Mark implementations of foreign interfaces and abstract classes as "probably reachable"

Mårten Åsberg committed on 2026-03-14 at 19:40

Core/ISymbolExtensions.cs +8 -4

diff --git a/Core/ISymbolExtensions.cs b/Core/ISymbolExtensions.cs
index d151ab7..c20c410 100644
@@ -5,14 +5,18 @@ namespace Reacher;
internal static class ISymbolExtensions
{
    public static HashSet<ISymbol> ExplicitOrImplicitInterfaceImplementations(this ISymbol member) =>
        [.. member.ExplicitInterfaceImplementations(), .. member.ImplicitInterfaceImplementations()];
    public static HashSet<ISymbol> ExplicitOrImplicitInterfaceImplementations(this ISymbol member)
    {
        var implementations = member.ExplicitInterfaceImplementations();
        implementations.UnionWith(member.ImplicitInterfaceImplementations());
        return implementations;
    }
    public static HashSet<ISymbol> ExplicitInterfaceImplementations(this ISymbol member) =>
        member switch
        {
            IMethodSymbol method => [.. method.ExplicitInterfaceImplementations],
            IPropertySymbol property => [.. property.ExplicitInterfaceImplementations],
            IMethodSymbol method => new(method.ExplicitInterfaceImplementations, SymbolEqualityComparer.Default),
            IPropertySymbol property => new(property.ExplicitInterfaceImplementations, SymbolEqualityComparer.Default),
            _ => [],
        };

Core/MemberCollectors/MembersCollector.cs +1 -1

diff --git a/Core/MemberCollectors/MembersCollector.cs b/Core/MemberCollectors/MembersCollector.cs
index 85e7a55..e9ad4b1 100644
@@ -6,7 +6,7 @@ namespace Reacher.MemberCollectors;
internal class MembersCollector : SymbolVisitor
{
    public IReadOnlySet<ISymbol> Members => members;
    private readonly HashSet<ISymbol> members = [];
    private readonly HashSet<ISymbol> members = new(SymbolEqualityComparer.Default);
    public override void VisitAssembly(IAssemblySymbol symbol)
    {

Core/ReachabilityAnalyzer.cs +8 -6

diff --git a/Core/ReachabilityAnalyzer.cs b/Core/ReachabilityAnalyzer.cs
index 5e6cd33..717be3c 100644
@@ -13,9 +13,9 @@ namespace Reacher;
internal sealed class ReachabilityAnalyzer(IReadOnlyCollection<Compilation> compilations)
{
    private readonly Dictionary<ISymbol, ReachabilityConfidence> reachableMembers = [];
    private readonly Dictionary<ISymbol, ReachabilityConfidence> reachableMembers = new(SymbolEqualityComparer.Default);
    private readonly HashSet<ISymbol> implementableMembers = [];
    private readonly HashSet<ISymbol> implementableMembers = new(SymbolEqualityComparer.Default);
    public void Analyze(ISymbol member, CancellationToken cancellationToken) =>
        Analyze(member, ReachabilityConfidence.DefinitelyReachable, cancellationToken);
@@ -57,8 +57,10 @@ internal sealed class ReachabilityAnalyzer(IReadOnlyCollection<Compilation> comp
            _ => member,
        };
    private static bool IsUserDefined(ISymbol member) =>
        !member.IsImplicitlyDeclared && (member.CanBeReferencedByName || member.Name is "<Main>$");
    private bool IsUserDefined(ISymbol member) =>
        !member.IsImplicitlyDeclared
        && (member.CanBeReferencedByName || member.Name is "<Main>$")
        && compilations.Any(c => SymbolEqualityComparer.Default.Equals(c.SourceModule, member.ContainingModule));
    private bool TryGetAssociatedCompilation(ISymbol member, [NotNullWhen(true)] out Compilation? compilation)
    {
@@ -124,7 +126,7 @@ internal sealed class ReachabilityAnalyzer(IReadOnlyCollection<Compilation> comp
    {
        var collector = new PredicateMembersCollector(m => IsUserDefined(m) && !reachableMembers.ContainsKey(m));
        compilations.Accept(collector);
        return [.. collector.Members];
        return new(collector.Members, SymbolEqualityComparer.Default);
    }
    private void AnalyzeProbablyReachableMembers(
@@ -148,6 +150,6 @@ internal sealed class ReachabilityAnalyzer(IReadOnlyCollection<Compilation> comp
        {
            possibleTransientTargets.Add(overriddenMember);
        }
        return possibleTransientTargets.Any(reachableMembers.ContainsKey);
        return possibleTransientTargets.Any(m => reachableMembers.ContainsKey(m) || !IsUserDefined(m));
    }
}