AL0030 - Use type hierarchy extensions

Replace manual type hierarchy traversal with Implements() and InheritsFrom() extension methods

Source: AL0030UseTypeHierarchyAnalyzer.cs

Description

Manual traversal of AllInterfaces and BaseType chains is error-prone and verbose. ANcpLua.Roslyn.Utilities provides Implements() and InheritsFrom() extension methods for cleaner type hierarchy checks.

Bad Code

using Microsoft.CodeAnalysis;

// Manual interface check - verbose and error-prone
foreach (var iface in typeSymbol.AllInterfaces)
{
    if (iface.Name == "IDisposable")
    {
        // ...
        break;
    }
}

// Manual base type traversal - easy to forget null check
var current = typeSymbol.BaseType;
while (current != null)
{
    if (current.Name == "Exception")
    {
        // ...
        break;
    }
    current = current.BaseType;
}

Good Code

using ANcpLua.Roslyn.Utilities;

// Clean interface check
if (typeSymbol.Implements("IDisposable"))
{
    // ...
}

// Clean base type check
if (typeSymbol.InheritsFrom("Exception"))
{
    // ...
}

// Or with full type names
if (typeSymbol.Implements("System.IDisposable"))
{
    // ...
}

Properties

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

Configuration

dotnet_diagnostic.AL0030.severity = suggestion

Notes

The type hierarchy extension methods:

• Implements() - checks AllInterfaces for interface implementation
• InheritsFrom() - traverses BaseType chain for inheritance
• Both handle null checks automatically
• Support simple names or fully qualified type names
• More readable and less error-prone than manual loops