1 files changed, 34 insertions, 0 deletions
diff --git a/src/diagnostics/html_tag.rs b/src/diagnostics/html_tag.rs
new file mode 100644
index 0000000..8cf7eb0
--- /dev/null
+++ b/src/diagnostics/html_tag.rs
@@ -0,0 +1,34 @@
+use miette::Diagnostic;
+use thiserror::Error;
+
+use crate::{
+	diagnostics::AstDiagnostic,
+	tokenize::{Span, TokenType},
+};
+
+#[derive(Error, Debug, Diagnostic)]
+#[error("html tags is not allowed in kuht")]
+#[diagnostic(code(HtmlTag), severity(Error))]
+pub struct HtmlTag {
+	#[label(primary, "invalid html tag")]
+	tag: Span,
+}
+
+impl AstDiagnostic for HtmlTag {
+	fn handle_element(element: &crate::parse::Element<'_>) -> Option<Self> {
+		let TokenType::Tag {
+			lowercase_tag_name, ..
+		} = element.start_tag.ty
+		else {
+			return None;
+		};
+
+		if lowercase_tag_name != "html" {
+			return None;
+		}
+
+		Some(Self {
+			tag: element.start_tag.span,
+		})
+	}
+}