Quick info tests for patterns

src/EditorFeatures/CSharpTest/QuickInfo/SemanticQuickInfoSourceTests.cs

@@ -6955,5 +6955,86 @@ class Program
                 Documentation("Summary text"),
                 Value($"\r\n{FeaturesResources.Value_colon}\r\n  Value text"));
         }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.QuickInfo)]
+        [WorkItem(42368, "https://github.com/dotnet/roslyn/issues/42368")]
+        public async Task QuickInfoNotPattern1()
+        {
+            await TestAsync(@"
+class Person
+{
+    void Goo(object o)
+    {
+        if (o is not $$Person p)
+        {
+        }
+    }
+}",
+                MainDescription("class Person"));
+        }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.QuickInfo)]
+        [WorkItem(42368, "https://github.com/dotnet/roslyn/issues/42368")]
+        public async Task QuickInfoNotPattern2()
+        {
+            await TestAsync(@"
+class Person
+{
+    void Goo(object o)
+    {
+        if (o is $$not Person p)
+        {
+        }
+    }
+}");
+        }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.QuickInfo)]
+        [WorkItem(42368, "https://github.com/dotnet/roslyn/issues/42368")]
+        public async Task QuickInfoOrPattern1()
+        {
+            await TestAsync(@"
+class Person
+{
+    void Goo(object o)
+    {
+        if (o is $$Person or int)
+        {
+        }
+    }
+}", MainDescription("class Person"));
+        }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.QuickInfo)]
+        [WorkItem(42368, "https://github.com/dotnet/roslyn/issues/42368")]
+        public async Task QuickInfoOrPattern2()
+        {
+            await TestAsync(@"
+class Person
+{
+    void Goo(object o)
+    {
+        if (o is Person or $$int)
+        {
+        }
+    }
+}", MainDescription("struct System.Int32"));
+        }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.QuickInfo)]
+        [WorkItem(42368, "https://github.com/dotnet/roslyn/issues/42368")]
+        public async Task QuickInfoOrPattern3()
+        {
+            await TestAsync(@"
+class Person
+{
+    void Goo(object o)
+    {
+        if (o is Person $$or int)
+        {
+        }
+    }
+}");
+        }
     }
 }

src/Features/CSharp/Portable/QuickInfo/CSharpSemanticQuickInfoProvider.cs

@@ -85,8 +85,8 @@ protected override ImmutableArray<TaggedText> TryGetNullabilityAnalysis(Workspac
             }
 
             var syntaxFacts = workspace.Services.GetLanguageServices(semanticModel.Language).GetRequiredService<ISyntaxFactsService>();
-            var bindableParent = syntaxFacts.GetBindableParent(token);
-            var symbolInfo = semanticModel.GetSymbolInfo(bindableParent, cancellationToken);
+            var bindableParent = syntaxFacts.TryGetBindableParent(token);
+            var symbolInfo = bindableParent != null ? semanticModel.GetSymbolInfo(bindableParent, cancellationToken) : default;
 
             if (symbolInfo.Symbol == null || string.IsNullOrEmpty(symbolInfo.Symbol.Name))
             {

src/Features/Core/Portable/QuickInfo/CommonSemanticQuickInfoProvider.cs

@@ -418,8 +418,10 @@ private ImmutableArray<TaggedText> GetValueDocumentationContent(
 
             var symbols = GetSymbolsFromToken(token, document.Project.Solution.Workspace, semanticModel, cancellationToken);
 
-            var bindableParent = syntaxFacts.GetBindableParent(token);
-            var overloads = semanticModel.GetMemberGroup(bindableParent, cancellationToken);
+            var bindableParent = syntaxFacts.TryGetBindableParent(token);
+            var overloads = bindableParent != null
+                ? semanticModel.GetMemberGroup(bindableParent, cancellationToken)
+                : ImmutableArray<ISymbol>.Empty;
 
             symbols = symbols.Where(IsOk)
                              .Where(s => IsAccessible(s, enclosingType))

src/Workspaces/Core/Portable/FindSymbols/FindReferences/Finders/ConstructorSymbolReferenceFinder.cs

@@ -2,6 +2,8 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+#nullable enable
+
 using System;
 using System.Collections.Immutable;
 using System.Linq;
@@ -70,7 +72,7 @@ internal async Task<ImmutableArray<FinderLocation>> FindAllReferencesInDocumentA
             SemanticModel semanticModel,
             CancellationToken cancellationToken)
         {
-            var syntaxFacts = document.GetLanguageService<ISyntaxFactsService>();
+            var syntaxFacts = document.GetRequiredLanguageService<ISyntaxFactsService>();
             var findParentNode = GetFindParentNodeFunction(syntaxFacts);
 
             var normalReferences = await FindReferencesInDocumentWorkerAsync(methodSymbol, document, semanticModel, findParentNode, cancellationToken).ConfigureAwait(false);
@@ -82,7 +84,7 @@ internal async Task<ImmutableArray<FinderLocation>> FindAllReferencesInDocumentA
         }
 
         private static Func<SyntaxToken, SyntaxNode> GetFindParentNodeFunction(ISyntaxFactsService syntaxFacts)
-            => t => syntaxFacts.GetBindableParent(t);
+            => t => syntaxFacts.TryGetBindableParent(t) ?? t.Parent!;
 
         private async Task<ImmutableArray<FinderLocation>> FindReferencesInDocumentWorkerAsync(
             IMethodSymbol symbol,
@@ -122,7 +124,7 @@ private Task<ImmutableArray<FinderLocation>> FindPredefinedTypeReferencesAsync(
                 return SpecializedTasks.EmptyImmutableArray<FinderLocation>();
             }
 
-            var syntaxFacts = document.GetLanguageService<ISyntaxFactsService>();
+            var syntaxFacts = document.GetRequiredLanguageService<ISyntaxFactsService>();
             return FindReferencesInDocumentAsync(symbol, document,
                 semanticModel,
                 t => IsPotentialReference(predefinedType, syntaxFacts, t),

src/Workspaces/Core/Portable/Shared/Extensions/SemanticModelExtensions.cs

@@ -124,8 +124,8 @@ public static TokenSemanticInfo GetSemanticInfo(
             else
             {
                 aliasSymbol = semanticModel.GetAliasInfo(token.Parent!, cancellationToken);
-                var bindableParent = syntaxFacts.GetBindableParent(token);
-                var typeInfo = semanticModel.GetTypeInfo(bindableParent, cancellationToken);
+                var bindableParent = syntaxFacts.TryGetBindableParent(token);
+                var typeInfo = bindableParent != null ? semanticModel.GetTypeInfo(bindableParent, cancellationToken) : default;
                 type = typeInfo.Type;
                 convertedType = typeInfo.ConvertedType;
                 declaredSymbol = MapSymbol(semanticFacts.GetDeclaredSymbol(semanticModel, token, cancellationToken), type);

src/Workspaces/SharedUtilitiesAndExtensions/Compiler/CSharp/Services/SyntaxFacts/CSharpSyntaxFacts.cs

@@ -1019,7 +1019,9 @@ private void CheckMemberId(SyntaxNode root, SyntaxNode node, int memberId)
             Contract.ThrowIfFalse(index == memberId);
         }
 
-        public SyntaxNode GetBindableParent(SyntaxToken token)
+#nullable enable
+
+        public SyntaxNode? TryGetBindableParent(SyntaxToken token)
         {
             var node = token.Parent;
             while (node != null)
@@ -1084,9 +1086,12 @@ public SyntaxNode GetBindableParent(SyntaxToken token)
                 node = parent;
             }
 
-            return node;
+            // Patterns are never bindable (though their constituent types/exprs may be).
+            return node is PatternSyntax ? null : node;
         }
 
+#nullable disable
+
         public IEnumerable<SyntaxNode> GetConstructors(SyntaxNode root, CancellationToken cancellationToken)
         {
             if (!(root is CompilationUnitSyntax compilationUnit))

src/Workspaces/SharedUtilitiesAndExtensions/Compiler/Core/Services/SyntaxFacts/ISyntaxFacts.cs

@@ -373,13 +373,14 @@ void GetPartsOfTupleExpression<TArgumentSyntax>(SyntaxNode node,
         /// </summary>
         TextSpan GetMemberBodySpanForSpeculativeBinding(SyntaxNode node);
 
+#nullable enable
         /// <summary>
-        /// Returns the parent node that binds to the symbols that the IDE prefers for features like
-        /// Quick Info and Find All References. For example, if the token is part of the type of
-        /// an object creation, the parenting object creation expression is returned so that binding
-        /// will return constructor symbols.
+        /// Returns the parent node that binds to the symbols that the IDE prefers for features like Quick Info and Find
+        /// All References. For example, if the token is part of the type of an object creation, the parenting object
+        /// creation expression is returned so that binding will return constructor symbols.
         /// </summary>
-        SyntaxNode GetBindableParent(SyntaxToken token);
+        SyntaxNode? TryGetBindableParent(SyntaxToken token);
+#nullable disable
 
         IEnumerable<SyntaxNode> GetConstructors(SyntaxNode root, CancellationToken cancellationToken);
         bool TryGetCorrespondingOpenBrace(SyntaxToken token, out SyntaxToken openBrace);

src/Workspaces/SharedUtilitiesAndExtensions/Compiler/VisualBasic/Services/SyntaxFacts/VisualBasicSyntaxFacts.vb

@@ -1104,7 +1104,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.LanguageServices
             Contract.ThrowIfFalse(index = memberId)
         End Sub
 
-        Public Function GetBindableParent(token As SyntaxToken) As SyntaxNode Implements ISyntaxFacts.GetBindableParent
+        Public Function TryGetBindableParent(token As SyntaxToken) As SyntaxNode Implements ISyntaxFacts.TryGetBindableParent
             Dim node = token.Parent
             While node IsNot Nothing
                 Dim parent = node.Parent

src/Workspaces/SharedUtilitiesAndExtensions/Workspace/CSharp/LanguageServices/CSharpSemanticFactsService.cs

@@ -329,16 +329,15 @@ public IParameterSymbol FindParameterForArgument(SemanticModel semanticModel, Sy
 
         public ImmutableArray<ISymbol> GetBestOrAllSymbols(SemanticModel semanticModel, SyntaxNode node, SyntaxToken token, CancellationToken cancellationToken)
         {
-            switch (node)
-            {
-                case AssignmentExpressionSyntax assignment when token.Kind() == SyntaxKind.EqualsToken:
-                    return GetDeconstructionAssignmentMethods(semanticModel, node).As<ISymbol>();
+            if (node == null)
+                return ImmutableArray<ISymbol>.Empty;
 
-                case ForEachVariableStatementSyntax deconstructionForeach when token.Kind() == SyntaxKind.InKeyword:
-                    return GetDeconstructionForEachMethods(semanticModel, node).As<ISymbol>();
-            }
-
-            return GetSymbolInfo(semanticModel, node, token, cancellationToken).GetBestOrAllSymbols();
+            return node switch
+            {
+                AssignmentExpressionSyntax _ when token.Kind() == SyntaxKind.EqualsToken => GetDeconstructionAssignmentMethods(semanticModel, node).As<ISymbol>(),
+                ForEachVariableStatementSyntax _ when token.Kind() == SyntaxKind.InKeyword => GetDeconstructionForEachMethods(semanticModel, node).As<ISymbol>(),
+                _ => GetSymbolInfo(semanticModel, node, token, cancellationToken).GetBestOrAllSymbols(),
+            };
         }
 
         private SymbolInfo GetSymbolInfo(SemanticModel semanticModel, SyntaxNode node, SyntaxToken token, CancellationToken cancellationToken)

src/Workspaces/SharedUtilitiesAndExtensions/Workspace/Core/LanguageServices/SemanticsFactsService/ISemanticFactsService.cs

@@ -104,7 +104,9 @@ internal interface ISemanticFactsService : ILanguageService
 
         IParameterSymbol FindParameterForArgument(SemanticModel semanticModel, SyntaxNode argumentNode, CancellationToken cancellationToken);
 
-        ImmutableArray<ISymbol> GetBestOrAllSymbols(SemanticModel semanticModel, SyntaxNode node, SyntaxToken token, CancellationToken cancellationToken);
+#nullable enable
+        ImmutableArray<ISymbol> GetBestOrAllSymbols(SemanticModel semanticModel, SyntaxNode? node, SyntaxToken token, CancellationToken cancellationToken);
+#nullable disable
 
         SyntaxToken GenerateUniqueName(
             SemanticModel semanticModel, SyntaxNode location,

src/Workspaces/SharedUtilitiesAndExtensions/Workspace/VisualBasic/LanguageServices/VisualBasicSemanticFactsService.vb

@@ -329,7 +329,9 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
         End Function
 
         Public Function GetBestOrAllSymbols(semanticModel As SemanticModel, node As SyntaxNode, token As SyntaxToken, cancellationToken As CancellationToken) As ImmutableArray(Of ISymbol) Implements ISemanticFactsService.GetBestOrAllSymbols
-            Return semanticModel.GetSymbolInfo(node, cancellationToken).GetBestOrAllSymbols()
+            Return If(node Is Nothing,
+                      ImmutableArray(Of ISymbol).Empty,
+                      semanticModel.GetSymbolInfo(node, cancellationToken).GetBestOrAllSymbols())
         End Function
 
         Private Function ISemanticFactsService_GenerateUniqueName(