f - More idiomatic MAX_TIMESTAMP

Author: jkczyz

lightning-invoice/src/lib.rs

@@ -88,9 +88,8 @@ pub use de::{ParseError, ParseOrSemanticError};
 /// The number of bits used to represent timestamps as defined in BOLT 11.
 const TIMESTAMP_BITS: usize = 35;
 
-/// The maximum timestamp that can be represented as a [`Duration`] since the UNIX epoch while
-/// allowing for adding an expiry without overflowing.
-const MAX_TIMESTAMP: u64 = core::u64::MAX >> (64 - TIMESTAMP_BITS);
+/// The maximum timestamp as [`Duration::as_secs`] since the UNIX epoch allowed by BOLT 11.
+const MAX_TIMESTAMP: u64 = (1 << TIMESTAMP_BITS) - 1;
 
 /// Default expiry time as defined by [BOLT 11].
 ///