* Bug 217740: Repro and test harness for C#

* Testing and fixing loading scenario in C# and VB

* Verifying VB case using attribute on field

* Adding more tests

* Adding VB tests

* Adding tests

* More tests on fields with double-attributes

* New test constraint

* Fixing VB side to new test constraints

* Fixing C# side to new test constraints

* Fixing remaining tests

* Adding comments

* Fixing VB field scenario too

Do not report warnings for malformed InformationalVersionAttribute values

Adjust implementation of MemberSemanticModel.GetEnclosingBinderInternal to avoid NullReferenceException.

The change addresses the situation when SemanticModel is created to speculate on a With block and the function is trying to locate a binder for the With expression within the block.

Fixes https://devdiv.visualstudio.com/DefaultCollection/DevDiv/_workitems?id=187910&_a=edit.

Restore backward compatibility in the way conversion from a reference type to an intrinsic value type is evaluated.

Fixes #9887.

* Move Roslyn to newer toolset packages

1. Move to 1.2.1 compiler toolset package.
2. Move to 1.2.0-beta1 analyzer packages.
3. Turn on IOperation feature flag for all projects as the new analyzer packages have IOperation based analyzers.

* Use the Roslyn wide default CA rulesets for newly added samples project.

* Fix couple of test projects to use the Roslyn wide rulesets for code analysis.

* Move to analyzers 1.2.0-beta2 packages (multiple fixes and enhancements to Roslyn diagnostic analyzers)

* Revert accidental file mode changes.

* Move shipped implicit constructors to public API shipped files.

Fixes #11446

These were workarounds for building with Visual Studio 2015 RTM. We
don't support that anymore.

Fixes #8767.

JSON spec makes escaping of forward slashes optional and many have
complained about the aesthetics of '\/'. Previously, we got this
behavior from the DataContractJsonSerializer and could not override
it, but now that the dependency has been removed, we can eliminate
the unnecessary escaping.

harden both DetectTypeCircularity and GetDependenceChain

* remove old syntax tree root tests

* fix vb tests

Ensure that we generated a CompilationCompletedEvent for compilations with no source files (example an empty VSIX projects).

Move lines appearing in PublicAPI.Unshipped.txt files to
PublicAPI.Shipped.txt files and re-sort the latter.

Note: VB scripting APIs and APIs for IOperation continue to remain
unshipped.

To prevent projects across the tree from having different dependencies, we unify
external package dependencies by creating empty C# projects that represent them.
We then make use of project.json package inheritance (where a project inherits
all packages dependencies from their dependencies) to unify it across the tree.

No projects outside of this tree, should be directly referencing versions of
these dependencies manually.

For this check-in I've tackled Metadata, Reflection, and DiaSymReader. Will tackle
the rest in future commits.

This reverts commit 92ff3f8d.

Make compiler produce the same Product Build, Major, Minor and Private Parts in VersionInfo as VS2013 compiler when Assembly ProductAssemblyFileVersionAttribute and AssemblyInformationalVersion contain invalid format. Also introduce warning diagnostic for AssemblyInformationalVersion with invalid version string

VB: Always import instance fields for an Enum type in order to be able to infer underlying type of its elements.

Address https://devdiv.visualstudio.com/DefaultCollection/DevDiv/_workitems?_a=edit&id=193333.

There is a small product change to fix https://devdiv.visualstudio.com/defaultcollection/DevDiv/_workitems?_a=edit&id=111538 and enable corresponding unit-test.