AL0039 - Use StringComparison extensions

Replace string methods with StringComparison parameter using named extensions

Source: AL0039UseStringComparisonExtensionsAnalyzer.cs

Description

String methods with StringComparison enum parameters are less readable. ANcpLua.Roslyn.Utilities provides named extension methods for clearer intent.

Bad Code

// Verbose StringComparison parameters
if (value.Equals("Warning", StringComparison.OrdinalIgnoreCase)) { }
if (path.StartsWith("/api/", StringComparison.Ordinal)) { }
if (text.Contains("error", StringComparison.OrdinalIgnoreCase)) { }

Good Code

using ANcpLua.Roslyn.Utilities;

// Clear intent with named extensions
if (value.EqualsIgnoreCase("Warning")) { }
if (path.StartsWithOrdinal("/api/")) { }
if (text.ContainsIgnoreCase("error")) { }

Properties

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

Configuration

dotnet_diagnostic.AL0039.severity = warning

Available Extensions

Method	Ordinal	IgnoreCase
Equals	EqualsOrdinal()	EqualsIgnoreCase()
StartsWith	StartsWithOrdinal()	StartsWithIgnoreCase()
EndsWith	EndsWithOrdinal()	EndsWithIgnoreCase()
Contains	ContainsOrdinal()	ContainsIgnoreCase()
IndexOf	IndexOfOrdinal()	IndexOfIgnoreCase()

Limitations

• LastIndexOf is not flagged - no extension method exists
• IndexOf with startIndex is not flagged - extensions only support simple (value, StringComparison) signatures