Merge pull request #6277 from dotty-staging/samMethod-safety

Add safety checks to `samMethod`

Author: anatoliykmetyuk

compiler/src/dotty/tools/backend/jvm/DottyBackendInterface.scala

@@ -841,8 +841,14 @@ 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)

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)); }

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)); }

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)); }

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)); }

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)); }

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)); }

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)); }

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)); }

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)); }