From 36a22d2a561ee3306e3abab2fc8f8dc7fbfa74bf Mon Sep 17 00:00:00 2001
From: William Kent <wjk011@gmail.com>
Date: Sun, 11 Jul 2021 15:47:01 -0400
Subject: [PATCH] Plug memory leak in StringMarshaller (#13)

---
 .../RuntimeCallableWrapperTest.cs                            | 1 +
 WinFormsComInterop.SourceGenerator/StringMarshaller.cs       | 5 +++++
 2 files changed, 6 insertions(+)

diff --git a/WinFormsComInterop.SourceGenerator.Tests/RuntimeCallableWrapperTest.cs b/WinFormsComInterop.SourceGenerator.Tests/RuntimeCallableWrapperTest.cs
index 64d64eb..db9873e 100644
--- a/WinFormsComInterop.SourceGenerator.Tests/RuntimeCallableWrapperTest.cs
+++ b/WinFormsComInterop.SourceGenerator.Tests/RuntimeCallableWrapperTest.cs
@@ -1105,6 +1105,7 @@ unsafe partial class C : global::Foo.IStr
                     Marshal.ThrowExceptionForHR(result);
                 }
 
+                Marshal.FreeCoTaskMem(local_1);
             }
             finally
             {
diff --git a/WinFormsComInterop.SourceGenerator/StringMarshaller.cs b/WinFormsComInterop.SourceGenerator/StringMarshaller.cs
index 5b141be..11e7a67 100644
--- a/WinFormsComInterop.SourceGenerator/StringMarshaller.cs
+++ b/WinFormsComInterop.SourceGenerator/StringMarshaller.cs
@@ -59,6 +59,11 @@ public override void UnmarshalParameter(IndentedStringBuilder builder)
             {
                 builder.AppendLine($"{Name} = Marshal.PtrToStringUni({LocalVariable});");
             }
+
+            if (RefKind != RefKind.Out && Index != -1)
+            {
+                builder.AppendLine($"Marshal.FreeCoTaskMem({LocalVariable});");
+            }
         }
     }
 }