introduce is_grammar_error in Diagnostic

to be able to know which diagnostics should also be emitted by the reference grammar

components/dada-ir/src/diagnostic.rs

@@ -13,6 +13,9 @@ pub struct ErrorReported;
 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
 #[non_exhaustive]
 pub struct Diagnostic {
+    /// This is only used for testing the reference grammar.
+    /// If it's true it means that the reference grammar should also emit an error.
+    pub is_grammar_error: bool,
     pub severity: Severity,
     pub span: FileSpan,
     pub message: String,
@@ -54,6 +57,15 @@ macro_rules! error {
     }
 }
 
+/// Convenience macro for avoiding `format!`
+/// Use this when the error should also be emitted by the reference grammar
+#[macro_export]
+macro_rules! grammar_error {
+    ($span:expr, $($message:tt)*) => {
+        $crate::diagnostic::Diagnostic::builder($crate::diagnostic::Severity::Error, $span, format!($($message)*)).is_grammar_error()
+    }
+}
+
 /// Convenience macro for avoiding `format!`
 #[macro_export]
 macro_rules! warning {
@@ -119,6 +131,8 @@ pub struct DiagnosticBuilder {
     /// label ("here") when the diagnostic is emitted. Set to false
     /// if user adds an explicit primary label or calls [`Self::skip_primary_label`].
     add_primary_label: bool,
+
+    is_grammar_error: bool,
 }
 
 impl DiagnosticBuilder {
@@ -130,9 +144,16 @@ impl DiagnosticBuilder {
             labels: vec![],
             children: vec![],
             add_primary_label: true,
+            is_grammar_error: false,
         }
     }
 
+    #[must_use = "you have not emitted the diagnostic"]
+    pub fn is_grammar_error(mut self) -> Self {
+        self.is_grammar_error = true;
+        self
+    }
+
     /// Replaces the "primary label", which is always placed on the source
     /// of the diagnostic. The default primary label, if nothing else is given,
     /// is just "here".
@@ -186,6 +207,7 @@ impl DiagnosticBuilder {
         }
 
         Diagnostic {
+            is_grammar_error: self.is_grammar_error,
             severity: self.severity,
             span: self.span,
             message: self.message,

components/dada-lex/src/lex.rs

@@ -216,7 +216,7 @@ where
                             .map(|pair| pair.0)
                             .unwrap_or(self.file_len),
                     );
-                    dada_ir::error!(
+                    dada_ir::grammar_error!(
                         Span {
                             start: ch_offset,
                             end,

components/dada-parse/src/parser.rs

@@ -198,7 +198,7 @@ impl<'me> Parser<'me> {
     }
 
     fn error(&self, span: Span, message: impl ToString) -> DiagnosticBuilder {
-        dada_ir::error!(span.in_file(self.input_file), "{}", message.to_string())
+        dada_ir::grammar_error!(span.in_file(self.input_file), "{}", message.to_string())
     }
 }
 

components/dada-parse/src/parser/items.rs

@@ -32,7 +32,8 @@ impl<'db> Parser<'db> {
             } else {
                 let span = self.tokens.last_span();
                 self.tokens.consume();
-                dada_ir::error!(span.in_file(self.input_file), "unexpected token").emit(self.db);
+                dada_ir::grammar_error!(span.in_file(self.input_file), "unexpected token")
+                    .emit(self.db);
             }
         }