Merge pull request #22791 from sharwell/see-langword

Avoid showing language keywords after typing < in a doc comment

src/EditorFeatures/CSharpTest/Completion/CompletionProviders/XmlDocumentationCommentCompletionProviderTests.cs

@@ -653,6 +653,70 @@ static void Goo()
 }", "cref", "langword");
         }
 
+        [WorkItem(22789, "https://github.com/dotnet/roslyn/issues/22789")]
+        [Fact, Trait(Traits.Feature, Traits.Features.Completion)]
+        public async Task LangwordCompletionInPlainText()
+        {
+            await VerifyItemsExistAsync(@"
+class C
+{
+    /// <summary>
+    /// Some text $$
+    /// </summary>
+    static void Goo()
+    {
+    }
+}", "null", "sealed", "true", "false", "await");
+        }
+
+        [WorkItem(22789, "https://github.com/dotnet/roslyn/issues/22789")]
+        [Fact, Trait(Traits.Feature, Traits.Features.Completion)]
+        public async Task LangwordCompletionAfterAngleBracket1()
+        {
+            await VerifyItemsAbsentAsync(@"
+class C
+{
+    /// <summary>
+    /// Some text <$$
+    /// </summary>
+    static void Goo()
+    {
+    }
+}", "null", "sealed", "true", "false", "await");
+        }
+
+        [WorkItem(22789, "https://github.com/dotnet/roslyn/issues/22789")]
+        [Fact, Trait(Traits.Feature, Traits.Features.Completion)]
+        public async Task LangwordCompletionAfterAngleBracket2()
+        {
+            await VerifyItemsAbsentAsync(@"
+class C
+{
+    /// <summary>
+    /// Some text <s$$
+    /// </summary>
+    static void Goo()
+    {
+    }
+}", "null", "sealed", "true", "false", "await");
+        }
+
+        [WorkItem(22789, "https://github.com/dotnet/roslyn/issues/22789")]
+        [Fact, Trait(Traits.Feature, Traits.Features.Completion)]
+        public async Task LangwordCompletionAfterAngleBracket3()
+        {
+            await VerifyItemsExistAsync(@"
+class C
+{
+    /// <summary>
+    /// Some text < $$
+    /// </summary>
+    static void Goo()
+    {
+    }
+}", "null", "sealed", "true", "false", "await");
+        }
+
         [WorkItem(11490, "https://github.com/dotnet/roslyn/issues/11490")]
         [Fact, Trait(Traits.Feature, Traits.Features.Completion)]
         public async Task SeeLangwordAttributeValue()

src/EditorFeatures/Test2/IntelliSense/CSharpCompletionCommandHandlerTests_XmlDoc.vb

@@ -577,6 +577,31 @@ class c
             End Using
         End Function
 
+        <WpfFact, Trait(Traits.Feature, Traits.Features.Completion)>
+        <WorkItem(22789, "https://github.com/dotnet/roslyn/issues/22789")>
+        Public Async Function InvokeWithOpenAngleCommitSeeOnTab() As Task
+
+            Using state = TestState.CreateCSharpTestState(
+                <Document><![CDATA[
+class c
+{
+    /// $$
+    void goo() { }
+}
+            ]]></Document>)
+
+                state.SendTypeChars("<")
+                Await state.AssertCompletionSession()
+                state.SendTypeChars("se")
+                Await state.AssertSelectedCompletionItem(displayText:="see")
+                state.SendTab()
+                Await state.AssertNoCompletionSession()
+
+                ' /// <see cref="$$"/>
+                Await state.AssertLineTextAroundCaret("    /// <see cref=""", """/>")
+            End Using
+        End Function
+
         <WpfFact, Trait(Traits.Feature, Traits.Features.Completion)>
         Public Async Function InvokeWithOpenAngleCommitSeeOnSpace() As Task
 

src/EditorFeatures/VisualBasicTest/Completion/CompletionProviders/XmlDocCommentCompletionProviderTests.vb

@@ -774,6 +774,66 @@ End Class
             Await VerifyItemsExistAsync(text, "cref", "langword")
         End Function
 
+        <WorkItem(22789, "https://github.com/dotnet/roslyn/issues/22789")>
+        <Fact, Trait(Traits.Feature, Traits.Features.Completion)>
+        Public Async Function TestLangwordCompletionInPlainText() As Task
+            Dim text = "
+Class C
+    ''' <summary>
+    ''' Some text $$
+    ''' </summary>
+    Sub Goo()
+    End Sub
+End Class
+"
+            Await VerifyItemsExistAsync(text, "Nothing", "Shared", "True", "False", "Await")
+        End Function
+
+        <WorkItem(22789, "https://github.com/dotnet/roslyn/issues/22789")>
+        <Fact, Trait(Traits.Feature, Traits.Features.Completion)>
+        Public Async Function LangwordCompletionAfterAngleBracket1() As Task
+            Dim text = "
+Class C
+    ''' <summary>
+    ''' Some text <$$
+    ''' </summary>
+    Sub Goo()
+    End Sub
+End Class
+"
+            Await VerifyItemsAbsentAsync(text, "Nothing", "Shared", "True", "False", "Await")
+        End Function
+
+        <WorkItem(22789, "https://github.com/dotnet/roslyn/issues/22789")>
+        <Fact, Trait(Traits.Feature, Traits.Features.Completion)>
+        Public Async Function LangwordCompletionAfterAngleBracket2() As Task
+            Dim text = "
+Class C
+    ''' <summary>
+    ''' Some text <s$$
+    ''' </summary>
+    Sub Goo()
+    End Sub
+End Class
+"
+            Await VerifyItemsAbsentAsync(text, "Nothing", "Shared", "True", "False", "Await")
+        End Function
+
+        <WorkItem(22789, "https://github.com/dotnet/roslyn/issues/22789")>
+        <Fact, Trait(Traits.Feature, Traits.Features.Completion)>
+        Public Async Function LangwordCompletionAfterAngleBracket3() As Task
+            Dim text = "
+Class C
+    ''' <summary>
+    ''' Some text < $$
+    ''' </summary>
+    Sub Goo()
+    End Sub
+End Class
+"
+            Await VerifyItemsAbsentAsync(text, "Nothing", "Shared", "True", "False", "Await")
+        End Function
+
         <WorkItem(11490, "https://github.com/dotnet/roslyn/issues/11490")>
         <Fact, Trait(Traits.Feature, Traits.Features.Completion)>
         Public Async Function TestSeeLangwordAttributeValue() As Task

src/Features/CSharp/Portable/Completion/CompletionProviders/XmlDocCommentCompletionProvider.cs

@@ -101,7 +101,15 @@ internal override bool IsInsertionTrigger(SourceText text, int characterPosition
                 if (token.Parent.Parent.Kind() == SyntaxKind.XmlElement ||
                     token.Parent.Parent.IsParentKind(SyntaxKind.XmlElement))
                 {
-                    items.AddRange(GetNestedItems(declaredSymbol));
+                    // Avoid including language keywords when following < or <text, since these cases should only be
+                    // attempting to complete the XML name (which for language keywords is 'see'). While the parser
+                    // treats the 'name' in '< name' as an XML name, we don't treat it like that here so the completion
+                    // experience is consistent for '< ' and '< n'.
+                    var xmlNameOnly = token.IsKind(SyntaxKind.LessThanToken)
+                        || (token.Parent.IsKind(SyntaxKind.XmlName) && !token.HasLeadingTrivia);
+                    var includeKeywords = !xmlNameOnly;
+
+                    items.AddRange(GetNestedItems(declaredSymbol, includeKeywords));
                 }
 
                 if (token.Parent.Parent.Kind() == SyntaxKind.XmlElement && ((XmlElementSyntax)token.Parent.Parent).StartTag.Name.LocalName.ValueText == ListElementName)

src/Features/Core/Portable/Completion/Providers/AbstractDocCommentCompletionProvider.cs

@@ -125,7 +125,7 @@ private CompletionItem GetCDataItem()
             return CreateCompletionItem(prefix, "<" + prefix, suffix);
         }
 
-        protected IEnumerable<CompletionItem> GetNestedItems(ISymbol symbol)
+        protected IEnumerable<CompletionItem> GetNestedItems(ISymbol symbol, bool includeKeywords)
         {
             var items = s_nestedTagNames.Select(GetItem);
 
@@ -135,7 +135,10 @@ protected IEnumerable<CompletionItem> GetNestedItems(ISymbol symbol)
                              .Concat(GetTypeParamRefItems(symbol));
             }
 
-            items = items.Concat(GetKeywordNames().Select(CreateLangwordCompletionItem));
+            if (includeKeywords)
+            {
+                items = items.Concat(GetKeywordNames().Select(CreateLangwordCompletionItem));
+            }
 
             return items;
         }

src/Features/VisualBasic/Portable/Completion/CompletionProviders/XmlDocCommentCompletionProvider.vb

@@ -110,7 +110,14 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Completion.Providers
             Dim grandParent = parentElement?.Parent
 
             If grandParent.IsKind(SyntaxKind.XmlElement) Then
-                items.AddRange(GetNestedItems(symbol))
+                ' Avoid including language keywords when following < Or <text, since these cases should only be
+                ' attempting to complete the XML name (which for language keywords Is 'see'). The VB parser treats
+                ' spaces after a < character as trailing whitespace, even if an identifier follows it on the same line.
+                ' Therefore, the consistent VB experience says we never show keywords for < followed by spaces.
+                Dim xmlNameOnly = token.IsKind(SyntaxKind.LessThanToken) OrElse token.Parent.IsKind(SyntaxKind.XmlName)
+                Dim includeKeywords = Not xmlNameOnly
+
+                items.AddRange(GetNestedItems(symbol, includeKeywords))
 
                 If GetStartTagName(grandParent) = ListElementName Then
                     items.AddRange(GetListItems())
@@ -125,7 +132,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Completion.Providers
                     '     ''' $$
                     items.AddRange(GetTopLevelItems(symbol, parent))
                 ElseIf token.Parent.IsParentKind(SyntaxKind.XmlElement) Then
-                    items.AddRange(GetNestedItems(symbol))
+                    items.AddRange(GetNestedItems(symbol, includeKeywords:=True))
 
                     If GetStartTagName(token.Parent.Parent) = ListElementName Then
                         items.AddRange(GetListItems())