error: must have type of `&mut Self::Context` as first argument
 --> tests/ui/fail/fn-missing-context-01.rs:7:5
  |
7 |     fn foo() {}
  |     ^^^^^^^^

error: since Context is defined here
 --> tests/ui/fail/fn-missing-context-01.rs:5:20
  |
5 |     type Context = i32;
  |                    ^^^