Add regression test for issue#20046

Resolved by #19377
Issue fixed since cast to base type is removed by nav expansion as it is redundant

Resolves #20046

test/EFCore.Relational.Specification.Tests/Query/InheritanceRelationalTestBase.cs

@@ -32,6 +32,36 @@ public virtual void FromSql_on_derived()
             context.Set<Eagle>().FromSqlRaw(NormalizeDelimitersInRawString("select * from [Animal]")).ToList();
         }
 
+        [ConditionalFact]
+        public virtual void Casting_to_base_type_joining_with_query_type_works()
+        {
+            using var context = CreateContext();
+            var query = context.Set<Eagle>();
+
+            GetEntityWithAuditHistoryQuery(context, query);
+        }
+
+        private void GetEntityWithAuditHistoryQuery<T>(InheritanceContext context, IQueryable<T> query)
+            where T : Animal
+        {
+            var queryTypeQuery = context.Set<AnimalQuery>().FromSqlRaw(NormalizeDelimitersInRawString("Select * from [Animal]"));
+
+            var animalQuery = query.Cast<Animal>();
+
+            var joinQuery =
+                from animal in animalQuery
+                join keylessanimal in queryTypeQuery on animal.Name equals keylessanimal.Name
+                select new
+                {
+                    animal,
+                    keylessanimal
+                };
+
+            var result = joinQuery.ToList();
+
+            Assert.Single(result);
+        }
+
         private string NormalizeDelimitersInRawString(string sql)
             => ((RelationalTestStore)Fixture.TestStore).NormalizeDelimitersInRawString(sql);
 

test/EFCore.SqlServer.FunctionalTests/Query/CompleteMappingInheritanceSqlServerTest.cs

@@ -491,6 +491,23 @@ FROM [Animal] AS [a]
 ORDER BY [a].[Name]");
         }
 
+        public override void Casting_to_base_type_joining_with_query_type_works()
+        {
+            base.Casting_to_base_type_joining_with_query_type_works();
+
+            AssertSql(
+                @"SELECT [a].[Species], [a].[CountryId], [a].[Discriminator], [a].[Name], [a].[EagleId], [a].[IsFlightless], [a].[Group], [t].[CountryId], [t].[Discriminator], [t].[Name], [t].[EagleId], [t].[IsFlightless], [t].[Group], [t].[FoundOn]
+FROM [Animal] AS [a]
+INNER JOIN (
+    SELECT [a0].[CountryId], [a0].[Discriminator], [a0].[Name], [a0].[EagleId], [a0].[IsFlightless], [a0].[Group], [a0].[FoundOn]
+    FROM (
+        Select * from ""Animal""
+    ) AS [a0]
+    WHERE [a0].[Discriminator] IN (N'Eagle', N'Kiwi')
+) AS [t] ON [a].[Name] = [t].[Name]
+WHERE [a].[Discriminator] = N'Eagle'");
+        }
+
         protected override void UseTransaction(DatabaseFacade facade, IDbContextTransaction transaction)
             => facade.UseTransaction(transaction.GetDbTransaction());
 

test/EFCore.SqlServer.FunctionalTests/Query/InheritanceSqlServerTest.cs

@@ -511,6 +511,23 @@ FROM [Animal] AS [a]
 ORDER BY [a].[Name]");
         }
 
+        public override void Casting_to_base_type_joining_with_query_type_works()
+        {
+            base.Casting_to_base_type_joining_with_query_type_works();
+
+            AssertSql(
+                @"SELECT [a].[Species], [a].[CountryId], [a].[Discriminator], [a].[Name], [a].[EagleId], [a].[IsFlightless], [a].[Group], [t].[CountryId], [t].[Discriminator], [t].[Name], [t].[EagleId], [t].[IsFlightless], [t].[Group], [t].[FoundOn]
+FROM [Animal] AS [a]
+INNER JOIN (
+    SELECT [a0].[CountryId], [a0].[Discriminator], [a0].[Name], [a0].[EagleId], [a0].[IsFlightless], [a0].[Group], [a0].[FoundOn]
+    FROM (
+        Select * from ""Animal""
+    ) AS [a0]
+    WHERE [a0].[Discriminator] IN (N'Eagle', N'Kiwi')
+) AS [t] ON [a].[Name] = [t].[Name]
+WHERE [a].[Discriminator] = N'Eagle'");
+        }
+
         protected override void UseTransaction(DatabaseFacade facade, IDbContextTransaction transaction)
             => facade.UseTransaction(transaction.GetDbTransaction());