Added struct `fmt::FormattingOptions`

This allows to build custom `std::Formatter`s at runtime.

Also added some related enums and two related methods on `std::Formatter`.

2 files changed, 2 insertions, 1 deletions

diff --git a/library/std/src/lib.rs b/library/std/src/lib.rs
index 6be27b283b2..49a03220039 100644
--- a/library/std/src/lib.rs
+++ b/library/std/src/lib.rs
@@ -292,6 +292,7 @@
 #![feature(dropck_eyepatch)]
 #![feature(f128)]
 #![feature(f16)]
+#![feature(formatting_options)]
 #![feature(if_let_guard)]
 #![feature(intra_doc_pointers)]
 #![feature(lang_items)]
diff --git a/library/std/src/panicking.rs b/library/std/src/panicking.rs
index 97f800dddaa..dca5ccca0c4 100644
--- a/library/std/src/panicking.rs
+++ b/library/std/src/panicking.rs
@@ -623,7 +623,7 @@ pub fn begin_panic_handler(info: &core::panic::PanicInfo<'_>) -> ! {
             // Lazily, the first time this gets called, run the actual string formatting.
             self.string.get_or_insert_with(|| {
                 let mut s = String::new();
-                let mut fmt = fmt::Formatter::new(&mut s);
+                let mut fmt = fmt::Formatter::new(&mut s, fmt::FormattingOptions::new());
                 let _err = fmt::Display::fmt(&inner, &mut fmt);
                 s
             })