* add vb version 15

* Fix case on LanguageVersion

because there are arguments missing, to force lambda binding
for error recovery.
Fixes #11053, #11358

* Tests: fix minasync Task<T> to derive from Task

* Tests: provide MinAsyncCorlibRef

This combines the async features of minasync with mincorlib to produce
a minimum unversioned corlib with async stubs.

* Compilation: use System.Object from target corlib

When creating a script compilation without an explicit return type,
System.Object was being resolved via reflection from the host.

This resulted in an implicit dependency of a script compilation on the
host corlib, even if a different corlib was specified as a reference
for the compilation (e.g. Xamarin.iOS).

Fix this by using System.Object as defined in the corlib resovled
for the compilation.

* Tests: fix minasync Task<T> to derive from Task

* Tests: provide MinAsyncCorlibRef

This combines the async features of minasync with mincorlib to produce
a minimum unversioned corlib with async stubs.

* Compilation: use System.Object from target corlib

When creating a script compilation without an explicit return type,
System.Object was being resolved via reflection from the host.

This resulted in an implicit dependency of a script compilation on the
host corlib, even if a different corlib was specified as a reference
for the compilation (e.g. Xamarin.iOS).

Fix this by using System.Object as defined in the corlib resovled
for the compilation.

Fixes some of the scenarios for https://devdiv.visualstudio.com/DefaultCollection/DevDiv/_workitems?id=204561&_a=edit.

to ensure that we bind the lambda for intellisense purposes.
I also hand-tested the scenario of #4480 to reproduce it on VS2015
and to verify that the problem does not occur on the master branch.
Fixes #4480

Fixes some of the scenarios for https://devdiv.visualstudio.com/DefaultCollection/DevDiv/_workitems?id=204561&_a=edit.

Add ChecksumAlgorithm to csc/vbc build task

Fixes #10451

Expression trees can naturally ignore return value when necessary and old compiler was skipping relaxation in this case.

Fixes: #8804

* 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

So far compiler knows about the following signatures of DeprecatedAttribute constructor.
   DeprecatedAttribute(String, DeprecationType, UInt32)
   DeprecatedAttribute(String, DeprecationType, UInt32, Platform)
   DeprecatedAttribute(String, DeprecationType, UInt32, Type)

As of TH2 and onwards  Windows SDK  uses the following signature for the DeprecatedAttribute:

     DeprecatedAttribute(String, DeprecationType, UInt32, String)

Notice the "String" at the end of the signature.
This change adds the TH2 attribute signature to the known set.

Fixes: #10630

Fixes https://github.com/dotnet/roslyn/issues/11368

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.

The intent of ServerRespectsAppConfig was to verify the server actually read the default timeout value from the application configuration file.  The test validated this in a very indirect way:

- Changing the value in app.config
- Starting the server
- Verifying it stopped in the given time frame

This can fail for a number of reasons: computer load during the test, another process communicating with the server, etc ...

Changed the test to just directly test the value being read from application settings.

Justification for ask mode: this test was flaky enough to break signed builds.

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

Fixes #9887.

* Fix reporting of EnC diagnostics

* Keep original overloads on DocumentDiagnosticAnalyzer for compat with TS and F#

* 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