Adjust .stderr files
diff --git a/tests/ui/abort.stderr b/tests/ui/abort.stderr
index c5399d9..1d702ff 100644
--- a/tests/ui/abort.stderr
+++ b/tests/ui/abort.stderr
@@ -1,3 +1,41 @@
+warning: panic message is not a string literal
+   --> $DIR/lib.rs:472:12
+    |
+472 |     panic!(AbortNow)
+    |            ^^^^^^^^
+    |
+    = note: `#[warn(non_fmt_panic)]` on by default
+    = note: this is no longer accepted in Rust 2021
+help: add a "{}" format string to Display the message
+    |
+472 |     panic!("{}", AbortNow)
+    |            ^^^^^
+help: or use std::panic::panic_any instead
+    |
+472 |     std::panic::panic_any(AbortNow)
+    |     ^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+
+warning: panic message is not a string literal
+   --> $DIR/lib.rs:472:12
+    |
+472 |     panic!(AbortNow)
+    |            ^^^^^^^^
+    |
+    = note: `#[warn(non_fmt_panic)]` on by default
+    = note: this is no longer accepted in Rust 2021
+help: add a "{}" format string to Display the message
+    |
+472 |     panic!("{}", AbortNow)
+    |            ^^^^^
+help: or use std::panic::panic_any instead
+    |
+472 |     std::panic::panic_any(AbortNow)
+    |     ^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+
 error: abort!(span, from) test
  --> $DIR/abort.rs:4:13
   |
diff --git a/tests/ui/append_dummy.stderr b/tests/ui/append_dummy.stderr
index 8a47dda..2ca2801 100644
--- a/tests/ui/append_dummy.stderr
+++ b/tests/ui/append_dummy.stderr
@@ -1,3 +1,41 @@
+warning: panic message is not a string literal
+   --> $DIR/lib.rs:472:12
+    |
+472 |     panic!(AbortNow)
+    |            ^^^^^^^^
+    |
+    = note: `#[warn(non_fmt_panic)]` on by default
+    = note: this is no longer accepted in Rust 2021
+help: add a "{}" format string to Display the message
+    |
+472 |     panic!("{}", AbortNow)
+    |            ^^^^^
+help: or use std::panic::panic_any instead
+    |
+472 |     std::panic::panic_any(AbortNow)
+    |     ^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+
+warning: panic message is not a string literal
+   --> $DIR/lib.rs:472:12
+    |
+472 |     panic!(AbortNow)
+    |            ^^^^^^^^
+    |
+    = note: `#[warn(non_fmt_panic)]` on by default
+    = note: this is no longer accepted in Rust 2021
+help: add a "{}" format string to Display the message
+    |
+472 |     panic!("{}", AbortNow)
+    |            ^^^^^
+help: or use std::panic::panic_any instead
+    |
+472 |     std::panic::panic_any(AbortNow)
+    |     ^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+
 error: append_dummy test
  --> $DIR/append_dummy.rs:9:15
   |
diff --git a/tests/ui/children_messages.stderr b/tests/ui/children_messages.stderr
index 3b49d83..e1cad58 100644
--- a/tests/ui/children_messages.stderr
+++ b/tests/ui/children_messages.stderr
@@ -1,3 +1,41 @@
+warning: panic message is not a string literal
+   --> $DIR/lib.rs:472:12
+    |
+472 |     panic!(AbortNow)
+    |            ^^^^^^^^
+    |
+    = note: `#[warn(non_fmt_panic)]` on by default
+    = note: this is no longer accepted in Rust 2021
+help: add a "{}" format string to Display the message
+    |
+472 |     panic!("{}", AbortNow)
+    |            ^^^^^
+help: or use std::panic::panic_any instead
+    |
+472 |     std::panic::panic_any(AbortNow)
+    |     ^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+
+warning: panic message is not a string literal
+   --> $DIR/lib.rs:472:12
+    |
+472 |     panic!(AbortNow)
+    |            ^^^^^^^^
+    |
+    = note: `#[warn(non_fmt_panic)]` on by default
+    = note: this is no longer accepted in Rust 2021
+help: add a "{}" format string to Display the message
+    |
+472 |     panic!("{}", AbortNow)
+    |            ^^^^^
+help: or use std::panic::panic_any instead
+    |
+472 |     std::panic::panic_any(AbortNow)
+    |     ^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+
 error: main macro message
  --> $DIR/children_messages.rs:4:20
   |
diff --git a/tests/ui/dummy.stderr b/tests/ui/dummy.stderr
index bae078a..b9001f5 100644
--- a/tests/ui/dummy.stderr
+++ b/tests/ui/dummy.stderr
@@ -1,3 +1,41 @@
+warning: panic message is not a string literal
+   --> $DIR/lib.rs:472:12
+    |
+472 |     panic!(AbortNow)
+    |            ^^^^^^^^
+    |
+    = note: `#[warn(non_fmt_panic)]` on by default
+    = note: this is no longer accepted in Rust 2021
+help: add a "{}" format string to Display the message
+    |
+472 |     panic!("{}", AbortNow)
+    |            ^^^^^
+help: or use std::panic::panic_any instead
+    |
+472 |     std::panic::panic_any(AbortNow)
+    |     ^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+
+warning: panic message is not a string literal
+   --> $DIR/lib.rs:472:12
+    |
+472 |     panic!(AbortNow)
+    |            ^^^^^^^^
+    |
+    = note: `#[warn(non_fmt_panic)]` on by default
+    = note: this is no longer accepted in Rust 2021
+help: add a "{}" format string to Display the message
+    |
+472 |     panic!("{}", AbortNow)
+    |            ^^^^^
+help: or use std::panic::panic_any instead
+    |
+472 |     std::panic::panic_any(AbortNow)
+    |     ^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+
 error: set_dummy test
  --> $DIR/dummy.rs:9:8
   |
diff --git a/tests/ui/emit.stderr b/tests/ui/emit.stderr
index 9484bd6..e4d68b7 100644
--- a/tests/ui/emit.stderr
+++ b/tests/ui/emit.stderr
@@ -1,3 +1,41 @@
+warning: panic message is not a string literal
+   --> $DIR/lib.rs:472:12
+    |
+472 |     panic!(AbortNow)
+    |            ^^^^^^^^
+    |
+    = note: `#[warn(non_fmt_panic)]` on by default
+    = note: this is no longer accepted in Rust 2021
+help: add a "{}" format string to Display the message
+    |
+472 |     panic!("{}", AbortNow)
+    |            ^^^^^
+help: or use std::panic::panic_any instead
+    |
+472 |     std::panic::panic_any(AbortNow)
+    |     ^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+
+warning: panic message is not a string literal
+   --> $DIR/lib.rs:472:12
+    |
+472 |     panic!(AbortNow)
+    |            ^^^^^^^^
+    |
+    = note: `#[warn(non_fmt_panic)]` on by default
+    = note: this is no longer accepted in Rust 2021
+help: add a "{}" format string to Display the message
+    |
+472 |     panic!("{}", AbortNow)
+    |            ^^^^^
+help: or use std::panic::panic_any instead
+    |
+472 |     std::panic::panic_any(AbortNow)
+    |     ^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+
 error: emit!(span, from) test
  --> $DIR/emit.rs:4:7
   |
diff --git a/tests/ui/explicit_span_range.stderr b/tests/ui/explicit_span_range.stderr
index 781a71e..7f80a22 100644
--- a/tests/ui/explicit_span_range.stderr
+++ b/tests/ui/explicit_span_range.stderr
@@ -1,3 +1,41 @@
+warning: panic message is not a string literal
+   --> $DIR/lib.rs:472:12
+    |
+472 |     panic!(AbortNow)
+    |            ^^^^^^^^
+    |
+    = note: `#[warn(non_fmt_panic)]` on by default
+    = note: this is no longer accepted in Rust 2021
+help: add a "{}" format string to Display the message
+    |
+472 |     panic!("{}", AbortNow)
+    |            ^^^^^
+help: or use std::panic::panic_any instead
+    |
+472 |     std::panic::panic_any(AbortNow)
+    |     ^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+
+warning: panic message is not a string literal
+   --> $DIR/lib.rs:472:12
+    |
+472 |     panic!(AbortNow)
+    |            ^^^^^^^^
+    |
+    = note: `#[warn(non_fmt_panic)]` on by default
+    = note: this is no longer accepted in Rust 2021
+help: add a "{}" format string to Display the message
+    |
+472 |     panic!("{}", AbortNow)
+    |            ^^^^^
+help: or use std::panic::panic_any instead
+    |
+472 |     std::panic::panic_any(AbortNow)
+    |     ^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+
 error: explicit SpanRange
  --> $DIR/explicit_span_range.rs:4:22
   |
diff --git a/tests/ui/misuse.stderr b/tests/ui/misuse.stderr
index a64991d..ed5f4c9 100644
--- a/tests/ui/misuse.stderr
+++ b/tests/ui/misuse.stderr
@@ -1,13 +1,51 @@
-error[E0599]: no method named `FIRST_ARG_MUST_EITHER_BE_Span_OR_IMPLEMENT_ToTokens_OR_BE_SpanRange` found for reference `&Foo` in the current scope
+warning: panic message is not a string literal
+   --> $DIR/lib.rs:472:12
+    |
+472 |     panic!(AbortNow)
+    |            ^^^^^^^^
+    |
+    = note: `#[warn(non_fmt_panic)]` on by default
+    = note: this is no longer accepted in Rust 2021
+help: add a "{}" format string to Display the message
+    |
+472 |     panic!("{}", AbortNow)
+    |            ^^^^^
+help: or use std::panic::panic_any instead
+    |
+472 |     std::panic::panic_any(AbortNow)
+    |     ^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+
+warning: panic message is not a string literal
+   --> $DIR/lib.rs:472:12
+    |
+472 |     panic!(AbortNow)
+    |            ^^^^^^^^
+    |
+    = note: `#[warn(non_fmt_panic)]` on by default
+    = note: this is no longer accepted in Rust 2021
+help: add a "{}" format string to Display the message
+    |
+472 |     panic!("{}", AbortNow)
+    |            ^^^^^
+help: or use std::panic::panic_any instead
+    |
+472 |     std::panic::panic_any(AbortNow)
+    |     ^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+
+error[E0599]: the method `FIRST_ARG_MUST_EITHER_BE_Span_OR_IMPLEMENT_ToTokens_OR_BE_SpanRange` exists for reference `&Foo`, but its trait bounds were not satisfied
  --> $DIR/misuse.rs:8:5
   |
 4 | struct Foo;
   | ----------- doesn't satisfy `Foo: quote::to_tokens::ToTokens`
 ...
 8 |     abort!(Foo, "BOOM");
-  |     ^^^^^^^^^^^^^^^^^^^^ method not found in `&Foo`
+  |     ^^^^^^^^^^^^^^^^^^^^ method cannot be called on `&Foo` due to unsatisfied trait bounds
   |
-  = note: the method `FIRST_ARG_MUST_EITHER_BE_Span_OR_IMPLEMENT_ToTokens_OR_BE_SpanRange` exists but the following trait bounds were not satisfied:
+  = note: the following trait bounds were not satisfied:
           `Foo: quote::to_tokens::ToTokens`
           which is required by `&Foo: ToTokensAsSpanRange`
   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
diff --git a/tests/ui/multiple_tokens.stderr b/tests/ui/multiple_tokens.stderr
index c6172c6..47dd9c4 100644
--- a/tests/ui/multiple_tokens.stderr
+++ b/tests/ui/multiple_tokens.stderr
@@ -1,3 +1,41 @@
+warning: panic message is not a string literal
+   --> $DIR/lib.rs:472:12
+    |
+472 |     panic!(AbortNow)
+    |            ^^^^^^^^
+    |
+    = note: `#[warn(non_fmt_panic)]` on by default
+    = note: this is no longer accepted in Rust 2021
+help: add a "{}" format string to Display the message
+    |
+472 |     panic!("{}", AbortNow)
+    |            ^^^^^
+help: or use std::panic::panic_any instead
+    |
+472 |     std::panic::panic_any(AbortNow)
+    |     ^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+
+warning: panic message is not a string literal
+   --> $DIR/lib.rs:472:12
+    |
+472 |     panic!(AbortNow)
+    |            ^^^^^^^^
+    |
+    = note: `#[warn(non_fmt_panic)]` on by default
+    = note: this is no longer accepted in Rust 2021
+help: add a "{}" format string to Display the message
+    |
+472 |     panic!("{}", AbortNow)
+    |            ^^^^^
+help: or use std::panic::panic_any instead
+    |
+472 |     std::panic::panic_any(AbortNow)
+    |     ^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+
 error: ...
  --> $DIR/multiple_tokens.rs:4:1
   |
diff --git a/tests/ui/not_proc_macro.stderr b/tests/ui/not_proc_macro.stderr
index f19f01b..6eae515 100644
--- a/tests/ui/not_proc_macro.stderr
+++ b/tests/ui/not_proc_macro.stderr
@@ -1,3 +1,41 @@
+warning: panic message is not a string literal
+   --> $DIR/lib.rs:472:12
+    |
+472 |     panic!(AbortNow)
+    |            ^^^^^^^^
+    |
+    = note: `#[warn(non_fmt_panic)]` on by default
+    = note: this is no longer accepted in Rust 2021
+help: add a "{}" format string to Display the message
+    |
+472 |     panic!("{}", AbortNow)
+    |            ^^^^^
+help: or use std::panic::panic_any instead
+    |
+472 |     std::panic::panic_any(AbortNow)
+    |     ^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+
+warning: panic message is not a string literal
+   --> $DIR/lib.rs:472:12
+    |
+472 |     panic!(AbortNow)
+    |            ^^^^^^^^
+    |
+    = note: `#[warn(non_fmt_panic)]` on by default
+    = note: this is no longer accepted in Rust 2021
+help: add a "{}" format string to Display the message
+    |
+472 |     panic!("{}", AbortNow)
+    |            ^^^^^
+help: or use std::panic::panic_any instead
+    |
+472 |     std::panic::panic_any(AbortNow)
+    |     ^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+
 error: #[proc_macro_error] attribute can be used only with procedural macros
 
   = hint: if you are really sure that #[proc_macro_error] should be applied to this exact function, use #[proc_macro_error(allow_not_macro)]
diff --git a/tests/ui/option_ext.stderr b/tests/ui/option_ext.stderr
index 91b151e..337a57c 100644
--- a/tests/ui/option_ext.stderr
+++ b/tests/ui/option_ext.stderr
@@ -1,3 +1,41 @@
+warning: panic message is not a string literal
+   --> $DIR/lib.rs:472:12
+    |
+472 |     panic!(AbortNow)
+    |            ^^^^^^^^
+    |
+    = note: `#[warn(non_fmt_panic)]` on by default
+    = note: this is no longer accepted in Rust 2021
+help: add a "{}" format string to Display the message
+    |
+472 |     panic!("{}", AbortNow)
+    |            ^^^^^
+help: or use std::panic::panic_any instead
+    |
+472 |     std::panic::panic_any(AbortNow)
+    |     ^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+
+warning: panic message is not a string literal
+   --> $DIR/lib.rs:472:12
+    |
+472 |     panic!(AbortNow)
+    |            ^^^^^^^^
+    |
+    = note: `#[warn(non_fmt_panic)]` on by default
+    = note: this is no longer accepted in Rust 2021
+help: add a "{}" format string to Display the message
+    |
+472 |     panic!("{}", AbortNow)
+    |            ^^^^^
+help: or use std::panic::panic_any instead
+    |
+472 |     std::panic::panic_any(AbortNow)
+    |     ^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+
 error: Option::expect_or_abort() test
  --> $DIR/option_ext.rs:4:1
   |
diff --git a/tests/ui/proc_macro_hack.stderr b/tests/ui/proc_macro_hack.stderr
index 0e984f9..519e75e 100644
--- a/tests/ui/proc_macro_hack.stderr
+++ b/tests/ui/proc_macro_hack.stderr
@@ -1,3 +1,41 @@
+warning: panic message is not a string literal
+   --> $DIR/lib.rs:472:12
+    |
+472 |     panic!(AbortNow)
+    |            ^^^^^^^^
+    |
+    = note: `#[warn(non_fmt_panic)]` on by default
+    = note: this is no longer accepted in Rust 2021
+help: add a "{}" format string to Display the message
+    |
+472 |     panic!("{}", AbortNow)
+    |            ^^^^^
+help: or use std::panic::panic_any instead
+    |
+472 |     std::panic::panic_any(AbortNow)
+    |     ^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+
+warning: panic message is not a string literal
+   --> $DIR/lib.rs:472:12
+    |
+472 |     panic!(AbortNow)
+    |            ^^^^^^^^
+    |
+    = note: `#[warn(non_fmt_panic)]` on by default
+    = note: this is no longer accepted in Rust 2021
+help: add a "{}" format string to Display the message
+    |
+472 |     panic!("{}", AbortNow)
+    |            ^^^^^
+help: or use std::panic::panic_any instead
+    |
+472 |     std::panic::panic_any(AbortNow)
+    |     ^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+
 error: BOOM
  --> $DIR/proc_macro_hack.rs:8:25
   |
diff --git a/tests/ui/result_ext.stderr b/tests/ui/result_ext.stderr
index f2dc0e4..53b8474 100644
--- a/tests/ui/result_ext.stderr
+++ b/tests/ui/result_ext.stderr
@@ -1,3 +1,41 @@
+warning: panic message is not a string literal
+   --> $DIR/lib.rs:472:12
+    |
+472 |     panic!(AbortNow)
+    |            ^^^^^^^^
+    |
+    = note: `#[warn(non_fmt_panic)]` on by default
+    = note: this is no longer accepted in Rust 2021
+help: add a "{}" format string to Display the message
+    |
+472 |     panic!("{}", AbortNow)
+    |            ^^^^^
+help: or use std::panic::panic_any instead
+    |
+472 |     std::panic::panic_any(AbortNow)
+    |     ^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+
+warning: panic message is not a string literal
+   --> $DIR/lib.rs:472:12
+    |
+472 |     panic!(AbortNow)
+    |            ^^^^^^^^
+    |
+    = note: `#[warn(non_fmt_panic)]` on by default
+    = note: this is no longer accepted in Rust 2021
+help: add a "{}" format string to Display the message
+    |
+472 |     panic!("{}", AbortNow)
+    |            ^^^^^
+help: or use std::panic::panic_any instead
+    |
+472 |     std::panic::panic_any(AbortNow)
+    |     ^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+
 error: Result::unwrap_or_abort() test
  --> $DIR/result_ext.rs:4:25
   |
diff --git a/tests/ui/to_tokens_span.stderr b/tests/ui/to_tokens_span.stderr
index b8c4968..d57e06a 100644
--- a/tests/ui/to_tokens_span.stderr
+++ b/tests/ui/to_tokens_span.stderr
@@ -1,3 +1,41 @@
+warning: panic message is not a string literal
+   --> $DIR/lib.rs:472:12
+    |
+472 |     panic!(AbortNow)
+    |            ^^^^^^^^
+    |
+    = note: `#[warn(non_fmt_panic)]` on by default
+    = note: this is no longer accepted in Rust 2021
+help: add a "{}" format string to Display the message
+    |
+472 |     panic!("{}", AbortNow)
+    |            ^^^^^
+help: or use std::panic::panic_any instead
+    |
+472 |     std::panic::panic_any(AbortNow)
+    |     ^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+
+warning: panic message is not a string literal
+   --> $DIR/lib.rs:472:12
+    |
+472 |     panic!(AbortNow)
+    |            ^^^^^^^^
+    |
+    = note: `#[warn(non_fmt_panic)]` on by default
+    = note: this is no longer accepted in Rust 2021
+help: add a "{}" format string to Display the message
+    |
+472 |     panic!("{}", AbortNow)
+    |            ^^^^^
+help: or use std::panic::panic_any instead
+    |
+472 |     std::panic::panic_any(AbortNow)
+    |     ^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+
 error: whole type
  --> $DIR/to_tokens_span.rs:4:17
   |
diff --git a/tests/ui/unknown_setting.stderr b/tests/ui/unknown_setting.stderr
index a55de0b..adbe089 100644
--- a/tests/ui/unknown_setting.stderr
+++ b/tests/ui/unknown_setting.stderr
@@ -1,3 +1,41 @@
+warning: panic message is not a string literal
+   --> $DIR/lib.rs:472:12
+    |
+472 |     panic!(AbortNow)
+    |            ^^^^^^^^
+    |
+    = note: `#[warn(non_fmt_panic)]` on by default
+    = note: this is no longer accepted in Rust 2021
+help: add a "{}" format string to Display the message
+    |
+472 |     panic!("{}", AbortNow)
+    |            ^^^^^
+help: or use std::panic::panic_any instead
+    |
+472 |     std::panic::panic_any(AbortNow)
+    |     ^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+
+warning: panic message is not a string literal
+   --> $DIR/lib.rs:472:12
+    |
+472 |     panic!(AbortNow)
+    |            ^^^^^^^^
+    |
+    = note: `#[warn(non_fmt_panic)]` on by default
+    = note: this is no longer accepted in Rust 2021
+help: add a "{}" format string to Display the message
+    |
+472 |     panic!("{}", AbortNow)
+    |            ^^^^^
+help: or use std::panic::panic_any instead
+    |
+472 |     std::panic::panic_any(AbortNow)
+    |     ^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+
 error: unknown setting `trololo`, expected one of `assert_unwind_safe`, `allow_not_macro`, `proc_macro_hack`
  --> $DIR/unknown_setting.rs:3:57
   |
diff --git a/tests/ui/unrelated_panic.stderr b/tests/ui/unrelated_panic.stderr
index d46d689..94c695e 100644
--- a/tests/ui/unrelated_panic.stderr
+++ b/tests/ui/unrelated_panic.stderr
@@ -1,3 +1,41 @@
+warning: panic message is not a string literal
+   --> $DIR/lib.rs:472:12
+    |
+472 |     panic!(AbortNow)
+    |            ^^^^^^^^
+    |
+    = note: `#[warn(non_fmt_panic)]` on by default
+    = note: this is no longer accepted in Rust 2021
+help: add a "{}" format string to Display the message
+    |
+472 |     panic!("{}", AbortNow)
+    |            ^^^^^
+help: or use std::panic::panic_any instead
+    |
+472 |     std::panic::panic_any(AbortNow)
+    |     ^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+
+warning: panic message is not a string literal
+   --> $DIR/lib.rs:472:12
+    |
+472 |     panic!(AbortNow)
+    |            ^^^^^^^^
+    |
+    = note: `#[warn(non_fmt_panic)]` on by default
+    = note: this is no longer accepted in Rust 2021
+help: add a "{}" format string to Display the message
+    |
+472 |     panic!("{}", AbortNow)
+    |            ^^^^^
+help: or use std::panic::panic_any instead
+    |
+472 |     std::panic::panic_any(AbortNow)
+    |     ^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+
 error: proc macro panicked
  --> $DIR/unrelated_panic.rs:4:1
   |