From 68375371a5fde6ee14f190c14e9a9cee0697f022 Mon Sep 17 00:00:00 2001
From: Joshua Barretto <joshua@jsbarretto.com>
Date: Wed, 28 Feb 2024 16:34:00 +0000
Subject: [PATCH] Attempted to fix labelling, added labelling test

---
 src/error.rs | 20 +++++++++++++++++++-
 src/label.rs |  2 +-
 src/lib.rs   | 26 ++++++++++++++++++++++++++
 3 files changed, 46 insertions(+), 2 deletions(-)

diff --git a/src/error.rs b/src/error.rs
index 7db01c7f..6892229b 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -426,6 +426,7 @@ impl<'a, T, L> RichReason<'a, T, L> {
         mut fmt_span: impl FnMut(&S, &mut fmt::Formatter<'_>) -> fmt::Result,
         mut fmt_label: impl FnMut(&L, &mut fmt::Formatter<'_>) -> fmt::Result,
         span: Option<&S>,
+        #[cfg(feature = "label")] context: &[(L, S)],
     ) -> fmt::Result {
         match self {
             RichReason::ExpectedFound { expected, found } => {
@@ -467,6 +468,13 @@ impl<'a, T, L> RichReason<'a, T, L> {
                 }
             }
         }
+        #[cfg(feature = "label")]
+        for (l, s) in context {
+            write!(f, " in ")?;
+            fmt_label(l, f)?;
+            write!(f, " at ")?;
+            fmt_span(s, f)?;
+        }
         Ok(())
     }
 }
@@ -526,7 +534,15 @@ where
     L: fmt::Display,
 {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        self.inner_fmt(f, T::fmt, |_: &(), _| Ok(()), L::fmt, None)
+        self.inner_fmt(
+            f,
+            T::fmt,
+            |_: &(), _| Ok(()),
+            L::fmt,
+            None,
+            #[cfg(feature = "label")]
+            &[],
+        )
     }
 }
 
@@ -557,6 +573,8 @@ impl<'a, T, S, L> Rich<'a, T, S, L> {
             fmt_span,
             fmt_label,
             if with_spans { Some(&self.span) } else { None },
+            #[cfg(feature = "label")]
+            &self.context,
         )
     }
 }
diff --git a/src/label.rs b/src/label.rs
index d0879bfc..4ba4d351 100644
--- a/src/label.rs
+++ b/src/label.rs
@@ -57,7 +57,7 @@ where
         inp.errors.alt = old_alt;
 
         if let Some(mut new_alt) = new_alt {
-            let before_next = before.offset.into() + 1;
+            let before_next = before.offset.into();
             if new_alt.pos.into() == before_next {
                 new_alt.err.label_with(self.label.clone());
             } else if self.is_context && new_alt.pos.into() > before_next {
diff --git a/src/lib.rs b/src/lib.rs
index 8abbe30a..8ebb8bf5 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -3518,4 +3518,30 @@ mod tests {
             todo().map_with(|expr, e| (expr, e.span()))
         }
     }
+
+    #[cfg(feature = "label")]
+    #[test]
+    fn label() {
+        use crate::label::LabelError;
+
+        fn parser<'src>() -> impl Parser<'src, &'src str, (), extra::Err<Rich<'src, char>>> {
+            just("hello").labelled("greeting").as_context().ignored()
+        }
+
+        let mut err = <Rich<_> as crate::Error<&str>>::expected_found(
+            Some(Some('h'.into())),
+            Some('g'.into()),
+            (0..1).into(),
+        );
+        <Rich<_, _, _> as LabelError<&str, _>>::label_with(&mut err, "greeting");
+        assert_eq!(parser().parse("goodbye").into_errors(), vec![err]);
+
+        let mut err = <Rich<_> as crate::Error<&str>>::expected_found(
+            Some(Some('l'.into())),
+            Some('p'.into()),
+            (3..4).into(),
+        );
+        <Rich<_, _, _> as LabelError<&str, _>>::in_context(&mut err, "greeting", (0..3).into());
+        assert_eq!(parser().parse("help").into_errors(), vec![err]);
+    }
 }