diff --git a/osu.Framework.SourceGeneration/Analysers/DiagnosticRules.cs b/osu.Framework.SourceGeneration/Analysers/DiagnosticRules.cs
index dc6a82786..c1af3c327 100644
--- a/osu.Framework.SourceGeneration/Analysers/DiagnosticRules.cs
+++ b/osu.Framework.SourceGeneration/Analysers/DiagnosticRules.cs
@@ -13,12 +13,12 @@ namespace osu.Framework.SourceGeneration.Analysers
 
         public static readonly DiagnosticDescriptor MAKE_DI_CLASS_PARTIAL = new DiagnosticDescriptor(
             "OFSG001",
-            "This class is a candidate for dependency injection and should be partial",
-            "This class is a candidate for dependency injection and should be partial",
+            "This type, or a nested type, is a candidate for dependency injection and should be partial",
+            "This type, or a nested type, is a candidate for dependency injection and should be partial",
             "Performance",
             DiagnosticSeverity.Warning,
             true,
-            "Classes that are candidates for dependency injection should be made partial to benefit from compile-time optimisations.");
+            "Types that are candidates for dependency injection should be made partial to benefit from compile-time optimisations.");
 
 #pragma warning restore RS2008
     }
diff --git a/osu.Framework.SourceGeneration/Analysers/DrawableAnalyser.cs b/osu.Framework.SourceGeneration/Analysers/DrawableAnalyser.cs
index ae43c90ab..ec18e5194 100644
--- a/osu.Framework.SourceGeneration/Analysers/DrawableAnalyser.cs
+++ b/osu.Framework.SourceGeneration/Analysers/DrawableAnalyser.cs
@@ -24,19 +24,38 @@ namespace osu.Framework.SourceGeneration.Analysers
         }
 
         /// <summary>
-        /// Analyses class definitions for implementations of IDrawable, ISourceGeneratedDependencyActivator, and Transformable.
+        /// Analyses class definitions for implementations of IDependencyInjectionCandidateInterface.
         /// </summary>
         private void analyseClass(SyntaxNodeAnalysisContext context)
         {
             var classSyntax = (ClassDeclarationSyntax)context.Node;
 
-            if (classSyntax.Modifiers.Any(m => m.IsKind(SyntaxKind.PartialKeyword)))
+            if (classSyntax.Ancestors().OfType<ClassDeclarationSyntax>().Any())
                 return;
 
-            INamedTypeSymbol? type = context.SemanticModel.GetDeclaredSymbol(classSyntax);
+            analyseRecursively(context, classSyntax);
 
-            if (type?.AllInterfaces.Any(SyntaxHelpers.IsIDependencyInjectionCandidateInterface) == true)
-                context.ReportDiagnostic(Diagnostic.Create(DiagnosticRules.MAKE_DI_CLASS_PARTIAL, context.Node.GetLocation(), context.Node));
+            static bool analyseRecursively(SyntaxNodeAnalysisContext context, ClassDeclarationSyntax node)
+            {
+                bool requiresPartial = false;
+
+                // Child nodes always have to be analysed to provide diagnostics.
+                foreach (var nested in node.DescendantNodes().OfType<ClassDeclarationSyntax>())
+                    requiresPartial |= analyseRecursively(context, nested);
+
+                // - If at least one child requires partial, then this node also needs to be partial regardless of its own type (optimisation).
+                // - If no child requires partial, we need to check if this node is a DI candidate (e.g. If the node has no nested types).
+                if (!requiresPartial)
+                    requiresPartial = context.SemanticModel.GetDeclaredSymbol(node)?.AllInterfaces.Any(SyntaxHelpers.IsIDependencyInjectionCandidateInterface) == true;
+
+                // Whether the node is already partial.
+                bool isPartial = node.Modifiers.Any(m => m.IsKind(SyntaxKind.PartialKeyword));
+
+                if (requiresPartial && !isPartial)
+                    context.ReportDiagnostic(Diagnostic.Create(DiagnosticRules.MAKE_DI_CLASS_PARTIAL, node.GetLocation(), node));
+
+                return requiresPartial;
+            }
         }
     }
 }