Fix #205

compiler/erg_parser/ast.rs

@@ -3450,6 +3450,10 @@ impl Expr {
         matches!(self, Expr::Accessor(acc) if acc.is_const())
     }
 
+    pub const fn is_definition(&self) -> bool {
+        matches!(self, Expr::Def(_) | Expr::ClassDef(_) | Expr::Methods(_))
+    }
+
     pub fn need_to_be_closed(&self) -> bool {
         matches!(
             self,

compiler/erg_parser/parse.rs

@@ -298,8 +298,15 @@ impl Parser {
                 .try_reduce_chunk(true, false)
                 .map_err(|_| self.stack_dec())?;
             block.push(chunk);
-            self.level -= 1;
+            if block.last().unwrap().is_definition() {
-            return Ok(block);
+                let err = ParseError::simple_syntax_error(0, block.last().unwrap().loc());
+                self.level -= 1;
+                self.errs.push(err);
+                return Err(());
+            } else {
+                self.level -= 1;
+                return Ok(block);
+            }
         }
         if !self.cur_is(Newline) {
             let err = self.skip_and_throw_syntax_err("try_reduce_block");
@@ -362,6 +369,21 @@ impl Parser {
             self.level -= 1;
             self.errs.push(err);
             Err(())
+        } else if block.last().unwrap().is_definition() {
+            let err = ParseError::syntax_error(
+                line!() as usize,
+                block.last().unwrap().loc(),
+                switch_lang!(
+                    "japanese" => "ブロックの終端で変数を定義することは出来ません",
+                    "simplified_chinese" => "无法在块的末尾定义变量",
+                    "traditional_chinese" => "無法在塊的末尾定義變量",
+                    "english" => "cannot define a variable at the end of a block",
+                ),
+                None,
+            );
+            self.level -= 1;
+            self.errs.push(err);
+            Err(())
         } else {
             self.level -= 1;
             Ok(block)