for_expr.rs

fn for_expr(&mut self) -> Result<ast::Expr> {
        self.expect(TokenKind::Reserved(Keyword::For))?;
        let lo = self.span;
        let pattern = self.local_pattern()?;
        self.expect(TokenKind::Reserved(Keyword::In))?;
        let expr = self.expr(Precedence::NONE)?;
        let block = self.block()?;
        let span = lo.merge(self.span);
        Ok(ast::Expr {
            id: DUMMY_NODE_ID,
            span,
            kind: ast::ExprKind::For(
                pattern,
                Box::new(expr),
                Box::new(block)
            ),
        })
    }