Check if syntax tree is present

Fix crash in Inline Rename

As the types into an Inline Rename field, the Rename engine attempts to resolve conflicts at each reference. It does this by expanding nodes are the references and then simplifying them down to the smallest node that does not change semantics.

During this process, one of the expansion steps is to add explicit types to lambda parameters that were defined without types. However, the expander wasn't rewriting lambdas with multiple parameters correctly. Essentially, the rewriter assumed that, when replacing a node within a `SeparatedSyntaxList<T>`, the identities of other nodes within the list would not change. However, that's not the case. So, it would successfully replace the first parameter within a lambda's parameter list. However, when it attempted to replace the second parameter, the *original* second parameter could no longer be found in the `SeparatedSyntaxList<T>` because the identity of the second parameter in the list had changed. At this point, `SepratedSyntaxList<T>.Replace(...)` would throw an `ArgumentOutOfRangeException` and VS would crash.

The user scenario is that typing within an Inline Rename field can cause Visual Studio to simply crash, resulting in potenal data loss.

The fix changes the rewriter to not pass the original parameters to `SeparatedSyntaxList<T>.Replace(...)`. Instead, it passes the parameters that are contained when the new list as it builds it up.

This is a regression introduced after Update 1 with PR #6432.

Update System.Reflection.Metadata to 1.2.0 release

[Stabilization, Crash] Rename: Don't restrict rename project search set for explicit interface implementations

Fix null ref in C# expander when adding cast to lambda return statement

[Stabilization] Codefix ordering: Prevent Low Priority fixes from interfering with Medium Priority fix ordering

Put the 'Add Nuget Reference' feature behind a disabled regkey option.

Explicitly list dependencies in TestUtilities project.json, the new nuget.exe doesn't flow them anymore.

Fix intermittent crash in CompilationWithAnalyzers due to an OjbectDi…

Fixes #8139

We were previously asserting that renaming a private member meant that the rename operation would occur entirely in that member's declaring project, but rename affect other projects if the private member is an explicit implementation of a public interface member.

Add a key binding of Ctrl+F12 for Go to Implementation

Handle base keyword for submission class speculation model

Fixes #9576

In the C# expander, we added a step to expand return statement expressions within lambda bodies to aid in conflict resolution for refactoring. However, we failed to account for the fact that lambda return statements can legally have no expression. A simple null-ref is all that's necessary to fix the crash.

Note: This bug was introduced (by me!) in #6432. It was not included in Update 1, so this is a newly-introduced regression in Update 2.

Fixes VSO Bug [199252](https://devdiv.visualstudio.com/DefaultCollection/DevDiv/_workitems?_a=edit&id=199252)

Root cause: We were attempting to access the cancellation token for a cancellation token source within a lambda within the using statement for the token source. If client fires a cancellation before the task within the lambda executes, the token source may have been disposed when the task is eventually activated.

Fix: This change saves the cancellation token for the token source upfront for use within the lambda and also checks for cancellation before computing diagnostics.

Justification for ask mode: We are hitting this intermittent crash in perf runs in an internal VSO branch and fix doesn't have any risks.

To enable the feature set the following DWORD regkey to 1:
Key: HKEY_CURRENT_USER\SOFTWARE\Microsoft\VisualStudio\<your hive>\Roslyn\Internal\OnOff\Components
Name: PackageSearch

To disable, set it to 0.

Fixed race in diagnostic tagger

Fixes #9596

To do this, we are relying on the support that Visual Studio provides
that lets us target a keybinding for a specific editor factory. This
has the downside that we must specify the keybinding for each editor
factory and if the user wants to change it they'll have to change it
for each context. It's our belief that to properly define a context
that can be consumed in this case requires either editor support (or
lots of debugging) so until then this is good enough.

Fixes #8226.

Non-Fatal Watson if ReiteratedVersionNumber matches when text does not.

change telemetry reporting for rename

Only log formatting events in telemetry when they are enacted by the …

Fix crash if client completes the event queue before the compiler is finished with it.

Allow null Compilation in SymbolDistinguisher.Description.GetHashCode

Disable diagnostic service for projects that we know we don't have all information to provide good results.

Revert "Revert "Disable diagnostic service for projects that we know we don't have all information to provide good results.""

Port analyzer allocation fixes from master to stabilization

Fix race condition when generating simulated compilation events