diff --git a/arangod/Aql/V8Executor.cpp b/arangod/Aql/V8Executor.cpp
index b2c9bc0092..11654e8480 100644
--- a/arangod/Aql/V8Executor.cpp
+++ b/arangod/Aql/V8Executor.cpp
@@ -153,7 +153,7 @@ std::unordered_map<std::string, Function const> const V8Executor::FunctionNames{
   { "ATTRIBUTES",                  Function("ATTRIBUTES",                  "ATTRIBUTES", "a|b,b", true, true) },
   { "MERGE",                       Function("MERGE",                       "MERGE", "a,a|+", true, true) },
   { "MERGE_RECURSIVE",             Function("MERGE_RECURSIVE",             "MERGE_RECURSIVE", "a,a|+", true, true) },
-  { "DOCUMENT",                    Function("DOCUMENT",                    "DOCUMENT", "h.|.", true, true) },
+  { "DOCUMENT",                    Function("DOCUMENT",                    "DOCUMENT", "h.|.", false, true) },
   { "MATCHES",                     Function("MATCHES",                     "MATCHES", ".,l|b", true, true) },
   { "UNSET",                       Function("UNSET",                       "UNSET", "a,sl|+", true, true) },
   { "KEEP",                        Function("KEEP",                        "KEEP", "a,sl|+", true, true) },
@@ -625,18 +625,20 @@ void V8Executor::generateCodeFunctionCall (AstNode const* node) {
 
     if (member != nullptr) {
       if (func->containsCollectionParameter && 
+          member->type == NODE_TYPE_COLLECTION &&
           func->mustConvertArgument(i)) {
-        // the parameter at this position must be a collection name that is converted to a string
-        if (member->type == NODE_TYPE_COLLECTION) {
-          // do a parameter conversion from a collection parameter to a collection name parameter
-          char const* name = member->getStringValue();
-          generateCodeString(name);
-        }
+        // the parameter at this position is a collection name that is converted to a string
+        // do a parameter conversion from a collection parameter to a collection name parameter
+        char const* name = member->getStringValue();
+        generateCodeString(name);
+      }
+      /*
         else {
           // the parameter at the position is not a collection name... fail
           THROW_ARANGO_EXCEPTION_PARAMS(TRI_ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH, func->internalName.c_str());
         }
       }
+      */
       else {
         // generate regular code for the node
         generateCodeNode(args->getMember(i));
diff --git a/js/server/modules/org/arangodb/ahuacatl.js b/js/server/modules/org/arangodb/ahuacatl.js
index 14ab58822c..78879784c9 100644
--- a/js/server/modules/org/arangodb/ahuacatl.js
+++ b/js/server/modules/org/arangodb/ahuacatl.js
@@ -3125,6 +3125,10 @@ function FLATTEN (values, maxDepth, depth) {
   if (TYPEWEIGHT(maxDepth) === TYPEWEIGHT_NULL) {
     maxDepth = 1;
   }
+  else if (TYPEWEIGHT(maxDepth) !== TYPEWEIGHT_NUMBER) {
+    THROW(INTERNAL.errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH, "FLATTEN");
+  }
+
   if (TYPEWEIGHT(depth) === TYPEWEIGHT_NULL) {
     depth = 0;
   }
@@ -3663,6 +3667,10 @@ function SKIPLIST_QUERY (collection, condition, skip, limit) {
 
 function HAS (element, name) {
   "use strict";
+  
+  if (TYPEWEIGHT(name) !== TYPEWEIGHT_STRING) {
+    THROW(INTERNAL.errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH, "HAS");
+  }
 
   if (TYPEWEIGHT(element) === TYPEWEIGHT_NULL) {
     return false;
diff --git a/js/server/tests/aql-functions.js b/js/server/tests/aql-functions.js
index 9e2683d8f4..babe5468c5 100644
--- a/js/server/tests/aql-functions.js
+++ b/js/server/tests/aql-functions.js
@@ -1329,13 +1329,12 @@ function ahuacatlFunctionsTestSuite () {
 ////////////////////////////////////////////////////////////////////////////////
     
     testUnsetInvalid : function () {
+      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_NUMBER_MISMATCH.code, "RETURN UNSET()"); 
+      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_NUMBER_MISMATCH.code, "RETURN UNSET({ })"); 
       assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN UNSET({ }, 1)"); 
       assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN UNSET({ }, { })"); 
       assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN UNSET({ }, 'foo', { })"); 
       assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN UNSET('foo', 'foo')"); 
-
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_NUMBER_MISMATCH.code, "RETURN UNSET()"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_NUMBER_MISMATCH.code, "RETURN UNSET({ })"); 
     },
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -2134,14 +2133,14 @@ function ahuacatlFunctionsTestSuite () {
     testFlattenInvalid : function () {
       assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_NUMBER_MISMATCH.code, "RETURN FLATTEN()");
       assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_NUMBER_MISMATCH.code, "RETURN FLATTEN([ ], 1, 1)");
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN FLATTEN(1)");
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN FLATTEN(null)");
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN FLATTEN(false)");
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN FLATTEN(1)");
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN FLATTEN('foo')");
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN FLATTEN(1)");
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN FLATTEN(null)");
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN FLATTEN(false)");
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN FLATTEN(1)");
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN FLATTEN('foo')");
       assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN FLATTEN([ ], 'foo')");
       assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN FLATTEN([ ], [ ])");
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN FLATTEN({ })");
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN FLATTEN({ })");
     },
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -2633,11 +2632,11 @@ function ahuacatlFunctionsTestSuite () {
     testMinInvalid : function () {
       assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_NUMBER_MISMATCH.code, "RETURN MIN()"); 
       assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_NUMBER_MISMATCH.code, "RETURN MIN([ ], 2)"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN MIN(null)"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN MIN(false)"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN MIN(3)"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN MIN(\"yes\")"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN MIN({ })"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN MIN(null)"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN MIN(false)"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN MIN(3)"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN MIN(\"yes\")"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN MIN({ })"); 
     },
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -2677,11 +2676,11 @@ function ahuacatlFunctionsTestSuite () {
     testMaxInvalid : function () {
       assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_NUMBER_MISMATCH.code, "RETURN MAX()"); 
       assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_NUMBER_MISMATCH.code, "RETURN MAX([ ], 2)"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN MAX(null)"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN MAX(false)"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN MAX(3)"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN MAX(\"yes\")"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN MAX({ })"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN MAX(null)"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN MAX(false)"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN MAX(3)"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN MAX(\"yes\")"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN MAX({ })"); 
     },
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -2718,11 +2717,11 @@ function ahuacatlFunctionsTestSuite () {
     testSumInvalid : function () {
       assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_NUMBER_MISMATCH.code, "RETURN SUM()"); 
       assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_NUMBER_MISMATCH.code, "RETURN SUM([ ], 2)"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN SUM(null)"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN SUM(false)"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN SUM(3)"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN SUM(\"yes\")"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN SUM({ })"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN SUM(null)"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN SUM(false)"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN SUM(3)"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN SUM(\"yes\")"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN SUM({ })"); 
     },
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -2765,11 +2764,11 @@ function ahuacatlFunctionsTestSuite () {
     testAverageInvalid : function () {
       assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_NUMBER_MISMATCH.code, "RETURN AVERAGE()"); 
       assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_NUMBER_MISMATCH.code, "RETURN AVERAGE([ ], 2)"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN AVERAGE(null)"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN AVERAGE(false)"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN AVERAGE(3)"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN AVERAGE(\"yes\")"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN AVERAGE({ })"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN AVERAGE(null)"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN AVERAGE(false)"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN AVERAGE(3)"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN AVERAGE(\"yes\")"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN AVERAGE({ })"); 
     },
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -2823,11 +2822,11 @@ function ahuacatlFunctionsTestSuite () {
     testMedianInvalid : function () {
       assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_NUMBER_MISMATCH.code, "RETURN MEDIAN()"); 
       assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_NUMBER_MISMATCH.code, "RETURN MEDIAN([ ], 2)"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN MEDIAN(null)"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN MEDIAN(false)"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN MEDIAN(3)"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN MEDIAN(\"yes\")"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN MEDIAN({ })"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN MEDIAN(null)"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN MEDIAN(false)"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN MEDIAN(3)"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN MEDIAN(\"yes\")"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN MEDIAN({ })"); 
     },
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -3870,11 +3869,11 @@ function ahuacatlFunctionsTestSuite () {
     testVariancePopulationInvalid : function () {
       assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_NUMBER_MISMATCH.code, "RETURN VARIANCE_POPULATION()"); 
       assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_NUMBER_MISMATCH.code, "RETURN VARIANCE_POPULATION([ ], 2)"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN VARIANCE_POPULATION(null)"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN VARIANCE_POPULATION(false)"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN VARIANCE_POPULATION(3)"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN VARIANCE_POPULATION(\"yes\")"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN VARIANCE_POPULATION({ })"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN VARIANCE_POPULATION(null)"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN VARIANCE_POPULATION(false)"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN VARIANCE_POPULATION(3)"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN VARIANCE_POPULATION(\"yes\")"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN VARIANCE_POPULATION({ })"); 
     },
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -3927,11 +3926,11 @@ function ahuacatlFunctionsTestSuite () {
     testVarianceSampleInvalid : function () {
       assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_NUMBER_MISMATCH.code, "RETURN VARIANCE_SAMPLE()"); 
       assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_NUMBER_MISMATCH.code, "RETURN VARIANCE_SAMPLE([ ], 2)"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN VARIANCE_SAMPLE(null)"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN VARIANCE_SAMPLE(false)"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN VARIANCE_SAMPLE(3)"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN VARIANCE_SAMPLE(\"yes\")"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN VARIANCE_SAMPLE({ })"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN VARIANCE_SAMPLE(null)"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN VARIANCE_SAMPLE(false)"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN VARIANCE_SAMPLE(3)"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN VARIANCE_SAMPLE(\"yes\")"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN VARIANCE_SAMPLE({ })"); 
     },
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -3989,11 +3988,11 @@ function ahuacatlFunctionsTestSuite () {
     testStddevPopulationInvalid : function () {
       assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_NUMBER_MISMATCH.code, "RETURN STDDEV_POPULATION()"); 
       assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_NUMBER_MISMATCH.code, "RETURN STDDEV_POPULATION([ ], 2)"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN STDDEV_POPULATION(null)"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN STDDEV_POPULATION(false)"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN STDDEV_POPULATION(3)"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN STDDEV_POPULATION(\"yes\")"); 
-      assertQueryError(errors.ERROR_QUERY_FUNCTION_ARGUMENT_TYPE_MISMATCH.code, "RETURN STDDEV_POPULATION({ })"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN STDDEV_POPULATION(null)"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN STDDEV_POPULATION(false)"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN STDDEV_POPULATION(3)"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN STDDEV_POPULATION(\"yes\")"); 
+      assertQueryError(errors.ERROR_QUERY_LIST_EXPECTED.code, "RETURN STDDEV_POPULATION({ })"); 
     },
 
 ////////////////////////////////////////////////////////////////////////////////