IDE Support for C# using static (changeset 1383492)

Src/Workspaces/CSharp/Portable/Extensions/ContextQuery/SyntaxTokenExtensions.cs

@@ -2,11 +2,9 @@
 
 using System.Linq;
 using Microsoft.CodeAnalysis;
-using Microsoft.CodeAnalysis.CSharp;
 using Microsoft.CodeAnalysis.CSharp.Symbols;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
 using Microsoft.CodeAnalysis.Shared.Extensions;
-using Microsoft.CodeAnalysis.Text;
 using Roslyn.Utilities;
 
 namespace Microsoft.CodeAnalysis.CSharp.Extensions.ContextQuery
@@ -20,6 +18,36 @@ public static bool IsUsingOrExternKeyword(this SyntaxToken token)
                 token.CSharpKind() == SyntaxKind.ExternKeyword;
         }
 
+        public static bool IsUsingKeywordInUsingDirective(this SyntaxToken token)
+        {
+            if (token.IsKind(SyntaxKind.UsingKeyword))
+            {
+                var usingDirective = token.GetAncestor<UsingDirectiveSyntax>();
+                if (usingDirective != null &&
+                    usingDirective.UsingKeyword == token)
+                {
+                    return true;
+                }
+            }
+
+            return false;
+        }
+
+        public static bool IsStaticKeywordInUsingDirective(this SyntaxToken token)
+        {
+            if (token.IsKind(SyntaxKind.StaticKeyword))
+            {
+                var usingDirective = token.GetAncestor<UsingDirectiveSyntax>();
+                if (usingDirective != null &&
+                    usingDirective.StaticKeyword == token)
+                {
+                    return true;
+                }
+            }
+
+            return false;
+        }
+
         public static bool IsBeginningOfStatementContext(this SyntaxToken token)
         {
             // cases:

Src/Workspaces/CSharp/Portable/Extensions/ContextQuery/SyntaxTreeExtensions.cs

@@ -506,6 +506,12 @@ public static bool IsAttributeNameContext(this SyntaxTree syntaxTree, int positi
                 return true;
             }
 
+            // using static | is never a type declaration context
+            if (token.IsStaticKeywordInUsingDirective())
+            {
+                return false;
+            }
+
             var modifierTokens = contextOpt != null
                 ? contextOpt.PrecedingModifiers
                 : syntaxTree.GetPrecedingModifiers(position, leftToken, cancellationToken);
@@ -577,6 +583,12 @@ public static bool IsAttributeNameContext(this SyntaxTree syntaxTree, int positi
                 }
             }
 
+            // using static |
+            if (token.IsStaticKeywordInUsingDirective())
+            {
+                return true;
+            }
+
             // if it is not using directive location, most of places where 
             // type can appear, namespace can appear as well
             return syntaxTree.IsTypeContext(position, cancellationToken, semanticModelOpt);
@@ -625,6 +637,7 @@ public static bool IsDefinitelyNotTypeContext(this SyntaxTree syntaxTree, int po
                 syntaxTree.IsStatementContext(position, tokenOnLeftOfPosition, cancellationToken) ||
                 syntaxTree.IsTypeParameterConstraintContext(position, tokenOnLeftOfPosition, cancellationToken) ||
                 syntaxTree.IsUsingAliasContext(position, cancellationToken) ||
+                syntaxTree.IsUsingStaticContext(position, cancellationToken) ||
                 syntaxTree.IsGlobalMemberDeclarationContext(position, SyntaxKindSet.AllGlobalMemberModifiers, cancellationToken) ||
                 syntaxTree.IsMemberDeclarationContext(
                     position,
@@ -671,6 +684,16 @@ public static bool IsUsingAliasContext(this SyntaxTree syntaxTree, int position,
             return false;
         }
 
+        public static bool IsUsingStaticContext(this SyntaxTree syntaxTree, int position, CancellationToken cancellationToken)
+        {
+            // using static |
+
+            var token = syntaxTree.FindTokenOnLeftOfPosition(position, cancellationToken);
+            token = token.GetPreviousTokenIfTouchingWord(position);
+
+            return token.IsStaticKeywordInUsingDirective();
+        }
+
         public static bool IsTypeArgumentOfConstraintClause(
             this SyntaxTree syntaxTree, int position, CancellationToken cancellationToken)
         {

Src/Workspaces/CSharp/Portable/Recommendations/CSharpRecommendationService.cs

@@ -220,6 +220,16 @@ internal class CSharpRecommendationService : AbstractRecommendationService
         {
             var symbols = context.SemanticModel.LookupNamespacesAndTypes(context.LeftToken.SpanStart);
 
+            if (context.TargetToken.IsUsingKeywordInUsingDirective())
+            {
+                return symbols.Where(s => s.IsNamespace());
+            }
+
+            if (context.TargetToken.IsStaticKeywordInUsingDirective())
+            {
+                return symbols.Where(s => !s.IsDelegateType() && !s.IsInterfaceType());
+            }
+
             return symbols;
         }
 
@@ -248,6 +258,9 @@ internal class CSharpRecommendationService : AbstractRecommendationService
                 ? context.SemanticModel.LookupStaticMembers(context.LeftToken.SpanStart)
                 : context.SemanticModel.LookupSymbols(context.LeftToken.SpanStart);
 
+            // Filter out any extension methods that might be imported by a using static directive.
+            symbols = symbols.Where(symbol => !symbol.IsExtensionMethod());
+
             // The symbols may include local variables that are declared later in the method and
             // should not be included in the completion list, so remove those. Filter them away,
             // unless we're in the debugger, where we show all locals in scope.
@@ -301,15 +314,16 @@ internal class CSharpRecommendationService : AbstractRecommendationService
                 // Filter the types when in a using directive, but not an alias.
                 // 
                 // Cases:
-                //    using | -- Show namespaces (and static types in C# v6)
+                //    using | -- Show namespaces
+                //    using A.| -- Show namespaces
+                //    using static | -- Show namespace and types
                 //    using A = B.| -- Show namespace and types
                 var usingDirective = name.GetAncestorOrThis<UsingDirectiveSyntax>();
                 if (usingDirective != null && usingDirective.Alias == null)
                 {
-                    // Do we also have inclusion of static types?
-                    if (((CSharpParseOptions)context.SyntaxTree.Options).LanguageVersion >= LanguageVersion.CSharp6)
+                    if (usingDirective.StaticKeyword.IsKind(SyntaxKind.StaticKeyword))
                     {
-                        symbols = symbols.Where(s => s.IsNamespace() || s.IsStaticType()).ToList();
+                        return symbols.Where(s => !s.IsDelegateType() && !s.IsInterfaceType());
                     }
                     else
                     {

Src/Workspaces/CSharp/Portable/Utilities/TokenComparer.cs

 // Copyright (c) Microsoft Open Technologies, Inc.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
-using System;
 using System.Collections.Generic;
 using System.Globalization;
-using Microsoft.CodeAnalysis.CSharp;
-using Microsoft.CodeAnalysis.CSharp.Symbols;
-using Microsoft.CodeAnalysis.CSharp.Syntax;
-using Microsoft.CodeAnalysis.Text;
+using Microsoft.CodeAnalysis.CSharp.Extensions;
 
 namespace Microsoft.CodeAnalysis.CSharp.Utilities
 {
@@ -32,8 +28,8 @@ private static bool IsSystem(string s)
         public int Compare(SyntaxToken x, SyntaxToken y)
         {
             if (specialCaseSystem &&
-                x.GetPreviousToken(includeSkipped: true).CSharpKind() == SyntaxKind.UsingKeyword &&
-                y.GetPreviousToken(includeSkipped: true).CSharpKind() == SyntaxKind.UsingKeyword)
+                x.GetPreviousToken(includeSkipped: true).IsKind(SyntaxKind.UsingKeyword, SyntaxKind.StaticKeyword) &&
+                y.GetPreviousToken(includeSkipped: true).IsKind(SyntaxKind.UsingKeyword, SyntaxKind.StaticKeyword))
             {
                 var token1IsSystem = IsSystem(x.ValueText);
                 var token2IsSystem = IsSystem(y.ValueText);

Src/Workspaces/CSharp/Portable/Utilities/UsingsAndExternAliasesDirectiveComparer.cs

 // Copyright (c) Microsoft Open Technologies, Inc.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
-using System;
 using System.Collections.Generic;
-using Microsoft.CodeAnalysis.CSharp;
-using Microsoft.CodeAnalysis.CSharp.Symbols;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
-using Microsoft.CodeAnalysis.Text;
 using Roslyn.Utilities;
 
 namespace Microsoft.CodeAnalysis.CSharp.Utilities
@@ -48,13 +44,21 @@ public int Compare(SyntaxNode directive1, SyntaxNode directive2)
             var directive1IsExtern = extern1 != null;
             var directive2IsExtern = extern2 != null;
 
-            var directive1IsNamespace = using1 != null && using1.Alias == null;
-            var directive2IsNamespace = using2 != null && using2.Alias == null;
+            var directive1IsNamespace = using1 != null && using1.Alias == null && !using1.StaticKeyword.IsKind(SyntaxKind.StaticKeyword);
+            var directive2IsNamespace = using2 != null && using2.Alias == null && !using2.StaticKeyword.IsKind(SyntaxKind.StaticKeyword);
+
+            var directive1IsUsingStatic = using1 != null && using1.StaticKeyword.IsKind(SyntaxKind.StaticKeyword);
+            var directive2IsUsingStatic = using2 != null && using2.StaticKeyword.IsKind(SyntaxKind.StaticKeyword);
 
             var directive1IsAlias = using1 != null && using1.Alias != null;
             var directive2IsAlias = using2 != null && using2.Alias != null;
 
             // different types of usings get broken up into groups.
+            //  * externs
+            //  * usings
+            //  * using statics
+            //  * aliases
+
             if (directive1IsExtern && !directive2IsExtern)
             {
                 return -1;
@@ -71,6 +75,14 @@ public int Compare(SyntaxNode directive1, SyntaxNode directive2)
             {
                 return 1;
             }
+            else if (directive1IsUsingStatic && !directive2IsUsingStatic)
+            {
+                return -1;
+            }
+            else if (directive2IsUsingStatic && !directive1IsUsingStatic)
+            {
+                return 1;
+            }
             else if (directive1IsAlias && !directive2IsAlias)
             {
                 return -1;

Src/Workspaces/Core/Portable/Shared/Extensions/ISymbolExtensions.cs

@@ -162,6 +162,13 @@ public static bool IsModuleType(this ISymbol symbol)
                 ((ITypeSymbol)symbol).TypeKind == TypeKind.Module;
         }
 
+        public static bool IsInterfaceType(this ISymbol symbol)
+        {
+            return
+                symbol is ITypeSymbol &&
+                ((ITypeSymbol)symbol).TypeKind == TypeKind.Interface;
+        }
+
         public static bool IsArrayType(this ISymbol symbol)
         {
             return