re-enable all target frameworks

src/Directory.Build.props

@@ -23,6 +23,7 @@
   </PropertyGroup>
 
   <PropertyGroup Condition="'$(Configuration)' == 'Release'">
+<!-- TODO: re-enable when all Obsolete warnings are fixed -->
 <!--    <TreatWarningsAsErrors>true</TreatWarningsAsErrors>-->
   </PropertyGroup>
 

src/ImageSharp/ImageSharp.csproj

@@ -10,8 +10,7 @@
     <VersionPrefix Condition="$(packageversion) != ''">$(packageversion)</VersionPrefix>
     <VersionPrefix Condition="$(packageversion) == ''">0.0.1</VersionPrefix>
 
-<!--    <TargetFrameworks>netcoreapp3.1;netcoreapp2.1;netstandard2.1;netstandard2.0;netstandard1.3;net472</TargetFrameworks>-->
-    <TargetFrameworks>netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netcoreapp3.1;netcoreapp2.1;netstandard2.1;netstandard2.0;netstandard1.3;net472</TargetFrameworks>
 
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>

src/ImageSharp/Memory/Buffer2DExtensions.cs

@@ -39,6 +39,7 @@ namespace SixLabors.ImageSharp.Memory
         /// Thrown when the backing group is discontiguous.
         /// </exception>
         // TODO: Review all usages, should be only used with buffers which do not scale fully with image size!
+        // Remove [Obsolete], when done!
         [Obsolete("TODO: Review all usages!")]
         internal static Span<T> GetSingleSpan<T>(this Buffer2D<T> buffer)
             where T : struct
@@ -64,6 +65,7 @@ namespace SixLabors.ImageSharp.Memory
         /// Thrown when the backing group is discontiguous.
         /// </exception>
         // TODO: Review all usages, should be only used with buffers which do not scale fully with image size!
+        // Remove [Obsolete], when done!
         [Obsolete("TODO: Review all usages!")]
         internal static Memory<T> GetSingleMemory<T>(this Buffer2D<T> buffer)
             where T : struct

src/ImageSharp/Memory/DiscontiguousBuffers/MemoryGroup{T}.cs

@@ -113,7 +113,7 @@ namespace SixLabors.ImageSharp.Memory
 
             if (bufferCount > 0)
             {
-                buffers[^1] = allocator.Allocate<T>(sizeOfLastBuffer, options);
+                buffers[buffers.Length - 1] = allocator.Allocate<T>(sizeOfLastBuffer, options);
             }
 
             return new Owned(buffers, bufferLength, totalLength, true);
@@ -130,12 +130,12 @@ namespace SixLabors.ImageSharp.Memory
                 }
             }
 
-            if (source.Length > 0 && source[^1].Length > bufferLength)
+            if (source.Length > 0 && source[source.Length - 1].Length > bufferLength)
             {
                 throw new InvalidMemoryOperationException("Wrap: the last buffer is too large!");
             }
 
-            long totalLength = bufferLength > 0 ? ((long)bufferLength * (source.Length - 1)) + source[^1].Length : 0;
+            long totalLength = bufferLength > 0 ? ((long)bufferLength * (source.Length - 1)) + source[source.Length - 1].Length : 0;
 
             return new Consumed(source, bufferLength, totalLength);
         }
@@ -151,12 +151,12 @@ namespace SixLabors.ImageSharp.Memory
                 }
             }
 
-            if (source.Length > 0 && source[^1].Memory.Length > bufferLength)
+            if (source.Length > 0 && source[source.Length - 1].Memory.Length > bufferLength)
             {
                 throw new InvalidMemoryOperationException("Wrap: the last buffer is too large!");
             }
 
-            long totalLength = bufferLength > 0 ? ((long)bufferLength * (source.Length - 1)) + source[^1].Memory.Length : 0;
+            long totalLength = bufferLength > 0 ? ((long)bufferLength * (source.Length - 1)) + source[source.Length - 1].Memory.Length : 0;
 
             return new Owned(source, bufferLength, totalLength, false);
         }

tests/ImageSharp.Benchmarks/ImageSharp.Benchmarks.csproj

@@ -5,8 +5,7 @@
     <AssemblyName>ImageSharp.Benchmarks</AssemblyName>
     <OutputType>Exe</OutputType>
     <RootNamespace>SixLabors.ImageSharp.Benchmarks</RootNamespace>
-    <!-- <TargetFrameworks>netcoreapp3.1;netcoreapp2.1;net472</TargetFrameworks> -->
-    <TargetFrameworks>netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netcoreapp3.1;netcoreapp2.1;net472</TargetFrameworks>
     <GenerateProgramFile>false</GenerateProgramFile>
     <!--Used to hide test project from dotnet test-->
     <IsTestProject>false</IsTestProject>

tests/ImageSharp.Tests.ProfilingSandbox/ImageSharp.Tests.ProfilingSandbox.csproj

@@ -8,8 +8,7 @@
     <Prefer32Bit>false</Prefer32Bit>
     <RootNamespace>SixLabors.ImageSharp.Tests.ProfilingSandbox</RootNamespace>
     <RuntimeIdentifier>win7-x64</RuntimeIdentifier>
-<!--    <TargetFrameworks>netcoreapp3.1;netcoreapp2.1;net472</TargetFrameworks>-->
-    <TargetFrameworks>netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netcoreapp3.1;netcoreapp2.1;net472</TargetFrameworks>
     <StartupObject>SixLabors.ImageSharp.Tests.ProfilingSandbox.Program</StartupObject>
     <!--Used to hide test project from dotnet test-->
     <IsTestProject>false</IsTestProject>

tests/ImageSharp.Tests/ImageSharp.Tests.csproj

@@ -2,8 +2,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-<!--    <TargetFrameworks>netcoreapp3.1;netcoreapp2.1;net472</TargetFrameworks>-->
-    <TargetFrameworks>netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netcoreapp3.1;netcoreapp2.1;net472</TargetFrameworks>
     <AllowUnsafeBlocks>True</AllowUnsafeBlocks>
     <DebugSymbols>True</DebugSymbols>
     <AssemblyName>SixLabors.ImageSharp.Tests</AssemblyName>

tests/ImageSharp.Tests/Memory/DiscontiguousBuffers/MemoryGroupIndex.cs

@@ -114,7 +114,7 @@ namespace SixLabors.ImageSharp.Tests.Memory.DiscontiguousBuffers
         {
             return group.Count == 0
                 ? new MemoryGroupIndex(group.BufferLength, 0, 0)
-                : new MemoryGroupIndex(group.BufferLength, group.Count - 1, group[^1].Length);
+                : new MemoryGroupIndex(group.BufferLength, group.Count - 1, group[group.Count - 1].Length);
         }
     }
 }