Fixes EnC function remapping of an active statement containing await expression

Honor requested categories and spans specified by light bulb

The previous code for PDB emit was erroneously assuming that extern
alias declarataions and usings/imports for those declarations could
only occur at the top-level namespace scope.

This changes PDB emit to walk through all scopes above the use site
instead of just the top-level scope.

Fixes #1764.

Fix a crash during IL generation for an Expression Tree involving an extension Add method used within a collection initializer

1. When light bulb asks us for suggestions (i.e. in HasSuggestedActionsAsync() and GetSuggestedActions()), it also specifies the category of suggestions that it is looking for (code fixes, refactorings, anything etc.). So far, we were completely ignoring the requested categories. HasSuggestedActionsAsync() would always return true so long as we had a code fix (that is not a suppression fix) and GetSuggestedActions() would always return all types of suggestions (fixes, suppressions and refactorings) regardless of what the light bulb is asking for. This led to strange bugs where we would return refactorings even when light bulb didn't ask for them. In other cases, HasSuggestedActionsAsync() and GetSuggestedActions() would disagree for the same requested categories. This change makes things consistent so that we always honor the suggestion categories that the light bulb is requesting.

2. When computing refactorings we were completely ignoring the span specified by light bulb and only considering selection specified by user. This led to incorrect behavior in some cases - for example, on mouse hover over a squiggle, we would return the code fixes corresponding to the squiggle along with refactorings for completely unrelated portions of the code that the user may have previously selected.

Fixes #1030, #1595, #1631

Fixed parsing logic for rsp file arguments to implement speced behavior.

make persistent service not to support project k for now.

...

also change to use cached IVsHierarchy only for error list filtering due to issue with caching it on shared projects

VisualBasicCodeModelService should handle Constructor case for Function ...

In particular, it is allowed for arguments to have embedded quoted portions like

/define:Unquoted"Quoted"Unquoted"Quoted"

wich means

/define:UnquotedQuotedUnquotedQuoted

when passed on command line, and should mean exactly the same when passed in an rsp file.

The change fixes #1784

Expand LINQ expression for building auto-completion brace chars to reduce JIT time in the "open file" scenario.

VisualBasic CodeModel Service should handle Declare Function and Sub for St...

Fix DiagnosticAnalyzerExtensions.GetDiagnosticAnalyzerCategory to return DiagnosticAnalyzerCategory.SemanticDocumentAnalysis if the analyzer has semantic actions and cannot support semantic span based analysis.

Fixes #1709 

Fix #1843 : VisualBasicCodeModelService to get the function kind for Constructor had
a syntactic blunder where the case was not allowed to fall through

Fix #1839 : Visual Basic CodeModelService not handles Declare Function
and Sub for StartPoint and EndPoint.

Fix DiagnosticAnalyzerExtensions.GetDiagnosticAnalyzerCategory to return DiagnosticAnalyzerCategory.SemanticDocumentAnalysis if the analyzer has semantic actions and cannot support semantic span based analysis.

Fixes #1709

also change to use cached IVsHierarchy only for error list filtering due to issue with caching it on shared projects

Require correct null constant encoding in metadata

Currently, a bug is present in the perf machine where the compiler
server parent directory and the client parent directory differ only by
casing. Rather than try to fix this specific instance, we should remove
the reliance on .NET APIs to return the same value for the client and the
server by simply passing the pipe name to the compiler server.

This should mean that every identical instantiation of the client results
in the same pipe name and remove the logic in the server.

Document moniker look up for shared item that is a contained document

Refactoring the code a bit. Pushed the mapping of hierarchy to shared hierarchy and itemId to shareditemId into LinkedFile Utility class. So now we give a hierarchy, itemId pair and get back a sharedhierarchy, itemId pair.

Port CA1813 (Avoid Unsealed Attributes) to System.Runtime.Analyzers.

Unskip tests fixed by #662 and #679. 

show conditional element access sig-help after arbitrary expressions

the old model would only appear after an identifier name

don't assume that a constructor's parent is a TypeBlockSyntax

Fix variable capturing for VB lambdas in EE...

Variables may have been captured by lambdas in the original method
or in the expression, and we need to preserve the existing values of
those variables in the expression. This requires rewriting the variables
in the expression based on the closure classes from both the original
method and the expression, and generating a preamble that copies
values into the expression closure classes.

Consider the original method:
```
Shared Sub M()
    Dim x, y, z as Integer
    ...
    F(Function() x + y)
End Sub
```
and the expression in the EE: "F(Function() x + z)".
The expression is first rewritten using the closure class and the local
`<1>` from the original method: F(Function() `<1>`.x + z)
Then lambda rewriting introduces a new closure class that includes
the locals `<1>` and z, and a corresponding local
`<2>`: F(Function() `<2>`.`<1>`.x + `<2>`.z)
And a preamble is added to initialize the fields of `<2>`:
```
    <2> = New <>c__DisplayClass0()
    <2>.<1> = <1>
    <2>.z = z
```

Activating a previously failed testcase

Merge branch 'master' of https://github.com/dotnet/roslyn into DocumentMonikerLookUpForSharedItemThatIsAContainedDocument

In script and error scenarios, VB and C# syntax nodes corresponding to
constructors/methods/properties/etc. won't necessarily have a parent.
Adding some null checks to prevent a future NRE.

Fixes #317 : This HandleSolutionProjectTypeSolutionFolder was failing
because the msbuild bits in Jenkins were older bits. Now the bits should
have been updated. Hence enabling the test.

Add ErrorCode checks for properties of Dkm*AsyncResult...

It appears that DkmGetFrameArgumentsAsyncResult.Arguments may throw in some cases (rather than an empty array).  We should be resiliant to that and behave as though there are no argument values available.

I threw in a similar check for generic type arguments as well (just for good measure).

display the class's doc comment in attribute quick info