Inconsistency between C# Nullable Reference Types (NRT) and EF Core LINQ Expression Trees for optional columns

[DUWENINK]

Bug description

Description

When Nullable Context is enabled (<Nullable>enable</Nullable>), writing a standard Where clause for a nullable string column (e.g., string?) causes either a CS8602 warning or a compilation error, creating a sub-optimal developer experience.

If we write:

C#

// CS8602: Dereference of a possibly null reference.
query = query.Where(x => x.ShortName.Contains(kw)); 

C# compiler generates a warning because ShortName is string?.

However, if we try to fix it using the standard C# null-safe approach:

C#

// Compiler Error: An expression tree lambda may not contain a null-propagating operator
query = query.Where(x => x.ShortName?.Contains(kw) ?? false); 

The compiler blocks this because Expression Trees do not support the ?. operator yet.

Current Workarounds (And why they are unsatisfying)

1. Verbose Null Checking:

   C#

   query = query.Where(x => x.ShortName != null && x.ShortName.Contains(kw));
   

   Issue: It is unnecessarily verbose, especially when chaining multiple fields (e.g., Name.Contains || ShortName.Contains || Code.Contains).

2. Using the Dammit Operator (!):

   C#

   query = query.Where(x => x.ShortName!.Contains(kw));
   

   Issue: This defeats the whole purpose of enabling NRT. We are forcing the compiler to ignore a potential null, even though EF Core will safely translate this into SQL LIKE (which handles NULL gracefully in the database).

Your code

### Proposal / Suggested Solution

We need a more elegant way to handle nullable properties inside EF Core LINQ queries without triggering CS8602 or resorting to `!`.

Ideally, either:

1. **C# Language Improvement:** Allow null-propagating operators (`?.`) inside Expression Trees so EF Core can translate them.
2. **EF Core Analyzer Improvement:** The EF Core Roslyn Analyzer should recognize that `x.ShortName.Contains()` inside an `IQueryable` context is safe (since SQL handles `NULL` propagation anyway) and suppress the CS8602 warning automatically for mapped columns.

### Steps to Reproduce

1. Enable `<Nullable>enable</Nullable>` in `.csproj`.
2. Define an entity with a nullable string: `public string? ShortName { get; set; }`
3. Attempt to query using `query.Where(x => x.ShortName.Contains(kw))`.

### Environment

- EF Core version: 8.0 / 9.0
- Database Provider: (e.g., Microsoft.EntityFrameworkCore.SqlServer / Pomelo.EntityFrameworkCore.MySql)
- Target Framework: .NET 8.0 / .NET 9.0

Stack traces

Verbose output

EF Core version

11.0

Database provider

No response

Target framework

.NET 11

Operating system

No response

IDE

No response

[MihuBot]

I'm a bot. Here is a possible related and/or duplicate issue (I may be wrong):

• Create DiagnosticSuppressor for CS8602 in Linq expressions and Includes #21663