fix: fix a few cases where safety comment wasn't correctly identified

compiler/noirc_frontend/src/parser/parser.rs

@@ -208,6 +208,9 @@ impl<'a> Parser<'a> {
             match self.tokens.next() {
                 Some(Ok(token)) => match token.token() {
                     Token::LineComment(comment, None) | Token::BlockComment(comment, None) => {
+                        if !last_comments.is_empty() {
+                            last_comments.push('\n');
+                        }
                         last_comments.push_str(comment);
                         continue;
                     }

compiler/noirc_frontend/src/parser/parser/expression.rs

@@ -388,20 +388,23 @@
     /// UnsafeExpression = 'unsafe' Block
     fn parse_unsafe_expr(&mut self) -> Option<ExpressionKind> {
         let start_location = self.current_token_location;
+        let comments_before_unsafe = self.current_token_comments.clone();
 
         if !self.eat_keyword(Keyword::Unsafe) {
             return None;
         }
 
-        if self.current_token_comments.is_empty() {
-            if let Some(statement_comments) = &mut self.statement_comments {
-                if !statement_comments.trim().to_lowercase().starts_with("safety:") {
-                    self.push_error(ParserErrorReason::MissingSafetyComment, start_location);
-                }
+        let comments: &str = if comments_before_unsafe.is_empty() {
+            if let Some(statement_comments) = &self.statement_comments {
+                statement_comments
             } else {
-                self.push_error(ParserErrorReason::MissingSafetyComment, start_location);
+                ""
             }
-        } else if !self.current_token_comments.trim().to_lowercase().starts_with("safety:") {
+        } else {
+            &comments_before_unsafe
+        };
+
+        if !comments.lines().any(|line| line.trim().to_lowercase().starts_with("safety:")) {
             self.push_error(ParserErrorReason::MissingSafetyComment, start_location);
         }
 
@@ -626,7 +629,7 @@
     ///     = bool
     ///     | int
     ///     | str
     ///     | rawstr
     ///     | fmtstr
     ///     | QuoteExpression
     ///     | ArrayExpression
@@ -1079,7 +1082,9 @@
         let src = "
         // Safety: test
         unsafe { 1 }";
-        let expr = parse_expression_no_errors(src);
+        let mut parser = Parser::for_str_with_dummy_file(src);
+        let expr = parser.parse_expression_or_error();
+        assert!(parser.errors.is_empty());
         let ExpressionKind::Unsafe(unsafe_expression) = expr.kind else {
             panic!("Expected unsafe expression");
         };

compiler/noirc_frontend/src/parser/parser/statement.rs

@@ -521,7 +521,9 @@ mod tests {
     fn parses_let_statement_with_unsafe() {
         let src = "// Safety: comment
         let x = unsafe { 1 };";
-        let statement = parse_statement_no_errors(src);
+        let mut parser = Parser::for_str_with_dummy_file(src);
+        let statement = parser.parse_statement_or_error();
+        assert!(parser.errors.is_empty());
         let StatementKind::Let(let_statement) = statement.kind else {
             panic!("Expected let statement");
         };
@@ -540,6 +542,20 @@ mod tests {
         assert_eq!(let_statement.pattern.to_string(), "x");
     }
 
+    #[test]
+    fn parses_let_statement_with_unsafe_after_some_other_comment() {
+        let src = "// Top comment
+        // Safety: comment
+        let x = unsafe { 1 };";
+        let mut parser = Parser::for_str_with_dummy_file(src);
+        let statement = parser.parse_statement_or_error();
+        assert!(parser.errors.is_empty());
+        let StatementKind::Let(let_statement) = statement.kind else {
+            panic!("Expected let statement");
+        };
+        assert_eq!(let_statement.pattern.to_string(), "x");
+    }
+
     #[test]
     fn parses_comptime_block() {
         let src = "comptime { 1 }";