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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
using System.Collections.Generic;
using System.Collections.Immutable;
using System.Diagnostics.CodeAnalysis;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.FindSymbols;
using Microsoft.CodeAnalysis.Host;
using Microsoft.CodeAnalysis.LanguageService;
using Microsoft.CodeAnalysis.PooledObjects;
using Microsoft.CodeAnalysis.Shared.Utilities;
using Roslyn.Utilities;
namespace Microsoft.CodeAnalysis.Shared.Extensions
{
internal static partial class ITypeSymbolExtensions
{
/// <summary>
/// Returns the corresponding symbol in this type or a base type that implements
/// interfaceMember (either implicitly or explicitly), or null if no such symbol exists
/// (which might be either because this type doesn't implement the container of
/// interfaceMember, or this type doesn't supply a member that successfully implements
/// interfaceMember).
/// </summary>
public static async Task<ImmutableArray<ISymbol>> FindImplementationsForInterfaceMemberAsync(
this ITypeSymbol typeSymbol,
ISymbol interfaceMember,
Solution solution,
CancellationToken cancellationToken)
{
// This method can return multiple results. Consider the case of:
//
// interface IGoo<X> { void Goo(X x); }
//
// class C : IGoo<int>, IGoo<string> { void Goo(int x); void Goo(string x); }
//
// If you're looking for the implementations of IGoo<X>.Goo then you want to find both
// results in C.
using var _ = ArrayBuilder<ISymbol>.GetInstance(out var builder);
// TODO(cyrusn): Implement this using the actual code for
// TypeSymbol.FindImplementationForInterfaceMember
if (typeSymbol == null || interfaceMember == null)
return ImmutableArray<ISymbol>.Empty;
if (interfaceMember.Kind is not SymbolKind.Event and
not SymbolKind.Method and
not SymbolKind.Property)
{
return ImmutableArray<ISymbol>.Empty;
}
// WorkItem(4843)
//
// 'typeSymbol' has to at least implement the interface containing the member. note:
// this just means that the interface shows up *somewhere* in the inheritance chain of
// this type. However, this type may not actually say that it implements it. For
// example:
//
// interface I { void Goo(); }
//
// class B { }
//
// class C : B, I { }
//
// class D : C { }
//
// D does implement I transitively through C. However, even if D has a "Goo" method, it
// won't be an implementation of I.Goo. The implementation of I.Goo must be from a type
// that actually has I in it's direct interface chain, or a type that's a base type of
// that. in this case, that means only classes C or B.
var interfaceType = interfaceMember.ContainingType;
if (!typeSymbol.ImplementsIgnoringConstruction(interfaceType))
return ImmutableArray<ISymbol>.Empty;
// We've ascertained that the type T implements some constructed type of the form I<X>.
// However, we're not precisely sure which constructions of I<X> are being used. For
// example, a type C might implement I<int> and I<string>. If we're searching for a
// method from I<X> we might need to find several methods that implement different
// instantiations of that method.
var originalInterfaceType = interfaceMember.ContainingType.OriginalDefinition;
var originalInterfaceMember = interfaceMember.OriginalDefinition;
var constructedInterfaces = typeSymbol.AllInterfaces.Where(i =>
SymbolEquivalenceComparer.Instance.Equals(i.OriginalDefinition, originalInterfaceType));
foreach (var constructedInterface in constructedInterfaces)
{
cancellationToken.ThrowIfCancellationRequested();
// OriginalSymbolMatch allows types to be matched across different assemblies if they are considered to
// be the same type, which provides a more accurate implementations list for interfaces.
var constructedInterfaceMember =
await constructedInterface.GetMembers(interfaceMember.Name).FirstOrDefaultAsync(
typeSymbol => SymbolFinder.OriginalSymbolsMatchAsync(solution, typeSymbol, interfaceMember, cancellationToken)).ConfigureAwait(false);
if (constructedInterfaceMember == null)
{
continue;
}
// Now we need to walk the base type chain, but we start at the first type that actually
// has the interface directly in its interface hierarchy.
var seenTypeDeclaringInterface = false;
for (var currentType = typeSymbol; currentType != null; currentType = currentType.BaseType)
{
seenTypeDeclaringInterface = seenTypeDeclaringInterface ||
currentType.GetOriginalInterfacesAndTheirBaseInterfaces().Contains(interfaceType.OriginalDefinition);
if (seenTypeDeclaringInterface)
{
var result = currentType.FindImplementations(constructedInterfaceMember, solution.Services);
if (result != null)
{
builder.Add(result);
break;
}
}
}
}
return builder.ToImmutable();
}
public static ISymbol? FindImplementations(this ITypeSymbol typeSymbol, ISymbol constructedInterfaceMember, SolutionServices services)
=> constructedInterfaceMember switch
{
IEventSymbol eventSymbol => typeSymbol.FindImplementations(eventSymbol, services),
IMethodSymbol methodSymbol => typeSymbol.FindImplementations(methodSymbol, services),
IPropertySymbol propertySymbol => typeSymbol.FindImplementations(propertySymbol, services),
_ => null,
};
private static ISymbol? FindImplementations<TSymbol>(
this ITypeSymbol typeSymbol,
TSymbol constructedInterfaceMember,
SolutionServices services) where TSymbol : class, ISymbol
{
// Check the current type for explicit interface matches. Otherwise, check
// the current type and base types for implicit matches.
var explicitMatches =
from member in typeSymbol.GetMembers().OfType<TSymbol>()
from explicitInterfaceMethod in member.ExplicitInterfaceImplementations()
where SymbolEquivalenceComparer.Instance.Equals(explicitInterfaceMethod, constructedInterfaceMember)
select member;
var provider = services.GetLanguageServices(typeSymbol.Language);
var semanticFacts = provider.GetRequiredService<ISemanticFactsService>();
// Even if a language only supports explicit interface implementation, we
// can't enforce it for types from metadata. For example, a VB symbol
// representing System.Xml.XmlReader will say it implements IDisposable, but
// the XmlReader.Dispose() method will not be an explicit implementation of
// IDisposable.Dispose()
if ((!semanticFacts.SupportsImplicitInterfaceImplementation &&
typeSymbol.Locations.Any(static location => location.IsInSource)) ||
typeSymbol.TypeKind == TypeKind.Interface)
{
return explicitMatches.FirstOrDefault();
}
var syntaxFacts = provider.GetRequiredService<ISyntaxFactsService>();
var implicitMatches =
from baseType in typeSymbol.GetBaseTypesAndThis()
from member in baseType.GetMembers(constructedInterfaceMember.Name).OfType<TSymbol>()
where member.DeclaredAccessibility == Accessibility.Public &&
SignatureComparer.Instance.HaveSameSignatureAndConstraintsAndReturnTypeAndAccessors(member, constructedInterfaceMember, syntaxFacts.IsCaseSensitive)
select member;
return explicitMatches.FirstOrDefault() ?? implicitMatches.FirstOrDefault();
}
[return: NotNullIfNotNull(parameterName: nameof(type))]
public static ITypeSymbol? RemoveUnavailableTypeParameters(
this ITypeSymbol? type,
Compilation compilation,
IEnumerable<ITypeParameterSymbol> availableTypeParameters)
{
return type?.RemoveUnavailableTypeParameters(compilation, availableTypeParameters.Select(t => t.Name).ToSet());
}
[return: NotNullIfNotNull(parameterName: nameof(type))]
private static ITypeSymbol? RemoveUnavailableTypeParameters(
this ITypeSymbol? type,
Compilation compilation,
ISet<string> availableTypeParameterNames)
{
return type?.Accept(new UnavailableTypeParameterRemover(compilation, availableTypeParameterNames));
}
[return: NotNullIfNotNull(parameterName: nameof(type))]
public static ITypeSymbol? RemoveAnonymousTypes(
this ITypeSymbol? type,
Compilation compilation)
{
return type?.Accept(new AnonymousTypeRemover(compilation));
}
[return: NotNullIfNotNull(parameterName: nameof(type))]
public static ITypeSymbol? RemoveUnnamedErrorTypes(
this ITypeSymbol? type,
Compilation compilation)
{
return type?.Accept(new UnnamedErrorTypeRemover(compilation));
}
[return: NotNullIfNotNull(parameterName: nameof(type))]
public static ITypeSymbol? SubstituteTypes<TType1, TType2>(
this ITypeSymbol? type,
IDictionary<TType1, TType2> mapping,
Compilation compilation)
where TType1 : ITypeSymbol
where TType2 : ITypeSymbol
{
return type.SubstituteTypes(mapping, new CompilationTypeGenerator(compilation));
}
[return: NotNullIfNotNull(parameterName: nameof(type))]
public static ITypeSymbol? SubstituteTypes<TType1, TType2>(
this ITypeSymbol? type,
IDictionary<TType1, TType2> mapping,
ITypeGenerator typeGenerator)
where TType1 : ITypeSymbol
where TType2 : ITypeSymbol
{
return type?.Accept(new SubstituteTypesVisitor<TType1, TType2>(mapping, typeGenerator));
}
}
}
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