Ensure BoundLValueToRValueWrapper nodes are marked as compiler generated.

Port2966

Correct the copyright header on four files.

Fix cast simplification to not offer cast removals for following cases:

1. Explicit numeric casts in explicit checked/unchecked context
2. Non-identity pointer-to-pointer conversions.

Fixes #2691

Description: Fix is to bail out early for these cases. As we are now more conservative, we cannot regress in offering any additional incorrect cast removals. #2987 tracks improving on this conservative approach post 1.0 milestone.

Testing Done: Existing cast simplification tests.

Approved by MattGe.

1) Explicit numeric casts in unchecked context
2) Non-identity pointer-to-pointer conversions.

Fixes #2691

Description: Fix is to bail out early for these cases. As we are now more conservative, we cannot regress in offering any additional incorrect cast removals.

Testing Done: Existing cast simplification tests.

Fix NullReferenceException in DependentProjectsFinder when we have an InternalsVisibleTo attribute with a null constructor arg.

Generate relative paths correctly.

**Bug:** Fixes #1579.

**Customer Scenario:**
The customer wishes to use a shared rule set file in their project to control their diagnostics. The .ruleset file is at the root of their solution, so the customer adds it to their project as a linked file. They then set it as the active rule set by right-clicking on the file in Solution Explorer and selecting "Set as Active Rule Set".

The file should become the active rule set for the project, turning various diagnostics on or off or altering their severity. Instead the customer gets an error in the Error List: "The file '..\\..\\..\\Rule.ruleset' cannot be found" and the rule set has no effect.

**Fix:**
When adding `..` to the relative path to backup to higher-level directories, we effectively add each one multiple times. The fix is to stop doing that.

**Testing:**
I manually tested the following variation on the original scenario:

* Rule set file in the same directory as the project file
* Rule set file one level above the project file
* Rule set file two levels above the project file
* Rule set file up two levels and then down in a subdirectory
* Rule set file one level below the project file
* Rule set file two levels below the project file
* Rule set file on a different directory

and verified that in each case the project file ends up with the correct path, and that the rule set takes effect as expected.

I also added unit tests to exercise the affected code.

Use a ConditionalWeakTable for SyntaxContext cache

Fix Code Model bug with adding attributes in presence of XML doc comments

Guard against concurrent callbacks into analyzers in IDE

Customer scenario: We need to do so for couple of scenarios:

1. Different diagnostic clients might end up requesting diagnostics at the same time and hence end up attempting to invoke into the same analyzer simultaneously.


2. FixAll occurrences computes diagnostics in parallel, hence can causes concurrent callbacks.

If the analyzer hasn't been written in a thread-safe way, then concurrent callbacks into it can cause analyzers to produce incorrect/misleading/duplicate diagnostics or the analyzer itself might throw and never execute again in the VS session.

Fixes #2410

Testing: There is no functional change here, so existing tests provide adequate coverage. I manually verified that FixAll performance is acceptable for simplify name/remove unnecessary usings across projects/solution in Roslyn.sln

Approved by MattGe.

Fixes #2662.

Make C# lexer resilient to binary data

Ensure anonymous types are always defined in a Global namespace.

Optimize away BoundReferenceAssignment in StackScheduler if the assigned local isn't used.

remove disposal logic from recoverable tree and text

remove rule about no line between attributes

Fixes #2771

Fix errors reported intermittently when changing the current IP by drag & drop right after edit

Use correct count in ReplaceSeparator

These unit tests will now assert that casing is unchanged by
`FilePathUtilities.GetRelativePath(...)`.

The bounds checking code for the existing separator has no need to do an
upper bound check on `index`.  The IndexOf method will return -1 or a
valid index into nodesWithSeps.  Hence the comparison with `this.Count`
here was both unnecessary and incorrect (should have been
`nodesWithSeps.Count`).

closes #2630

The `FilePathUtilities.GetRelativePath(...)` method is used in various
places in the Workspaces and VS layers to generate a relative path from
a starting directory to a target file or directory. However, it has a
bug where it will generate an incorrect path if you need to go up more
than one level from the starting directory to get to the target.

For example, if the starting directory is `C:\Alpha\Beta\Gamma` and the
target is `C:\Alpha\SomeFile.txt`, the correct relative path would be
`..\..\SomeFile.txt`. Instead, we get `..\..\..\SomeFile.txt` (note the
extra `..`).

This commit fixes the issue and adds unit tests for this method.

We need to do so for couple of scenarios:

1. Different diagnostic clients might end up requesting diagnostics at the same time and hence end up attempting to invoke into the same analyzer simultaneously.

2. FixAll occurrences computes diagnostics in parallel, hence can causes concurrent callbacks.

Fixes #2928.

Fixes #2640.

Update PublicAPI.txt to reflect recent changes to Scripting APIs.

added build only filter support to error list

Refine hoisted local scopes in async methods

Make APIs related to scripting and interactive internal for RTM