Lazy doc comments for signature help

src/EditorFeatures/CSharp/SignatureHelp/AbstractCSharpSignatureHelpProvider.cs

@@ -61,7 +61,7 @@ protected static SignatureHelpParameter Convert(
             return new SignatureHelpParameter(
                 parameter.Name,
                 parameter.IsOptional,
-                parameter.GetDocumentationParts(semanticModel, position, formatter, cancellationToken),
+                parameter.GetDocumentationPartsFactory(semanticModel, position, formatter),
                 parameter.ToMinimalDisplayParts(semanticModel, position));
         }
 

src/EditorFeatures/CSharp/SignatureHelp/AttributeSignatureHelpProvider.cs

@@ -135,7 +135,7 @@ private SignatureHelpItem Convert(
                 constructor, semanticModel, position,
                 symbolDisplayService, anonymousTypeDisplayService,
                 isVariadic,
-                constructor.GetDocumentationParts(semanticModel, position, documentationCommentFormatter, cancellationToken),
+                constructor.GetDocumentationPartsFactory(semanticModel, position, documentationCommentFormatter),
                 GetPreambleParts(constructor, semanticModel, position),
                 GetSeparatorParts(),
                 GetPostambleParts(constructor),
@@ -158,6 +158,8 @@ private IEnumerable<SignatureHelpParameter> GetParameters(
 
             for (int i = 0; i < namedParameters.Count; i++)
             {
+                cancellationToken.ThrowIfCancellationRequested();
+
                 var namedParameter = namedParameters[i];
 
                 var type = namedParameter is IFieldSymbol ? ((IFieldSymbol)namedParameter).Type : ((IPropertySymbol)namedParameter).Type;
@@ -175,7 +177,7 @@ private IEnumerable<SignatureHelpParameter> GetParameters(
                 yield return new SignatureHelpParameter(
                     namedParameter.Name,
                     isOptional: true,
-                    documentation: namedParameter.GetDocumentationParts(semanticModel, position, documentationCommentFormatter, cancellationToken),
+                    documentationFactory: namedParameter.GetDocumentationPartsFactory(semanticModel, position, documentationCommentFormatter),
                     displayParts: displayParts,
                     prefixDisplayParts: GetParameterPrefixDisplayParts(i));
             }

src/EditorFeatures/CSharp/SignatureHelp/ConstructorInitializerSignatureHelpProvider.cs

@@ -135,7 +135,7 @@ private SignatureHelpItem Convert(
                 constructor, semanticModel, position,
                 symbolDisplayService, anonymousTypeDisplayService,
                 constructor.IsParams(),
-                constructor.GetDocumentationParts(semanticModel, position, documentationCommentFormattingService, cancellationToken),
+                constructor.GetDocumentationPartsFactory(semanticModel, position, documentationCommentFormattingService),
                 GetPreambleParts(constructor, semanticModel, position),
                 GetSeparatorParts(),
                 GetPostambleParts(constructor),

src/EditorFeatures/CSharp/SignatureHelp/ElementAccessExpressionSignatureHelpProvider.cs

@@ -200,7 +200,7 @@ private SignatureHelpItem Convert(
             var item = CreateItem(indexer, semanticModel, position,
                 symbolDisplayService, anonymousTypeDisplayService,
                 indexer.IsParams(),
-                indexer.GetDocumentationParts(semanticModel, position, documentationCommentFormattingService, cancellationToken),
+                indexer.GetDocumentationPartsFactory(semanticModel, position, documentationCommentFormattingService),
                 GetPreambleParts(indexer, position, semanticModel),
                 GetSeparatorParts(),
                 GetPostambleParts(indexer),

src/EditorFeatures/CSharp/SignatureHelp/GenericNameSignatureHelpProvider.cs

@@ -183,7 +183,7 @@ private SignatureHelpItem Convert(
                     symbol, semanticModel, position,
                     symbolDisplayService, anonymousTypeDisplayService,
                     false,
-                    symbol.GetDocumentationParts(semanticModel, position, documentationCommentFormattingService, cancellationToken),
+                    symbol.GetDocumentationPartsFactory(semanticModel, position, documentationCommentFormattingService),
                     GetPreambleParts(namedType, semanticModel, position),
                     GetSeparatorParts(),
                     GetPostambleParts(namedType),
@@ -196,7 +196,7 @@ private SignatureHelpItem Convert(
                     symbol, semanticModel, position,
                     symbolDisplayService, anonymousTypeDisplayService,
                     false,
-                    symbol.GetDocumentationParts(semanticModel, position, documentationCommentFormattingService, cancellationToken).Concat(GetAwaitableUsage(method, semanticModel, position)),
+                    c => symbol.GetDocumentationParts(semanticModel, position, documentationCommentFormattingService, c).Concat(GetAwaitableUsage(method, semanticModel, position)),
                     GetPreambleParts(method, semanticModel, position),
                     GetSeparatorParts(),
                     GetPostambleParts(method, semanticModel, position),
@@ -220,7 +220,7 @@ private SignatureHelpParameter Convert(
             return new SignatureHelpParameter(
                 parameter.Name,
                 isOptional: false,
-                documentation: parameter.GetDocumentationParts(semanticModel, position, formatter, cancellationToken),
+                documentationFactory: parameter.GetDocumentationPartsFactory(semanticModel, position, formatter),
                 displayParts: parameter.ToMinimalDisplayParts(semanticModel, position, s_minimallyQualifiedFormat),
                 selectedDisplayParts: GetSelectedDisplayParts(parameter, semanticModel, position, cancellationToken));
         }

src/EditorFeatures/CSharp/SignatureHelp/InvocationExpressionSignatureHelpProvider_DelegateInvoke.cs

@@ -37,7 +37,7 @@ private IEnumerable<SignatureHelpItem> GetDelegateInvokeItems(
                 invokeMethod, semanticModel, position,
                 symbolDisplayService, anonymousTypeDisplayService,
                 isVariadic: invokeMethod.IsParams(),
-                documentation: SpecializedCollections.EmptyEnumerable<SymbolDisplayPart>(),
+                documentationFactory: null,
                 prefixParts: GetDelegateInvokePreambleParts(invokeMethod, semanticModel, position),
                 separatorParts: GetSeparatorParts(),
                 suffixParts: GetDelegateInvokePostambleParts(),
@@ -62,10 +62,11 @@ private IEnumerable<SignatureHelpParameter> GetDelegateInvokeParameters(
         {
             foreach (var parameter in invokeMethod.Parameters)
             {
+                cancellationToken.ThrowIfCancellationRequested();
                 yield return new SignatureHelpParameter(
                     parameter.Name,
                     parameter.IsOptional,
-                    parameter.GetDocumentationParts(semanticModel, position, formattingService, cancellationToken),
+                    parameter.GetDocumentationPartsFactory(semanticModel, position, formattingService),
                     parameter.ToMinimalDisplayParts(semanticModel, position));
             }
         }

src/EditorFeatures/CSharp/SignatureHelp/InvocationExpressionSignatureHelpProvider_MethodGroup.cs

@@ -108,7 +108,7 @@ private SignatureHelpItem ConvertMethodGroupMethod(
                 method, semanticModel, position,
                 symbolDisplayService, anonymousTypeDisplayService,
                 method.IsParams(),
-                method.OriginalDefinition.GetDocumentationParts(semanticModel, position, documentationCommentFormattingService, cancellationToken).Concat(GetAwaitableUsage(method, semanticModel, position)),
+                c => method.OriginalDefinition.GetDocumentationParts(semanticModel, position, documentationCommentFormattingService, c).Concat(GetAwaitableUsage(method, semanticModel, position)),
                 GetMethodGroupPreambleParts(method, semanticModel, position),
                 GetSeparatorParts(),
                 GetMethodGroupPostambleParts(method),

src/EditorFeatures/CSharp/SignatureHelp/ObjectCreationExpressionSignatureHelpProvider_DelegateType.cs

@@ -32,7 +32,7 @@ private IEnumerable<SignatureHelpItem> GetDelegateTypeConstructors(
                 invokeMethod, semanticModel, position,
                 symbolDisplayService, anonymousTypeDispalyService,
                 isVariadic: false,
-                documentation: SpecializedCollections.EmptyEnumerable<SymbolDisplayPart>(),
+                documentationFactory: null,
                 prefixParts: GetDelegateTypePreambleParts(invokeMethod, semanticModel, position),
                 separatorParts: GetSeparatorParts(),
                 suffixParts: GetDelegateTypePostambleParts(invokeMethod),
@@ -80,7 +80,7 @@ private IEnumerable<SignatureHelpParameter> GetDelegateTypeParameters(IMethodSym
             yield return new SignatureHelpParameter(
                 TargetName,
                 isOptional: false,
-                documentation: SpecializedCollections.EmptyEnumerable<SymbolDisplayPart>(),
+                documentationFactory: null,
                 displayParts: parts);
         }
 

src/EditorFeatures/CSharp/SignatureHelp/ObjectCreationExpressionSignatureHelpProvider_NormalType.cs

@@ -56,7 +56,7 @@ private SignatureHelpItem ConvertNormalTypeConstructor(
                 constructor, semanticModel, position,
                 symbolDisplayService, anonymousTypeDisplayService,
                 constructor.IsParams(),
-                constructor.GetDocumentationParts(semanticModel, position, documentationCommentFormattingService, cancellationToken),
+                constructor.GetDocumentationPartsFactory(semanticModel, position, documentationCommentFormattingService),
                 GetNormalTypePreambleParts(constructor, semanticModel, position),
                 GetSeparatorParts(),
                 GetNormalTypePostambleParts(constructor),

src/EditorFeatures/Core/Extensibility/SignatureHelp/SignatureHelpItem.cs

@@ -2,7 +2,9 @@
 
 using System;
 using System.Collections.Generic;
+using System.Collections.Immutable;
 using System.Linq;
+using System.Threading;
 using Microsoft.CodeAnalysis;
 using Roslyn.Utilities;
 
@@ -16,25 +18,26 @@ internal class SignatureHelpItem
         /// selected parameter index strictly goes past the number of defined parameters for this
         /// item.
         /// </summary>
-        public bool IsVariadic { get; private set; }
+        public bool IsVariadic { get; }
 
-        public IList<SymbolDisplayPart> PrefixDisplayParts { get; private set; }
-        public IList<SymbolDisplayPart> SuffixDisplayParts { get; private set; }
+        public ImmutableArray<SymbolDisplayPart> PrefixDisplayParts { get; }
+        public ImmutableArray<SymbolDisplayPart> SuffixDisplayParts { get; }
 
-        // TODO(cyrusn): This probably won't be sufficient for VB query signature help.  It has
+        // TODO: This probably won't be sufficient for VB query signature help.  It has
         // arbitrary separators between parameters.
-        public IList<SymbolDisplayPart> SeparatorDisplayParts { get; private set; }
+        public ImmutableArray<SymbolDisplayPart> SeparatorDisplayParts { get; }
 
-        public IList<SignatureHelpParameter> Parameters { get; private set; }
+        public ImmutableArray<SignatureHelpParameter> Parameters { get; }
 
-        public IList<SymbolDisplayPart> DescriptionParts { get; internal set; }
+        public ImmutableArray<SymbolDisplayPart> DescriptionParts { get; internal set; }
 
-        // TODO(cyrusn): This may be unnecessary.  How would a user ever see this.
-        public IList<SymbolDisplayPart> Documentation { get; set; }
+        public Func<CancellationToken, IEnumerable<SymbolDisplayPart>> DocumenationFactory { get; }
+
+        private static readonly Func<CancellationToken, IEnumerable<SymbolDisplayPart>> s_emptyDocumentationFactory = _ => SpecializedCollections.EmptyEnumerable<SymbolDisplayPart>();
 
         public SignatureHelpItem(
             bool isVariadic,
-            IEnumerable<SymbolDisplayPart> documentation,
+            Func<CancellationToken, IEnumerable<SymbolDisplayPart>> documentationFactory,
             IEnumerable<SymbolDisplayPart> prefixParts,
             IEnumerable<SymbolDisplayPart> separatorParts,
             IEnumerable<SymbolDisplayPart> suffixParts,
@@ -47,7 +50,7 @@ public SignatureHelpItem(
             }
 
             this.IsVariadic = isVariadic;
-            this.Documentation = documentation.ToImmutableArrayOrEmpty();
+            this.DocumenationFactory = documentationFactory ?? s_emptyDocumentationFactory;
             this.PrefixDisplayParts = prefixParts.ToImmutableArrayOrEmpty();
             this.SeparatorDisplayParts = separatorParts.ToImmutableArrayOrEmpty();
             this.SuffixDisplayParts = suffixParts.ToImmutableArrayOrEmpty();

src/EditorFeatures/Core/Extensibility/SignatureHelp/SignatureHelpParameter.cs

@@ -1,9 +1,10 @@
 // Copyright (c) Microsoft.  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.Linq;
+using System.Threading;
 using Microsoft.CodeAnalysis;
-using Microsoft.CodeAnalysis.Shared.Extensions;
 using Roslyn.Utilities;
 
 namespace Microsoft.CodeAnalysis.Editor
@@ -13,54 +14,56 @@ internal class SignatureHelpParameter
         /// <summary>
         /// The name of this parameter.
         /// </summary>
-        public string Name { get; private set; }
+        public string Name { get; }
 
         /// <summary>
         /// Documentation for this parameter.  This should normally be presented to the user when
         /// this parameter is selected.
         /// </summary>
-        public IList<SymbolDisplayPart> Documentation { get; private set; }
+        public Func<CancellationToken, IEnumerable<SymbolDisplayPart>> DocumentationFactory { get; }
 
         /// <summary>
         /// Display parts to show before the normal display parts for the parameter.
         /// </summary>
-        public IList<SymbolDisplayPart> PrefixDisplayParts { get; private set; }
+        public IList<SymbolDisplayPart> PrefixDisplayParts { get; }
 
         /// <summary>
         /// Display parts to show after the normal display parts for the parameter.
         /// </summary>
-        public IList<SymbolDisplayPart> SuffixDisplayParts { get; private set; }
+        public IList<SymbolDisplayPart> SuffixDisplayParts { get; }
 
         /// <summary>
         /// Display parts for this parameter.  This should normally be presented to the user as part
         /// of the entire signature display.
         /// </summary>
-        public IList<SymbolDisplayPart> DisplayParts { get; private set; }
+        public IList<SymbolDisplayPart> DisplayParts { get; }
 
         /// <summary>
         /// True if this parameter is optional or not.  Optional parameters may be presented in a
         /// different manner to users.
         /// </summary>
-        public bool IsOptional { get; private set; }
+        public bool IsOptional { get; }
 
         /// <summary>
         /// Display parts for this parameter that should be presented to the user when this
         /// parameter is selected.
         /// </summary>
-        public IList<SymbolDisplayPart> SelectedDisplayParts { get; private set; }
+        public IList<SymbolDisplayPart> SelectedDisplayParts { get; }
+
+        private static readonly Func<CancellationToken, IEnumerable<SymbolDisplayPart>> s_emptyDocumentationFactory = _ => SpecializedCollections.EmptyEnumerable<SymbolDisplayPart>();
 
         public SignatureHelpParameter(
             string name,
             bool isOptional,
-            IEnumerable<SymbolDisplayPart> documentation,
+            Func<CancellationToken, IEnumerable<SymbolDisplayPart>> documentationFactory,
             IEnumerable<SymbolDisplayPart> displayParts,
             IEnumerable<SymbolDisplayPart> prefixDisplayParts = null,
             IEnumerable<SymbolDisplayPart> suffixDisplayParts = null,
             IEnumerable<SymbolDisplayPart> selectedDisplayParts = null)
         {
             this.Name = name ?? string.Empty;
             this.IsOptional = isOptional;
-            this.Documentation = documentation.ToImmutableArrayOrEmpty();
+            this.DocumentationFactory = documentationFactory ?? s_emptyDocumentationFactory;
             this.DisplayParts = displayParts.ToImmutableArrayOrEmpty();
             this.PrefixDisplayParts = prefixDisplayParts.ToImmutableArrayOrEmpty();
             this.SuffixDisplayParts = suffixDisplayParts.ToImmutableArrayOrEmpty();

src/EditorFeatures/Core/Implementation/IntelliSense/SignatureHelp/AbstractSignatureHelpProvider.SymbolKeySignatureHelpItem.cs

@@ -2,27 +2,25 @@
 
 using System;
 using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
+using System.Threading;
 
 namespace Microsoft.CodeAnalysis.Editor.Implementation.IntelliSense.SignatureHelp
 {
     internal abstract partial class AbstractSignatureHelpProvider
     {
         internal class SymbolKeySignatureHelpItem : SignatureHelpItem, IEquatable<SymbolKeySignatureHelpItem>
         {
-            public SymbolKey SymbolKey { get; private set; }
+            public SymbolKey SymbolKey { get; }
 
             public SymbolKeySignatureHelpItem(
                 ISymbol symbol,
                 bool isVariadic,
-                IEnumerable<SymbolDisplayPart> documentation,
+                Func<CancellationToken, IEnumerable<SymbolDisplayPart>> documentationFactory,
                 IEnumerable<SymbolDisplayPart> prefixParts,
                 IEnumerable<SymbolDisplayPart> separatorParts,
                 IEnumerable<SymbolDisplayPart> suffixParts,
                 IEnumerable<SignatureHelpParameter> parameters,
-                IEnumerable<SymbolDisplayPart> descriptionParts) : base(isVariadic, documentation, prefixParts, separatorParts, suffixParts, parameters, descriptionParts)
+                IEnumerable<SymbolDisplayPart> descriptionParts) : base(isVariadic, documentationFactory, prefixParts, separatorParts, suffixParts, parameters, descriptionParts)
             {
                 this.SymbolKey = symbol == null ? null : symbol.GetSymbolKey();
             }