diff --git a/pycuda/gpuarray.py b/pycuda/gpuarray.py
index 420e5d7ad96e6eca54cdfeda25c1d21e21391146..e4bd10afbae6ecfb4f4c8a6ecf36d86ba5237236 100644
--- a/pycuda/gpuarray.py
+++ b/pycuda/gpuarray.py
@@ -385,6 +385,13 @@ class GPUArray:
     def __hash__(self):
         raise TypeError("GPUArrays are not hashable.")
 
+    def __bool__(self):
+        if self.size == 1:
+            return bool(self.get())
+        else:
+            raise ValueError("The truth value of an array with "
+                    "more than one element is ambiguous. Use a.any() or a.all()")
+
     @property
     def ptr(self):
         return self.gpudata.__int__()
@@ -732,7 +739,7 @@ class GPUArray:
         if len(self.shape):
             return self.shape[0]
         else:
-            return TypeError("scalar has no len()")
+            raise TypeError("len() of unsized object")
 
     def __abs__(self):
         """Return a `GPUArray` of the absolute values of the elements
@@ -1114,7 +1121,10 @@ class GPUArray:
         )
 
     def __setitem__(self, index, value):
-        _memcpy_discontig(self[index], value)
+        if np.isscalar(value):
+            self[index].fill(value)
+        else:
+            _memcpy_discontig(self[index], value)
 
     # }}}
 
diff --git a/test/test_gpuarray.py b/test/test_gpuarray.py
index 1d618e1ddde85c93f38be00092f536e8d96cb0dd..cce2de92f93bcc31d508b226655b06ca3a5b9cde 100644
--- a/test/test_gpuarray.py
+++ b/test/test_gpuarray.py
@@ -1366,6 +1366,20 @@ class TestGPUArray:
             gpuarray.logical_not(gpuarray.ones(10)).get(),
             np.logical_not(np.ones(10)))
 
+    def test_truth_value(self):
+        for i in range(5):
+            shape = (1,)*i
+            zeros = gpuarray.zeros(shape, dtype="float32")
+            ones = gpuarray.ones(shape, dtype="float32")
+            assert bool(ones)
+            assert not bool(zeros)
+
+    def test_setitem_scalar(self):
+        a = gpuarray.zeros(5, "float64") + 42
+        np.testing.assert_allclose(a.get(), 42)
+        a[...] = 1729
+        np.testing.assert_allclose(a.get(), 1729)
+
 
 if __name__ == "__main__":
     # make sure that import failures get reported, instead of skipping the tests.