diff --git a/Sources/SwiftDoc/Interface.swift b/Sources/SwiftDoc/Interface.swift
index 8f5137ed..49e5008d 100644
--- a/Sources/SwiftDoc/Interface.swift
+++ b/Sources/SwiftDoc/Interface.swift
@@ -134,7 +134,7 @@ public final class Interface {
             var superclasses = Set(CollectionOfOne(baseClass))
 
             while !superclasses.isEmpty {
-                let subclasses = Set(superclasses.flatMap { typesInheriting(from: $0) }.filter { $0.isPublic })
+                let subclasses = Set(superclasses.flatMap { typesInheriting(from: $0) })
                 defer { superclasses = subclasses }
                 classClusters[baseClass, default: []].formUnion(subclasses)
             }
diff --git a/Sources/swift-doc/Subcommands/Diagram.swift b/Sources/swift-doc/Subcommands/Diagram.swift
index 1487ea1d..360f5815 100644
--- a/Sources/swift-doc/Subcommands/Diagram.swift
+++ b/Sources/swift-doc/Subcommands/Diagram.swift
@@ -35,7 +35,7 @@ fileprivate func diagram(of module: Module, including symbolFilter: (Symbol) ->
     for (baseClass, subclasses) in module.interface.classHierarchies {
         var subgraph = Subgraph(id: "cluster_\(baseClass.id.description.replacingOccurrences(of: ".", with: "_"))")
 
-        for subclass in subclasses {
+        for subclass in subclasses.filter(symbolFilter) {
             var subclassNode = Node("\(subclass.id)")
             subclassNode.shape = .box
 
@@ -54,7 +54,7 @@ fileprivate func diagram(of module: Module, including symbolFilter: (Symbol) ->
             }
         }
         
-        if subclasses.count > 1 {
+        if subgraph.nodes.count > 1 {
             graph.append(subgraph)
         } else {
             subgraph.nodes.forEach { graph.append($0) }
@@ -67,7 +67,7 @@ fileprivate func diagram(of module: Module, including symbolFilter: (Symbol) ->
         let symbolNode = Node("\(symbol.id)")
         graph.append(symbolNode)
 
-        for inherited in module.interface.typesConformed(by: symbol) {
+        for inherited in module.interface.typesConformed(by: symbol).filter(symbolFilter) {
             let inheritedNode = Node("\(inherited.id.description)")
             let edge = Edge(from: symbolNode, to: inheritedNode)
 
diff --git a/Sources/swift-doc/Supporting Types/Components/Relationships.swift b/Sources/swift-doc/Supporting Types/Components/Relationships.swift
index 116adc2a..7db15956 100644
--- a/Sources/swift-doc/Supporting Types/Components/Relationships.swift	
+++ b/Sources/swift-doc/Supporting Types/Components/Relationships.swift	
@@ -36,7 +36,7 @@ struct Relationships: Component {
     init(of symbol: Symbol, in module: Module, baseURL: String, includingChildren symbolFilter: @escaping (Symbol) -> Bool) {
         self.module = module
         self.symbol = symbol
-        self.inheritedTypes = module.interface.typesInherited(by: symbol) + module.interface.typesConformed(by: symbol)
+        self.inheritedTypes = (module.interface.typesInherited(by: symbol) + module.interface.typesConformed(by: symbol)).filter(symbolFilter)
         self.baseURL = baseURL
         self.symbolFilter = symbolFilter
     }
@@ -68,7 +68,7 @@ struct Relationships: Component {
             ("Subclasses", module.interface.typesInheriting(from: symbol)),
             ("Conforms To", module.interface.typesConformed(by: symbol)),
             ("Types Conforming to <code>\(softbreak(symbol.id.description))</code>", module.interface.typesConforming(to: symbol)),
-        ].map { (title: $0.0, symbols: $0.1.filter { $0.isPublic }) }.filter { !$0.symbols.isEmpty }
+        ].map { (title: $0.0, symbols: $0.1.filter(symbolFilter)) }.filter { !$0.symbols.isEmpty }
     }
 
     // MARK: - Component