Add comment explaining safe usage of typename T::element_type in not_null_hash

Copilot · carsonRadtke · Copilot · commit 87b3085f6ec2 · 2025-07-26T03:12:56.000Z
Co-authored-by: carsonRadtke &lt;10507970+carsonRadtke@users.noreply.github.com&gt;
diff --git a/include/gsl/pointers b/include/gsl/pointers
@@ -231,6 +231,7 @@ template <class T>
 not_null<T> operator+(std::ptrdiff_t, const not_null<T>&) = delete;
 
 
+// T is conceptually a pointer so we don't have to worry about it being a reference and violating std::hash requirements
 template <class T, class U = typename T::element_type, bool = std::is_default_constructible<std::hash<U>>::value>
 struct not_null_hash
 {

Original file line number	Diff line number	Diff line change
`@@ -231,6 +231,7 @@ template <class T>`
`231`	`231`	`not_null<T> operator+(std::ptrdiff_t, const not_null<T>&) = delete;`
`232`	`232`
`233`	`233`
	`234`	`+// T is conceptually a pointer so we don't have to worry about it being a reference and violating std::hash requirements`
`234`	`235`	`template <class T, class U = typename T::element_type, bool = std::is_default_constructible<std::hash<U>>::value>`
`235`	`236`	`struct not_null_hash`
`236`	`237`	`{`