Merge remote-tracking branch 'm-labs/master' into spimaster

* m-labs/master:
  Fix tests.
  types.TypePrinter: don't waste screen space on empty attribute lists.
  Revert wrong parts of 6bd16e44.
  examples/notebook: cleanup, and fix spelling
  test/LoopbackCount: request correct devices

artiq/compiler/types.py

@@ -703,12 +703,15 @@ class TypePrinter(object):
         elif isinstance(typ, TInstance):
             if typ in self.recurse_guard or depth >= max_depth:
                 return "<instance {}>".format(typ.name)
-            else:
+            elif len(typ.attributes) > 0:
                 self.recurse_guard.add(typ)
                 attrs = ",\n\t\t".join(["{}: {}".format(attr, self.name(typ.attributes[attr],
                                                                         depth + 1))
                                       for attr in typ.attributes])
                 return "<instance {} {{\n\t\t{}\n\t}}>".format(typ.name, attrs)
+            else:
+                self.recurse_guard.add(typ)
+                return "<instance {} {{}}>".format(typ.name)
         elif isinstance(typ, TMono):
             if typ.params == {}:
                 return typ.name
@@ -745,12 +748,15 @@ class TypePrinter(object):
         elif isinstance(typ, (TConstructor, TExceptionConstructor)):
             if typ in self.recurse_guard or depth >= max_depth:
                 return "<constructor {}>".format(typ.name)
-            else:
+            elif len(typ.attributes) > 0:
                 self.recurse_guard.add(typ)
                 attrs = ", ".join(["{}: {}".format(attr, self.name(typ.attributes[attr],
                                                                    depth + 1))
                                    for attr in typ.attributes])
                 return "<constructor {} {{{}}}>".format(typ.name, attrs)
+            else:
+                self.recurse_guard.add(typ)
+                return "<constructor {} {{}}>".format(typ.name)
         elif isinstance(typ, TBuiltin):
             return "<builtin {}>".format(typ.name)
         elif isinstance(typ, TValue):

artiq/test/coredevice/test_rtio.py

@@ -104,7 +104,8 @@ class Watchdog(EnvExperiment):
 class LoopbackCount(EnvExperiment):
     def build(self):
         self.setattr_device("core")
-        self.setattr_device("ttl_inout")
+        self.setattr_device("loop_in")
+        self.setattr_device("loop_out")
         self.setattr_argument("npulses")
 
     def set_count(self, count):

artiq/test/lit/inferencer/error_with_self.py

@@ -11,7 +11,7 @@ class contextmgr:
 def foo():
     contextmgr.__enter__(1)
     # CHECK-L: ${LINE:+3}: error: cannot unify <instance contextmgr> with int(width='a) while inferring the type for self argument
-    # CHECK-L: ${LINE:+2}: note: expression of type <instance contextmgr>
+    # CHECK-L: ${LINE:+2}: note: expression of type <instance contextmgr {}>
     # CHECK-L: ${LINE:+1}: note: reference to an instance with a method '__enter__(self:int(width='a))->NoneType delay('b)'
     with contextmgr():
         pass