BUG: don't override casting errors with matmul or inner

2 files changed, 19 insertions, 11 deletions

diff --git a/numpy/core/src/multiarray/multiarraymodule.c b/numpy/core/src/multiarray/multiarraymodule.c
index 22909ae1a..909a24359 100644
--- a/numpy/core/src/multiarray/multiarraymodule.c
+++ b/numpy/core/src/multiarray/multiarraymodule.c
@@ -833,7 +833,10 @@ PyArray_InnerProduct(PyObject *op1, PyObject *op2)
     typenum = PyArray_ObjectType(op2, typenum);
     typec = PyArray_DescrFromType(typenum);
     if (typec == NULL) {
-        PyErr_SetString(PyExc_TypeError, "Cannot find a common data type.");
+        if (!PyErr_Occurred()) {
+            PyErr_SetString(PyExc_TypeError,
+                            "Cannot find a common data type.");
+        }
         goto fail;
     }
 
@@ -2361,7 +2364,10 @@ array_matmul(PyObject *NPY_UNUSED(m), PyObject *args, PyObject* kwds)
     dtype = PyArray_DescrFromObject(in1, NULL);
     dtype = PyArray_DescrFromObject(in2, dtype);
     if (dtype == NULL) {
-        PyErr_SetString(PyExc_ValueError, "Cannot find a common data type.");
+        if (!PyErr_Occurred()) {
+            PyErr_SetString(PyExc_ValueError,
+                            "Cannot find a common data type.");
+        }
         return NULL;
     }
     typenum = dtype->type_num;
diff --git a/numpy/core/tests/test_multiarray.py b/numpy/core/tests/test_multiarray.py
index 68fb6acf7..51fe6e9ef 100644
--- a/numpy/core/tests/test_multiarray.py
+++ b/numpy/core/tests/test_multiarray.py
@@ -2693,15 +2693,6 @@ class TestMethods(object):
         assert_raises(TypeError, np.dot, c, A)
         assert_raises(TypeError, np.dot, A, c)
 
-    def test_dot_casting_fails(self):
-
-        class A(object):
-            def __array__(self, *args, **kwargs):
-                raise NotImplementedError
-
-        # Don't override the error from calling __array__()
-        assert_raises(NotImplementedError, np.dot, A(), A())
-
     def test_dot_out_mem_overlap(self):
         np.random.seed(1)
 
@@ -2736,6 +2727,17 @@ class TestMethods(object):
         np.dot(a, b, out=out)
         np.matmul(a, b, out=out)
 
+    def test_dot_matmul_inner_array_casting_fails(self):
+
+        class A(object):
+            def __array__(self, *args, **kwargs):
+                raise NotImplementedError
+
+        # Don't override the error from calling __array__()
+        assert_raises(NotImplementedError, np.dot, A(), A())
+        assert_raises(NotImplementedError, np.matmul, A(), A())
+        assert_raises(NotImplementedError, np.inner, A(), A())
+
     def test_diagonal(self):
         a = np.arange(12).reshape((3, 4))
         assert_equal(a.diagonal(), [0, 5, 10])