Revise Concat op

ngraph/core/src/op/concat.cpp

@@ -71,10 +71,14 @@ void op::Concat::validate_and_infer_types()
             }
             auto concat_axis = get_concatenation_axis();
             NODE_VALIDATION_CHECK(this,
-                                  concat_axis < this_input_rank.get_length(),
+                                  concat_axis < this_input_rank.get_length() && concat_axis >= 0,
                                   "Concatenation axis (",
                                   concat_axis,
-                                  ") is out of bounds for ",
+                                  ") is out of bounds [",
+                                  -this_input_rank.get_length(),
+                                  ", ",
+                                  this_input_rank.get_length() - 1,
+                                  "] for ",
                                   "argument ",
                                   i,
                                   ", which has shape ",

ngraph/test/type_prop/concat.cpp

@@ -367,3 +367,37 @@ TEST(type_prop, concat_partial_all_static_with_concat_axis_static_dims_incompati
         FAIL() << "Deduced type check failed for unexpected reason";
     }
 }
+
+TEST(type_prop, concat_partial_negative_axis_correct)
+{
+    auto param0 = make_shared<op::Parameter>(element::f32, Shape{3, 2, 4});
+    auto param1 = make_shared<op::Parameter>(element::f32, Shape{7, 2, 4});
+    auto param2 = make_shared<op::Parameter>(element::f32, Shape{2, 2, 4});
+
+    auto c = make_shared<op::Concat>(NodeVector{param0, param1, param2}, -3);
+
+    ASSERT_EQ(c->get_element_type(), element::f32);
+    ASSERT_EQ(c->get_shape(), (Shape{12, 2, 4}));
+}
+
+TEST(type_prop, concat_partial_negative_axis_incorrect)
+{
+    auto param0 = make_shared<op::Parameter>(element::f32, Shape{2, 3, 4});
+    auto param1 = make_shared<op::Parameter>(element::f32, Shape{2, 7, 4});
+    auto param2 = make_shared<op::Parameter>(element::f32, Shape{2, 2, 4});
+
+    try
+    {
+        auto c = make_shared<op::Concat>(NodeVector{param0, param1, param2}, -4);
+        // Should have thrown, so fail if it didn't
+        FAIL() << "Incorrect negative axis value not detected (out of bounds)";
+    }
+    catch (const NodeValidationFailure& error)
+    {
+        EXPECT_HAS_SUBSTRING(error.what(), std::string("Concatenation axis (-1) is out of bounds"));
+    }
+    catch (...)
+    {
+        FAIL() << "Deduced type check failed for unexpected reason";
+    }
+}