diff --git a/ExternalProjects/BizHawk.Analyzer/FirstOrDefaultOnStructAnalyzer.cs b/ExternalProjects/BizHawk.Analyzer/FirstOrDefaultOnStructAnalyzer.cs
index ae888bb3a1..0424d99a33 100644
--- a/ExternalProjects/BizHawk.Analyzer/FirstOrDefaultOnStructAnalyzer.cs
+++ b/ExternalProjects/BizHawk.Analyzer/FirstOrDefaultOnStructAnalyzer.cs
@@ -1,5 +1,6 @@
 namespace BizHawk.Analyzers;
 
+using System;
 using System.Collections.Immutable;
 using System.Linq;
 
@@ -42,8 +43,13 @@ public sealed class FirstOrDefaultOnStructAnalyzer : DiagnosticAnalyzer
 					var operation = (IInvocationOperation) oac.Operation;
 					var calledSym = operation.TargetMethod.ConstructedFrom;
 					if (!(firstOrDefaultWithPredSym!.Matches(calledSym) || firstOrDefaultNoPredSym!.Matches(calledSym))) return;
-					var receiverExprType = (INamedTypeSymbol) operation.SemanticModel!.GetTypeInfo((CSharpSyntaxNode) operation.Arguments[0].Syntax)!.ConvertedType!;
-					if (receiverExprType.TypeArguments[0].IsValueType) oac.ReportDiagnostic(Diagnostic.Create(DiagUseFirstOrNull, operation.Syntax.GetLocation()));
+					var receiverExprType = operation.SemanticModel!.GetTypeInfo((CSharpSyntaxNode) operation.Arguments[0].Syntax).ConvertedType!;
+					var collectionElemType = receiverExprType switch {
+						INamedTypeSymbol nts => nts.TypeArguments[0],
+						IArrayTypeSymbol ats => ats.ElementType,
+						_ => throw new InvalidOperationException($"receiver parameter's effective type was of an unexpected kind (neither class/struct nor array): {receiverExprType}")
+					};
+					if (collectionElemType.IsValueType) oac.ReportDiagnostic(Diagnostic.Create(DiagUseFirstOrNull, operation.Syntax.GetLocation()));
 				},
 				OperationKind.Invocation);
 		});
diff --git a/References/BizHawk.Analyzer.dll b/References/BizHawk.Analyzer.dll
index 62e21f6ee4..cefe7b12f3 100644
Binary files a/References/BizHawk.Analyzer.dll and b/References/BizHawk.Analyzer.dll differ