3 files changed, 24 insertions, 7 deletions
diff --git a/src/tokenizer/error.rs b/src/tokenizer/error.rs
index 0acc88f..dad3fd2 100644
--- a/src/tokenizer/error.rs
+++ b/src/tokenizer/error.rs
@@ -6,7 +6,12 @@ use std::fmt::Display;
 pub enum Error {
     AttributesOnEndTag,
     SelfClosingEndTag,
-    DuplicateAttribute,
+    DuplicateAttribute {
+        #[cfg(feature = "spans")]
+        #[cfg_attr(docsrs, doc(cfg(feature = "spans")))]
+        /// Span of the duplicate attribute name.
+        span: std::ops::Range<usize>,
+    },
     BadCharacter(char),
     UnexpectedCharacter(char, InternalState),
     UnexpectedEOF(InternalState),
@@ -22,7 +27,7 @@ impl Display for Error {
         match self {
             Error::AttributesOnEndTag => write!(f, "attributes on an end tag"),
             Error::SelfClosingEndTag => write!(f, "self-closing end tag"),
-            Error::DuplicateAttribute => write!(f, "duplicate attribute"),
+            Error::DuplicateAttribute { .. } => write!(f, "duplicate attribute"),
             Error::BadCharacter(char) => write!(f, "bad character {:?}", char),
             Error::UnexpectedCharacter(char, state) => {
                 write!(
diff --git a/src/tokenizer/interface.rs b/src/tokenizer/interface.rs
index 715f9bc..128807e 100644
--- a/src/tokenizer/interface.rs
+++ b/src/tokenizer/interface.rs
@@ -112,7 +112,12 @@ pub enum Token {
     CharacterTokens(String),
     NullCharacterToken,
     EOFToken,
-    ParseError(Error),
+    ParseError {
+        error: Error,
+        #[cfg(feature = "spans")]
+        #[cfg_attr(docsrs, doc(cfg(feature = "spans")))]
+        span: std::ops::Range<usize>,
+    },
 }
 
 #[derive(Debug, PartialEq)]
diff --git a/src/tokenizer/mod.rs b/src/tokenizer/mod.rs
index 6793eb2..1809275 100644
--- a/src/tokenizer/mod.rs
+++ b/src/tokenizer/mod.rs
@@ -538,7 +538,10 @@ impl<Sink: TokenSink> Tokenizer<Sink> {
         };
 
         if dup {
-            self.emit_error(Error::DuplicateAttribute);
+            self.emit_error(Error::DuplicateAttribute {
+                #[cfg(feature = "spans")]
+                span: self.spans.current_attr_name.clone(),
+            });
             self.current_attr_name.clear();
             self.current_attr_value.clear();
         } else {
@@ -598,7 +601,11 @@ impl<Sink: TokenSink> Tokenizer<Sink> {
     }
 
     fn emit_error(&mut self, error: Error) {
-        self.process_token_and_continue(ParseError(error));
+        self.process_token_and_continue(ParseError {
+            error,
+            #[cfg(feature = "spans")]
+            span: self.spans.current_pos - 1..self.spans.current_pos - 1,
+        });
     }
 }
 //§ END
@@ -2293,7 +2300,7 @@ mod test {
                     self.current_str.push('\0');
                 }
 
-                token @ ParseError(_) => {
+                token @ ParseError { .. } => {
                     self.push(token, line_number);
                 }
 
@@ -2453,7 +2460,7 @@ mod test {
                 (3, CharacterTokens(c1)),
                 (
                     3,
-                    ParseError(Error::CharRef(CharRefError::InvalidNamedCharRef)),
+                    ParseError{error: Error::CharRef(CharRefError::InvalidNamedCharRef), ..},
                 ),
                 (4, CharacterTokens(c2)),
             ] if c1 == "&\n" && c2 == "&aamp;\n"