Don't return reference on copy assignment operators

We prefer to prevent using chained assignment (`T a = b = c = T();`) as this
can lead to confusing code and subtle bugs.

According to https://en.wikipedia.org/wiki/Assignment_operator_(C%2B%2B), C++
allows any arbitrary return type, so this is standard compliant.

This could be re-assessed if/when we have an actual need for a behavior more
akin to that of the C++ STL, for now this PR simply changes a handful of
cases which were inconsistent with the rest of the codebase (`void` return
type was already the most common case prior to this commit).

1 files changed, 4 insertions, 1 deletions

diff --git a/tests/core/templates/test_oa_hash_map.cpp b/tests/core/templates/test_oa_hash_map.cpp
index 904c01642d..f7b2b7cdb0 100644
--- a/tests/core/templates/test_oa_hash_map.cpp
+++ b/tests/core/templates/test_oa_hash_map.cpp
@@ -55,7 +55,10 @@ struct CountedItem {
 		count++;
 	}
 
-	CountedItem &operator=(const CountedItem &p_other) = default;
+	void operator=(const CountedItem &p_other) {
+		id = p_other.id;
+		count++;
+	}
 
 	~CountedItem() {
 		CRASH_COND(destroyed);