Auto merge of #34638 - zackmdavis:if_let_over_none_empty_block_arm, r=jseyfried

prefer `if let` to match with `None => {}` arm in some places

This is a spiritual succesor to #34268 / 8531d581, in which we replaced a
number of matches of None to the unit value with `if let` conditionals
where it was judged that this made for clearer/simpler code (as would be
recommended by Manishearth/rust-clippy's `single_match` lint). The same
rationale applies to matches of None to the empty block.

----

r? @jseyfried

1 files changed, 2 insertions, 5 deletions

diff --git a/src/libcore/fmt/mod.rs b/src/libcore/fmt/mod.rs
index 4ac134c2b59..895a679fc3d 100644
--- a/src/libcore/fmt/mod.rs
+++ b/src/libcore/fmt/mod.rs
@@ -840,11 +840,8 @@ pub fn write(output: &mut Write, args: Arguments) -> Result {
     }
 
     // There can be only one trailing string piece left.
-    match pieces.next() {
-        Some(piece) => {
-            formatter.buf.write_str(*piece)?;
-        }
-        None => {}
+    if let Some(piece) = pieces.next() {
+        formatter.buf.write_str(*piece)?;
     }
 
     Ok(())