Remove apis that duplicate implicit operators. (#27744)

* Remove apis that duplicate implicit operators.

https://github.com/dotnet/corefx/issues/26894

Last set of approved api changes from this issue.

Since we have to get this in by 3/7, we're doing
the minbar here of removing the methods from the
reference assemblies only and (in some cases) adding the
"api" internally in some test assemblies rather
than clean up dozens of individual callsites.
(I wouldn't be surprised if we end up adding
these back in the next version anyway...)

* Fix infinite stack overflow

* PR Feedback

2 files changed, 13 insertions, 0 deletions

diff --git a/src/System.Security.Cryptography.Encoding/tests/System.Security.Cryptography.Encoding.Tests.csproj b/src/System.Security.Cryptography.Encoding/tests/System.Security.Cryptography.Encoding.Tests.csproj
index e8d377c7e7..51ad291d9b 100644
--- a/src/System.Security.Cryptography.Encoding/tests/System.Security.Cryptography.Encoding.Tests.csproj
+++ b/src/System.Security.Cryptography.Encoding/tests/System.Security.Cryptography.Encoding.Tests.csproj
@@ -59,6 +59,7 @@
     <Compile Include="DerSequenceReaderTests.cs" />
     <Compile Include="Oid.cs" />
     <Compile Include="OidCollectionTests.cs" />
+    <Compile Include="TestHelpers.cs" />
     <Compile Include="$(CommonPath)\System\Security\Cryptography\Asn1V2.cs">
       <Link>Common\System\Security\Cryptography\Asn1V2.cs</Link>
     </Compile>
diff --git a/src/System.Security.Cryptography.Encoding/tests/TestHelpers.cs b/src/System.Security.Cryptography.Encoding/tests/TestHelpers.cs
new file mode 100644
index 0000000000..5b9d84697a
--- /dev/null
+++ b/src/System.Security.Cryptography.Encoding/tests/TestHelpers.cs
@@ -0,0 +1,12 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace System
+{
+    // @todo: https://github.com/dotnet/corefx/issues/26894 - these emulate MemoryExtension apis that we removed. Clean up the callsites and remove this class.
+    internal static class TestHelpers
+    {
+        public static ReadOnlySpan<T> AsReadOnlySpan<T>(this T[] array) => new ReadOnlySpan<T>(array);
+    }
+}