Clean up location handling, which wsa kind of a pain.

src/syntax/tokens.rs

@@ -2,6 +2,7 @@ use internment::ArcIntern;
 use logos::{Lexer, Logos};
 use std::fmt;
 use std::num::ParseIntError;
+use thiserror::Error;
 
 #[derive(Logos, Clone, Debug, PartialEq, Eq)]
 pub enum Token {
@@ -54,6 +55,12 @@ impl fmt::Display for Token {
     }
 }
 
+#[derive(Debug, Error, PartialEq, Eq)]
+pub enum LexerError {
+    #[error("Failed lexing at {0}")]
+    LexFailure(usize),
+}
+
 #[cfg(test)]
 impl Token {
     pub(crate) fn var(s: &str) -> Token {