[llvm] [ADT] Apply Rule of Five to StringTable::Iterator (PR #160815)

[Kazu Hirata via llvm-commits]

https://github.com/kazutakahirata created https://github.com/llvm/llvm-project/pull/160815

StringTable::Iterator has a user-defined copy assignment operator, a
defaulted copy constructor, and a defaulted move constructor.

This patch makes the copy assignment operator defaulted and adds a
defaulted move assignment operator to adhere to the Rule of Five while
making the operators constexpr.


>From ff832a57b402a583a9411c17143f7f6308460b15 Mon Sep 17 00:00:00 2001
From: Kazu Hirata <kazu at google.com>
Date: Mon, 22 Sep 2025 23:55:19 -0700
Subject: [PATCH] [ADT] Apply Rule of Five to StringTable::Iterator

StringTable::Iterator has a user-defined copy assignment operator, a
defaulted copy constructor, and a defaulted move constructor.

This patch makes the copy assignment operator defaulted and adds a
defaulted move assignment operator to adhere to the Rule of Five while
making the operators constexpr.
---
 llvm/include/llvm/ADT/StringTable.h | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/llvm/include/llvm/ADT/StringTable.h b/llvm/include/llvm/ADT/StringTable.h
index 575b3c929e40c..9422a6da1ce8e 100644
--- a/llvm/include/llvm/ADT/StringTable.h
+++ b/llvm/include/llvm/ADT/StringTable.h
@@ -118,12 +118,8 @@ class StringTable {
     constexpr Iterator(const Iterator &RHS) = default;
     constexpr Iterator(Iterator &&RHS) = default;
 
-    Iterator &operator=(const Iterator &RHS) {
-      Table = RHS.Table;
-      O = RHS.O;
-      S = RHS.S;
-      return *this;
-    }
+    constexpr Iterator &operator=(const Iterator &RHS) = default;
+    constexpr Iterator &operator=(Iterator &&RHS) = default;
 
     bool operator==(const Iterator &RHS) const {
       assert(Table == RHS.Table && "Compared iterators for unrelated tables!");