diff options
| -rw-r--r-- | src/libsyntax/print/pprust.rs | 33 |
1 files changed, 30 insertions, 3 deletions
diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs index 8b01c10bf49..b93a244df13 100644 --- a/src/libsyntax/print/pprust.rs +++ b/src/libsyntax/print/pprust.rs @@ -1555,6 +1555,21 @@ impl<'a> State<'a> { self.pclose() } + pub fn check_expr_bin_needs_paren(&mut self, sub_expr: &ast::Expr, + binop: ast::BinOp) -> bool { + match sub_expr.node { + ast::ExprBinary(ref sub_op, _, _) => { + if ast_util::operator_prec(sub_op.node) < + ast_util::operator_prec(binop.node) { + true + } else { + false + } + } + _ => true + } + } + pub fn print_expr_maybe_paren(&mut self, expr: &ast::Expr) -> io::Result<()> { let needs_par = needs_parentheses(expr); if needs_par { @@ -1670,10 +1685,18 @@ impl<'a> State<'a> { op: ast::BinOp, lhs: &ast::Expr, rhs: &ast::Expr) -> io::Result<()> { - try!(self.print_expr(lhs)); + if self.check_expr_bin_needs_paren(lhs, op) { + try!(self.print_expr_maybe_paren(lhs)); + } else { + try!(self.print_expr(lhs)); + } try!(space(&mut self.s)); try!(self.word_space(ast_util::binop_to_string(op.node))); - self.print_expr(rhs) + if self.check_expr_bin_needs_paren(rhs, op) { + self.print_expr_maybe_paren(rhs) + } else { + self.print_expr(rhs) + } } fn print_expr_unary(&mut self, @@ -1730,7 +1753,11 @@ impl<'a> State<'a> { try!(self.print_literal(&**lit)); } ast::ExprCast(ref expr, ref ty) => { - try!(self.print_expr(&**expr)); + if let ast::ExprCast(..) = expr.node { + try!(self.print_expr(&**expr)); + } else { + try!(self.print_expr_maybe_paren(&**expr)); + } try!(space(&mut self.s)); try!(self.word_space("as")); try!(self.print_type(&**ty)); |