* Add ITypeSymbol.IsReadOnly public API

* Fix build failures in Roslyn.sln

* Update doc comment

* Add syntax tests for readonly members

* Add simple test for readonly struct method

* Allow readonly modifier on methods in structs

* Add simple readonly class method test

* Add SourceMemberMethodSymbol.IsReadOnly

* Test readonly static method

* Disallow readonly accessors on static properties

* Check usages of readonly keyword in property (not accessor) declarations

* Add ref-returning readonly method test

* Add readonly ref readonly parsing test

* Allow readonly modifier on property decls in general. Add more tests.

* Add indexer tests

* Readonly events on structs

* Remove comment

* Disallow readonly on events with associated fields

* Test static readonly auto properties and destructors

* Disallow redundant readonly on accessor. Simplify diagnostics for static readonly property.

* Add tests based on feedback

* Note that feature checks and corresponding tests are needed

Merge master to features/readonly-members

Merge dev16.0 to master

Merge master to features/readonly-members

Allow specific exception without crash in integration tests

Merge master to features/readonly-members

Delayed failures in integration tests

Revise NullableWalker to use a two-state solution

Merge master to features/readonly-members

Reflects the changes described in https://github.com/dotnet/csharplang/pull/2214.

Range now looks optimistically for some special members with optional
parameters, but will fall back to the Range constructor if they aren't
present.

This change also removes all of the specialized codegen that was going
on with arrays and strings in favor of expected helpers or real members.

Merge remote-tracking branch 'dotnet/master' into pr/33648-revise-nullablewalker-to-use-a-two-state-solution

This change ensures that logs are created even if the application fails
to capture a screenshot.

VisualStudioInstanceFactory failures now occur in a context where they
are reported as test failures instead of test runner crashes.

Undo arcade work arounds

* Fixes 33602

* respond to comments

I verified that this test crashes the compiler in Preview3
but no longer repros.

Fixes #33537

Marshal.SizeOf is not a direct replacement for `sizeof` and the issues around it are subtle.

Fix #26513

Now that we have the version of arcade that supports
Microsoft.Net.Compilers.Toolset we can remove a few work arounds.

Mark Roslyn.VisualStudio.DiagnosticsWindow as a build dependency…

[master] Update dependencies from dotnet/arcade

* Nullability for NVT with no constructor argument:
- Explicitly check if an object creation is a nullable value type
- Set its state to nullable when it is the default constructor that is being called
- Update tests

Mark Roslyn.VisualStudio.DiagnosticsWindow as a build dependency of Microsoft.VisualStudio.IntegrationTest.Setup

Fixes #33762

Non-private readonly fields are PascalCase

Auto-attach debugger to target instance of Visual Studio during integration tests

Enable C# 8.0 in the code base

Merge master to features/readonly-members

This change updates the following dependencies
- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19127.8

Merge dev16.0 to master

* Update dependencies from https://github.com/dotnet/arcade build 20190116.1

This change updates the following dependencies
- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19066.1

* Update dependencies from https://github.com/dotnet/arcade build 20190117.6

This change updates the following dependencies
- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19067.6

* Update dependencies from https://github.com/dotnet/arcade build 20190118.4

This change updates the following dependencies
- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19068.4

* Update dependencies from https://github.com/dotnet/arcade build 20190119.2

This change updates the following dependencies
- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19069.2

* Update dependencies from https://github.com/dotnet/arcade build 20190120.2

This change updates the following dependencies
- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19070.2

* Update dependencies from https://github.com/dotnet/arcade build 20190122.5

This change updates the following dependencies
- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19072.5

* Update dependencies from https://github.com/dotnet/arcade build 20190123.5

This change updates the following dependencies
- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19073.5

* Update dependencies from https://github.com/dotnet/arcade build 20190130.6

This change updates the following dependencies
- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19080.6

* Update dependencies from https://github.com/dotnet/arcade build 20190131.3

This change updates the following dependencies
- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19081.3

* Update dependencies from https://github.com/dotnet/arcade build 20190201.16

This change updates the following dependencies
- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19101.16

* Update dependencies from https://github.com/dotnet/arcade build 20190202.1

This change updates the following dependencies
- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19102.1

* Update dependencies from https://github.com/dotnet/arcade build 20190203.1

This change updates the following dependencies
- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19103.1

* Update dependencies from https://github.com/dotnet/arcade build 20190204.18

This change updates the following dependencies
- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19104.18

* Update dependencies from https://github.com/dotnet/arcade build 20190205.5

This change updates the following dependencies
- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19105.5

* Update dependencies from https://github.com/dotnet/arcade build 20190206.4

This change updates the following dependencies
- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19106.4

* Update dependencies from https://github.com/dotnet/arcade build 20190207.1

This change updates the following dependencies
- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19107.1

* Update dependencies from https://github.com/dotnet/arcade build 20190208.1

This change updates the following dependencies
- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19108.1

* Update dependencies from https://github.com/dotnet/arcade build 20190212.3

This change updates the following dependencies
- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19112.3

* Update dependencies from https://github.com/dotnet/arcade build 20190213.1

This change updates the following dependencies
- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19113.1

* Update dependencies from https://github.com/dotnet/arcade build 20190214.4

This change updates the following dependencies
- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19114.4

* Update dependencies from https://github.com/dotnet/arcade build 20190215.1

This change updates the following dependencies
- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19115.1

* Update dependencies from https://github.com/dotnet/arcade build 20190219.2

This change updates the following dependencies
- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19119.2

* Update dependencies from https://github.com/dotnet/arcade build 20190221.1

This change updates the following dependencies
- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19121.1

* Update dependencies from https://github.com/dotnet/arcade build 20190221.5

This change updates the following dependencies
- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19121.5

* Update dependencies from https://github.com/dotnet/arcade build 20190222.3

This change updates the following dependencies
- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19122.3

* Update dependencies from https://github.com/dotnet/arcade build 20190223.1

This change updates the following dependencies
- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19123.1

* Update dependencies from https://github.com/dotnet/arcade build 20190224.1

This change updates the following dependencies
- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19124.1

* Update dependencies from https://github.com/dotnet/arcade build 20190225.2

This change updates the following dependencies
- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19125.2

* Update dependencies from https://github.com/dotnet/arcade build 20190226.6

This change updates the following dependencies
- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19126.6