error[E0308]: mismatched types
  --> $DIR/issue-110017-format-into-help-deletes-macro.rs:5:10
   |
LL |      Err(format!("error: {x}"))
   |          ^^^^^^^^^^^^^^^^^^^^^ expected `Box<dyn Error>`, found `String`
   |
   = note: expected struct `Box<dyn std::error::Error>`
              found struct `String`
   = note: this error originates in the macro `format` (in Nightly builds, run with -Z macro-backtrace for more info)
help: call `Into::into` on this expression to convert `String` into `Box<dyn std::error::Error>`
   |
LL |      Err(format!("error: {x}").into())
   |                               +++++++

error[E0308]: mismatched types
  --> $DIR/issue-110017-format-into-help-deletes-macro.rs:23:10
   |
LL |      Err(outer!(x))
   |          ^^^^^^^^^ expected `Box<dyn Error>`, found `String`
   |
   = note: expected struct `Box<dyn std::error::Error>`
              found struct `String`
   = note: this error originates in the macro `format` which comes from the expansion of the macro `outer` (in Nightly builds, run with -Z macro-backtrace for more info)
help: call `Into::into` on this expression to convert `String` into `Box<dyn std::error::Error>`
   |
LL |          format!("error: {}", $x).into()
   |                                  +++++++

error[E0308]: mismatched types
  --> $DIR/issue-110017-format-into-help-deletes-macro.rs:41:2
   |
LL |  entire_fn_outer!();
   |  ^^^^^^^^^^^^^^^^^^ expected `Box<dyn Error>`, found `String`
   |
   = note: expected struct `Box<dyn std::error::Error>`
              found struct `String`
   = note: this error originates in the macro `format` which comes from the expansion of the macro `entire_fn_outer` (in Nightly builds, run with -Z macro-backtrace for more info)
help: call `Into::into` on this expression to convert `String` into `Box<dyn std::error::Error>`
   |
LL |              Err(format!("error: {x}").into())
   |                                       +++++++

error[E0308]: mismatched types
  --> $DIR/issue-110017-format-into-help-deletes-macro.rs:51:5
   |
LL |     nontrivial!(x)
   |     ^^^^^^^^^^^^^^ expected `Box<dyn Error>`, found `String`
   |
   = note: expected struct `Box<dyn std::error::Error>`
              found struct `String`
   = note: this error originates in the macro `format` which comes from the expansion of the macro `nontrivial` (in Nightly builds, run with -Z macro-backtrace for more info)
help: call `Into::into` on this expression to convert `String` into `Box<dyn std::error::Error>`
   |
LL |         Err(format!("error: {}", $x).into())
   |                                     +++++++

error: aborting due to 4 previous errors

For more information about this error, try `rustc --explain E0308`.