Don't catch IndexError where we don't have to

jedi/evaluate/base_context.py

@@ -12,6 +12,8 @@ from jedi import debug
 from jedi._compatibility import Python3Method, zip_longest, unicode
 from jedi.parser_utils import clean_scope_docstring, get_doc_with_call_signature
 from jedi.common import BaseContextSet, BaseContext
+from jedi.evaluate.helpers import EvaluatorIndexError, EvaluatorTypeError, \
+    EvaluatorKeyError
 
 
 class Context(BaseContext):
@@ -128,11 +130,15 @@ class Context(BaseContext):
             else:
                 try:
                     result |= getitem(index)
-                except IndexError:
+                except EvaluatorIndexError:
                     result |= iterate_contexts(ContextSet(self))
-                except KeyError:
+                except EvaluatorKeyError:
                     # Must be a dict. Lists don't raise KeyErrors.
                     result |= self.dict_values()
+                except EvaluatorTypeError:
+                    # The type is wrong and therefore it makes no sense to do
+                    # anything anymore.
+                    result = NO_CONTEXTS
         return result
 
     def eval_node(self, node):

jedi/evaluate/compiled/context.py

@@ -13,6 +13,7 @@ from jedi.evaluate.base_context import Context, ContextSet
 from jedi.evaluate.lazy_context import LazyKnownContext
 from jedi.evaluate.compiled.access import _sentinel
 from jedi.evaluate.cache import evaluator_function_cache
+from jedi.evaluate.helpers import reraise_as_evaluator
 from . import fake
 
 
@@ -145,6 +146,7 @@ class CompiledObject(Context):
 
     @CheckAttribute
     def py__getitem__(self, index):
+        with reraise_as_evaluator(IndexError, KeyError, TypeError):
             access = self.access_handle.py__getitem__(index)
         if access is None:
             return ContextSet()

jedi/evaluate/context/iterable.py

@@ -30,7 +30,8 @@ from jedi.evaluate import recursion
 from jedi.evaluate.lazy_context import LazyKnownContext, LazyKnownContexts, \
     LazyTreeContext
 from jedi.evaluate.helpers import get_int_or_none, is_string, \
-    predefine_names, evaluate_call_of_leaf
+    predefine_names, evaluate_call_of_leaf, reraise_as_evaluator, \
+    EvaluatorKeyError
 from jedi.evaluate.utils import safe_property
 from jedi.evaluate.utils import to_list
 from jedi.evaluate.cache import evaluator_method_cache
@@ -219,7 +220,9 @@ class ListComprehension(ComprehensionMixin, Sequence):
             return ContextSet(self)
 
         all_types = list(self.py__iter__())
-        return all_types[index].infer()
+        with reraise_as_evaluator(IndexError, TypeError):
+            lazy_context = all_types[index]
+        return lazy_context.infer()
 
 
 class SetComprehension(ComprehensionMixin, Sequence):
@@ -293,13 +296,15 @@ class SequenceLiteralContext(Sequence):
                     if isinstance(k, compiled.CompiledObject) \
                             and k.execute_operation(compiled_obj_index, u'==').get_safe_value():
                         return self._defining_context.eval_node(value)
-            raise KeyError('No key found in dictionary %s.' % self)
+            raise EvaluatorKeyError('No key found in dictionary %s.' % self)
 
         # Can raise an IndexError
         if isinstance(index, slice):
             return ContextSet(self)
         else:
-            return self._defining_context.eval_node(self._items()[index])
+            with reraise_as_evaluator(TypeError, KeyError, IndexError):
+                node = self._items()[index]
+            return self._defining_context.eval_node(node)
 
     def py__iter__(self):
         """
@@ -413,7 +418,9 @@ class FakeSequence(_FakeArray):
         self._lazy_context_list = lazy_context_list
 
     def py__getitem__(self, index):
-        return self._lazy_context_list[index].infer()
+        with reraise_as_evaluator(IndexError, TypeError):
+            lazy_context = self._lazy_context_list[index]
+        return lazy_context.infer()
 
     def py__iter__(self):
         return self._lazy_context_list
@@ -450,7 +457,9 @@ class FakeDict(_FakeArray):
                 except KeyError:
                     pass
 
-        return self._dct[index].infer()
+        with reraise_as_evaluator(KeyError):
+            lazy_context = self._dct[index]
+        return lazy_context.infer()
 
     @publish_method('values')
     def _values(self):

jedi/evaluate/helpers.py

@@ -9,7 +9,6 @@ from parso.python import tree
 
 from jedi._compatibility import unicode
 from jedi.parser_utils import get_parent_scope
-from jedi.evaluate.compiled import CompiledObject
 
 
 def is_stdlib_path(path):
@@ -184,6 +183,7 @@ def predefine_names(context, flow_scope, dct):
 
 
 def is_compiled(context):
+    from jedi.evaluate.compiled import CompiledObject
     return isinstance(context, CompiledObject)
 
 
@@ -212,3 +212,24 @@ def get_int_or_none(context):
 
 def is_number(context):
     return _get_safe_value_or_none(context, (int, float)) is not None
+
+
+class EvaluatorTypeError(Exception):
+    pass
+
+
+class EvaluatorIndexError(Exception):
+    pass
+
+
+class EvaluatorKeyError(Exception):
+    pass
+
+
+@contextmanager
+def reraise_as_evaluator(*exception_classes):
+    try:
+        yield
+    except exception_classes as e:
+        new_exc_cls = globals()['Evaluator' + e.__class__.__name__]
+        raise new_exc_cls(e)

test/completion/arrays.py

@@ -29,6 +29,9 @@ b = [6,7]
 
 #? int()
 b[8-7]
+# Something unreasonable:
+#?
+b['']
 
 # -----------------
 # Slices