
+        match *cursor.entry() {
+            Entry::Group(ref group, _) => group.span_close(),
+            _ => cursor.span(),
+        }
+    }
+}

src/error.rs

diff --git a/src/error.rs b/src/error.rs
index 6a1a200..e07051d 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -10,6 +10,8 @@
 
 #[cfg(feature = "parsing")]
 use buffer::Cursor;
+#[cfg(all(procmacro2_semver_exempt, feature = "parsing"))]
+use private;
 use thread::ThreadBound;
 
 /// The result of a Syn parser.
@@ -171,7 +173,11 @@
     if cursor.eof() {
         Error::new(scope, format!("unexpected end of input, {}", message))
     } else {
-        Error::new(cursor.span(), message)
+        #[cfg(procmacro2_semver_exempt)]
+        let span = private::open_span_of_group(cursor);
+        #[cfg(not(procmacro2_semver_exempt))]
+        let span = cursor.span();
+        Error::new(span, message)
     }
 }
 

src/group.rs

diff --git a/src/group.rs b/src/group.rs
index 7a6556c..272e435 100644
--- a/src/group.rs
+++ b/src/group.rs
@@ -74,9 +74,13 @@
 fn parse_delimited(input: ParseStream, delimiter: Delimiter) -> Result<(Span, ParseBuffer)> {
     input.step(|cursor| {
         if let Some((content, span, rest)) = cursor.group(delimiter) {
-            let unexpected = private::get_unexpected(input);
+            #[cfg(procmacro2_semver_exempt)]
+            let scope = private::close_span_of_group(*cursor);
+            #[cfg(not(procmacro2_semver_exempt))]
+            let scope = span;
             let nested = private::advance_step_cursor(cursor, content);
-            let content = private::new_parse_buffer(span, nested, unexpected);
+            let unexpected = private::get_unexpected(input);
+            let content = private::new_parse_buffer(scope, nested, unexpected);
             Ok(((span, content), rest))
         } else {
             let message = match delimiter {