Fix NRE in BasicOverrideEqualsOnOverloadingOperatorEqualsAnalyzer

Fixes #6778

Author: mavasani

src/NetAnalyzers/UnitTests/Microsoft.CodeQuality.Analyzers/ApiDesignGuidelines/OverrideEqualsOnOverloadingOperatorEqualsTests.cs

@@ -1,7 +1,8 @@
-// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the MIT license.  See License.txt in the project root for license information.
+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the MIT license.  See License.txt in the project root for license information.
 
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.Testing;
+using Test.Utilities;
 using Xunit;
 using VerifyVB = Test.Utilities.VisualBasicCodeFixVerifier<
     Microsoft.CodeQuality.VisualBasic.Analyzers.ApiDesignGuidelines.BasicOverrideEqualsOnOverloadingOperatorEqualsAnalyzer,
@@ -167,6 +168,25 @@ End Function
             GetBasicResultAt(8, 7));
         }
 
+        [Fact, WorkItem(6778, "https://github.com/dotnet/roslyn-analyzers/issues/6778")]
+        public async Task Bad_Structure_WithNonMethodMember_Async()
+        {
+            await VerifyVB.VerifyAnalyzerAsync(@"
+Structure C
+    Public Field As Integer
+
+    Public Shared Operator =(a As C, b As C)
+        Return True
+    End Operator
+    
+    Public Shared Operator <>(a As C, b As C)
+        Return True
+    End Operator
+End Structure",
+            // Test0.vb(2,11): warning CA2224: Override Equals on overloading operator equals
+            GetBasicResultAt(2, 11));
+        }
+
         private static DiagnosticResult GetBasicResultAt(int line, int column)
 #pragma warning disable RS0030 // Do not use banned APIs
             => VerifyVB.Diagnostic()

src/NetAnalyzers/VisualBasic/Microsoft.CodeQuality.Analyzers/ApiDesignGuidelines/BasicOverrideEqualsOnOverloadingOperatorEquals.vb

@@ -63,8 +63,9 @@ Namespace Microsoft.CodeQuality.VisualBasic.Analyzers.ApiDesignGuidelines
         Private Shared Function HasEqualityOperator(type As INamedTypeSymbol) As Boolean
             For Each member In type.GetMembers()
                 Dim method = TryCast(member, IMethodSymbol)
-                If method?.MethodKind = MethodKind.UserDefinedOperator AndAlso
-                    CaseInsensitiveComparison.Equals(method.Name, WellKnownMemberNames.EqualityOperatorName) Then
+                If method IsNot Nothing AndAlso
+                   method.MethodKind = MethodKind.UserDefinedOperator AndAlso
+                   CaseInsensitiveComparison.Equals(method.Name, WellKnownMemberNames.EqualityOperatorName) Then
 
                     Return True
                 End If