Fixes for CodeQL reliability warnings.

src/AutoMapper.Extensions.ExpressionMapping/ConfigurationHelper.cs

@@ -7,12 +7,12 @@ public static class ConfigurationHelper
     {
         public static MapperConfiguration GetMapperConfiguration(Action<IMapperConfigurationExpression> configure)
         {
-            return new MapperConfiguration(configure, new NullLoggerFactory());
+            return new MapperConfiguration(configure, NullLoggerFactory.Instance);
         }
 
         public static MapperConfiguration GetMapperConfiguration(MapperConfigurationExpression configurationExpression)
         {
-            return new MapperConfiguration(configurationExpression, new NullLoggerFactory());
+            return new MapperConfiguration(configurationExpression, NullLoggerFactory.Instance);
         }
     }
 }

src/AutoMapper.Extensions.ExpressionMapping/ExpressionMapper.cs

@@ -267,7 +267,7 @@ private static Type GetSourceType(PropertyMap propertyMap) =>
             private PropertyMap FindPropertyMapOfExpression(MemberExpression expression)
             {
                 var propertyMap = PropertyMap(expression);
-                return propertyMap == null && expression.Expression is MemberExpression memberExpression
+                return propertyMap == null && expression?.Expression is MemberExpression memberExpression
                     ? FindPropertyMapOfExpression(memberExpression)
                     : propertyMap;
             }

src/AutoMapper.Extensions.ExpressionMapping/Extensions/VisitorExtensions.cs

@@ -62,7 +62,7 @@ public static MemberExpression GetMemberExpression(this LambdaExpression expr)
             => expr.Body.GetUnconvertedExpression() as MemberExpression;
 
         public static MemberExpression GetMemberExpression(this Expression expr)
-            => expr.GetUnconvertedExpression() as MemberExpression;
+            => expr?.GetUnconvertedExpression() as MemberExpression;
 
         /// <summary>
         /// Returns the ParameterExpression for the LINQ parameter.
@@ -101,6 +101,9 @@ public static ParameterExpression GetParameterExpression(this Expression express
                     if (isExtension && parentExpression == null && methodExpression.Arguments.Count > 0)
                         parentExpression = methodExpression.Arguments[0];//Method is an extension method based on the type of methodExpression.Arguments[0].
 
+                    if (parentExpression == null) 
+                        return null;
+
                     return GetParameterExpression(parentExpression);
             }
 

tests/AutoMapper.Extensions.ExpressionMapping.UnitTests/MemberMappingsOfLiteralParentTypesMustMatch.cs

@@ -11,7 +11,7 @@ public void MappingMemberOfNullableParentToMemberOfNonNullableParentWithoutCusto
         {
             //arrange
             var mapper = GetMapper();
-            Expression<Func<ProductModel, bool>> expression = x => x.DateTimeOffset.Value.Day.ToString() == "2";
+            Expression<Func<ProductModel, bool>> expression = x => x.DateTimeOffset.HasValue && x.DateTimeOffset.Value.Day.ToString() == "2";
 
             //act
             var exception = Assert.Throws<InvalidOperationException>(() => mapper.MapExpression<Expression<Func<Product, bool>>>(expression));
@@ -47,7 +47,7 @@ public void MappingMemberOfNullableParentToMemberOfNonNullableParentWorksUsingCu
         {
             //arrange
             var mapper = GetMapperWithCustomExpressions();
-            Expression<Func<ProductModel, bool>> expression = x => x.DateTimeOffset.Value.Day.ToString() == "2";
+            Expression<Func<ProductModel, bool>> expression = x => x.DateTimeOffset.HasValue && x.DateTimeOffset.Value.Day.ToString() == "2";
 
             //act
             var mappedExpression = mapper.MapExpression<Expression<Func<Product, bool>>>(expression);
@@ -92,7 +92,7 @@ private static IMapper GetMapperWithCustomExpressions()
             var config = ConfigurationHelper.GetMapperConfiguration(c =>
             {
                 c.CreateMap<Product, ProductModel>()
-                    .ForMember(d => d.DateTime, o => o.MapFrom(s => s.DateTime.Value))
+                    .ForMember(d => d.DateTime, o => o.MapFrom(s => s.DateTime ?? default))
                     .ForMember(d => d.DateTimeOffset, o => o.MapFrom(s => (DateTimeOffset?)s.DateTimeOffset));
             });
             config.AssertConfigurationIsValid();

tests/AutoMapper.Extensions.ExpressionMapping.UnitTests/Structures/DeclaringMemberKeyTest.cs

@@ -74,34 +74,6 @@ public void Equals_NullDeclaringMemberKey_ReturnsFalse()
             Assert.False(result);
         }
 
-        [Fact]
-        public void Equals_DifferentTypeObject_ReturnsFalse()
-        {
-            // Arrange
-            var key = new DeclaringMemberKey(_testMemberInfo1, TestFullName1);
-            var otherObject = "some string";
-
-            // Act
-            var result = key.Equals(otherObject);
-
-            // Assert
-            Assert.False(result);
-        }
-
-        [Fact]
-        public void Equals_SameValues_ReturnsTrue()
-        {
-            // Arrange
-            var key1 = new DeclaringMemberKey(_testMemberInfo1, TestFullName1);
-            var key2 = new DeclaringMemberKey(_testMemberInfo1, TestFullName1);
-
-            // Act
-            var result = key1.Equals(key2);
-
-            // Assert
-            Assert.True(result);
-        }
-
         [Fact]
         public void Equals_DifferentMemberInfo_ReturnsFalse()
         {

tests/AutoMapper.Extensions.ExpressionMapping.UnitTests/XpressionMapperTests.cs

@@ -276,7 +276,7 @@ public void Map__flattened_property()
         {
             //Arrange
             int age = 25;
-            Expression<Func<UserModel, bool>> selection = s => ((s != null ? s.AccountName : null) ?? "").ToLower().StartsWith("P".ToLower()) && ((s.AgeInYears == age) && s.IsActive);
+            Expression<Func<UserModel, bool>> selection = s => ((s != null ? s.AccountName : null) ?? "").ToLower().StartsWith("P".ToLower()) && s != null && s.AgeInYears == age && s.IsActive;
 
             //Act
             Expression<Func<User, bool>> selectionMapped = mapper.Map<Expression<Func<User, bool>>>(selection);
@@ -531,7 +531,7 @@ public void Map_to_anonymous_type_when_init_member_is_not_a_literal()
         public void Map_to_anonymous_type_when_init_member_is_not_a_literal_and_parameter_is_anonymous_type()
         {
             //Arrange
-            Expression<Func<IQueryable<UserModel>, IEnumerable<object>>> expression = q => q.OrderBy(s => s.Id).Select(u => new { UserId = u.Id, Account = u.AccountModel }).Where(a => a.Account.Bal != -1);
+            Expression<Func<IQueryable<UserModel>, IEnumerable<object>>> expression = q => q.OrderBy(s => s.Id).Select(u => new { UserId = u.Id, Account = u.AccountModel }).Where(a => Math.Abs(a.Account.Bal + 1) > double.Epsilon);
 
             //Act
             Expression<Func<IQueryable<User>, IEnumerable<object>>> expMapped = (Expression<Func<IQueryable<User>, IEnumerable<object>>>)mapper.MapExpression