* Add ITypeSymbol.IsUnmanagedType and ITypeSymbol.IsRefLikeType

Fixes #30427 and #30426

Fix the InvalidCastException when trying to introduce a variable

Handle null value for `IDeclarationPatternOperation.DeclaredSymbol`

Merge dev16.0-preview2 to master

Pattern-based 'await foreach' should find parameterless 'GetAsyncEnumerator' and 'MoveNextAsync' (#32184)

Merge dev16.0-preview2 to master

Fix IDE0055 formatting errors

Handle recursive patterns in IOperation based GetValueUsageInfo method

https://github.com/dotnet/roslyn/commit/6224a5c2feb8c9096cf5765f3d8d2ded396e7e88#diff-b68aa1802251151217571a56d9bfd2b8R31 changed the semantics of `IDeclarationPatternOperation` to allow null `DeclaredSymbol`. Fix SymbolUsageAnalysis invoked by unused parameters/values analyzer to handle this case. Confirmed the NRE in the unit test prior to the fix.

Fixes #32287

* Run CI builds for 16.0 preview2 vs-deps PRs

* Trigger branch builds on commit for preview branches

Fix brace placement for destructor in "Implement interface with Dispose pattern"

Added unit tests for remove unused values analyzer/fix, which invokes this method, and was asserting with the repro in the issue.
Fixes #32271

Use PipeOptions.CurrentUserOnly

Fix simplifier when reducing nodes inside a C# AnonymousObjectMemberDeclarator

Now that we are targetting netcoreapp2.1 we can use the
`PipeOptions.CurrentUserOnly` option:

- https://github.com/dotnet/corefx/issues/25427

This is implemented by both CoreClr and Mono. It covers all of the
identity checking to make sure the same user is connected to both ends
of a named pipe. This is mostly just an implementation of what we were
already doing via ACLS and private reflection. But now it can simply be
delegated to the runtime entirely

Merge dev16.0-preview2 to master

Filter out wpftemp projects.

Unify StrongNameProvider implementations

Fixup the triggers

Fixup our triggers for branches.

Publish VSIX installer with build

IDE0060 doesn't warn about unused params in ISerializable constructors