From f732b1d3cc2b3f9d012b3eeecc70d007666d4f1d Mon Sep 17 00:00:00 2001
From: "Tobin C. Harding" <me@tobin.cc>
Date: Thu, 8 May 2025 10:20:27 +1000
Subject: [PATCH] units: Use functional style

This is Rust not C, use functional style.

Close: #4464
---
 units/src/block.rs | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/units/src/block.rs b/units/src/block.rs
index 778fb1bea..83770a5fa 100644
--- a/units/src/block.rs
+++ b/units/src/block.rs
@@ -158,12 +158,9 @@ impl TryFrom<BlockHeightInterval> for relative::NumberOfBlocks {
     /// A relative locktime block height has a maximum value of `u16::MAX` where as a
     /// [`BlockHeightInterval`] is a thin wrapper around a `u32`, the two types are not interchangeable.
     fn try_from(h: BlockHeightInterval) -> Result<Self, Self::Error> {
-        let h = h.to_u32();
-
-        if h > u32::from(u16::MAX) {
-            return Err(TooBigForRelativeHeightError(h));
-        }
-        Ok(relative::NumberOfBlocks::from(h as u16)) // Cast ok, value checked above.
+        u16::try_from(h.to_u32())
+            .map(relative::NumberOfBlocks::from)
+            .map_err(|_| TooBigForRelativeHeightError(h.into()))
     }
 }