diff --git a/compiler/erg_parser/parse.rs b/compiler/erg_parser/parse.rs
index 7b882630..454254ce 100644
--- a/compiler/erg_parser/parse.rs
+++ b/compiler/erg_parser/parse.rs
@@ -291,7 +291,12 @@ impl Parser {
             self.level -= 1;
             return Ok(block);
         }
-        assert!(self.cur_is(Newline));
+        if !self.cur_is(Newline) {
+            let err = self.skip_and_throw_syntax_err("try_reduce_block");
+            self.level -= 1;
+            self.errs.push(err);
+            return Err(());
+        }
         self.skip();
         if !self.cur_is(Indent) {
             let err = self.skip_and_throw_syntax_err("try_reduce_block");