61 lines
2.7 KiB
C#
61 lines
2.7 KiB
C#
namespace BizHawk.Analyzers;
|
|
|
|
using System;
|
|
using System.Collections.Immutable;
|
|
using System.Linq;
|
|
|
|
using Microsoft.CodeAnalysis;
|
|
using Microsoft.CodeAnalysis.CSharp;
|
|
using Microsoft.CodeAnalysis.Diagnostics;
|
|
using Microsoft.CodeAnalysis.Operations;
|
|
|
|
[DiagnosticAnalyzer(LanguageNames.CSharp)]
|
|
public sealed class FirstOrDefaultOnStructAnalyzer : DiagnosticAnalyzer
|
|
{
|
|
private static readonly DiagnosticDescriptor DiagUseFirstOrNull = new(
|
|
id: "BHI3100",
|
|
title: "Call to FirstOrDefault when elements are of a value type; FirstOrNull may have been intended",
|
|
messageFormat: "Call to FirstOrDefault when elements are of a value type; did you mean FirstOrNull?",
|
|
category: "Usage",
|
|
defaultSeverity: DiagnosticSeverity.Warning,
|
|
isEnabledByDefault: true);
|
|
|
|
public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics { get; } = ImmutableArray.Create(DiagUseFirstOrNull);
|
|
|
|
public override void Initialize(AnalysisContext context)
|
|
{
|
|
context.ConfigureGeneratedCodeAnalysis(GeneratedCodeAnalysisFlags.None);
|
|
context.EnableConcurrentExecution();
|
|
context.RegisterCompilationStartAction(initContext =>
|
|
{
|
|
if (initContext.Compilation.GetTypeByMetadataName("BizHawk.Common.CollectionExtensions.CollectionExtensions") is null) return; // project does not have BizHawk.Common dependency
|
|
var linqExtClassSym = initContext.Compilation.GetTypeByMetadataName("System.Linq.Enumerable")!;
|
|
IMethodSymbol? firstOrDefaultNoPredSym = null;
|
|
IMethodSymbol? firstOrDefaultWithPredSym = null;
|
|
foreach (var sym in linqExtClassSym.GetMembers("FirstOrDefault").Cast<IMethodSymbol>())
|
|
{
|
|
if (sym.Parameters.Length is 2) firstOrDefaultWithPredSym = sym;
|
|
else firstOrDefaultNoPredSym = sym;
|
|
}
|
|
initContext.RegisterOperationAction(
|
|
oac =>
|
|
{
|
|
var operation = (IInvocationOperation) oac.Operation;
|
|
var calledSym = operation.TargetMethod.ConstructedFrom;
|
|
if (!(firstOrDefaultWithPredSym!.Matches(calledSym) || firstOrDefaultNoPredSym!.Matches(calledSym))) return;
|
|
var receiverExprType = operation.SemanticModel!.GetTypeInfo(
|
|
(CSharpSyntaxNode) operation.Arguments[0].Syntax,
|
|
oac.CancellationToken).ConvertedType!;
|
|
var collectionElemType = receiverExprType switch
|
|
{
|
|
INamedTypeSymbol nts => nts.TypeArguments[0],
|
|
IArrayTypeSymbol ats => ats.ElementType,
|
|
_ => throw new InvalidOperationException($"receiver parameter's effective type was of an unexpected kind (neither class/struct nor array): {receiverExprType.GetType().FullName}")
|
|
};
|
|
if (collectionElemType.IsValueType) oac.ReportDiagnostic(Diagnostic.Create(DiagUseFirstOrNull, operation.Syntax.GetLocation()));
|
|
},
|
|
OperationKind.Invocation);
|
|
});
|
|
}
|
|
}
|