upgrade compiler to nightly-2019-12-17

plume-common/src/lib.rs

@@ -1,4 +1,4 @@
-#![feature(custom_attribute, associated_type_defaults)]
+#![feature(associated_type_defaults)]
 
 extern crate activitypub;
 #[macro_use]

plume-common/src/utils.rs

@@ -97,7 +97,7 @@ fn inline_tags<'a>(
     }
 }
 
-pub type MediaProcessor<'a> = Box<'a + Fn(i32) -> Option<(String, Option<String>)>>;
+pub type MediaProcessor<'a> = Box<dyn 'a + Fn(i32) -> Option<(String, Option<String>)>>;
 
 fn process_image<'a, 'b>(
     evt: Event<'a>,