Merge pull request #5573 from CyrusNajmabadi/awaitClassification

Optimistically classify the 'await' keyword

Fixes #2301

src/EditorFeatures/CSharpTest/Classification/SyntacticClassifierTests.cs

@@ -3605,5 +3605,48 @@ public void LoadDirective()
                 PPKeyword("load"),
                 String("\"file.csx\""));
         }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.Classification)]
+        public void IncompleteAwaitInNonAsyncContext()
+        {
+            var code = @"
+void M()
+{
+    var x = await
+}";
+            TestInClass(code,
+                Keyword("void"),
+                Identifier("M"),
+                Punctuation.OpenParen,
+                Punctuation.CloseParen,
+                Punctuation.OpenCurly,
+                Keyword("var"),
+                Identifier("x"),
+                Operators.Equals,
+                Keyword("await"),
+                Punctuation.CloseCurly);
+        }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.Classification)]
+        public void CompleteAwaitInNonAsyncContext()
+        {
+            var code = @"
+void M()
+{
+    var x = await;
+}";
+            TestInClass(code,
+                Keyword("void"),
+                Identifier("M"),
+                Punctuation.OpenParen,
+                Punctuation.CloseParen,
+                Punctuation.OpenCurly,
+                Keyword("var"),
+                Identifier("x"),
+                Operators.Equals,
+                Identifier("await"),
+                Punctuation.Semicolon,
+                Punctuation.CloseCurly);
+        }
     }
 }

src/EditorFeatures/VisualBasicTest/Classification/SemanticClassifierTests.vb

@@ -518,5 +518,31 @@ End Class
                  Keyword("My"))
         End Sub
 
+        <Fact, Trait(Traits.Feature, Traits.Features.Classification)>
+        Public Sub TestAwaitInNonAsyncFunction1()
+            Dim text =
+<code>
+dim m = Await
+</code>.NormalizedValue()
+
+            TestInMethod(text,
+                 Keyword("Await"))
+        End Sub
+
+        <Fact, Trait(Traits.Feature, Traits.Features.Classification)>
+        Public Sub TestAwaitInNonAsyncFunction2()
+            Dim text =
+<code>
+sub await()
+end sub
+
+sub test()
+    dim m = Await
+end sub
+</code>.NormalizedValue()
+
+            TestInClass(text)
+        End Sub
+
     End Class
 End Namespace

src/Workspaces/CSharp/Portable/Classification/ClassificationHelpers.cs

@@ -14,6 +14,7 @@ internal static class ClassificationHelpers
         private const string FromKeyword = "from";
         private const string ValueKeyword = "value";
         private const string VarKeyword = "var";
+        private const string AwaitKeyword = "await";
 
         /// <summary>
         /// Determine the classification type for a given token.
@@ -114,7 +115,7 @@ private static string GetClassificationForIdentifier(SyntaxToken token)
             {
                 return ClassificationTypeNames.TypeParameterName;
             }
-            else if (IsActualContextualKeyword(token) || CouldBeVarKeywordInDeclaration(token))
+            else if (IsActualContextualKeyword(token))
             {
                 return ClassificationTypeNames.Keyword;
             }
@@ -259,11 +260,20 @@ private static bool IsActualContextualKeyword(SyntaxToken token)
             {
                 switch (token.ValueText)
                 {
+                    case AwaitKeyword:
+                        return token.GetNextToken(includeZeroWidth: true).IsMissing;
+
                     case FromKeyword:
                         var fromClause = token.Parent.FirstAncestorOrSelf<FromClauseSyntax>();
                         return fromClause != null && fromClause.FromKeyword == token;
 
                     case VarKeyword:
+                        // var
+                        if (token.Parent is IdentifierNameSyntax && token.Parent?.Parent is ExpressionStatementSyntax)
+                        {
+                            return true;
+                        }
+
                         // we allow var any time it looks like a variable declaration, and is not in a
                         // field or event field.
                         return
@@ -277,18 +287,6 @@ private static bool IsActualContextualKeyword(SyntaxToken token)
             return false;
         }
 
-        private static bool CouldBeVarKeywordInDeclaration(SyntaxToken token)
-        {
-            if (token.ValueText == VarKeyword && token.Parent != null && token.Parent.Parent != null)
-            {
-                // cases:
-                //   var
-                return token.Parent is IdentifierNameSyntax && token.Parent.Parent is ExpressionStatementSyntax;
-            }
-
-            return false;
-        }
-
         internal static void AddLexicalClassifications(SourceText text, TextSpan textSpan, List<ClassifiedSpan> result, CancellationToken cancellationToken)
         {
             var text2 = text.ToString(textSpan);

src/Workspaces/VisualBasic/Portable/BasicWorkspace.vbproj

@@ -65,6 +65,7 @@
     <Compile Include="CaseCorrection\VisualBasicCaseCorrectionServiceFactory.vb" />
     <Compile Include="Classification\ClassificationHelpers.vb" />
     <Compile Include="Classification\Classifiers\AbstractSyntaxClassifier.vb" />
+    <Compile Include="Classification\Classifiers\IdentifierNameSyntaxClassifier.vb" />
     <Compile Include="Classification\Classifiers\ImportAliasClauseSyntaxClassifier.vb" />
     <Compile Include="Classification\Classifiers\NameSyntaxClassifier.vb" />
     <Compile Include="Classification\SyntaxClassifier.vb" />

src/Workspaces/VisualBasic/Portable/Classification/Classifiers/IdentifierNameSyntaxClassifier.vb

+' Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+Imports System.Threading
+Imports Microsoft.CodeAnalysis.Classification
+Imports Microsoft.CodeAnalysis.VisualBasic.Syntax
+Imports Microsoft.CodeAnalysis.VisualBasic.Extensions.ContextQuery
+Imports Microsoft.CodeAnalysis.VisualBasic.Symbols
+
+Namespace Microsoft.CodeAnalysis.VisualBasic.Classification.Classifiers
+    Friend Class IdentifierNameSyntaxClassifier
+        Inherits AbstractSyntaxClassifier
+
+        Private Const AwaitText = "Await"
+
+        Public Overrides ReadOnly Property SyntaxNodeTypes As IEnumerable(Of Type)
+            Get
+                Return {GetType(IdentifierNameSyntax)}
+            End Get
+        End Property
+
+        Public Overrides Function ClassifyNode(syntax As SyntaxNode, semanticModel As SemanticModel, cancellationToken As CancellationToken) As IEnumerable(Of ClassifiedSpan)
+            Dim identifierName = DirectCast(syntax, IdentifierNameSyntax)
+            Dim identifier = identifierName.Identifier
+            If CaseInsensitiveComparison.Equals(identifier.ValueText, AwaitText) Then
+                Dim symbolInfo = semanticModel.GetSymbolInfo(identifier)
+                If symbolInfo.GetAnySymbol() Is Nothing Then
+                    Return SpecializedCollections.SingletonEnumerable(New ClassifiedSpan(ClassificationTypeNames.Keyword, identifier.Span))
+                End If
+            End If
+
+            Return MyBase.ClassifyNode(syntax, semanticModel, cancellationToken)
+        End Function
+    End Class
+End Namespace
\ No newline at end of file

src/Workspaces/VisualBasic/Portable/Classification/SyntaxClassifier.vb

@@ -9,7 +9,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Classification
         Public ReadOnly DefaultSyntaxClassifiers As IEnumerable(Of ISyntaxClassifier) =
             ImmutableArray.Create(Of ISyntaxClassifier)(
                 New NameSyntaxClassifier(),
-                New ImportAliasClauseSyntaxClassifier()
-            )
+                New ImportAliasClauseSyntaxClassifier(),
+                New IdentifierNameSyntaxClassifier())
     End Module
 End Namespace