Differentiate between default errors for at-rule parsing.

Author: jdm

src/parser.rs

@@ -30,7 +30,9 @@ pub enum BasicParseError<'a> {
     /// The end of the input was encountered unexpectedly.
     EndOfInput,
     /// An `@` rule was encountered that was invalid.
-    AtRuleInvalid,
+    AtRuleInvalid(CompactCowStr<'a>),
+    /// The body of an '@' rule was invalid.
+    AtRuleBodyInvalid,
     /// A qualified rule was encountered that was invalid.
     QualifiedRuleInvalid,
 }

src/rules_and_declarations.rs

@@ -116,7 +116,7 @@ pub trait AtRuleParser<'i> {
                      -> Result<AtRuleType<Self::Prelude, Self::AtRule>, ParseError<'i, Self::Error>> {
         let _ = name;
         let _ = input;
-        Err(ParseError::Basic(BasicParseError::AtRuleInvalid))
+        Err(ParseError::Basic(BasicParseError::AtRuleInvalid(name)))
     }
 
     /// Parse the content of a `{ /* ... */ }` block for the body of the at-rule.
@@ -131,7 +131,7 @@ pub trait AtRuleParser<'i> {
                        -> Result<Self::AtRule, ParseError<'i, Self::Error>> {
         let _ = prelude;
         let _ = input;
-        Err(ParseError::Basic(BasicParseError::AtRuleInvalid))
+        Err(ParseError::Basic(BasicParseError::AtRuleBodyInvalid))
     }
 
     /// An `OptionalBlock` prelude was followed by `;`.