diff options
Diffstat (limited to 'Lib/ast.py')
| -rw-r--r-- | Lib/ast.py | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/Lib/ast.py b/Lib/ast.py index 03ae2ec44e..e46ab43d5c 100644 --- a/Lib/ast.py +++ b/Lib/ast.py @@ -1199,8 +1199,13 @@ class _Unparser(NodeVisitor): def _write_constant(self, value): if isinstance(value, (float, complex)): - # Substitute overflowing decimal literal for AST infinities. - self.write(repr(value).replace("inf", _INFSTR)) + # Substitute overflowing decimal literal for AST infinities, + # and inf - inf for NaNs. + self.write( + repr(value) + .replace("inf", _INFSTR) + .replace("nan", f"({_INFSTR}-{_INFSTR})") + ) elif self._avoid_backslashes and isinstance(value, str): self._write_str_avoiding_backslashes(value) else: @@ -1273,10 +1278,13 @@ class _Unparser(NodeVisitor): self.traverse(node.orelse) def visit_Set(self, node): - if not node.elts: - raise ValueError("Set node should have at least one item") - with self.delimit("{", "}"): - self.interleave(lambda: self.write(", "), self.traverse, node.elts) + if node.elts: + with self.delimit("{", "}"): + self.interleave(lambda: self.write(", "), self.traverse, node.elts) + else: + # `{}` would be interpreted as a dictionary literal, and + # `set` might be shadowed. Thus: + self.write('{*()}') def visit_Dict(self, node): def write_key_value_pair(k, v): |