From f785e6ab3e9ef8b34fe215cc32874839911a1624 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?G=C3=A9rald=20Barr=C3=A9?= <git@meziantou.net>
Date: Tue, 22 Sep 2026 21:02:05 -0400
Subject: [PATCH] Fix MA0073 false positive on user-defined equality operators

---
 docs/Rules/MA0073.md                          |  2 ++
 ...AvoidComparisonWithBoolConstantAnalyzer.cs |  7 +++++++
 ...ComparisonWithBoolConstantAnalyzerTests.cs | 19 +++++++++++++++++++
 3 files changed, 28 insertions(+)

diff --git a/docs/Rules/MA0073.md b/docs/Rules/MA0073.md
index 4f35f2d5c..3e34e378c 100644
--- a/docs/Rules/MA0073.md
+++ b/docs/Rules/MA0073.md
@@ -24,3 +24,5 @@ if (!value)
 {
 }
 ```
+
+The rule only reports the built-in `bool` equality operators. It does not report the comparisons that use a user-defined operator, such as `operator ==(MyType, bool)`, as removing the constant would change the meaning of the code.
diff --git a/src/Meziantou.Analyzer/Rules/AvoidComparisonWithBoolConstantAnalyzer.cs b/src/Meziantou.Analyzer/Rules/AvoidComparisonWithBoolConstantAnalyzer.cs
index 28ee3362d..6a3e9b1b8 100644
--- a/src/Meziantou.Analyzer/Rules/AvoidComparisonWithBoolConstantAnalyzer.cs
+++ b/src/Meziantou.Analyzer/Rules/AvoidComparisonWithBoolConstantAnalyzer.cs
@@ -34,6 +34,10 @@ private static void AnalyzeBinaryOperation(OperationAnalysisContext context)
             return;
         }
 
+        // Only the built-in bool operators can be replaced by the operand
+        if (binaryOperation.OperatorMethod is not null)
+            return;
+
         // There must be 2 valid operands
         if (binaryOperation.LeftOperand?.Type is null || binaryOperation.RightOperand?.Type is null)
             return;
@@ -63,6 +67,9 @@ private static void AnalyzeBinaryOperation(OperationAnalysisContext context)
             return;
         }
 
+        if (!nodeToKeep.Type.IsBoolean())
+            return;
+
         // The fixer will need to prefix the remaining operand with '!' if the original comparison is "!= true" or "== false"
         var logicalNotOperatorNeeded = (bool)nodeToRemove.ConstantValue.Value! ?
             binaryOperation.OperatorKind == BinaryOperatorKind.NotEquals :
diff --git a/tests/Meziantou.Analyzer.Test/Rules/AvoidComparisonWithBoolConstantAnalyzerTests.cs b/tests/Meziantou.Analyzer.Test/Rules/AvoidComparisonWithBoolConstantAnalyzerTests.cs
index 4d2d8d665..b2409df5f 100644
--- a/tests/Meziantou.Analyzer.Test/Rules/AvoidComparisonWithBoolConstantAnalyzerTests.cs
+++ b/tests/Meziantou.Analyzer.Test/Rules/AvoidComparisonWithBoolConstantAnalyzerTests.cs
@@ -390,4 +390,23 @@ void Test(long? number)
 
         return test.RunAsync();
     }
+
+    [Fact]
+    public Task ComparingWithUserDefinedOperator_NoDiagnosticReported()
+    {
+        var test = CreateTest();
+        test.TestCode = """
+            class C
+            {
+                public static bool operator ==(C a, bool b) => true;
+                public static bool operator !=(C a, bool b) => false;
+                public override bool Equals(object o) => true;
+                public override int GetHashCode() => 0;
+
+                bool M(C c) => c == true;
+            }
+            """;
+
+        return test.RunAsync();
+    }
 }