Support for declaring projectables on generic classes

tests/EntityFrameworkCore.Projectables.FunctionalTests/Generics/GenericEntityTests.HasMatchingStringKeyConversion_GetsTranslated.verified.txt

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+DECLARE @__key_0 nvarchar(4000) = N'x';
+
+SELECT [c].[Id]
+FROM [ConcreteEntity] AS [c]
+WHERE CONVERT(varchar(11), [c].[Id]) = @__key_0

tests/EntityFrameworkCore.Projectables.FunctionalTests/Generics/GenericEntityTests.cs

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+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using EntityFrameworkCore.Projectables.FunctionalTests.Helpers;
+using Microsoft.EntityFrameworkCore;
+using VerifyXunit;
+using Xunit;
+
+namespace EntityFrameworkCore.Projectables.FunctionalTests.Generics
+{
+    [UsesVerify]
+    public class GenericEntityTests
+    {
+        public abstract class BaseEntity<TSelf, TKey>
+            where TSelf : BaseEntity<TSelf, TKey>
+        {
+            public TKey Id { get; set; } = default!;
+
+            [Projectable(NullConditionalRewriteSupport = NullConditionalRewriteSupport.Ignore)]
+            public bool HasMatchingStringKeyConversion(string key)
+                => Id?.ToString() == key;
+        }
+
+        public class ConcreteEntity : BaseEntity<ConcreteEntity, int>
+        {
+
+        }
+
+        [Fact]
+        public Task HasMatchingStringKeyConversion_GetsTranslated()
+        {
+            using var context = new SampleDbContext<ConcreteEntity>();
+            var key = "x";
+            var query = context.Set<ConcreteEntity>()
+                .Where(x => x.HasMatchingStringKeyConversion(key))
+                .Select(x => x.Id);
+
+            return Verifier.Verify(query.ToQueryString());
+        }
+    }
+}