From 355c22219ae19010d7289e44af8f8fa29dc97618 Mon Sep 17 00:00:00 2001
From: Trung Nguyen <57174311+trungnt2910@users.noreply.github.com>
Date: Sun, 9 Jul 2023 19:50:23 +0700
Subject: [PATCH] CSharpExpressionPrinter: Wrap expression in parenthesis

Wrap default parameter expressions in parentheses to ensure whole expressions are casted instead of only the first operand.
---
 src/Generator/Generators/CSharp/CSharpExpressionPrinter.cs | 6 +++---
 tests/dotnet/Common/Common.cpp                             | 6 +++++-
 tests/dotnet/Common/Common.h                               | 2 ++
 3 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/src/Generator/Generators/CSharp/CSharpExpressionPrinter.cs b/src/Generator/Generators/CSharp/CSharpExpressionPrinter.cs
index c4c2f1d5..c625164a 100644
--- a/src/Generator/Generators/CSharp/CSharpExpressionPrinter.cs
+++ b/src/Generator/Generators/CSharp/CSharpExpressionPrinter.cs
@@ -27,11 +27,11 @@ namespace CppSharp.Generators.CSharp
             if (desugared.IsPrimitiveType() &&
                 (parameter.DefaultArgument.Declaration != null ||
                  parameter.DefaultArgument.Class == StatementClass.BinaryOperator))
-                return $"({desugared.Visit(typePrinter)}) {expression}";
+                return $"({desugared.Visit(typePrinter)}) ({expression})";
             var finalType = (desugared.GetFinalPointee() ?? desugared).Desugar();
             if (finalType.TryGetClass(out var @class) && @class.IsInterface)
                 return $@"({@class.Visit(typePrinter)}) ({
-                    @class.OriginalClass.Visit(typePrinter)}) {expression}";
+                    @class.OriginalClass.Visit(typePrinter)}) ({expression})";
             return expression;
         }
 
@@ -88,4 +88,4 @@ namespace CppSharp.Generators.CSharp
 
         private readonly TypePrinter typePrinter;
     }
-}
\ No newline at end of file
+}
diff --git a/tests/dotnet/Common/Common.cpp b/tests/dotnet/Common/Common.cpp
index 04d63cdd..d985b92c 100644
--- a/tests/dotnet/Common/Common.cpp
+++ b/tests/dotnet/Common/Common.cpp
@@ -1273,4 +1273,8 @@ extern "C"
         s.field2 = 10;
         return s;
     }
-} // extern "C"
\ No newline at end of file
+} // extern "C"
+
+void DLL_API FunctionWithFlagsAsDefaultParameter(int defaultParam)
+{
+}
diff --git a/tests/dotnet/Common/Common.h b/tests/dotnet/Common/Common.h
index c018c422..3b4af82c 100644
--- a/tests/dotnet/Common/Common.h
+++ b/tests/dotnet/Common/Common.h
@@ -1567,3 +1567,5 @@ extern "C"
     DLL_API void takeConflictName(struct system* self);
     DLL_API struct system freeFunctionReturnByValue();
 } // extern "C"
+
+void DLL_API FunctionWithFlagsAsDefaultParameter(int defaultParam = A | B);