Don't generate bodies of built-in stub methods into interfaces

compiler/backend/src/org/jetbrains/jet/codegen/AsmUtil.java

@@ -292,7 +292,7 @@ public class AsmUtil {
                    : sort == Type.BYTE || sort == Type.SHORT ? Type.INT_TYPE : type;
     }
 
-    public static void genThrow(MethodVisitor mv, String exception, String message) {
+    public static void genThrow(@NotNull MethodVisitor mv, @NotNull String exception, @NotNull String message) {
         InstructionAdapter iv = new InstructionAdapter(mv);
         iv.anew(Type.getObjectType(exception));
         iv.dup();
@@ -301,13 +301,6 @@ public class AsmUtil {
         iv.athrow();
     }
 
-    public static void genMethodThrow(MethodVisitor mv, String exception, String message) {
-        mv.visitCode();
-        genThrow(mv, exception, message);
-        mv.visitMaxs(-1, -1);
-        mv.visitEnd();
-    }
-
     public static void genClosureFields(CalculatedClosure closure, ClassBuilder v, JetTypeMapper typeMapper) {
         ClassifierDescriptor captureThis = closure.getCaptureThis();
         int access = NO_FLAG_PACKAGE_PRIVATE | ACC_SYNTHETIC | ACC_FINAL;

compiler/backend/src/org/jetbrains/jet/codegen/ImplementationBodyCodegen.java

@@ -489,11 +489,16 @@ public class ImplementationBodyCodegen extends ClassBodyCodegen {
 
     private void generateToArray() {
         KotlinBuiltIns builtIns = KotlinBuiltIns.getInstance();
-        if (isSubclass(descriptor, builtIns.getCollection())) {
+        if (!isSubclass(descriptor, builtIns.getCollection())) return;
-            if (CodegenUtil.getDeclaredFunctionByRawSignature(descriptor, Name.identifier("toArray"), builtIns.getArray()) == null) {
-                MethodVisitor mv = v.getVisitor().visitMethod(ACC_PUBLIC, "toArray", "()[Ljava/lang/Object;", null, null);
-                InstructionAdapter iv = new InstructionAdapter(mv);
 
+        int access = descriptor.getKind() == ClassKind.TRAIT ?
+                     ACC_PUBLIC | ACC_ABSTRACT :
+                     ACC_PUBLIC;
+        if (CodegenUtil.getDeclaredFunctionByRawSignature(descriptor, Name.identifier("toArray"), builtIns.getArray()) == null) {
+            MethodVisitor mv = v.getVisitor().visitMethod(access, "toArray", "()[Ljava/lang/Object;", null, null);
+
+            if (descriptor.getKind() != ClassKind.TRAIT) {
+                InstructionAdapter iv = new InstructionAdapter(mv);
                 mv.visitCode();
 
                 iv.load(0, classAsmType);
@@ -502,11 +507,13 @@ public class ImplementationBodyCodegen extends ClassBodyCodegen {
 
                 FunctionCodegen.endVisit(mv, "toArray", myClass);
             }
+        }
 
-            if (!isGenericToArrayPresent()) {
+        if (!isGenericToArrayPresent()) {
-                MethodVisitor mv = v.getVisitor().visitMethod(ACC_PUBLIC, "toArray", "([Ljava/lang/Object;)[Ljava/lang/Object;", null, null);
+            MethodVisitor mv = v.getVisitor().visitMethod(access, "toArray", "([Ljava/lang/Object;)[Ljava/lang/Object;", null, null);
+
+            if (descriptor.getKind() != ClassKind.TRAIT) {
                 InstructionAdapter iv = new InstructionAdapter(mv);
-
                 mv.visitCode();
 
                 iv.load(0, classAsmType);
@@ -528,8 +535,15 @@ public class ImplementationBodyCodegen extends ClassBodyCodegen {
     ) {
         if (CodegenUtil.getDeclaredFunctionByRawSignature(
                 descriptor, Name.identifier(name), returnedClassifier, valueParameterClassifiers) == null) {
-            MethodVisitor mv = v.getVisitor().visitMethod(ACC_PUBLIC, name, desc, null, null);
+            int access = descriptor.getKind() == ClassKind.TRAIT ?
-            AsmUtil.genMethodThrow(mv, "java/lang/UnsupportedOperationException", "Mutating immutable collection");
+                         ACC_PUBLIC | ACC_ABSTRACT :
+                         ACC_PUBLIC;
+            MethodVisitor mv = v.getVisitor().visitMethod(access, name, desc, null, null);
+            if (descriptor.getKind() != ClassKind.TRAIT) {
+                mv.visitCode();
+                genThrow(mv, "java/lang/UnsupportedOperationException", "Mutating immutable collection");
+                FunctionCodegen.endVisit(mv, "built-in stub for " + name + desc, null);
+            }
         }
     }
 

compiler/testData/codegen/box/builtinStubMethods/dontGenerateBodyInTrait.kt

@@ -0,0 +1,10 @@
+trait A : Collection<String>
+trait B : List<String>
+trait C : Map<Long, Double>
+trait D : Map.Entry<Any, Nothing>
+trait E : Iterator<Int>
+
+fun box(): String {
+    trait F : A, B, C, D, E
+    return "OK"
+}

compiler/tests/org/jetbrains/jet/codegen/generated/BlackBoxCodegenTestGenerated.java

@@ -477,6 +477,11 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             doTest("compiler/testData/codegen/box/builtinStubMethods/Collection.kt");
         }
         
+        @TestMetadata("dontGenerateBodyInTrait.kt")
+        public void testDontGenerateBodyInTrait() throws Exception {
+            doTest("compiler/testData/codegen/box/builtinStubMethods/dontGenerateBodyInTrait.kt");
+        }
+        
         @TestMetadata("Iterator.kt")
         public void testIterator() throws Exception {
             doTest("compiler/testData/codegen/box/builtinStubMethods/Iterator.kt");