Add failing test

IntelliTect.Analyzer/IntelliTect.Analyzer.Test/Data/DateTime_ImplicitConversion_InLinq.cs

@@ -0,0 +1,27 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace ConsoleApp1
+{
+    internal class Pair
+    {
+        public DateTimeOffset DateTimeOffset { get; init; }
+        public DateTime DateTime { get; init; }
+
+        public Pair(DateTimeOffset dateTimeOffset, DateTime dateTime)
+        {
+            DateTimeOffset = dateTimeOffset;
+            DateTime = dateTime;
+        }
+    }
+
+    internal class Program
+    {
+        static void Main(string[] args)
+        {
+            List<Pair> list = new(){ new(DateTimeOffset.Now, DateTime.Now) };
+            _ = list.Where(pair => pair.DateTimeOffset < pair.DateTime);
+        }
+    }
+}

IntelliTect.Analyzer/IntelliTect.Analyzer.Test/DateTimeConversionTests.cs

@@ -1,4 +1,6 @@
-using Microsoft.CodeAnalysis;
+using System;
+using System.IO;
+using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.Diagnostics;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using TestHelper;
@@ -40,7 +42,7 @@ static void Main(string[] args)
         }
 
         [TestMethod]
-        public void UsageOfImplicitConversionInComparison_ProducesWarningMessage()
+        public void UsageOfImplicitConversionInComparison_DateTimeToDateTimeOffset_ProducesWarningMessage()
         {
             string source = @"
 using System;
@@ -53,15 +55,42 @@ internal class Program
         static void Main(string[] args)
         {
             DateTime first = DateTime.Now;
+            DateTimeOffset second = DateTimeOffset.Now;
+            _ = first < second
+        }
+    }
+}";
 
-            Thread.Sleep(10);
+            VerifyCSharpDiagnostic(source,
+                           new DiagnosticResult
+                           {
+                               Id = "INTL0202",
+                               Severity = DiagnosticSeverity.Warning,
+                               Message = "Using the symbol 'DateTimeOffset.implicit operator DateTimeOffset(DateTime)' can result in unpredictable behavior",
+                               Locations =
+                                   new[] {
+                            new DiagnosticResultLocation("Test0.cs", 13, 17)
+                                   }
+                           });
 
-            DateTimeOffset second = DateTimeOffset.Now;
+        }
 
-            if (first < second)
-            {
-                Console.WriteLine(""Time has passed..."");
-            }
+        [TestMethod]
+        public void UsageOfImplicitConversionInComparison_DateTimeOffsetToDateTime_ProducesWarningMessage()
+        {
+            string source = @"
+using System;
+using System.Threading;
+
+namespace ConsoleApp1
+{
+    internal class Program
+    {
+        static void Main(string[] args)
+        {
+            DateTimeOffset first = DateTimeOffset.Now;
+            DateTime second = DateTime.Now;
+            _ = first < second
         }
     }
 }";
@@ -74,12 +103,70 @@ static void Main(string[] args)
                                Message = "Using the symbol 'DateTimeOffset.implicit operator DateTimeOffset(DateTime)' can result in unpredictable behavior",
                                Locations =
                                    new[] {
-                            new DiagnosticResultLocation("Test0.cs", 17, 17)
+                            new DiagnosticResultLocation("Test0.cs", 13, 25)
                                    }
                            });
 
         }
 
+        [TestMethod]
+        public void UsageOfImplicitConversionInComparison_NullableDateTimeOffsetToDateTime_ProducesWarningMessage()
+        {
+            string source = @"
+using System;
+using System.Threading;
+
+namespace ConsoleApp1
+{
+    internal class Program
+    {
+        static void Main(string[] args)
+        {
+            DateTimeOffset? first = DateTimeOffset.Now;
+            DateTime second = DateTime.Now;
+            _ = first < second
+        }
+    }
+}";
+
+            VerifyCSharpDiagnostic(
+                source,
+                new DiagnosticResult
+                {
+                    Id = "INTL0202",
+                    Severity = DiagnosticSeverity.Warning,
+                    Message = "Using the symbol 'DateTimeOffset.implicit operator DateTimeOffset(DateTime)' can result in unpredictable behavior",
+                    Locations = new[] {
+                        new DiagnosticResultLocation("Test0.cs", 13, 25)
+                    }
+                }
+            );
+
+        }
+
+        [TestMethod]
+        public void UsageOfImplicitConversion_InLinq_ProducesWarningMessage()
+        {
+            string dir = Directory.GetParent(Environment.CurrentDirectory).Parent.Parent.FullName;
+            string path = Path.Combine(dir, "Data", "DateTime_ImplicitConversion_InLinq.cs");
+            string source = File.ReadAllText(path);
+
+            VerifyCSharpDiagnostic(
+                source,
+                new DiagnosticResult
+                {
+                    Id = "INTL0202",
+                    Severity = DiagnosticSeverity.Warning,
+                    Message = "Using the symbol 'DateTimeOffset.implicit operator DateTimeOffset(DateTime)' can result in unpredictable behavior",
+                    Locations =
+                    new[] {
+                        new DiagnosticResultLocation("Test0.cs", 17, 25)
+                    }
+                }
+            );
+        }
+
+
         [TestMethod]
         public void UsageOfExplicitConversion_ProducesNothing()
         {

IntelliTect.Analyzer/IntelliTect.Analyzer.Test/IntelliTect.Analyzer.Tests.csproj

@@ -5,6 +5,10 @@
     <NoWarn>CA2007,CA1815,CA1303,CA1707,CA1305</NoWarn>
   </PropertyGroup>
 
+  <ItemGroup>
+    <Compile Remove="Data\**" />
+  </ItemGroup>
+
   <ItemGroup>
     <PackageReference Include="Microsoft.CodeAnalysis.Analyzers" Version="3.3.4-beta1.22559.1">
       <PrivateAssets>all</PrivateAssets>