generates remove method

throwing exception
in Kotlin class extending Iterator

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

@@ -24,6 +24,7 @@ import org.jetbrains.jet.lang.descriptors.ClassDescriptor;
 import org.jetbrains.jet.lang.descriptors.PropertyDescriptor;
 import org.jetbrains.jet.lang.psi.*;
 import org.jetbrains.jet.lang.resolve.BindingContext;
+import org.jetbrains.jet.lang.resolve.DescriptorUtils;
 
 import java.util.ArrayList;
 import java.util.Collections;
@@ -64,6 +65,8 @@ public abstract class ClassBodyCodegen {
         generateSyntheticParts();
 
         generateStaticInitializer();
+
+        generateRemoveInIterator();
     }
 
     protected abstract void generateDeclaration();
@@ -137,4 +140,12 @@ public abstract class ClassBodyCodegen {
             }
         }
     }
+
+    private void generateRemoveInIterator() {
+        // generates stub 'remove' function for subclasses of Iterator to be compatible with java.util.Iterator
+        if (DescriptorUtils.isIteratorWithoutRemoveImpl(descriptor)) {
+            final MethodVisitor mv = v.getVisitor().visitMethod(ACC_PUBLIC, "remove", "()V", null, null);
+            CodegenUtil.generateMethodThrow(mv, "java/lang/UnsupportedOperationException", "Mutating method called on a Kotlin Iterator");
+        }
+    }
 }

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

@@ -18,6 +18,9 @@ package org.jetbrains.jet.codegen;
 
 import com.intellij.psi.PsiElement;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.asm4.MethodVisitor;
+import org.jetbrains.asm4.Type;
+import org.jetbrains.asm4.commons.InstructionAdapter;
 import org.jetbrains.jet.lang.descriptors.*;
 import org.jetbrains.jet.lang.descriptors.annotations.AnnotationDescriptor;
 import org.jetbrains.jet.lang.psi.*;
@@ -121,4 +124,20 @@ public class CodegenUtil {
         }
         return flags;
     }
+
+    public static void generateThrow(MethodVisitor mv, String exception, String message) {
+        InstructionAdapter instructionAdapter = new InstructionAdapter(mv);
+        instructionAdapter.anew(Type.getObjectType(exception));
+        instructionAdapter.dup();
+        instructionAdapter.aconst(message);
+        instructionAdapter.invokespecial(exception, "<init>", "(Ljava/lang/String;)V");
+        instructionAdapter.athrow();
+    }
+
+    public static void generateMethodThrow(MethodVisitor mv, String exception, String message) {
+        mv.visitCode();
+        generateThrow(mv, exception, message);
+        mv.visitMaxs(-1, -1);
+        mv.visitEnd();
+    }
 }

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

@@ -17,29 +17,22 @@
 package org.jetbrains.jet.codegen;
 
 import org.jetbrains.asm4.MethodVisitor;
-import org.jetbrains.asm4.Type;
-import org.jetbrains.asm4.commons.InstructionAdapter;
 
 /**
  * @author Stepan Koltsov
  */
 public class StubCodegen {
+    private static String STUB_EXCEPTION = "java/lang/RuntimeException";
+    private static String STUB_EXCEPTION_MESSAGE = "Stubs are for compiler only, do not add them to runtime classpath";
+
     private StubCodegen() {
     }
 
     public static void generateStubThrow(MethodVisitor mv) {
-        InstructionAdapter iv = new InstructionAdapter(mv);
+        CodegenUtil.generateThrow(mv, STUB_EXCEPTION, STUB_EXCEPTION_MESSAGE);
-        iv.anew(Type.getObjectType("java/lang/RuntimeException"));
-        iv.dup();
-        iv.aconst("Stubs are for compiler only, do not add them to runtime classpath");
-        iv.invokespecial("java/lang/RuntimeException", "<init>", "(Ljava/lang/String;)V");
-        iv.athrow();
     }
 
     public static void generateStubCode(MethodVisitor mv) {
-        mv.visitCode();
+        CodegenUtil.generateMethodThrow(mv, STUB_EXCEPTION, STUB_EXCEPTION_MESSAGE);
-        generateStubThrow(mv);
-        mv.visitMaxs(-1, -1);
-        mv.visitEnd();
     }
 }

compiler/frontend/src/org/jetbrains/jet/lang/resolve/DescriptorUtils.java

@@ -28,7 +28,9 @@ import org.jetbrains.jet.lang.resolve.name.FqNameUnsafe;
 import org.jetbrains.jet.lang.resolve.name.Name;
 import org.jetbrains.jet.lang.resolve.scopes.receivers.ReceiverDescriptor;
 import org.jetbrains.jet.lang.types.*;
+import org.jetbrains.jet.lang.types.checker.JetTypeChecker;
 import org.jetbrains.jet.lang.types.lang.JetStandardClasses;
+import org.jetbrains.jet.lang.types.lang.JetStandardLibrary;
 
 import java.util.*;
 
@@ -345,4 +347,22 @@ public class DescriptorUtils {
         }
         return false;
     }
+
+    public static boolean isIteratorWithoutRemoveImpl(@NotNull ClassDescriptor classDescriptor) {
+        ClassDescriptor iteratorOfT = JetStandardLibrary.getInstance().getIterator();
+        JetType iteratorOfAny = TypeUtils.substituteParameters(iteratorOfT, Collections.singletonList(JetStandardClasses.getAnyType()));
+        boolean isIterator = JetTypeChecker.INSTANCE.isSubtypeOf(classDescriptor.getDefaultType(), iteratorOfAny);
+        boolean hasRemove = hasMethod(classDescriptor, Name.identifier("remove"));
+        return isIterator && !hasRemove;
+    }
+
+    private static boolean hasMethod(ClassDescriptor classDescriptor, Name name) {
+        Collection<FunctionDescriptor> removeFunctions = classDescriptor.getDefaultType().getMemberScope().getFunctions(name);
+        for (FunctionDescriptor function : removeFunctions) {
+            if (function.getValueParameters().isEmpty() && function.getTypeParameters().isEmpty()) {
+                return true;
+            }
+        }
+        return false;
+    }
 }

compiler/testData/codegen/functions/removeInIterator.java

@@ -0,0 +1,5 @@
+public class removeInIterator {
+    public static void bar(java.util.Iterator<Integer> it) {
+        it.remove();
+    }
+}

compiler/testData/codegen/functions/removeInIterator.kt

@@ -0,0 +1,13 @@
+fun box() : String {
+    try {
+        removeInIterator.bar(object : Iterator<Int> {
+            public override fun hasNext(): Boolean = false
+            public override fun next(): Int = 1
+        })
+    }
+    catch (e: UnsupportedOperationException) {
+        if (e.getMessage() == "Mutating method called on a Kotlin Iterator")
+            return "OK"
+    }
+    return "fail"
+}

compiler/tests/org/jetbrains/jet/codegen/FunctionGenTest.java

@@ -180,5 +180,9 @@ public class FunctionGenTest extends CodegenTestCase {
         public void testReferencesStaticInnerClassMethodTwoLevels() throws Exception {
             blackBoxFileWithJava("functions/referencesStaticInnerClassMethodL2.kt");
         }
+
+        public void testRemoveInIterator() throws Exception {
+            blackBoxFileWithJava("functions/removeInIterator.kt");
+        }
     }
 }