v2.9.0

• Switch to Roslyn 3.x libraries
• Add Directory.Build.props file
• Add open configuration commands to Command Palette (VS Code) (PR)

Bug Fixes

• Fix key duplication/handle camel case names in omnisharp.json (PR)
• Use prefix unary operator instead of postfix unary operator (RCS1089) (issue)
• Cast of this to its interface cannot be null (RCS1202) (issue)
• Do not remove braces in switch section if it contains 'using variable' (RCS1031) (issue)

New Analyzers

• RCS1242 (DoNotPassNonReadOnlyStructByReadOnlyReference).
• RCS1243 (DuplicateWordInComment).
• RCS1244 (SimplifyDefaultExpression).
• RCS1245 (SimplifyConditionalExpression2) (issue).

Analyzers

• Disable analyzer RCS1057 by default (issue).
• Merge analyzer RCS1156 with RCS1113 (issue).
  • x == "" should be replaced with string.IsNullOrEmpty(x)
• Improve analyzer RCS1215 (commit).
  • x == double.NaN should be replaced with double.IsNaN(x)
• Enable RCS1169 and RCS1170 if the type is read-only struct (commit).
• Improve analyzer RCS1077 (commit).
  • x.OrderBy(y => y).Reverse() can be simplified to x.OrderByDescending(y => y)
  • x.SelectMany(y => y).Count() can be simplified to x.Sum(y => y.Count) if x has Count or Length property
• Improve analyzer RCS1161 - Declare explicit enum value using << operator (commit).
• Improve analyzer RCS1036 - remove empty line between documentation comment and declaration (commit).
• Improve analyzer RCS1037 - remove trailing white-space from documentation comment (commit).
• Improve analyzer RCS1143 (commit)
  • x?.M() ?? default(int?) can be simplified to x?.M() if x is a nullable struct.
• Improve analyzer RCS1206 (commit)
  • (x != null) ? x.M() : default(int?) can be simplified to x?.M() if x is a nullable struct.