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MA0007: Support multiline pattern-matching expressions #997

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meziantou merged 3 commits into from
Feb 4, 2026
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Merged

MA0007: Support multiline pattern-matching expressions #997

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3b2ad3f
Initial plan
Copilot Feb 4, 2026
699fa96
Add support for multiline pattern-matching expressions in MA0007
Copilot Feb 4, 2026
d719c21
Fix test naming: use TrailingComma instead of LeadingComma
Copilot Feb 4, 2026
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10 changes: 10 additions & 0 deletions src/Meziantou.Analyzer/Rules/CommaAnalyzer.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -36,6 +36,7 @@ public override void Initialize(AnalysisContext context)
context.RegisterSyntaxNodeAction(HandleEnumDeclaration, SyntaxKind.EnumDeclaration);
context.RegisterSyntaxNodeAction(HandleWithExpression, SyntaxKind.WithExpression);
context.RegisterSyntaxNodeAction(HandleSwitchExpression, SyntaxKind.SwitchExpression);
context.RegisterSyntaxNodeAction(HandleRecursivePattern, SyntaxKind.RecursivePattern);
#if CSHARP12_OR_GREATER
context.RegisterSyntaxNodeAction(HandleCollectionExpression, SyntaxKind.CollectionExpression);
#endif
Expand Down Expand Up @@ -101,4 +102,13 @@ private static void HandleAnonymousObjectInitializer(SyntaxNodeAnalysisContext c
var node = (AnonymousObjectCreationExpressionSyntax)context.Node;
HandleSeparatedList(context, node, node.Initializers);
}

private static void HandleRecursivePattern(SyntaxNodeAnalysisContext context)
{
var node = (RecursivePatternSyntax)context.Node;
if (node.PropertyPatternClause is null)
return;

HandleSeparatedList(context, node, node.PropertyPatternClause.Subpatterns);
}
}
82 changes: 82 additions & 0 deletions tests/Meziantou.Analyzer.Test/Rules/CommaAnalyzerTests.cs
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Expand Up @@ -421,4 +421,86 @@ public Task WithExpressionWithoutLeadingCommaSingleLine()
record Sample(int A, int B);
""")
.ValidateAsync();

[Fact]
public Task PropertyPatternWithoutTrailingComma()
=> CreateProjectBuilder()
.WithLanguageVersion(Microsoft.CodeAnalysis.CSharp.LanguageVersion.CSharp8)
.WithSourceCode("""
class TypeName
{
public int A { get; set; }
public int B { get; set; }

public void Test()
{
var obj = new TypeName();
_ = obj is
{
A: 1,
[||]B: 2
};
}
}
""")
.ShouldFixCodeWith("""
class TypeName
{
public int A { get; set; }
public int B { get; set; }

public void Test()
{
var obj = new TypeName();
_ = obj is
{
A: 1,
B: 2,
};
}
}
""")
.ValidateAsync();

[Fact]
public Task PropertyPatternWithTrailingComma()
=> CreateProjectBuilder()
.WithLanguageVersion(Microsoft.CodeAnalysis.CSharp.LanguageVersion.CSharp8)
.WithSourceCode("""
class TypeName
{
public int A { get; set; }
public int B { get; set; }

public void Test()
{
var obj = new TypeName();
_ = obj is
{
A: 1,
B: 2,
};
}
}
""")
.ValidateAsync();

[Fact]
public Task PropertyPatternSingleLine()
=> CreateProjectBuilder()
.WithLanguageVersion(Microsoft.CodeAnalysis.CSharp.LanguageVersion.CSharp8)
.WithSourceCode("""
class TypeName
{
public int A { get; set; }
public int B { get; set; }

public void Test()
{
var obj = new TypeName();
_ = obj is { A: 1, B: 2 };
}
}
""")
.ValidateAsync();
}