ToCharArray can be omitted when the operation on the array could have been done directly on the string, such as when iterating over the characters in a string, and when accessing a character in a string via an array index. In those cases, explicit ToCharArray calls should be omitted.

C#11 introduced support for UTF-8 string literals, which are stored as ReadOnlySpan<byte> objects. For that reason, the rule also raises on ToArray invocations of ReadOnlySpan<T>.

Noncompliant Code Example

string str = "some string";
foreach (var c in str.ToCharArray()) // Noncompliant
{
  // ...
}

ReadOnlySpan<byte> span = "some UTF-8 string literal"u8;
foreach (var c in span.ToArray()) // Noncompliant
{
  // ...
}

Compliant Solution

string str = "some string";
foreach (var c in str)
{
  // ...
}

ReadOnlySpan<byte> span = "some UTF-8 string literal"u8;
foreach (var b in span) // Compliant
{
  // ...
}