Chasm.Compatibility 2.6.0

Chasm.Compatibility

Provides a bunch of compatibility stuff, polyfills and shims.

Uses officially provided packages when possible, and uses its own when official ones aren't available.

Chasm.Compatibility extends support down to netcoreapp1.0, netstandard1.0 and net35.

DO NOT use this for other packages!

[!CAUTION]

But if, for some reason, you need to, make sure you're targeting the same framework versions as this package!
Otherwise, your users may end up with ambiguous type reference errors!

For example:
Your package targets Standard 2.0, and uses this package's target for Standard 2.0, which polyfills AllowNullAttribute (that was introduced in Standard 2.1). Then, the user of your package targets Standard 2.1 (which already has an AllowNullAttribute) and uses your library for Standard 2.0, which in turn references this package (with polyfilled AllowNullAttribute).

How does this compare to PolySharp?

PolySharp only polyfills types that are actually used (which is a good thing) and puts them in the project's own DLL file. But it doesn't work well in multi-project setups, with <InternalsVisibleTo> exposing one project's PolySharp generated files to another, causing ambiguous type errors.

Chasm.Compatibility, on the other hand, includes all of the types in a separate DLL. Nothing fancy, but it works fine with multiple projects, as long as you're careful with their targets.

Compatibility Table

<table> <thead> <tr> <th rowspan="2">Features</th> <th rowspan="2">Compatibility type</th> <th colspan="3">Framework support</th> </tr> <tr> <th>.NET / .NET Core</th> <th>.NET Standard</th> <th>.NET Framework</th> </tr> </thead> <tbody>

<tr>
  <td rowspan="3">
    <code>System.ValueTuple</code>
  </td>
  <td>Core libraries</td>
  <td><code>netcoreapp2.0</code></td><td><code>netstandard2.0</code></td><td><code>net47</code></td>
</tr>
<tr>
  <td>Official packages</td>
  <td><code>netcoreapp1.0</code></td><td><code>netstandard1.0</code></td><td><code>net45</code></td>
</tr>
<tr>
  <td>Chasm.Compatibility</td>
  <td><code>netcoreapp1.0</code></td><td><code>netstandard1.0</code></td><td><code>net35</code></td>
</tr>

<tr><td colspan="5"></td></tr>
<tr>
  <td rowspan="4">
    <code>System.Index</code> and <code>System.Range</code>
  </td>
  <td>Core libraries</td>
  <td><code>netcoreapp3.0</code></td><td><code>netstandard2.1</code></td><td>—</td>
</tr>
<tr>
  <td>Official packages</td>
  <td>—</td><td>—</td><td>—</td>
</tr>
<tr>
  <td>IndexRange package</td>
  <td><code>netcoreapp2.0</code></td><td><code>netstandard2.0</code></td><td><code>net35</code></td>
</tr>
<tr>
  <td>Chasm.Compatibility</td>
  <td><code>netcoreapp1.0</code></td><td><code>netstandard1.0</code></td><td><code>net35</code></td>
</tr>

<tr></tr> 
<tr><td colspan="5"></td></tr>
<tr>
  <td rowspan="4">
    <code>System.Runtime.CompilerServices.Unsafe</code>
  </td>
  <td>Core libraries</td>
  <td><code>netcoreapp3.0</code></td><td>—</td><td>—</td>
</tr>
<tr>
  <td>Official packages (v6)</td>
  <td><code>netcoreapp2.0</code></td><td><code>netstandard2.0</code></td><td><code>net461</code></td>
</tr>
<tr>
  <td>Official packages (v5)</td>
  <td><code>netcoreapp1.0</code></td><td><code>netstandard1.0</code></td><td><code>net45</code></td>
</tr>
<tr>
  <td>Chasm.Compatibility</td>
  <td><code>netcoreapp1.0</code></td><td><code>netstandard1.0</code></td><td><code>net35</code></td>
</tr>

<tr></tr> 
<tr><td colspan="5"></td></tr>
<tr>
  <td rowspan="3">
    <code>System.HashCode</code>
  </td>
  <td>Core libraries</td>
  <td><code>netcoreapp2.1</code></td><td><code>netstandard2.1</code></td><td>—</td>
</tr>
<tr>
  <td>Official packages</td>
  <td><code>netcoreapp2.0</code></td><td><code>netstandard2.0</code></td><td><code>net461</code></td>
</tr>
<tr>
  <td>Chasm.Compatibility</td>
  <td><code>netcoreapp1.0</code></td><td><code>netstandard1.0</code></td><td><code>net35</code></td>
</tr>

</tbody> </table>