chore: fix lexer errors for unexpected characters (#1955)

fix lexer errors for unexpected characters and attribute parsing
noir-lang · Jul 18, 2023 · f62ace9 · f62ace9
1 parent 211e251
commit f62ace9
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Showing 2 changed files with 22 additions and 9 deletions.
diff --git a/crates/noirc_frontend/src/lexer/errors.rs b/crates/noirc_frontend/src/lexer/errors.rs
@@ -8,7 +8,7 @@ use thiserror::Error;
 #[derive(Error, Clone, Debug, PartialEq, Eq)]
 pub enum LexerErrorKind {
     #[error("An unexpected character {:?} was found.", found)]
-    UnexpectedCharacter { span: Span, expected: String, found: char },
+    UnexpectedCharacter { span: Span, expected: String, found: Option<char> },
     #[error("NotADoubleChar : {:?} is not a double char token", found)]
     NotADoubleChar { span: Span, found: Token },
     #[error("InvalidIntegerLiteral : {:?} is not a integer", found)]
@@ -39,11 +39,15 @@ impl LexerErrorKind {
                 span,
                 expected,
                 found,
-            } => (
-                "an unexpected character was found".to_string(),
-                format!(" expected {expected} , but got {found}"),
-                *span,
-            ),
+            } => {
+                let found: String = found.map(Into::into).unwrap_or_else(|| "<eof>".into());
+
+                (
+                    "an unexpected character was found".to_string(),
+                    format!(" expected {expected} , but got {}", found),
+                    *span,
+                )
+            },
             LexerErrorKind::NotADoubleChar { span, found } => (
                 format!("tried to parse {found} as double char"),
                 format!(

diff --git a/crates/noirc_frontend/src/lexer/lexer.rs b/crates/noirc_frontend/src/lexer/lexer.rs
@@ -244,7 +244,7 @@ impl<'a> Lexer<'a> {
             '0'..='9' => self.eat_digit(initial_char),
             _ => Err(LexerErrorKind::UnexpectedCharacter {
                 span: Span::single_char(self.position),
-                found: initial_char,
+                found: initial_char.into(),
                 expected: "an alpha numeric character".to_owned(),
             }),
         }
@@ -254,7 +254,7 @@ impl<'a> Lexer<'a> {
         if !self.peek_char_is('[') {
             return Err(LexerErrorKind::UnexpectedCharacter {
                 span: Span::single_char(self.position),
-                found: self.next_char().unwrap(),
+                found: self.next_char(),
                 expected: "[".to_owned(),
             });
         }
@@ -269,7 +269,7 @@ impl<'a> Lexer<'a> {
             return Err(LexerErrorKind::UnexpectedCharacter {
                 span: Span::single_char(self.position),
                 expected: "]".to_owned(),
-                found: self.next_char().unwrap(),
+                found: self.next_char(),
             });
         }
         self.next_char();
@@ -427,6 +427,15 @@ fn test_single_double_char() {
     }
 }
 
+#[test]
+fn invalid_attribute() {
+    let input = "#";
+    let mut lexer = Lexer::new(input);
+
+    let token = lexer.next().unwrap();
+    assert!(token.is_err());
+}
+
 #[test]
 fn test_custom_gate_syntax() {
     let input = "#[foreign(sha256)]#[foreign(blake2s)]#[builtin(sum)]";