From 57c9e17e84cbdad35cc3420306d59f6cc3f4c98c Mon Sep 17 00:00:00 2001
From: Robert Zakrzewski <robert.zakrzewski1@stellantis.com>
Date: Tue, 3 Dec 2024 15:32:06 +0100
Subject: [PATCH] Improve error when a keyword is used as identifier

---
 src/error.rs        |  3 +++
 src/parser/mod.rs   | 16 ++++++++++++++++
 src/parser/types.rs |  7 +++++++
 3 files changed, 26 insertions(+)

diff --git a/src/error.rs b/src/error.rs
index b6ec94e24..a4542e4a2 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -104,6 +104,9 @@ pub enum ErrorKind {
     #[error("invalid token, expected: {0}")]
     ExpectedToken(TokenKind),
 
+    #[error("invalid token, unexpected keyword: {0}, expected: {1}")]
+    ExpectedTokenNotKeyword(String, TokenKind),
+
     #[error("invalid path: {0}")]
     InvalidPath(&'static str),
 
diff --git a/src/parser/mod.rs b/src/parser/mod.rs
index 3f09d2da0..e69ee0ee3 100644
--- a/src/parser/mod.rs
+++ b/src/parser/mod.rs
@@ -238,4 +238,20 @@ mod tests {
         let parsed = Stmt::parse(ctx, tokens).unwrap();
         println!("{:?}", parsed);
     }
+
+    #[test]
+    fn expected_token_not_keyword_as_identifier() {
+        let code = r#"Foo { pub: Field }"#;
+        let tokens = &mut Token::parse(0, code).unwrap();
+        let ctx = &mut ParserCtx::default();
+        let parsed = StructDef::parse(ctx, tokens);
+        assert!(parsed.is_err());
+        assert!(parsed.as_ref().err().is_some());
+        match &parsed.as_ref().err().unwrap().kind {
+            ErrorKind::ExpectedTokenNotKeyword(keyword, _) => {
+                assert_eq!(keyword, "pub");
+            }
+            _ => panic!("expected error: ExpectedTokenNotKeyword"),
+        }
+    }
 }
diff --git a/src/parser/types.rs b/src/parser/types.rs
index a68a3c566..4b79db677 100644
--- a/src/parser/types.rs
+++ b/src/parser/types.rs
@@ -674,6 +674,13 @@ impl Ident {
                 value: ident,
                 span: token.span,
             }),
+            TokenKind::Keyword(keyword) => Err(ctx.error(
+                ErrorKind::ExpectedTokenNotKeyword(
+                    keyword.to_string(),
+                    TokenKind::Identifier("".to_string()),
+                ),
+                token.span,
+            )),
 
             _ => Err(ctx.error(
                 ErrorKind::ExpectedToken(TokenKind::Identifier("".to_string())),