SQ -> Allow TypeAlias and PlaceholderNode to be stringified/printed

Author: davidfstr

mypy/strconv.py

@@ -213,10 +213,10 @@ def visit_nonlocal_decl(self, o: mypy.nodes.NonlocalDecl) -> str:
     def visit_decorator(self, o: mypy.nodes.Decorator) -> str:
         return self.dump([o.var, o.decorators, o.func], o)
 
-    def visit_type_alias(self, o: mypy.nodes.TypeAlias, /) -> T:
+    def visit_type_alias(self, o: mypy.nodes.TypeAlias, /) -> str:
         return self.dump([o.name, o.target, o.alias_tvars, o.no_args], o)
 
-    def visit_placeholder_node(self, o: mypy.nodes.PlaceholderNode, /) -> T:
+    def visit_placeholder_node(self, o: mypy.nodes.PlaceholderNode, /) -> str:
         return self.dump([o.fullname], o)
 
     # Statements