Null semantics compensation missing for LIKE negation

[roji]

When negating EF.Functions.Like, we don't add null compensation, so EF.Functions.Like || !EF.Functions.Like does not yield the full set of rows.

var blog = await ctx.Blogs.Where(b => EF.Functions.Like(b.Name, "f%")).SingleAsync();
Console.WriteLine($"Blog {blog.Id}: {blog.Name}");

var blogs = await ctx.Blogs.Where(b => !EF.Functions.Like(b.Name, "f%")).ToListAsync();
Console.WriteLine($"Blogs: {blogs.Count}");

blog = await ctx.Blogs.Where(b => b.Name == null || !EF.Functions.Like(b.Name, "f%")).SingleAsync();
Console.WriteLine($"Blog {blog.Id}: {blog.Name}");

[joakimriedel]

Isn't this quite expected, since a "Name not like 'f%'" SQL statement will not returns rows where Name is null?

However, if I want the null rows to be returned the only workaround from C# world I've found is to do Where(b => !EF.Functions.Like(b.Name ?? '', "f%")) to translate to not (COALESCE(Name, '') like 'f%') (in MS SQL I believe ISNULL would be better since it has stricter nullability but it's not in EF.Functions)

[smitpatel]

Looking at current processing, when ! is applied to any term we try to push it inside if the term is non-nullable (2-value logic). If the inner term is nullable then we leave the not operator as is. With that implementation, something OR !something may not give all results if something is nullable.
@maumar should know reason behind why we don't try to convert something to 2-value logic to apply ! operator over it.