diff --git a/Cargo.lock b/Cargo.lock
index 1a740aa..146214e 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -67,12 +67,12 @@ checksum = "f538837af36e6f6a9be0faa67f9a314f8119e4e4b5867c6ab40ed60360142519"
 
 [[package]]
 name = "ariadne"
-version = "0.4.0"
+version = "0.4.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dd002a6223f12c7a95cdd4b1cb3a0149d22d37f7a9ecdb2cb691a071fe236c29"
+checksum = "44055e597c674aef7cb903b2b9f6e4cba1277ed0d2d61dae7cd52d7ffa81f8e2"
 dependencies = [
  "unicode-width",
- "yansi",
+ "yansi 1.0.1",
 ]
 
 [[package]]
@@ -476,7 +476,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "af7cee1a6c8a5b9208b3cb1061f10c0cb689087b3d8ce85fb9d2dd7a29b6ba66"
 dependencies = [
  "diff",
- "yansi",
+ "yansi 0.5.1",
 ]
 
 [[package]]
@@ -931,3 +931,9 @@ name = "yansi"
 version = "0.5.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "09041cd90cf85f7f8b2df60c646f853b7f535ce68f85244eb6731cf89fa498ec"
+
+[[package]]
+name = "yansi"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cfe53a6657fd280eaa890a3bc59152892ffa3e30101319d168b781ed6529b049"
diff --git a/Cargo.toml b/Cargo.toml
index c83d575..e97d00a 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -20,7 +20,7 @@ harness = false
 
 [dependencies]
 anyhow = "1.0"
-ariadne = "0.4"
+ariadne = "0.4.1"
 base64 = "0.22"
 blake3 = "1.5"
 cargo_metadata = "0.18"
diff --git a/src/diagnostic.rs b/src/diagnostic.rs
index fa8bc52..ba16f48 100644
--- a/src/diagnostic.rs
+++ b/src/diagnostic.rs
@@ -3,6 +3,10 @@ use std::{io, ops::Range};
 
 pub type Span = Range<usize>;
 
+fn config() -> ariadne::Config {
+	ariadne::Config::default().with_index_type(ariadne::IndexType::Byte)
+}
+
 pub struct Diagnostic {
 	filename: String,
 	code: String,
@@ -41,7 +45,7 @@ impl Diagnostic {
 			.code
 			.split('\n')
 			.take(at.line - 1)
-			.map(|line| line.chars().count() + 1)
+			.map(|line| line.len() + 1)
 			.sum();
 		line_offset + at.column
 	}
@@ -57,6 +61,7 @@ impl Diagnostic {
 				self.filename.clone(),
 				0
 			)
+			.with_config(config())
 			.with_message(msg)
 			.finish()
 		);
@@ -69,6 +74,7 @@ impl Diagnostic {
 	{
 		self.reports.push(
 			Report::build(ReportKind::Warning, self.filename.clone(), 0)
+				.with_config(config())
 				.with_message(msg)
 				.finish()
 		);
@@ -83,6 +89,7 @@ impl Diagnostic {
 		let span = self.offset(span.start()) .. self.offset(span.end());
 		self.reports.push(
 			Report::build(ReportKind::Warning, self.filename.clone(), span.start)
+				.with_config(config())
 				.with_message(msg)
 				.with_label(Label::new((self.filename.clone(), span)).with_message(label))
 				.finish()
@@ -94,6 +101,7 @@ impl Diagnostic {
 		let span = self.offset(span.start()) .. self.offset(span.end());
 		self.reports.push(
 			Report::build(ReportKind::Warning, self.filename.clone(), span.start)
+			.with_config(config())
 			.with_message("Macro not expanded")
 			.with_label(Label::new((self.filename.clone(), span)).with_message("This macro was not expanded"))
 			.with_help("You can use `--expand-macros` on a nightly Rust toolchain to expand macros.")
@@ -107,7 +115,8 @@ impl Diagnostic {
 			ReportKind::Error,
 			self.filename.clone(),
 			self.offset(err.span().start())
-		);
+		)
+		.with_config(config());
 		report.set_message("Syntax Error");
 		for err in err {
 			let span = err.span();
@@ -130,6 +139,7 @@ impl Diagnostic {
 	{
 		self.reports.push(
 			Report::build(ReportKind::Error, self.filename.clone(), 0)
+				.with_config(config())
 				.with_message(msg)
 				.finish()
 		);