Commit missing parts of a5bb4a24.

artiq/compiler/transforms/artiq_ir_generator.py

@@ -599,7 +599,7 @@ class ARTIQIRGenerator(algorithm.Visitor):
                 self.append(ir.Reraise())
 
     def visit_Raise(self, node):
-        if types.is_exn_constructor(node.exc.type):
+        if node.exc is not None and types.is_exn_constructor(node.exc.type):
             self.raise_exn(self.alloc_exn(node.exc.type.instance), loc=self.current_loc)
         else:
             self.raise_exn(self.visit(node.exc), loc=self.current_loc)

artiq/test/lit/exceptions/error_raise_class.py

@@ -1,5 +0,0 @@
-# RUN: %python -m artiq.compiler.testbench.signature +diag %s >%t
-# RUN: OutputCheck %s --file-to-check=%t
-
-# CHECK-L: ${LINE:+1}: note: this value is an exception constructor; use IndexError() instead
-raise IndexError