AL0034 - Use WhereNotNull()

Replace Where(x => x != null) with WhereNotNull() extension

Source: AL0034UseWhereNotNullAnalyzer.cs

Description

Filtering null values with Where(x => x != null) is a common pattern that can be simplified using the WhereNotNull() extension.

Bad Code

// Verbose null filtering
var nonNull = items.Where(x => x != null);
var filtered = symbols.Where(s => s is not null);

Good Code

using ANcpLua.Roslyn.Utilities;

// Clean extension
var nonNull = items.WhereNotNull();
var filtered = symbols.WhereNotNull();

Properties

• Category: Usage
• Severity: Info
• Enabled by default: True
• Code fix available: False

Configuration

dotnet_diagnostic.AL0034.severity = suggestion

Notes

• Also changes the return type from IEnumerable<T?> to IEnumerable<T>
• Eliminates nullable warnings in subsequent code
• Clearer intent than explicit null check