* Initial UseConditional work.

* Initial UseConditional work.

* Working replacement.

* Extract common code.

* Make 'var' work properly in the simplifier service.

* Move types to their own files.

* Provide a way to create types that are not simplified to 'var'.

* Update test options.

* Update test.

* Move CSharp code style code down to the Workspace layer.

* Rename config value.

* Add ui options.

* Add VB ui options.

* Add VB support

* Strip trivia

* Initial stubs for 'use conditional for returns'

* Add VB impl.

* Only support processing of real trees.

* Actually assign variable.

* Don't assume a single variable.

* Share more code.

* Fix shared code.

* Add check.

* Simplify code.

* Only the analyzer needs to check the severity.

* Generalize loc strings.

* remove static.

* Remove unneeded methods.

* Do cheap checks first.

* Handle more cases.

* Handle more cases.

* Add test.

* Add tests.

* Add test.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Fix tests.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Format multiline conditions.

* Add multiline formatting for VB.

* Move code.

* Simpler formilization of casts.

* Extract out code.

* Remove file.

* Move files.

* Share more code.

* Share more code.

* Break out types.

* Share more code.

* Add more tests.

* Add VB tests.

* Simplify.

* Add comment.

* Remove newlines.

* Move method.

* Move method.

* Add comments.

* Simplify

* Update comment.

* Update comment.

* Remove line.

* Update comment.

* Update comment.

* Update comment.

* Fix comment.

* Wrap long lines.

* Wrap long lines.

* Wrap long lines.

* Handle trivia.

* Simplify.

* Fix check.

* better support for else-if chains.

* Add comments.

* Remove 'Use Conditional Expressoin'

* Remove more vestiges of
 feature.

* Remove code.

* Add back newline.

* Remove helper.  The simplifier will do the right thing now.

* try to use var first, before removing casts.

* Update tests.

Don't try to create a XamlProject for a null hierarchy.

Fixing NullReferenceException inside ConvertToInterpolatedString

Changing some IDE tests from async void to Task

* move back to debug assert.

realized why this was debug assert. if user kills OOP explicitly, connection can disconnect without us explicitly disposing it. especially for connection that kept alive (KeepAliveConnection). that is why this was debug assert.

moving back to debug assert.

* updated wording on assert

* Initial UseConditional work.

* Initial UseConditional work.

* Working replacement.

* Extract common code.

* Make 'var' work properly in the simplifier service.

* Move types to their own files.

* Provide a way to create types that are not simplified to 'var'.

* Update test options.

* Update test.

* Move CSharp code style code down to the Workspace layer.

* Rename config value.

* Add ui options.

* Add VB ui options.

* Add VB support

* Strip trivia

* Initial stubs for 'use conditional for returns'

* Add VB impl.

* Only support processing of real trees.

* Actually assign variable.

* Don't assume a single variable.

* Share more code.

* Fix shared code.

* Add check.

* Simplify code.

* Only the analyzer needs to check the severity.

* Generalize loc strings.

* remove static.

* Remove unneeded methods.

* Do cheap checks first.

* Handle more cases.

* Handle more cases.

* Add test.

* Add tests.

* Add test.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Fix tests.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Add tests.

* Format multiline conditions.

* Add multiline formatting for VB.

* Move code.

* Simpler formilization of casts.

* Extract out code.

* Remove file.

* Move files.

* Share more code.

* Share more code.

* Break out types.

* Share more code.

* Add more tests.

* Add VB tests.

* Simplify.

* Add comment.

* Remove newlines.

* Move method.

* Move method.

* Add comments.

* Simplify

* Update comment.

* Update comment.

* Remove line.

* Update comment.

* Update comment.

* Update comment.

* Fix comment.

* Wrap long lines.

* Wrap long lines.

* Wrap long lines.

* Handle trivia.

* Simplify.

* Fix check.

* better support for else-if chains.

* Add comments.

* Remove 'Use Conditional Expressoin'

* Remove more vestiges of
 feature.

* Remove code.

* Add back newline.

Merge dev15.8-preview1 to master

Update Developing a Language Feature.md

* Adding support for for each variable

* Adding support for for statement variables

* Adding named arguments

* Adding support for using statement

* Addressing feedback

Remove build logic for old VS versions

Remove SynchronizationContext monitoring from WpfFactAttribute

Test timeouts and deadlocks are handled by other infrastructure in Roslyn. This
functionality from WpfFactAttribute was interfering.

Closes #26247

This logic is for both Dev14 and Dev15RC, neither of which is supported
by our infrastructure anymore. Removing as it's not needed.

closes #26249

* add callstack on debug to make investigation easier

* if GetPinnedScopeAsync throws cancellation exception, connection can be leaked not disposed.

fixed the issue and added test

* make sure cancellation is thrown in test

* PR feedbacks

* more feedbacks

* address PR feedback

Skip WorkspaceCoordinatorTests.FileFromSameProjectTogetherTest

Log the path to procdump

Add Microsoft.CodeAnalysis.Workspaces.MSBuild.dll to our setup deploy

Remove unnecessary Microsoft.Build.Runtime package reference from EditorServicesTest2

Merge dev15.7.x to dev15.8-preview1

This diagnostic will tell us what ProcDump is being used during builds.
Needed to help us understand why we aren't getting crash dumps on our
Spanish jobs.

Merging on behalf of @Neme12. Thanks!

Enable implicit framework references

Although taking a dependency on this in Visual Studio isn't recommended,
not including this means any extension who do will end up with a
smorgasboard of versions that they are trying to deploy, which will
probably conflict with the versions that we are deploying and everything
would explode.

Implicit framework references were disabled at the time we moved over to
the new SDK due to some remanants of project.json in our build. Those
have all been cleaned up now and hence moving us over to using implicit
framework references.

Not having this enabled meant the API surface we were targeting in our
projects was not actually what was available in the project target
framework. Instead it was the intersection of the target framework and
the set of NuGet packages we reference. This meant that code which
should work simply wasn't due to the API surface not being correct.