diff --git a/compiler/backend/src/org/jetbrains/jet/codegen/intrinsics/IntrinsicMethods.java b/compiler/backend/src/org/jetbrains/jet/codegen/intrinsics/IntrinsicMethods.java
index a07dc71387a..4602a05c2a8 100644
--- a/compiler/backend/src/org/jetbrains/jet/codegen/intrinsics/IntrinsicMethods.java
+++ b/compiler/backend/src/org/jetbrains/jet/codegen/intrinsics/IntrinsicMethods.java
@@ -24,7 +24,7 @@ import org.jetbrains.jet.lang.descriptors.SimpleFunctionDescriptor;
 import org.jetbrains.jet.lang.resolve.CompileTimeConstantUtils;
 import org.jetbrains.jet.lang.resolve.DescriptorUtils;
 import org.jetbrains.jet.lang.resolve.java.JvmPrimitiveType;
-import org.jetbrains.jet.lang.resolve.name.FqName;
+import org.jetbrains.jet.lang.resolve.name.FqNameUnsafe;
 import org.jetbrains.jet.lang.resolve.name.Name;
 import org.jetbrains.jet.lang.types.expressions.OperatorConventions;
 import org.jetbrains.jet.lang.types.lang.KotlinBuiltIns;
@@ -59,8 +59,8 @@ public class IntrinsicMethods {
     private static final EnumValueOf ENUM_VALUE_OF = new EnumValueOf();
     private static final ToString TO_STRING = new ToString();
 
-    private static final FqName KOTLIN_ANY_FQ_NAME = DescriptorUtils.getFqNameSafe(KotlinBuiltIns.getInstance().getAny());
-    private static final FqName KOTLIN_STRING_FQ_NAME = DescriptorUtils.getFqNameSafe(KotlinBuiltIns.getInstance().getString());
+    private static final FqNameUnsafe KOTLIN_ANY_FQ_NAME = DescriptorUtils.getFqName(KotlinBuiltIns.getInstance().getAny());
+    private static final FqNameUnsafe KOTLIN_STRING_FQ_NAME = DescriptorUtils.getFqName(KotlinBuiltIns.getInstance().getString());
 
     private final Map<String, IntrinsicMethod> namedMethods = new HashMap<String, IntrinsicMethod>();
     private static final IntrinsicMethod ARRAY_ITERATOR = new ArrayIterator();
diff --git a/compiler/backend/src/org/jetbrains/jet/codegen/intrinsics/IntrinsicsMap.java b/compiler/backend/src/org/jetbrains/jet/codegen/intrinsics/IntrinsicsMap.java
index 2371bedb8b7..a402857ab8e 100644
--- a/compiler/backend/src/org/jetbrains/jet/codegen/intrinsics/IntrinsicsMap.java
+++ b/compiler/backend/src/org/jetbrains/jet/codegen/intrinsics/IntrinsicsMap.java
@@ -32,11 +32,11 @@ import java.util.Map;
 class IntrinsicsMap {
     private static final class Key {
         private final FqNameUnsafe owner;
-        private final FqName receiverParameter;
+        private final FqNameUnsafe receiverParameter;
         private final String name;
         private final int valueParameterCount;
 
-        private Key(@NotNull FqNameUnsafe owner, @Nullable FqName receiverParameter, @NotNull String name, int valueParameterCount) {
+        private Key(@NotNull FqNameUnsafe owner, @Nullable FqNameUnsafe receiverParameter, @NotNull String name, int valueParameterCount) {
             this.owner = owner;
             this.receiverParameter = receiverParameter;
             this.name = name;
@@ -85,7 +85,7 @@ class IntrinsicsMap {
      */
     public void registerIntrinsic(
             @NotNull FqName owner,
-            @Nullable FqName receiverParameter,
+            @Nullable FqNameUnsafe receiverParameter,
             @NotNull String name,
             int valueParameterCount,
             @NotNull IntrinsicMethod impl
@@ -105,13 +105,13 @@ class IntrinsicsMap {
     }
 
     @Nullable
-    private static FqName getReceiverParameterFqName(@NotNull CallableMemberDescriptor descriptor) {
+    private static FqNameUnsafe getReceiverParameterFqName(@NotNull CallableMemberDescriptor descriptor) {
         ReceiverParameterDescriptor receiverParameter = descriptor.getReceiverParameter();
         if (receiverParameter == null) return null;
 
         ClassifierDescriptor classifier = receiverParameter.getType().getConstructor().getDeclarationDescriptor();
         if (classifier == null) return null;
 
-        return DescriptorUtils.getFqNameSafe(classifier);
+        return DescriptorUtils.getFqName(classifier);
     }
 }
diff --git a/compiler/testData/codegen/box/functions/localFunctions/kt4777.kt b/compiler/testData/codegen/box/functions/localFunctions/kt4777.kt
new file mode 100644
index 00000000000..416151632cb
--- /dev/null
+++ b/compiler/testData/codegen/box/functions/localFunctions/kt4777.kt
@@ -0,0 +1,14 @@
+var result = "Fail"
+
+val p = object : Runnable {
+    override fun run() {
+        fun <T : Any> T.id() = this
+
+        result = "OK".id()
+    }
+}
+
+fun box(): String {
+    p.run()
+    return result
+}
diff --git a/compiler/tests/org/jetbrains/jet/codegen/generated/BlackBoxCodegenTestGenerated.java b/compiler/tests/org/jetbrains/jet/codegen/generated/BlackBoxCodegenTestGenerated.java
index 36eba9bc1e2..aa25125d309 100644
--- a/compiler/tests/org/jetbrains/jet/codegen/generated/BlackBoxCodegenTestGenerated.java
+++ b/compiler/tests/org/jetbrains/jet/codegen/generated/BlackBoxCodegenTestGenerated.java
@@ -2961,6 +2961,11 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
                 doTest("compiler/testData/codegen/box/functions/localFunctions/kt4119_2.kt");
             }
             
+            @TestMetadata("kt4777.kt")
+            public void testKt4777() throws Exception {
+                doTest("compiler/testData/codegen/box/functions/localFunctions/kt4777.kt");
+            }
+            
             @TestMetadata("localFunctionInConstructor.kt")
             public void testLocalFunctionInConstructor() throws Exception {
                 doTest("compiler/testData/codegen/box/functions/localFunctions/localFunctionInConstructor.kt");