1 files changed, 35 insertions, 0 deletions
diff --git a/src/diagnostics/too_many_equal_signs.rs b/src/diagnostics/too_many_equal_signs.rs
new file mode 100644
index 0000000..b20cb83
--- /dev/null
+++ b/src/diagnostics/too_many_equal_signs.rs
@@ -0,0 +1,35 @@
+use miette::Diagnostic;
+use thiserror::Error;
+
+use crate::{diagnostics::AstDiagnostic, parse::Attribute, tokenize::Span};
+
+#[derive(Error, Debug, Diagnostic)]
+#[error("Multiple equal signs in a row")]
+#[diagnostic(code(TooManyEqualSigns), severity(Error))]
+pub struct TooManyEqualSigns {
+	#[label(primary, "only one equal sign should be present")]
+	token: Span,
+}
+
+impl AstDiagnostic for TooManyEqualSigns {
+	fn handle_attribute(attribute: &crate::parse::Attribute<'_>) -> Option<Self> {
+		let Attribute::NamedArgumentWithTooManyEqualSigns { equal_signs, .. } = attribute else {
+			return None;
+		};
+
+		Some(Self {
+			token: Span {
+				start: equal_signs
+					.first()
+					.expect("at least two equal signs")
+					.span
+					.start,
+				end: equal_signs
+					.last()
+					.expect("at least two equal signs")
+					.span
+					.end,
+			},
+		})
+	}
+}