Permit const assertions in stdlib

Author: jhpratt

core/src/panicking.rs

@@ -36,6 +36,7 @@ use crate::panic::{Location, PanicInfo};
 #[cfg_attr(not(feature = "panic_immediate_abort"), inline(never))]
 #[cfg_attr(feature = "panic_immediate_abort", inline)]
 #[track_caller]
+#[rustc_const_unstable(feature = "core_panic", issue = "none")]
 #[lang = "panic"] // needed by codegen for panic on overflow and other `Assert` MIR terminators
 pub const fn panic(expr: &'static str) -> ! {
     // Use Arguments::new_v1 instead of format_args!("{}", expr) to potentially

core/src/time.rs

@@ -727,7 +727,7 @@ impl Duration {
     pub const fn from_secs_f64(secs: f64) -> Duration {
         match Duration::try_from_secs_f64(secs) {
             Ok(v) => v,
-            Err(e) => crate::panicking::panic(e.description()),
+            Err(e) => panic!("{}", e.description()),
         }
     }
 
@@ -788,7 +788,7 @@ impl Duration {
     pub const fn from_secs_f32(secs: f32) -> Duration {
         match Duration::try_from_secs_f32(secs) {
             Ok(v) => v,
-            Err(e) => crate::panicking::panic(e.description()),
+            Err(e) => panic!("{}", e.description()),
         }
     }