Fix MA0141 fixer to preserve parentheses when needed

meziantou · Nov 13, 2023 · b1e7508 · b1e7508
1 parent a5b7251
commit b1e7508
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Showing 2 changed files with 17 additions and 1 deletion.
diff --git a/src/Meziantou.Analyzer.CodeFixers/Rules/UsePatternMatchingForNullCheckFixer.cs b/src/Meziantou.Analyzer.CodeFixers/Rules/UsePatternMatchingForNullCheckFixer.cs
@@ -9,6 +9,7 @@
 using Microsoft.CodeAnalysis.CSharp.Syntax;
 using Microsoft.CodeAnalysis.Editing;
 using Microsoft.CodeAnalysis.Operations;
+using Microsoft.CodeAnalysis.Simplification;
 using static Microsoft.CodeAnalysis.CSharp.SyntaxFactory;
 
 namespace Meziantou.Analyzer.Rules;
@@ -51,7 +52,7 @@ private static async Task<Document> Update(Document document, BinaryExpressionSy
             constantExpression = UnaryPattern(constantExpression);
         }
 
-        var newSyntax = IsPatternExpression(expression, constantExpression);
+        var newSyntax = IsPatternExpression(ParenthesizedExpression(expression).WithAdditionalAnnotations(Simplifier.Annotation), constantExpression);
         editor.ReplaceNode(node, newSyntax);
         return editor.GetChangedDocument();
     }

diff --git a/tests/Meziantou.Analyzer.Test/Rules/UsePatternMatchingForNullCheckAnalyzerTests.cs b/tests/Meziantou.Analyzer.Test/Rules/UsePatternMatchingForNullCheckAnalyzerTests.cs
@@ -59,6 +59,21 @@ await CreateProjectBuilder()
               .ShouldFixCodeWith("_ = new object() is not null;")
               .ValidateAsync();
     }
+
+    [Fact]
+    public async Task NullCheckForObject_FixerKeepParentheses()
+    {
+        await CreateProjectBuilder()
+              .WithSourceCode("""
+                  string line;
+                  while ([|(line = null) != null|]) { }
+                  """)
+              .ShouldFixCodeWith("""
+                  string line;
+                  while ((line = null) is not null) { }
+                  """)
+              .ValidateAsync();
+    }
 
     [Fact]
     public async Task NullEqualsNull()