error: format argument must be a string literal
  --> $DIR/missing-writer.rs:5:21
   |
LL |     write!("{}_{}", x, y);
   |                     ^
   |
help: you might be missing a string literal to format with
   |
LL |     write!("{}_{}", "{} {}", x, y);
   |                     ++++++++

error: format argument must be a string literal
  --> $DIR/missing-writer.rs:11:23
   |
LL |     writeln!("{}_{}", x, y);
   |                       ^
   |
help: you might be missing a string literal to format with
   |
LL |     writeln!("{}_{}", "{} {}", x, y);
   |                       ++++++++

error[E0599]: cannot write into `&'static str`
  --> $DIR/missing-writer.rs:5:12
   |
LL |     write!("{}_{}", x, y);
   |     -------^^^^^^^------- method not found in `&str`
   |
note: must implement `io::Write`, `fmt::Write`, or have a `write_fmt` method
  --> $DIR/missing-writer.rs:5:12
   |
LL |     write!("{}_{}", x, y);
   |            ^^^^^^^
help: a writer is needed before this format string
  --> $DIR/missing-writer.rs:5:12
   |
LL |     write!("{}_{}", x, y);
   |            ^

error[E0599]: cannot write into `&'static str`
  --> $DIR/missing-writer.rs:11:14
   |
LL |     writeln!("{}_{}", x, y);
   |     ---------^^^^^^^------- method not found in `&str`
   |
note: must implement `io::Write`, `fmt::Write`, or have a `write_fmt` method
  --> $DIR/missing-writer.rs:11:14
   |
LL |     writeln!("{}_{}", x, y);
   |              ^^^^^^^
help: a writer is needed before this format string
  --> $DIR/missing-writer.rs:11:14
   |
LL |     writeln!("{}_{}", x, y);
   |              ^

error: aborting due to 4 previous errors

For more information about this error, try `rustc --explain E0599`.