From 4ea2a11d10485d7f68579816a57854221ce0043a Mon Sep 17 00:00:00 2001
From: Suzanne Millstein <smillst@cs.washington.edu>
Date: Thu, 3 Oct 2024 09:37:11 -0700
Subject: [PATCH 1/4] copy annotations for anonymous.

---
 .../checkerframework/framework/type/AnnotatedTypeFactory.java   | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/framework/src/main/java/org/checkerframework/framework/type/AnnotatedTypeFactory.java b/framework/src/main/java/org/checkerframework/framework/type/AnnotatedTypeFactory.java
index d0b39de5baf..e631649d6d7 100644
--- a/framework/src/main/java/org/checkerframework/framework/type/AnnotatedTypeFactory.java
+++ b/framework/src/main/java/org/checkerframework/framework/type/AnnotatedTypeFactory.java
@@ -2826,7 +2826,7 @@ protected ParameterizedExecutableType constructorFromUse(
         p.addAll(1, superCon.getParameterTypes());
         con.setParameterTypes(p);
       }
-      con.getReturnType().replaceAnnotations(superCon.getReturnType().getPrimaryAnnotations());
+      con.getReturnType().replaceAnnotations(type.getPrimaryAnnotations());
     } else {
       con = AnnotatedTypes.asMemberOf(types, this, type, ctor, con);
     }

From b58824e407ab8db821a72690f3526470982beb4e Mon Sep 17 00:00:00 2001
From: Suzanne Millstein <smillst@cs.washington.edu>
Date: Thu, 3 Oct 2024 09:45:45 -0700
Subject: [PATCH 2/4] lub.

---
 .../tests/mustcall/FunctionalInterfaces.java  | 52 +++++++++++++++++++
 .../framework/type/AnnotatedTypeFactory.java  |  8 ++-
 2 files changed, 59 insertions(+), 1 deletion(-)
 create mode 100644 checker/tests/mustcall/FunctionalInterfaces.java

diff --git a/checker/tests/mustcall/FunctionalInterfaces.java b/checker/tests/mustcall/FunctionalInterfaces.java
new file mode 100644
index 00000000000..d60efbbec07
--- /dev/null
+++ b/checker/tests/mustcall/FunctionalInterfaces.java
@@ -0,0 +1,52 @@
+// Test that the correct type is assigned to instantiations of functional
+// interfaces.
+// https://github.com/typetools/checker-framework/issues/6823
+
+import java.io.Closeable;
+import org.checkerframework.checker.mustcall.qual.*;
+
+public abstract class FunctionalInterfaces {
+
+  @FunctionalInterface
+  public interface Actor extends Closeable {
+    void act();
+
+    @Override
+    default void close() {}
+  }
+
+  public static class ActorImpl implements Actor {
+    @Override
+    public void act() {}
+  }
+
+  public abstract void run(@MustCall({}) Actor a);
+
+  public static void method() {}
+
+  public void normalConstruction() {
+
+    // :: error: (assignment)
+    @MustCall({}) Actor a = new ActorImpl();
+  }
+
+  public void inlineClass() {
+
+    class ActorImplInline implements Actor {
+      @Override
+      public void act() {}
+    }
+
+    // :: error: (assignment)
+    @MustCall({}) Actor a = new ActorImplInline();
+  }
+
+  public void anonymousClass() {
+
+    // :: error: (assignment)
+    @MustCall({}) Actor a =
+        new Actor() {
+          public void act() {}
+        };
+  }
+}
diff --git a/framework/src/main/java/org/checkerframework/framework/type/AnnotatedTypeFactory.java b/framework/src/main/java/org/checkerframework/framework/type/AnnotatedTypeFactory.java
index e631649d6d7..f61a85ddd26 100644
--- a/framework/src/main/java/org/checkerframework/framework/type/AnnotatedTypeFactory.java
+++ b/framework/src/main/java/org/checkerframework/framework/type/AnnotatedTypeFactory.java
@@ -2826,7 +2826,13 @@ protected ParameterizedExecutableType constructorFromUse(
         p.addAll(1, superCon.getParameterTypes());
         con.setParameterTypes(p);
       }
-      con.getReturnType().replaceAnnotations(type.getPrimaryAnnotations());
+      Set<? extends AnnotationMirror> lub =
+          qualHierarchy.leastUpperBoundsShallow(
+              type.getPrimaryAnnotations(),
+              type.getUnderlyingType(),
+              superCon.getReturnType().getPrimaryAnnotations(),
+              superCon.getReturnType().getUnderlyingType());
+      con.getReturnType().replaceAnnotations(lub);
     } else {
       con = AnnotatedTypes.asMemberOf(types, this, type, ctor, con);
     }

From 33fda208696337bd2f0d8d00202b0393e33a2f8d Mon Sep 17 00:00:00 2001
From: Suzanne Millstein <smillst@cs.washington.edu>
Date: Fri, 4 Oct 2024 09:32:07 -0700
Subject: [PATCH 3/4] Move expected error to correct line.

---
 checker/tests/mustcall/FunctionalInterfaces.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/checker/tests/mustcall/FunctionalInterfaces.java b/checker/tests/mustcall/FunctionalInterfaces.java
index d60efbbec07..b556623ffa5 100644
--- a/checker/tests/mustcall/FunctionalInterfaces.java
+++ b/checker/tests/mustcall/FunctionalInterfaces.java
@@ -43,8 +43,8 @@ public void act() {}
 
   public void anonymousClass() {
 
-    // :: error: (assignment)
     @MustCall({}) Actor a =
+        // :: error: (assignment)
         new Actor() {
           public void act() {}
         };

From 95240ef5c449387f4cd772013d67e045107b34b4 Mon Sep 17 00:00:00 2001
From: Michael Ernst <mernst@cs.washington.edu>
Date: Fri, 4 Oct 2024 12:13:31 -0700
Subject: [PATCH 4/4] Adjust expected diagnostic

---
 framework/tests/h1h2checker/AnonymousClasses.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/framework/tests/h1h2checker/AnonymousClasses.java b/framework/tests/h1h2checker/AnonymousClasses.java
index 3caa087de6a..b373de987cb 100644
--- a/framework/tests/h1h2checker/AnonymousClasses.java
+++ b/framework/tests/h1h2checker/AnonymousClasses.java
@@ -4,7 +4,7 @@
 
 public class AnonymousClasses {
   private <@H1S1 T extends @H1S1 Comparator<T>> void testGenericAnonymous() {
-    // :: error: (type.argument) :: error: (constructor.invocation)
+    // :: error: (type.argument) :: warning: (cast.unsafe.constructor.invocation)
     new @H1S1 Gen<T>() {};
     // :: error: (type.argument) :: warning: (cast.unsafe.constructor.invocation)
     new @H1S1 GenInter<T>() {};