Fix IncompatibleClassChangeError under Java 9

src/compiler/scala/tools/nsc/backend/jvm/BCodeBodyBuilder.scala

@@ -691,15 +691,15 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
           val nativeKind = tpeTK(expr)
           genLoad(expr, nativeKind)
           val MethodNameAndType(mname, methodType) = asmBoxTo(nativeKind)
-          bc.invokestatic(BoxesRunTime.internalName, mname, methodType.descriptor)
+          bc.invokestatic(BoxesRunTime.internalName, mname, methodType.descriptor, itf = false)
           generatedType = boxResultType(fun.symbol) // was toTypeKind(fun.symbol.tpe.resultType)
 
         case Apply(fun, List(expr)) if isUnbox(fun.symbol) =>
           genLoad(expr)
           val boxType = unboxResultType(fun.symbol) // was toTypeKind(fun.symbol.owner.linkedClassOfClass.tpe)
           generatedType = boxType
           val MethodNameAndType(mname, methodType) = asmUnboxTo(boxType)
-          bc.invokestatic(BoxesRunTime.internalName, mname, methodType.descriptor)
+          bc.invokestatic(BoxesRunTime.internalName, mname, methodType.descriptor, itf = false)
 
         case app @ Apply(fun, args) =>
           val sym = fun.symbol
@@ -1150,15 +1150,16 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
         }
       }
 
-      if (style.isStatic)                 { bc.invokestatic   (jowner, jname, mdescr) }
-      else if (style.isSpecial)           { bc.invokespecial  (jowner, jname, mdescr) }
+      val isInterface = receiver.isEmittedInterface
+      if (style.isStatic)                 { bc.invokestatic   (jowner, jname, mdescr, itf = isInterface) }
+      else if (style.isSpecial)           { bc.invokespecial  (jowner, jname, mdescr, itf = isInterface) }
       else if (style.isVirtual) {
         if (needsInterfaceCall(receiver)) { bc.invokeinterface(jowner, jname, mdescr) }
         else                              { bc.invokevirtual  (jowner, jname, mdescr) }
       }
       else {
         assert(style.isSuper, s"An unknown InvokeStyle: $style")
-        bc.invokespecial(jowner, jname, mdescr)
+        bc.invokespecial(jowner, jname, mdescr, itf = isInterface)
         initModule()
       }
 
@@ -1405,7 +1406,7 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
     def genInvokeDynamicLambda(ctor: Symbol, lambdaTarget: Symbol, environmentSize: Int, functionalInterface: Symbol): BType = {
       debuglog(s"Using invokedynamic rather than `new ${ctor.owner}`")
       val generatedType = classBTypeFromSymbol(functionalInterface)
-      val isInterface = lambdaTarget.owner.isInterface
+      val isInterface = lambdaTarget.owner.isEmittedInterface
       val invokeStyle =
         if (lambdaTarget.isStaticMember) asm.Opcodes.H_INVOKESTATIC
         else if (lambdaTarget.isPrivate || lambdaTarget.isClassConstructor) asm.Opcodes.H_INVOKESPECIAL
@@ -1417,7 +1418,7 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
           classBTypeFromSymbol(lambdaTarget.owner).internalName,
           lambdaTarget.name.mangledString,
           asmMethodType(lambdaTarget).descriptor,
-          isInterface)
+          /* itf = */ isInterface)
 
       val (a,b) = lambdaTarget.info.paramTypes.splitAt(environmentSize)
       var (capturedParamsTypes, lambdaParamTypes) = if(int.doLabmdasFollowJVMMetafactoryOrder) (a,b) else (b,a)
@@ -1448,6 +1449,6 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
     new asm.Handle(asm.Opcodes.H_INVOKESTATIC,
       int.LambdaMetaFactory.javaBinaryName, int.MetafactoryName,
       "(Ljava/lang/invoke/MethodHandles$Lookup;Ljava/lang/String;Ljava/lang/invoke/MethodType;Ljava/lang/invoke/MethodType;Ljava/lang/invoke/MethodHandle;Ljava/lang/invoke/MethodType;)Ljava/lang/invoke/CallSite;",
-      int.LambdaMetaFactory.isInterface)
+      /* itf = */  int.LambdaMetaFactory.isEmittedInterface)
 
 }

src/compiler/scala/tools/nsc/backend/jvm/BCodeHelpers.scala

@@ -443,7 +443,7 @@ trait BCodeHelpers extends BCodeIdiomatic with BytecodeWriters {
         "serialVersionUID",
         "J",
         null, // no java-generic-signature
-        new java.lang.Long(id)
+        java.lang.Long.valueOf(id)
       ).visitEnd()
     }
   } // end of trait BCClassGen

src/compiler/scala/tools/nsc/backend/jvm/BCodeIdiomatic.scala

@@ -136,7 +136,7 @@ trait BCodeIdiomatic {
             emit(Opcodes.ICONST_M1)
             emit(Opcodes.IXOR)
           } else if (kind == LONG) {
-            jmethod.visitLdcInsn(new java.lang.Long(-1))
+            jmethod.visitLdcInsn(java.lang.Long.valueOf(-1))
             jmethod.visitInsn(Opcodes.LXOR)
           } else {
             abort(s"Impossible to negate an $kind")
@@ -215,7 +215,8 @@ trait BCodeIdiomatic {
       invokespecial(
         JavaStringBuilderClassName,
         INSTANCE_CONSTRUCTOR_NAME,
-        "()V"
+        "()V",
+        itf = false
       )
     }
 
@@ -325,7 +326,7 @@ trait BCodeIdiomatic {
       } else if (cst >= java.lang.Short.MIN_VALUE && cst <= java.lang.Short.MAX_VALUE) {
         jmethod.visitIntInsn(Opcodes.SIPUSH, cst)
       } else {
-        jmethod.visitLdcInsn(new Integer(cst))
+        jmethod.visitLdcInsn(Integer.valueOf(cst))
       }
     }
 
@@ -334,7 +335,7 @@ trait BCodeIdiomatic {
       if (cst == 0L || cst == 1L) {
         emit(Opcodes.LCONST_0 + cst.asInstanceOf[Int])
       } else {
-        jmethod.visitLdcInsn(new java.lang.Long(cst))
+        jmethod.visitLdcInsn(java.lang.Long.valueOf(cst))
       }
     }
 
@@ -344,7 +345,7 @@ trait BCodeIdiomatic {
       if (bits == 0L || bits == 0x3f800000 || bits == 0x40000000) { // 0..2
         emit(Opcodes.FCONST_0 + cst.asInstanceOf[Int])
       } else {
-        jmethod.visitLdcInsn(new java.lang.Float(cst))
+        jmethod.visitLdcInsn(java.lang.Float.valueOf(cst))
       }
     }
 
@@ -354,7 +355,7 @@ trait BCodeIdiomatic {
       if (bits == 0L || bits == 0x3ff0000000000000L) { // +0.0d and 1.0d
         emit(Opcodes.DCONST_0 + cst.asInstanceOf[Int])
       } else {
-        jmethod.visitLdcInsn(new java.lang.Double(cst))
+        jmethod.visitLdcInsn(java.lang.Double.valueOf(cst))
       }
     }
 
@@ -398,12 +399,12 @@ trait BCodeIdiomatic {
     final def rem(tk: BType): Unit = { emitPrimitive(JCodeMethodN.remOpcodes, tk) } // can-multi-thread
 
     // can-multi-thread
-    final def invokespecial(owner: String, name: String, desc: String): Unit = {
-      jmethod.visitMethodInsn(Opcodes.INVOKESPECIAL, owner, name, desc, false)
+    final def invokespecial(owner: String, name: String, desc: String, itf: Boolean): Unit = {
+      jmethod.visitMethodInsn(Opcodes.INVOKESPECIAL, owner, name, desc, itf)
     }
     // can-multi-thread
-    final def invokestatic(owner: String, name: String, desc: String): Unit = {
-      jmethod.visitMethodInsn(Opcodes.INVOKESTATIC, owner, name, desc, false)
+    final def invokestatic(owner: String, name: String, desc: String, itf: Boolean): Unit = {
+      jmethod.visitMethodInsn(Opcodes.INVOKESTATIC, owner, name, desc, itf)
     }
     // can-multi-thread
     final def invokeinterface(owner: String, name: String, desc: String): Unit = {
@@ -414,10 +415,6 @@ trait BCodeIdiomatic {
       jmethod.visitMethodInsn(Opcodes.INVOKEVIRTUAL, owner, name, desc, false)
     }
 
-    final def invokedynamic(owner: String, name: String, desc: String): Unit = {
-      jmethod.visitMethodInsn(Opcodes.INVOKEDYNAMIC, owner, name, desc, false)
-     }
-
     // can-multi-thread
     final def goTo(label: asm.Label): Unit = { jmethod.visitJumpInsn(Opcodes.GOTO, label) }
     // can-multi-thread

src/compiler/scala/tools/nsc/backend/jvm/BackendInterface.scala

@@ -440,6 +440,14 @@ abstract class BackendInterface extends BackendInterfaceDefinitions {
     def tpe: Type // todo whats the differentce between tpe and info?
     def thisType: Type
 
+    /** Does this symbol actually correspond to an interface that will be emitted?
+     *  In the backend, this should be preferred over `isInterface` because it
+     *  also returns true for the symbols of the fake companion objects we
+     *  create for Java-defined classes.
+     */
+    final def isEmittedInterface: Boolean = isInterface ||
+      isJavaDefined && isModuleClass && companionClass.isInterface
+
     // tests
     def isClass: Boolean
     def isType: Boolean

src/compiler/scala/tools/nsc/backend/jvm/GenASM.scala

@@ -1585,7 +1585,7 @@ abstract class GenASM extends SubComponent with BytecodeWriters { self =>
         if (cst == 0L || cst == 1L) {
           jmethod.visitInsn(Opcodes.LCONST_0 + cst.asInstanceOf[Int])
         } else {
-          jmethod.visitLdcInsn(new java.lang.Long(cst))
+          jmethod.visitLdcInsn(java.lang.Long.valueOf(cst))
         }
       }
 
@@ -2567,7 +2567,7 @@ abstract class GenASM extends SubComponent with BytecodeWriters { self =>
                   emit(Opcodes.ICONST_M1)
                   emit(Opcodes.IXOR)
                 } else if(kind == LONG) {
-                  jmethod.visitLdcInsn(new java.lang.Long(-1))
+                  jmethod.visitLdcInsn(java.lang.Long.valueOf(-1))
                   jmethod.visitInsn(Opcodes.LXOR)
                 } else {
                   abort("Impossible to negate an " + kind)