From 6b7f916008f48b9a8635d461dc33f7c5621611a2 Mon Sep 17 00:00:00 2001
From: Dan Zwell <devel@zwell.net>
Date: Tue, 14 Sep 2021 14:22:49 +0800
Subject: [PATCH] Document the closure arguments for `reduce`.

Fixes issue #88927.
---
 library/core/src/iter/traits/iterator.rs | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/library/core/src/iter/traits/iterator.rs b/library/core/src/iter/traits/iterator.rs
index 330d3714247c5..b0a9d9f5ef5c9 100644
--- a/library/core/src/iter/traits/iterator.rs
+++ b/library/core/src/iter/traits/iterator.rs
@@ -2172,8 +2172,9 @@ pub trait Iterator {
     /// If the iterator is empty, returns [`None`]; otherwise, returns the
     /// result of the reduction.
     ///
+    /// The reducing function is a closure with two arguments: an 'accumulator', and an element.
     /// For iterators with at least one element, this is the same as [`fold()`]
-    /// with the first element of the iterator as the initial value, folding
+    /// with the first element of the iterator as the initial accumulator value, folding
     /// every subsequent element into it.
     ///
     /// [`fold()`]: Iterator::fold
@@ -2187,8 +2188,8 @@ pub trait Iterator {
     ///     where I: Iterator,
     ///           I::Item: Ord,
     /// {
-    ///     iter.reduce(|a, b| {
-    ///         if a >= b { a } else { b }
+    ///     iter.reduce(|accum, item| {
+    ///         if accum >= item { accum } else { item }
     ///     })
     /// }
     /// let a = [10, 20, 5, -23, 0];