diff --git a/compiler/src/dotty/tools/backend/jvm/DottyBackendInterface.scala b/compiler/src/dotty/tools/backend/jvm/DottyBackendInterface.scala
index d85bc0ed75d0..97a29444cf93 100644
--- a/compiler/src/dotty/tools/backend/jvm/DottyBackendInterface.scala
+++ b/compiler/src/dotty/tools/backend/jvm/DottyBackendInterface.scala
@@ -853,8 +853,14 @@ class DottyBackendInterface(outputDirectory: AbstractFile, val superCallsMap: Ma
 
     def addRemoteRemoteExceptionAnnotation: Unit = ()
 
-    def samMethod(): Symbol =
-      toDenot(sym).info.abstractTermMembers.headOption.getOrElse(toDenot(sym).info.member(nme.apply)).symbol
+    def samMethod(): Symbol = ctx.atPhase(ctx.erasurePhase) { implicit ctx =>
+      toDenot(sym).info.abstractTermMembers.toList match {
+        case x :: Nil => x.symbol
+        case Nil => abort(s"${sym.show} is not a functional interface. It doesn't have abstract methods")
+        case xs => abort(s"${sym.show} is not a functional interface. " +
+          s"It has the following abstract methods: ${xs.map(_.name).mkString(", ")}")
+      }
+    }
 
     def isFunctionClass: Boolean =
       defn.isFunctionClass(sym)
diff --git a/library/src/dotty/runtime/function/JFunction1$mcDD$sp.java b/library/src/dotty/runtime/function/JFunction1$mcDD$sp.java
index 3f9b7e183af0..732c9678c8a9 100644
--- a/library/src/dotty/runtime/function/JFunction1$mcDD$sp.java
+++ b/library/src/dotty/runtime/function/JFunction1$mcDD$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction1$mcDD$sp extends JFunction1 {
+public interface JFunction1$mcDD$sp extends JFunction1<Object, Object> {
     abstract double apply$mcDD$sp(double v1);
 
     default Object apply(Object t) { return (Double) apply$mcDD$sp(scala.runtime.BoxesRunTime.unboxToDouble(t)); }
diff --git a/library/src/dotty/runtime/function/JFunction1$mcDF$sp.java b/library/src/dotty/runtime/function/JFunction1$mcDF$sp.java
index 7b570cfee3cb..411140d5a4ce 100644
--- a/library/src/dotty/runtime/function/JFunction1$mcDF$sp.java
+++ b/library/src/dotty/runtime/function/JFunction1$mcDF$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction1$mcDF$sp extends JFunction1 {
+public interface JFunction1$mcDF$sp extends JFunction1<Object, Object> {
     abstract double apply$mcDF$sp(float v1);
 
     default Object apply(Object t) { return (Double) apply$mcDF$sp(scala.runtime.BoxesRunTime.unboxToFloat(t)); }
diff --git a/library/src/dotty/runtime/function/JFunction1$mcDI$sp.java b/library/src/dotty/runtime/function/JFunction1$mcDI$sp.java
index ee20690bae11..73f41d148e4b 100644
--- a/library/src/dotty/runtime/function/JFunction1$mcDI$sp.java
+++ b/library/src/dotty/runtime/function/JFunction1$mcDI$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction1$mcDI$sp extends JFunction1 {
+public interface JFunction1$mcDI$sp extends JFunction1<Object, Object> {
     abstract double apply$mcDI$sp(int v1);
 
     default Object apply(Object t) { return (Double) apply$mcDI$sp(scala.runtime.BoxesRunTime.unboxToInt(t)); }
diff --git a/library/src/dotty/runtime/function/JFunction1$mcDJ$sp.java b/library/src/dotty/runtime/function/JFunction1$mcDJ$sp.java
index df3b8f29dafa..34ae757fc37a 100644
--- a/library/src/dotty/runtime/function/JFunction1$mcDJ$sp.java
+++ b/library/src/dotty/runtime/function/JFunction1$mcDJ$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction1$mcDJ$sp extends JFunction1 {
+public interface JFunction1$mcDJ$sp extends JFunction1<Object, Object> {
     abstract double apply$mcDJ$sp(long v1);
 
     default Object apply(Object t) { return (Double) apply$mcDJ$sp(scala.runtime.BoxesRunTime.unboxToLong(t)); }
diff --git a/library/src/dotty/runtime/function/JFunction1$mcFD$sp.java b/library/src/dotty/runtime/function/JFunction1$mcFD$sp.java
index 2fb150fedc3e..2fd970ca71c7 100644
--- a/library/src/dotty/runtime/function/JFunction1$mcFD$sp.java
+++ b/library/src/dotty/runtime/function/JFunction1$mcFD$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction1$mcFD$sp extends JFunction1 {
+public interface JFunction1$mcFD$sp extends JFunction1<Object, Object> {
     abstract float apply$mcFD$sp(double v1);
 
     default Object apply(Object t) { return (Float) apply$mcFD$sp(scala.runtime.BoxesRunTime.unboxToDouble(t)); }
diff --git a/library/src/dotty/runtime/function/JFunction1$mcFF$sp.java b/library/src/dotty/runtime/function/JFunction1$mcFF$sp.java
index 84454e9eed1d..3f2ecf3ce226 100644
--- a/library/src/dotty/runtime/function/JFunction1$mcFF$sp.java
+++ b/library/src/dotty/runtime/function/JFunction1$mcFF$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction1$mcFF$sp extends JFunction1 {
+public interface JFunction1$mcFF$sp extends JFunction1<Object, Object> {
     abstract float apply$mcFF$sp(float v1);
 
     default Object apply(Object t) { return (Float) apply$mcFF$sp(scala.runtime.BoxesRunTime.unboxToFloat(t)); }
diff --git a/library/src/dotty/runtime/function/JFunction1$mcFI$sp.java b/library/src/dotty/runtime/function/JFunction1$mcFI$sp.java
index 9a4140eb71b0..20d3e32fb678 100644
--- a/library/src/dotty/runtime/function/JFunction1$mcFI$sp.java
+++ b/library/src/dotty/runtime/function/JFunction1$mcFI$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction1$mcFI$sp extends JFunction1 {
+public interface JFunction1$mcFI$sp extends JFunction1<Object, Object> {
     abstract float apply$mcFI$sp(int v1);
 
     default Object apply(Object t) { return (Float) apply$mcFI$sp(scala.runtime.BoxesRunTime.unboxToInt(t)); }
diff --git a/library/src/dotty/runtime/function/JFunction1$mcFJ$sp.java b/library/src/dotty/runtime/function/JFunction1$mcFJ$sp.java
index 07b890be6bcb..fb82267e2c98 100644
--- a/library/src/dotty/runtime/function/JFunction1$mcFJ$sp.java
+++ b/library/src/dotty/runtime/function/JFunction1$mcFJ$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction1$mcFJ$sp extends JFunction1 {
+public interface JFunction1$mcFJ$sp extends JFunction1<Object, Object> {
     abstract float apply$mcFJ$sp(long v1);
 
     default Object apply(Object t) { return (Float) apply$mcFJ$sp(scala.runtime.BoxesRunTime.unboxToLong(t)); }
diff --git a/library/src/dotty/runtime/function/JFunction1$mcID$sp.java b/library/src/dotty/runtime/function/JFunction1$mcID$sp.java
index fdf45522747d..190b1fcf9c99 100644
--- a/library/src/dotty/runtime/function/JFunction1$mcID$sp.java
+++ b/library/src/dotty/runtime/function/JFunction1$mcID$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction1$mcID$sp extends JFunction1 {
+public interface JFunction1$mcID$sp extends JFunction1<Object, Object> {
     abstract int apply$mcID$sp(double v1);
 
     default Object apply(Object t) { return (Integer) apply$mcID$sp(scala.runtime.BoxesRunTime.unboxToDouble(t)); }
diff --git a/library/src/dotty/runtime/function/JFunction1$mcIF$sp.java b/library/src/dotty/runtime/function/JFunction1$mcIF$sp.java
index 34cb92bf9321..89d2fa504326 100644
--- a/library/src/dotty/runtime/function/JFunction1$mcIF$sp.java
+++ b/library/src/dotty/runtime/function/JFunction1$mcIF$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction1$mcIF$sp extends JFunction1 {
+public interface JFunction1$mcIF$sp extends JFunction1<Object, Object> {
     abstract int apply$mcIF$sp(float v1);
 
     default Object apply(Object t) { return (Integer) apply$mcIF$sp(scala.runtime.BoxesRunTime.unboxToFloat(t)); }
diff --git a/library/src/dotty/runtime/function/JFunction1$mcII$sp.java b/library/src/dotty/runtime/function/JFunction1$mcII$sp.java
index f9dd9eb42339..827ac0262785 100644
--- a/library/src/dotty/runtime/function/JFunction1$mcII$sp.java
+++ b/library/src/dotty/runtime/function/JFunction1$mcII$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction1$mcII$sp extends JFunction1 {
+public interface JFunction1$mcII$sp extends JFunction1<Object, Object> {
     abstract int apply$mcII$sp(int v1);
 
     default Object apply(Object t) { return (Integer) apply$mcII$sp(scala.runtime.BoxesRunTime.unboxToInt(t)); }
diff --git a/library/src/dotty/runtime/function/JFunction1$mcIJ$sp.java b/library/src/dotty/runtime/function/JFunction1$mcIJ$sp.java
index 14fe725ab591..806b624810f3 100644
--- a/library/src/dotty/runtime/function/JFunction1$mcIJ$sp.java
+++ b/library/src/dotty/runtime/function/JFunction1$mcIJ$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction1$mcIJ$sp extends JFunction1 {
+public interface JFunction1$mcIJ$sp extends JFunction1<Object, Object> {
     abstract int apply$mcIJ$sp(long v1);
 
     default Object apply(Object t) { return (Integer) apply$mcIJ$sp(scala.runtime.BoxesRunTime.unboxToLong(t)); }
diff --git a/library/src/dotty/runtime/function/JFunction1$mcJD$sp.java b/library/src/dotty/runtime/function/JFunction1$mcJD$sp.java
index ae72d57ce6ea..027d86ca2456 100644
--- a/library/src/dotty/runtime/function/JFunction1$mcJD$sp.java
+++ b/library/src/dotty/runtime/function/JFunction1$mcJD$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction1$mcJD$sp extends JFunction1 {
+public interface JFunction1$mcJD$sp extends JFunction1<Object, Object> {
     abstract long apply$mcJD$sp(double v1);
 
     default Object apply(Object t) { return (Long) apply$mcJD$sp(scala.runtime.BoxesRunTime.unboxToDouble(t)); }
diff --git a/library/src/dotty/runtime/function/JFunction1$mcJF$sp.java b/library/src/dotty/runtime/function/JFunction1$mcJF$sp.java
index 3dd9043cf3a6..c79b6340d00f 100644
--- a/library/src/dotty/runtime/function/JFunction1$mcJF$sp.java
+++ b/library/src/dotty/runtime/function/JFunction1$mcJF$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction1$mcJF$sp extends JFunction1 {
+public interface JFunction1$mcJF$sp extends JFunction1<Object, Object> {
     abstract long apply$mcJF$sp(float v1);
 
     default Object apply(Object t) { return (Long) apply$mcJF$sp(scala.runtime.BoxesRunTime.unboxToFloat(t)); }
diff --git a/library/src/dotty/runtime/function/JFunction1$mcJI$sp.java b/library/src/dotty/runtime/function/JFunction1$mcJI$sp.java
index 58d24f4dfa05..5d36f7b272db 100644
--- a/library/src/dotty/runtime/function/JFunction1$mcJI$sp.java
+++ b/library/src/dotty/runtime/function/JFunction1$mcJI$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction1$mcJI$sp extends JFunction1 {
+public interface JFunction1$mcJI$sp extends JFunction1<Object, Object> {
     abstract long apply$mcJI$sp(int v1);
 
     default Object apply(Object t) { return (Long) apply$mcJI$sp(scala.runtime.BoxesRunTime.unboxToInt(t)); }
diff --git a/library/src/dotty/runtime/function/JFunction1$mcJJ$sp.java b/library/src/dotty/runtime/function/JFunction1$mcJJ$sp.java
index 7bc1122975ce..be5f8a365cb0 100644
--- a/library/src/dotty/runtime/function/JFunction1$mcJJ$sp.java
+++ b/library/src/dotty/runtime/function/JFunction1$mcJJ$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction1$mcJJ$sp extends JFunction1 {
+public interface JFunction1$mcJJ$sp extends JFunction1<Object, Object> {
     abstract long apply$mcJJ$sp(long v1);
 
     default Object apply(Object t) { return (Long) apply$mcJJ$sp(scala.runtime.BoxesRunTime.unboxToLong(t)); }
diff --git a/library/src/dotty/runtime/function/JFunction1$mcVD$sp.java b/library/src/dotty/runtime/function/JFunction1$mcVD$sp.java
index d2bd8add39ad..b922382b5783 100644
--- a/library/src/dotty/runtime/function/JFunction1$mcVD$sp.java
+++ b/library/src/dotty/runtime/function/JFunction1$mcVD$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction1$mcVD$sp extends JFunction1 {
+public interface JFunction1$mcVD$sp extends JFunction1<Object, Object> {
     abstract void apply$mcVD$sp(double v1);
 
     default Object apply(Object t) { apply$mcVD$sp(scala.runtime.BoxesRunTime.unboxToDouble(t)); return scala.runtime.BoxedUnit.UNIT; }
diff --git a/library/src/dotty/runtime/function/JFunction1$mcVF$sp.java b/library/src/dotty/runtime/function/JFunction1$mcVF$sp.java
index 996f2b4eb7c4..15edfca38dd0 100644
--- a/library/src/dotty/runtime/function/JFunction1$mcVF$sp.java
+++ b/library/src/dotty/runtime/function/JFunction1$mcVF$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction1$mcVF$sp extends JFunction1 {
+public interface JFunction1$mcVF$sp extends JFunction1<Object, Object> {
     abstract void apply$mcVF$sp(float v1);
 
     default Object apply(Object t) { apply$mcVF$sp(scala.runtime.BoxesRunTime.unboxToFloat(t)); return scala.runtime.BoxedUnit.UNIT; }
diff --git a/library/src/dotty/runtime/function/JFunction1$mcVI$sp.java b/library/src/dotty/runtime/function/JFunction1$mcVI$sp.java
index bb859ffee4d8..324968f99467 100644
--- a/library/src/dotty/runtime/function/JFunction1$mcVI$sp.java
+++ b/library/src/dotty/runtime/function/JFunction1$mcVI$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction1$mcVI$sp extends JFunction1 {
+public interface JFunction1$mcVI$sp extends JFunction1<Object, Object> {
     abstract void apply$mcVI$sp(int v1);
 
     default Object apply(Object t) { apply$mcVI$sp(scala.runtime.BoxesRunTime.unboxToInt(t)); return scala.runtime.BoxedUnit.UNIT; }
diff --git a/library/src/dotty/runtime/function/JFunction1$mcVJ$sp.java b/library/src/dotty/runtime/function/JFunction1$mcVJ$sp.java
index 343a82158fca..8e6357c507bd 100644
--- a/library/src/dotty/runtime/function/JFunction1$mcVJ$sp.java
+++ b/library/src/dotty/runtime/function/JFunction1$mcVJ$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction1$mcVJ$sp extends JFunction1 {
+public interface JFunction1$mcVJ$sp extends JFunction1<Object, Object> {
     abstract void apply$mcVJ$sp(long v1);
 
     default Object apply(Object t) { apply$mcVJ$sp(scala.runtime.BoxesRunTime.unboxToLong(t)); return scala.runtime.BoxedUnit.UNIT; }
diff --git a/library/src/dotty/runtime/function/JFunction1$mcZD$sp.java b/library/src/dotty/runtime/function/JFunction1$mcZD$sp.java
index 4042c3710521..965f62f681e1 100644
--- a/library/src/dotty/runtime/function/JFunction1$mcZD$sp.java
+++ b/library/src/dotty/runtime/function/JFunction1$mcZD$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction1$mcZD$sp extends JFunction1 {
+public interface JFunction1$mcZD$sp extends JFunction1<Object, Object> {
     abstract boolean apply$mcZD$sp(double v1);
 
     default Object apply(Object t) { return (Boolean) apply$mcZD$sp(scala.runtime.BoxesRunTime.unboxToDouble(t)); }
diff --git a/library/src/dotty/runtime/function/JFunction1$mcZF$sp.java b/library/src/dotty/runtime/function/JFunction1$mcZF$sp.java
index 6dcddbae8f04..ef092d24982f 100644
--- a/library/src/dotty/runtime/function/JFunction1$mcZF$sp.java
+++ b/library/src/dotty/runtime/function/JFunction1$mcZF$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction1$mcZF$sp extends JFunction1 {
+public interface JFunction1$mcZF$sp extends JFunction1<Object, Object> {
     abstract boolean apply$mcZF$sp(float v1);
 
     default Object apply(Object t) { return (Boolean) apply$mcZF$sp(scala.runtime.BoxesRunTime.unboxToFloat(t)); }
diff --git a/library/src/dotty/runtime/function/JFunction1$mcZI$sp.java b/library/src/dotty/runtime/function/JFunction1$mcZI$sp.java
index a0d129807dce..2bb46d0ec706 100644
--- a/library/src/dotty/runtime/function/JFunction1$mcZI$sp.java
+++ b/library/src/dotty/runtime/function/JFunction1$mcZI$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction1$mcZI$sp extends JFunction1 {
+public interface JFunction1$mcZI$sp extends JFunction1<Object, Object> {
     abstract boolean apply$mcZI$sp(int v1);
 
     default Object apply(Object t) { return (Boolean) apply$mcZI$sp(scala.runtime.BoxesRunTime.unboxToInt(t)); }
diff --git a/library/src/dotty/runtime/function/JFunction1$mcZJ$sp.java b/library/src/dotty/runtime/function/JFunction1$mcZJ$sp.java
index b1e76ca39f50..e59327403864 100644
--- a/library/src/dotty/runtime/function/JFunction1$mcZJ$sp.java
+++ b/library/src/dotty/runtime/function/JFunction1$mcZJ$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction1$mcZJ$sp extends JFunction1 {
+public interface JFunction1$mcZJ$sp extends JFunction1<Object, Object> {
     abstract boolean apply$mcZJ$sp(long v1);
 
     default Object apply(Object t) { return (Boolean) apply$mcZJ$sp(scala.runtime.BoxesRunTime.unboxToLong(t)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcDDD$sp.java b/library/src/dotty/runtime/function/JFunction2$mcDDD$sp.java
index e3fd5f5a6769..13b5ee6c40ea 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcDDD$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcDDD$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcDDD$sp extends JFunction2 {
+public interface JFunction2$mcDDD$sp extends JFunction2<Object, Object, Object> {
     abstract double apply$mcDDD$sp(double v1, double v2);
 
     default Object apply(Object v1, Object v2) { return (Double) apply$mcDDD$sp(scala.runtime.BoxesRunTime.unboxToDouble(v1), scala.runtime.BoxesRunTime.unboxToDouble(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcDDI$sp.java b/library/src/dotty/runtime/function/JFunction2$mcDDI$sp.java
index 53c936350894..734ffcac194c 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcDDI$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcDDI$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcDDI$sp extends JFunction2 {
+public interface JFunction2$mcDDI$sp extends JFunction2<Object, Object, Object> {
     abstract double apply$mcDDI$sp(double v1, int v2);
 
     default Object apply(Object v1, Object v2) { return (Double) apply$mcDDI$sp(scala.runtime.BoxesRunTime.unboxToDouble(v1), scala.runtime.BoxesRunTime.unboxToInt(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcDDJ$sp.java b/library/src/dotty/runtime/function/JFunction2$mcDDJ$sp.java
index 383ad215c3da..a6b968dac7c5 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcDDJ$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcDDJ$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcDDJ$sp extends JFunction2 {
+public interface JFunction2$mcDDJ$sp extends JFunction2<Object, Object, Object> {
     abstract double apply$mcDDJ$sp(double v1, long v2);
 
     default Object apply(Object v1, Object v2) { return (Double) apply$mcDDJ$sp(scala.runtime.BoxesRunTime.unboxToDouble(v1), scala.runtime.BoxesRunTime.unboxToLong(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcDID$sp.java b/library/src/dotty/runtime/function/JFunction2$mcDID$sp.java
index 443ebb76dde1..0b0e3b58aea3 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcDID$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcDID$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcDID$sp extends JFunction2 {
+public interface JFunction2$mcDID$sp extends JFunction2<Object, Object, Object> {
     abstract double apply$mcDID$sp(int v1, double v2);
 
     default Object apply(Object v1, Object v2) { return (Double) apply$mcDID$sp(scala.runtime.BoxesRunTime.unboxToInt(v1), scala.runtime.BoxesRunTime.unboxToDouble(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcDII$sp.java b/library/src/dotty/runtime/function/JFunction2$mcDII$sp.java
index bf0499d3b4f9..c0a072637b0f 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcDII$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcDII$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcDII$sp extends JFunction2 {
+public interface JFunction2$mcDII$sp extends JFunction2<Object, Object, Object> {
     abstract double apply$mcDII$sp(int v1, int v2);
 
     default Object apply(Object v1, Object v2) { return (Double) apply$mcDII$sp(scala.runtime.BoxesRunTime.unboxToInt(v1), scala.runtime.BoxesRunTime.unboxToInt(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcDIJ$sp.java b/library/src/dotty/runtime/function/JFunction2$mcDIJ$sp.java
index 589af38ddf72..90e7b0cb4219 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcDIJ$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcDIJ$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcDIJ$sp extends JFunction2 {
+public interface JFunction2$mcDIJ$sp extends JFunction2<Object, Object, Object> {
     abstract double apply$mcDIJ$sp(int v1, long v2);
 
     default Object apply(Object v1, Object v2) { return (Double) apply$mcDIJ$sp(scala.runtime.BoxesRunTime.unboxToInt(v1), scala.runtime.BoxesRunTime.unboxToLong(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcDJD$sp.java b/library/src/dotty/runtime/function/JFunction2$mcDJD$sp.java
index 203fd3164e35..ef6d2353f11d 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcDJD$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcDJD$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcDJD$sp extends JFunction2 {
+public interface JFunction2$mcDJD$sp extends JFunction2<Object, Object, Object> {
     abstract double apply$mcDJD$sp(long v1, double v2);
 
     default Object apply(Object v1, Object v2) { return (Double) apply$mcDJD$sp(scala.runtime.BoxesRunTime.unboxToLong(v1), scala.runtime.BoxesRunTime.unboxToDouble(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcDJI$sp.java b/library/src/dotty/runtime/function/JFunction2$mcDJI$sp.java
index f1c889c66cd0..260dba9b0bf8 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcDJI$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcDJI$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcDJI$sp extends JFunction2 {
+public interface JFunction2$mcDJI$sp extends JFunction2<Object, Object, Object> {
     abstract double apply$mcDJI$sp(long v1, int v2);
 
     default Object apply(Object v1, Object v2) { return (Double) apply$mcDJI$sp(scala.runtime.BoxesRunTime.unboxToLong(v1), scala.runtime.BoxesRunTime.unboxToInt(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcDJJ$sp.java b/library/src/dotty/runtime/function/JFunction2$mcDJJ$sp.java
index 18f4f6a005c5..10dd64857e15 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcDJJ$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcDJJ$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcDJJ$sp extends JFunction2 {
+public interface JFunction2$mcDJJ$sp extends JFunction2<Object, Object, Object> {
     abstract double apply$mcDJJ$sp(long v1, long v2);
 
     default Object apply(Object v1, Object v2) { return (Double) apply$mcDJJ$sp(scala.runtime.BoxesRunTime.unboxToLong(v1), scala.runtime.BoxesRunTime.unboxToLong(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcFDD$sp.java b/library/src/dotty/runtime/function/JFunction2$mcFDD$sp.java
index 9fcb2489aceb..aff62c1e6596 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcFDD$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcFDD$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcFDD$sp extends JFunction2 {
+public interface JFunction2$mcFDD$sp extends JFunction2<Object, Object, Object> {
     abstract float apply$mcFDD$sp(double v1, double v2);
 
     default Object apply(Object v1, Object v2) { return (Float) apply$mcFDD$sp(scala.runtime.BoxesRunTime.unboxToDouble(v1), scala.runtime.BoxesRunTime.unboxToDouble(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcFDI$sp.java b/library/src/dotty/runtime/function/JFunction2$mcFDI$sp.java
index 9880b607e793..3e7b996c0ec4 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcFDI$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcFDI$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcFDI$sp extends JFunction2 {
+public interface JFunction2$mcFDI$sp extends JFunction2<Object, Object, Object> {
     abstract float apply$mcFDI$sp(double v1, int v2);
 
     default Object apply(Object v1, Object v2) { return (Float) apply$mcFDI$sp(scala.runtime.BoxesRunTime.unboxToDouble(v1), scala.runtime.BoxesRunTime.unboxToInt(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcFDJ$sp.java b/library/src/dotty/runtime/function/JFunction2$mcFDJ$sp.java
index d514e77af3cb..3e98cbf50bfb 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcFDJ$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcFDJ$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcFDJ$sp extends JFunction2 {
+public interface JFunction2$mcFDJ$sp extends JFunction2<Object, Object, Object> {
     abstract float apply$mcFDJ$sp(double v1, long v2);
 
     default Object apply(Object v1, Object v2) { return (Float) apply$mcFDJ$sp(scala.runtime.BoxesRunTime.unboxToDouble(v1), scala.runtime.BoxesRunTime.unboxToLong(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcFID$sp.java b/library/src/dotty/runtime/function/JFunction2$mcFID$sp.java
index c59974f0ab7d..8a6b87637416 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcFID$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcFID$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcFID$sp extends JFunction2 {
+public interface JFunction2$mcFID$sp extends JFunction2<Object, Object, Object> {
     abstract float apply$mcFID$sp(int v1, double v2);
 
     default Object apply(Object v1, Object v2) { return (Float) apply$mcFID$sp(scala.runtime.BoxesRunTime.unboxToInt(v1), scala.runtime.BoxesRunTime.unboxToDouble(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcFII$sp.java b/library/src/dotty/runtime/function/JFunction2$mcFII$sp.java
index 7c3e7af963c2..19bb0d7bc57b 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcFII$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcFII$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcFII$sp extends JFunction2 {
+public interface JFunction2$mcFII$sp extends JFunction2<Object, Object, Object> {
     abstract float apply$mcFII$sp(int v1, int v2);
 
     default Object apply(Object v1, Object v2) { return (Float) apply$mcFII$sp(scala.runtime.BoxesRunTime.unboxToInt(v1), scala.runtime.BoxesRunTime.unboxToInt(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcFIJ$sp.java b/library/src/dotty/runtime/function/JFunction2$mcFIJ$sp.java
index 2fdeac11d8d2..a235727978f0 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcFIJ$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcFIJ$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcFIJ$sp extends JFunction2 {
+public interface JFunction2$mcFIJ$sp extends JFunction2<Object, Object, Object> {
     abstract float apply$mcFIJ$sp(int v1, long v2);
 
     default Object apply(Object v1, Object v2) { return (Float) apply$mcFIJ$sp(scala.runtime.BoxesRunTime.unboxToInt(v1), scala.runtime.BoxesRunTime.unboxToLong(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcFJD$sp.java b/library/src/dotty/runtime/function/JFunction2$mcFJD$sp.java
index 74e7252e41e3..d4b766e38877 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcFJD$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcFJD$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcFJD$sp extends JFunction2 {
+public interface JFunction2$mcFJD$sp extends JFunction2<Object, Object, Object> {
     abstract float apply$mcFJD$sp(long v1, double v2);
 
     default Object apply(Object v1, Object v2) { return (Float) apply$mcFJD$sp(scala.runtime.BoxesRunTime.unboxToLong(v1), scala.runtime.BoxesRunTime.unboxToDouble(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcFJI$sp.java b/library/src/dotty/runtime/function/JFunction2$mcFJI$sp.java
index a8a53d7097d9..c20a78637c66 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcFJI$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcFJI$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcFJI$sp extends JFunction2 {
+public interface JFunction2$mcFJI$sp extends JFunction2<Object, Object, Object> {
     abstract float apply$mcFJI$sp(long v1, int v2);
 
     default Object apply(Object v1, Object v2) { return (Float) apply$mcFJI$sp(scala.runtime.BoxesRunTime.unboxToLong(v1), scala.runtime.BoxesRunTime.unboxToInt(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcFJJ$sp.java b/library/src/dotty/runtime/function/JFunction2$mcFJJ$sp.java
index 2c96fc46275e..34ec65abd708 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcFJJ$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcFJJ$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcFJJ$sp extends JFunction2 {
+public interface JFunction2$mcFJJ$sp extends JFunction2<Object, Object, Object> {
     abstract float apply$mcFJJ$sp(long v1, long v2);
 
     default Object apply(Object v1, Object v2) { return (Float) apply$mcFJJ$sp(scala.runtime.BoxesRunTime.unboxToLong(v1), scala.runtime.BoxesRunTime.unboxToLong(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcIDD$sp.java b/library/src/dotty/runtime/function/JFunction2$mcIDD$sp.java
index daf6f5308a74..f86a107a7044 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcIDD$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcIDD$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcIDD$sp extends JFunction2 {
+public interface JFunction2$mcIDD$sp extends JFunction2<Object, Object, Object> {
     abstract int apply$mcIDD$sp(double v1, double v2);
 
     default Object apply(Object v1, Object v2) { return (Integer) apply$mcIDD$sp(scala.runtime.BoxesRunTime.unboxToDouble(v1), scala.runtime.BoxesRunTime.unboxToDouble(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcIDI$sp.java b/library/src/dotty/runtime/function/JFunction2$mcIDI$sp.java
index 47efcf768558..48e816d3efb8 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcIDI$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcIDI$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcIDI$sp extends JFunction2 {
+public interface JFunction2$mcIDI$sp extends JFunction2<Object, Object, Object> {
     abstract int apply$mcIDI$sp(double v1, int v2);
 
     default Object apply(Object v1, Object v2) { return (Integer) apply$mcIDI$sp(scala.runtime.BoxesRunTime.unboxToDouble(v1), scala.runtime.BoxesRunTime.unboxToInt(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcIDJ$sp.java b/library/src/dotty/runtime/function/JFunction2$mcIDJ$sp.java
index fc744d121477..be42851595c7 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcIDJ$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcIDJ$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcIDJ$sp extends JFunction2 {
+public interface JFunction2$mcIDJ$sp extends JFunction2<Object, Object, Object> {
     abstract int apply$mcIDJ$sp(double v1, long v2);
 
     default Object apply(Object v1, Object v2) { return (Integer) apply$mcIDJ$sp(scala.runtime.BoxesRunTime.unboxToDouble(v1), scala.runtime.BoxesRunTime.unboxToLong(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcIID$sp.java b/library/src/dotty/runtime/function/JFunction2$mcIID$sp.java
index 107f247d65ab..6f3bec43eae8 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcIID$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcIID$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcIID$sp extends JFunction2 {
+public interface JFunction2$mcIID$sp extends JFunction2<Object, Object, Object> {
     abstract int apply$mcIID$sp(int v1, double v2);
 
     default Object apply(Object v1, Object v2) { return (Integer) apply$mcIID$sp(scala.runtime.BoxesRunTime.unboxToInt(v1), scala.runtime.BoxesRunTime.unboxToDouble(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcIII$sp.java b/library/src/dotty/runtime/function/JFunction2$mcIII$sp.java
index 58f921f8097c..31507325f37c 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcIII$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcIII$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcIII$sp extends JFunction2 {
+public interface JFunction2$mcIII$sp extends JFunction2<Object, Object, Object> {
     abstract int apply$mcIII$sp(int v1, int v2);
 
     default Object apply(Object v1, Object v2) { return (Integer) apply$mcIII$sp(scala.runtime.BoxesRunTime.unboxToInt(v1), scala.runtime.BoxesRunTime.unboxToInt(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcIIJ$sp.java b/library/src/dotty/runtime/function/JFunction2$mcIIJ$sp.java
index 41ed81ea43d5..b332822542c7 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcIIJ$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcIIJ$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcIIJ$sp extends JFunction2 {
+public interface JFunction2$mcIIJ$sp extends JFunction2<Object, Object, Object> {
     abstract int apply$mcIIJ$sp(int v1, long v2);
 
     default Object apply(Object v1, Object v2) { return (Integer) apply$mcIIJ$sp(scala.runtime.BoxesRunTime.unboxToInt(v1), scala.runtime.BoxesRunTime.unboxToLong(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcIJD$sp.java b/library/src/dotty/runtime/function/JFunction2$mcIJD$sp.java
index 273495e31fa9..05bdb221ddec 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcIJD$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcIJD$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcIJD$sp extends JFunction2 {
+public interface JFunction2$mcIJD$sp extends JFunction2<Object, Object, Object> {
     abstract int apply$mcIJD$sp(long v1, double v2);
 
     default Object apply(Object v1, Object v2) { return (Integer) apply$mcIJD$sp(scala.runtime.BoxesRunTime.unboxToLong(v1), scala.runtime.BoxesRunTime.unboxToDouble(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcIJI$sp.java b/library/src/dotty/runtime/function/JFunction2$mcIJI$sp.java
index 7520ba068226..3cc57aa05f10 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcIJI$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcIJI$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcIJI$sp extends JFunction2 {
+public interface JFunction2$mcIJI$sp extends JFunction2<Object, Object, Object> {
     abstract int apply$mcIJI$sp(long v1, int v2);
 
     default Object apply(Object v1, Object v2) { return (Integer) apply$mcIJI$sp(scala.runtime.BoxesRunTime.unboxToLong(v1), scala.runtime.BoxesRunTime.unboxToInt(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcIJJ$sp.java b/library/src/dotty/runtime/function/JFunction2$mcIJJ$sp.java
index 4ac15744f061..55bd0d356e4d 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcIJJ$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcIJJ$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcIJJ$sp extends JFunction2 {
+public interface JFunction2$mcIJJ$sp extends JFunction2<Object, Object, Object> {
     abstract int apply$mcIJJ$sp(long v1, long v2);
 
     default Object apply(Object v1, Object v2) { return (Integer) apply$mcIJJ$sp(scala.runtime.BoxesRunTime.unboxToLong(v1), scala.runtime.BoxesRunTime.unboxToLong(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcJDD$sp.java b/library/src/dotty/runtime/function/JFunction2$mcJDD$sp.java
index ea57c0427c58..8a035e7e5024 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcJDD$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcJDD$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcJDD$sp extends JFunction2 {
+public interface JFunction2$mcJDD$sp extends JFunction2<Object, Object, Object> {
     abstract long apply$mcJDD$sp(double v1, double v2);
 
     default Object apply(Object v1, Object v2) { return (Long) apply$mcJDD$sp(scala.runtime.BoxesRunTime.unboxToDouble(v1), scala.runtime.BoxesRunTime.unboxToDouble(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcJDI$sp.java b/library/src/dotty/runtime/function/JFunction2$mcJDI$sp.java
index cf4d13f3a37c..6e1cf1c94091 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcJDI$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcJDI$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcJDI$sp extends JFunction2 {
+public interface JFunction2$mcJDI$sp extends JFunction2<Object, Object, Object> {
     abstract long apply$mcJDI$sp(double v1, int v2);
 
     default Object apply(Object v1, Object v2) { return (Long) apply$mcJDI$sp(scala.runtime.BoxesRunTime.unboxToDouble(v1), scala.runtime.BoxesRunTime.unboxToInt(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcJDJ$sp.java b/library/src/dotty/runtime/function/JFunction2$mcJDJ$sp.java
index 5eff9ba6db21..ac5d5af882d7 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcJDJ$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcJDJ$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcJDJ$sp extends JFunction2 {
+public interface JFunction2$mcJDJ$sp extends JFunction2<Object, Object, Object> {
     abstract long apply$mcJDJ$sp(double v1, long v2);
 
     default Object apply(Object v1, Object v2) { return (Long) apply$mcJDJ$sp(scala.runtime.BoxesRunTime.unboxToDouble(v1), scala.runtime.BoxesRunTime.unboxToLong(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcJID$sp.java b/library/src/dotty/runtime/function/JFunction2$mcJID$sp.java
index ffa488229e4b..c2776900e633 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcJID$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcJID$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcJID$sp extends JFunction2 {
+public interface JFunction2$mcJID$sp extends JFunction2<Object, Object, Object> {
     abstract long apply$mcJID$sp(int v1, double v2);
 
     default Object apply(Object v1, Object v2) { return (Long) apply$mcJID$sp(scala.runtime.BoxesRunTime.unboxToInt(v1), scala.runtime.BoxesRunTime.unboxToDouble(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcJII$sp.java b/library/src/dotty/runtime/function/JFunction2$mcJII$sp.java
index b7a08689a805..4fad1885f3b3 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcJII$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcJII$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcJII$sp extends JFunction2 {
+public interface JFunction2$mcJII$sp extends JFunction2<Object, Object, Object> {
     abstract long apply$mcJII$sp(int v1, int v2);
 
     default Object apply(Object v1, Object v2) { return (Long) apply$mcJII$sp(scala.runtime.BoxesRunTime.unboxToInt(v1), scala.runtime.BoxesRunTime.unboxToInt(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcJIJ$sp.java b/library/src/dotty/runtime/function/JFunction2$mcJIJ$sp.java
index 72d37ccdbcc6..2dc9c13e7118 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcJIJ$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcJIJ$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcJIJ$sp extends JFunction2 {
+public interface JFunction2$mcJIJ$sp extends JFunction2<Object, Object, Object> {
     abstract long apply$mcJIJ$sp(int v1, long v2);
 
     default Object apply(Object v1, Object v2) { return (Long) apply$mcJIJ$sp(scala.runtime.BoxesRunTime.unboxToInt(v1), scala.runtime.BoxesRunTime.unboxToLong(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcJJD$sp.java b/library/src/dotty/runtime/function/JFunction2$mcJJD$sp.java
index 6e99b3457fd2..e2600c681ed1 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcJJD$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcJJD$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcJJD$sp extends JFunction2 {
+public interface JFunction2$mcJJD$sp extends JFunction2<Object, Object, Object> {
     abstract long apply$mcJJD$sp(long v1, double v2);
 
     default Object apply(Object v1, Object v2) { return (Long) apply$mcJJD$sp(scala.runtime.BoxesRunTime.unboxToLong(v1), scala.runtime.BoxesRunTime.unboxToDouble(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcJJI$sp.java b/library/src/dotty/runtime/function/JFunction2$mcJJI$sp.java
index c2a77ad99be8..140553d6749a 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcJJI$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcJJI$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcJJI$sp extends JFunction2 {
+public interface JFunction2$mcJJI$sp extends JFunction2<Object, Object, Object> {
     abstract long apply$mcJJI$sp(long v1, int v2);
 
     default Object apply(Object v1, Object v2) { return (Long) apply$mcJJI$sp(scala.runtime.BoxesRunTime.unboxToLong(v1), scala.runtime.BoxesRunTime.unboxToInt(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcJJJ$sp.java b/library/src/dotty/runtime/function/JFunction2$mcJJJ$sp.java
index badd63219a61..1c7257f2904c 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcJJJ$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcJJJ$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcJJJ$sp extends JFunction2 {
+public interface JFunction2$mcJJJ$sp extends JFunction2<Object, Object, Object> {
     abstract long apply$mcJJJ$sp(long v1, long v2);
 
     default Object apply(Object v1, Object v2) { return (Long) apply$mcJJJ$sp(scala.runtime.BoxesRunTime.unboxToLong(v1), scala.runtime.BoxesRunTime.unboxToLong(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcVDD$sp.java b/library/src/dotty/runtime/function/JFunction2$mcVDD$sp.java
index 8e786e1ac9ff..ba9b5f89ada7 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcVDD$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcVDD$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcVDD$sp extends JFunction2 {
+public interface JFunction2$mcVDD$sp extends JFunction2<Object, Object, Object> {
     abstract void apply$mcVDD$sp(double v1, double v2);
 
     default Object apply(Object v1, Object v2) { apply$mcVDD$sp(scala.runtime.BoxesRunTime.unboxToDouble(v1), scala.runtime.BoxesRunTime.unboxToDouble(v2)); return scala.runtime.BoxedUnit.UNIT; }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcVDI$sp.java b/library/src/dotty/runtime/function/JFunction2$mcVDI$sp.java
index 4d7a42587685..dd07c768c6f4 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcVDI$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcVDI$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcVDI$sp extends JFunction2 {
+public interface JFunction2$mcVDI$sp extends JFunction2<Object, Object, Object> {
     abstract void apply$mcVDI$sp(double v1, int v2);
 
     default Object apply(Object v1, Object v2) { apply$mcVDI$sp(scala.runtime.BoxesRunTime.unboxToDouble(v1), scala.runtime.BoxesRunTime.unboxToInt(v2)); return scala.runtime.BoxedUnit.UNIT; }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcVDJ$sp.java b/library/src/dotty/runtime/function/JFunction2$mcVDJ$sp.java
index ed0aab94bb6c..0f532f3655fb 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcVDJ$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcVDJ$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcVDJ$sp extends JFunction2 {
+public interface JFunction2$mcVDJ$sp extends JFunction2<Object, Object, Object> {
     abstract void apply$mcVDJ$sp(double v1, long v2);
 
     default Object apply(Object v1, Object v2) { apply$mcVDJ$sp(scala.runtime.BoxesRunTime.unboxToDouble(v1), scala.runtime.BoxesRunTime.unboxToLong(v2)); return scala.runtime.BoxedUnit.UNIT; }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcVID$sp.java b/library/src/dotty/runtime/function/JFunction2$mcVID$sp.java
index e8bda5799866..fb75f14c3410 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcVID$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcVID$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcVID$sp extends JFunction2 {
+public interface JFunction2$mcVID$sp extends JFunction2<Object, Object, Object> {
     abstract void apply$mcVID$sp(int v1, double v2);
 
     default Object apply(Object v1, Object v2) { apply$mcVID$sp(scala.runtime.BoxesRunTime.unboxToInt(v1), scala.runtime.BoxesRunTime.unboxToDouble(v2)); return scala.runtime.BoxedUnit.UNIT; }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcVII$sp.java b/library/src/dotty/runtime/function/JFunction2$mcVII$sp.java
index 9ca34e6722be..d33560c61828 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcVII$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcVII$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcVII$sp extends JFunction2 {
+public interface JFunction2$mcVII$sp extends JFunction2<Object, Object, Object> {
     abstract void apply$mcVII$sp(int v1, int v2);
 
     default Object apply(Object v1, Object v2) { apply$mcVII$sp(scala.runtime.BoxesRunTime.unboxToInt(v1), scala.runtime.BoxesRunTime.unboxToInt(v2)); return scala.runtime.BoxedUnit.UNIT; }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcVIJ$sp.java b/library/src/dotty/runtime/function/JFunction2$mcVIJ$sp.java
index ef358c0d35bd..c38ac3b59e59 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcVIJ$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcVIJ$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcVIJ$sp extends JFunction2 {
+public interface JFunction2$mcVIJ$sp extends JFunction2<Object, Object, Object> {
     abstract void apply$mcVIJ$sp(int v1, long v2);
 
     default Object apply(Object v1, Object v2) { apply$mcVIJ$sp(scala.runtime.BoxesRunTime.unboxToInt(v1), scala.runtime.BoxesRunTime.unboxToLong(v2)); return scala.runtime.BoxedUnit.UNIT; }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcVJD$sp.java b/library/src/dotty/runtime/function/JFunction2$mcVJD$sp.java
index 03b8d7bf431f..444cfb49b581 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcVJD$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcVJD$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcVJD$sp extends JFunction2 {
+public interface JFunction2$mcVJD$sp extends JFunction2<Object, Object, Object> {
     abstract void apply$mcVJD$sp(long v1, double v2);
 
     default Object apply(Object v1, Object v2) { apply$mcVJD$sp(scala.runtime.BoxesRunTime.unboxToLong(v1), scala.runtime.BoxesRunTime.unboxToDouble(v2)); return scala.runtime.BoxedUnit.UNIT; }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcVJI$sp.java b/library/src/dotty/runtime/function/JFunction2$mcVJI$sp.java
index 60269e52c7ca..f3159c0eec4f 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcVJI$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcVJI$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcVJI$sp extends JFunction2 {
+public interface JFunction2$mcVJI$sp extends JFunction2<Object, Object, Object> {
     abstract void apply$mcVJI$sp(long v1, int v2);
 
     default Object apply(Object v1, Object v2) { apply$mcVJI$sp(scala.runtime.BoxesRunTime.unboxToLong(v1), scala.runtime.BoxesRunTime.unboxToInt(v2)); return scala.runtime.BoxedUnit.UNIT; }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcVJJ$sp.java b/library/src/dotty/runtime/function/JFunction2$mcVJJ$sp.java
index c957803c3f40..82b3846604ab 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcVJJ$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcVJJ$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcVJJ$sp extends JFunction2 {
+public interface JFunction2$mcVJJ$sp extends JFunction2<Object, Object, Object> {
     abstract void apply$mcVJJ$sp(long v1, long v2);
 
     default Object apply(Object v1, Object v2) { apply$mcVJJ$sp(scala.runtime.BoxesRunTime.unboxToLong(v1), scala.runtime.BoxesRunTime.unboxToLong(v2)); return scala.runtime.BoxedUnit.UNIT; }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcZDD$sp.java b/library/src/dotty/runtime/function/JFunction2$mcZDD$sp.java
index 5b0d95b9594c..fd10be5e4ba2 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcZDD$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcZDD$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcZDD$sp extends JFunction2 {
+public interface JFunction2$mcZDD$sp extends JFunction2<Object, Object, Object> {
     abstract boolean apply$mcZDD$sp(double v1, double v2);
 
     default Object apply(Object v1, Object v2) { return (Boolean) apply$mcZDD$sp(scala.runtime.BoxesRunTime.unboxToDouble(v1), scala.runtime.BoxesRunTime.unboxToDouble(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcZDI$sp.java b/library/src/dotty/runtime/function/JFunction2$mcZDI$sp.java
index e29eb8bb9905..222197db0e44 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcZDI$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcZDI$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcZDI$sp extends JFunction2 {
+public interface JFunction2$mcZDI$sp extends JFunction2<Object, Object, Object> {
     abstract boolean apply$mcZDI$sp(double v1, int v2);
 
     default Object apply(Object v1, Object v2) { return (Boolean) apply$mcZDI$sp(scala.runtime.BoxesRunTime.unboxToDouble(v1), scala.runtime.BoxesRunTime.unboxToInt(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcZDJ$sp.java b/library/src/dotty/runtime/function/JFunction2$mcZDJ$sp.java
index 69cdcd8fe189..92f49143fe36 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcZDJ$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcZDJ$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcZDJ$sp extends JFunction2 {
+public interface JFunction2$mcZDJ$sp extends JFunction2<Object, Object, Object> {
     abstract boolean apply$mcZDJ$sp(double v1, long v2);
 
     default Object apply(Object v1, Object v2) { return (Boolean) apply$mcZDJ$sp(scala.runtime.BoxesRunTime.unboxToDouble(v1), scala.runtime.BoxesRunTime.unboxToLong(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcZID$sp.java b/library/src/dotty/runtime/function/JFunction2$mcZID$sp.java
index 66a68bb8aeec..a478a1aaf335 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcZID$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcZID$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcZID$sp extends JFunction2 {
+public interface JFunction2$mcZID$sp extends JFunction2<Object, Object, Object> {
     abstract boolean apply$mcZID$sp(int v1, double v2);
 
     default Object apply(Object v1, Object v2) { return (Boolean) apply$mcZID$sp(scala.runtime.BoxesRunTime.unboxToInt(v1), scala.runtime.BoxesRunTime.unboxToDouble(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcZII$sp.java b/library/src/dotty/runtime/function/JFunction2$mcZII$sp.java
index 2c51b28f19d6..57c61adea13e 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcZII$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcZII$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcZII$sp extends JFunction2 {
+public interface JFunction2$mcZII$sp extends JFunction2<Object, Object, Object> {
     abstract boolean apply$mcZII$sp(int v1, int v2);
 
     default Object apply(Object v1, Object v2) { return (Boolean) apply$mcZII$sp(scala.runtime.BoxesRunTime.unboxToInt(v1), scala.runtime.BoxesRunTime.unboxToInt(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcZIJ$sp.java b/library/src/dotty/runtime/function/JFunction2$mcZIJ$sp.java
index 246b94e36ac9..be41d435736d 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcZIJ$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcZIJ$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcZIJ$sp extends JFunction2 {
+public interface JFunction2$mcZIJ$sp extends JFunction2<Object, Object, Object> {
     abstract boolean apply$mcZIJ$sp(int v1, long v2);
 
     default Object apply(Object v1, Object v2) { return (Boolean) apply$mcZIJ$sp(scala.runtime.BoxesRunTime.unboxToInt(v1), scala.runtime.BoxesRunTime.unboxToLong(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcZJD$sp.java b/library/src/dotty/runtime/function/JFunction2$mcZJD$sp.java
index e9f0ad8c651c..771ca8511478 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcZJD$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcZJD$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcZJD$sp extends JFunction2 {
+public interface JFunction2$mcZJD$sp extends JFunction2<Object, Object, Object> {
     abstract boolean apply$mcZJD$sp(long v1, double v2);
 
     default Object apply(Object v1, Object v2) { return (Boolean) apply$mcZJD$sp(scala.runtime.BoxesRunTime.unboxToLong(v1), scala.runtime.BoxesRunTime.unboxToDouble(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcZJI$sp.java b/library/src/dotty/runtime/function/JFunction2$mcZJI$sp.java
index c5b20f94f102..ed8932414a41 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcZJI$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcZJI$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcZJI$sp extends JFunction2 {
+public interface JFunction2$mcZJI$sp extends JFunction2<Object, Object, Object> {
     abstract boolean apply$mcZJI$sp(long v1, int v2);
 
     default Object apply(Object v1, Object v2) { return (Boolean) apply$mcZJI$sp(scala.runtime.BoxesRunTime.unboxToLong(v1), scala.runtime.BoxesRunTime.unboxToInt(v2)); }
diff --git a/library/src/dotty/runtime/function/JFunction2$mcZJJ$sp.java b/library/src/dotty/runtime/function/JFunction2$mcZJJ$sp.java
index 0f11186d78c5..3e7657ac6cd4 100644
--- a/library/src/dotty/runtime/function/JFunction2$mcZJJ$sp.java
+++ b/library/src/dotty/runtime/function/JFunction2$mcZJJ$sp.java
@@ -6,7 +6,7 @@
 package dotty.runtime.function;
 
 @FunctionalInterface
-public interface JFunction2$mcZJJ$sp extends JFunction2 {
+public interface JFunction2$mcZJJ$sp extends JFunction2<Object, Object, Object> {
     abstract boolean apply$mcZJJ$sp(long v1, long v2);
 
     default Object apply(Object v1, Object v2) { return (Boolean) apply$mcZJJ$sp(scala.runtime.BoxesRunTime.unboxToLong(v1), scala.runtime.BoxesRunTime.unboxToLong(v2)); }
diff --git a/tests/run-with-compiler/i3876-c.scala b/tests/run-with-compiler/i3876-c.scala
index 519f8f625892..1f8cef379856 100644
--- a/tests/run-with-compiler/i3876-c.scala
+++ b/tests/run-with-compiler/i3876-c.scala
@@ -1,7 +1,7 @@
 import scala.quoted._
 object Test {
   def main(args: Array[String]): Unit = {
-    implicit val toolbox: scala.quoted.Toolbox = scala.quoted.Toolbox.make(getClass.getClassLoader)
+    implicit def toolbox: scala.quoted.Toolbox = scala.quoted.Toolbox.make(getClass.getClassLoader)
 
     val x: Expr[Int] = '{3}