error message enhancement for Conv2D, test=develop (#23561)

python/paddle/fluid/dygraph/nn.py

@@ -243,6 +243,9 @@ class Conv2D(layers.Layer):
             'use_cudnn': self._use_cudnn,
             'use_mkldnn': False,
         }
+
+        check_variable_and_dtype(input, 'input',
+                                 ['float16', 'float32', 'float64'], 'Conv2D')
         pre_bias = self._helper.create_variable_for_type_inference(
             dtype=self._dtype)
 

python/paddle/fluid/tests/unittests/test_layers.py

@@ -286,6 +286,27 @@ class TestLayer(LayerTest):
             dy_ret = conv2d(base.to_variable(images))
             self.assertTrue(conv2d.bias is None)
 
+        with self.static_graph():
+            # the input of Conv2D must be Variable.
+            def test_Variable():
+                images = np.ones([2, 3, 5, 5], dtype='float32')
+                conv2d = nn.Conv2D(
+                    num_channels=3, num_filters=3, filter_size=[2, 2])
+                conv2d_ret1 = conv2d(images)
+
+            self.assertRaises(TypeError, test_Variable)
+
+            # the input dtype of Conv2D must be float16 or float32 or float64
+            # float16 only can be set on GPU place
+            def test_type():
+                images = layers.data(
+                    name='pixel', shape=[3, 5, 5], dtype='int32')
+                conv2d = nn.Conv2D(
+                    num_channels=3, num_filters=3, filter_size=[2, 2])
+                conv2d_ret2 = conv2d(images)
+
+            self.assertRaises(TypeError, test_type)
+
         self.assertTrue(np.allclose(static_ret, dy_ret_value))
         self.assertTrue(np.allclose(static_ret, static_ret2))