diff --git a/jedi/api/__init__.py b/jedi/api/__init__.py
index 3d204a01..7750c244 100644
--- a/jedi/api/__init__.py
+++ b/jedi/api/__init__.py
@@ -13,7 +13,6 @@ import os
 import warnings
 import sys
 
-from jedi._compatibility import unicode
 from jedi.parser import load_grammar
 from jedi.parser import tree
 from jedi.parser.fast import FastParser
@@ -195,7 +194,7 @@ class Script(object):
             if leaf is None:
                 return []
 
-        context = self._evaluator.create_context(self._get_module(), leaf.parent)
+        context = self._evaluator.create_context(self._get_module(), leaf)
         definitions = helpers.evaluate_goto_definition(self._evaluator, context, leaf)
 
         names = [s.name for s in definitions]
@@ -328,11 +327,12 @@ class Script(object):
         self._evaluator.analysis_modules = [module_node]
         try:
             for node in module_node.nodes_to_execute():
+                context = self._get_module().create_context(node)
                 if node.type in ('funcdef', 'classdef'):
-                    if node.type == 'classdef':
-                        continue
-                        raise NotImplementedError
-                    er.Function(self._evaluator, node).get_decorated_func()
+                    # TODO This is stupid, should be private
+                    from jedi.evaluate.finder import _name_to_types
+                    # Resolve the decorators.
+                    _name_to_types(self._evaluator, context, node.children[1])
                 elif isinstance(node, tree.Import):
                     import_names = set(node.get_defined_names())
                     if node.is_nested():
@@ -340,12 +340,12 @@ class Script(object):
                     for n in import_names:
                         imports.ImportWrapper(context, n).follow()
                 elif node.type == 'expr_stmt':
-                    types = self._evaluator.eval_element(node)
+                    types = context.eval_node(node)
                     for testlist in node.children[:-1:2]:
                         # Iterate tuples.
                         unpack_tuple_to_dict(self._evaluator, types, testlist)
                 else:
-                    try_iter_content(self._evaluator.goto_definitions(node))
+                    try_iter_content(self._evaluator.goto_definitions(context, node))
                 self._evaluator.reset_recursion_limitations()
 
             ana = [a for a in self._evaluator.analysis if self.path == a.path]
diff --git a/jedi/api/classes.py b/jedi/api/classes.py
index 0380d544..b86ce09d 100644
--- a/jedi/api/classes.py
+++ b/jedi/api/classes.py
@@ -133,7 +133,7 @@ class BaseDefinition(object):
         >>> defs = sorted(defs, key=lambda d: d.line)
         >>> defs                           # doctest: +NORMALIZE_WHITESPACE
         [<Definition module keyword>, <Definition class C>,
-         <Definition class D>, <Definition def f>]
+         <Definition instance D>, <Definition def f>]
 
         Finally, here is what you can get from :attr:`type`:
 
@@ -489,7 +489,7 @@ class Completion(BaseDefinition):
         return '%s: %s%s' % (t, desc, line)
 
     def __repr__(self):
-        return '<%s: %s>' % (type(self).__name__, self._name)
+        return '<%s: %s>' % (type(self).__name__, self._name.string_name)
 
     @memoize_method
     def _follow_statements_imports(self):
@@ -556,7 +556,7 @@ class Definition(BaseDefinition):
         """
         typ = self.type
         tree_name = self._name.tree_name
-        if typ in ('function', 'class', 'module') or tree_name is None:
+        if typ in ('function', 'class', 'module', 'instance') or tree_name is None:
             if typ == 'function':
                 # For the description we want a short and a pythonic way.
                 typ = 'def'
@@ -743,8 +743,8 @@ class CallSignature(Definition):
         return self._executable.get_parent_until()
 
     def __repr__(self):
-        return '<%s: %s index %s>' % (type(self).__name__, self._name,
-                                      self.index)
+        return '<%s: %s index %s>' % \
+            (type(self).__name__, self._name.string_name, self.index)
 
 
 class _Param(Definition):
diff --git a/jedi/api/usages.py b/jedi/api/usages.py
index b404d97e..9519c0b1 100644
--- a/jedi/api/usages.py
+++ b/jedi/api/usages.py
@@ -9,19 +9,31 @@ def usages(evaluator, definition_names, mods):
     """
     :param definitions: list of Name
     """
+    def resolve_names(definition_names):
+        for name in definition_names:
+            if name.api_type == 'module':
+                found = False
+                for context in name.infer():
+                    found = True
+                    yield context.name
+                if not found:
+                    yield name
+            else:
+                yield name
+
     def compare_array(definition_names):
         """ `definitions` are being compared by module/start_pos, because
         sometimes the id's of the objects change (e.g. executions).
         """
         return [
-            (d.get_root_context(), d.start_pos)
-            for d in definition_names
+            (name.get_root_context(), name.start_pos)
+            for name in resolve_names(definition_names)
         ]
 
     search_name = list(definition_names)[0].string_name
     compare_definitions = compare_array(definition_names)
     mods = mods | set([d.get_root_context() for d in definition_names])
-    definition_names = set(definition_names)
+    definition_names = set(resolve_names(definition_names))
     for m in imports.get_modules_containing_name(evaluator, mods, search_name):
         if isinstance(m, ModuleContext):
             for name_node in m.module_node.used_names.get(search_name, []):
diff --git a/jedi/evaluate/__init__.py b/jedi/evaluate/__init__.py
index 80a6eade..3e251319 100644
--- a/jedi/evaluate/__init__.py
+++ b/jedi/evaluate/__init__.py
@@ -169,10 +169,10 @@ class Evaluator(object):
                     dct = {str(for_stmt.children[1]): lazy_context.infer()}
                     with helpers.predefine_names(context, for_stmt, dct):
                         t = self.eval_element(context, rhs)
-                        left = precedence.calculate(self, left, operator, t)
+                        left = precedence.calculate(self, context, left, operator, t)
                 types = left
             else:
-                types = precedence.calculate(self, left, operator, types)
+                types = precedence.calculate(self, context, left, operator, types)
         debug.dbg('eval_statement result %s', types)
         return types
 
@@ -180,9 +180,16 @@ class Evaluator(object):
         if isinstance(context, iterable.CompForContext):
             return self._eval_element_not_cached(context, element)
 
-        if_stmt = element.get_parent_until((tree.IfStmt, tree.ForStmt, tree.IsScope))
+        if_stmt = element
+        while if_stmt is not None:
+            if_stmt = if_stmt.parent
+            if if_stmt.type in ('if_stmt', 'for_stmt'):
+                break
+            if if_stmt.is_scope():
+                if_stmt = None
+                break
         predefined_if_name_dict = context.predefined_names.get(if_stmt)
-        if predefined_if_name_dict is None and isinstance(if_stmt, tree.IfStmt):
+        if predefined_if_name_dict is None and if_stmt and if_stmt.type == 'if_stmt':
             if_stmt_test = if_stmt.children[1]
             name_dicts = [{}]
             # If we already did a check, we don't want to do it again -> If
@@ -274,7 +281,7 @@ class Evaluator(object):
             for trailer in element.children[1:]:
                 if trailer == '**':  # has a power operation.
                     right = self.eval_element(context, element.children[2])
-                    types = set(precedence.calculate(self, types, trailer, right))
+                    types = set(precedence.calculate(self, context, types, trailer, right))
                     break
                 types = self.eval_trailer(context, types, trailer)
         elif element.type in ('testlist_star_expr', 'testlist',):
@@ -344,7 +351,7 @@ class Evaluator(object):
                 types = self._eval_atom(context, c[0])
                 for string in c[1:]:
                     right = self._eval_atom(context, string)
-                    types = precedence.calculate(self, types, '+', right)
+                    types = precedence.calculate(self, context, types, '+', right)
                 return types
             # Parentheses without commas are not tuples.
             elif c[0] == '(' and not len(c) == 2 \
@@ -491,11 +498,6 @@ class Evaluator(object):
             # a name it's something you can "goto" again.
             return [TreeNameDefinition(context, name)]
         elif isinstance(par, (tree.Param, tree.Function, tree.Class)) and par.name is name:
-            if par.type in ('funcdef', 'classdef', 'module'):
-                if par.type == 'funcdef':
-                    return [context.function_context.name]
-                else:
-                    return [context.name]
             return [TreeNameDefinition(context, name)]
         elif isinstance(stmt, tree.Import):
             module_names = imports.ImportWrapper(context, name).follow(is_goto=True)
@@ -600,5 +602,9 @@ class Evaluator(object):
         if node_is_context and node.is_scope():
             scope_node = node
         else:
+            if node.parent.type in ('funcdef', 'classdef'):
+                # When we're on class/function names/leafs that define the
+                # object itself and not its contents.
+                node = node.parent
             scope_node = parent_scope(node)
         return from_scope_node(scope_node)
diff --git a/jedi/evaluate/analysis.py b/jedi/evaluate/analysis.py
index dfbb6d97..8c75cf5d 100644
--- a/jedi/evaluate/analysis.py
+++ b/jedi/evaluate/analysis.py
@@ -58,8 +58,8 @@ class Error(object):
         return self.__unicode__()
 
     def __eq__(self, other):
-        return (self.path == other.path and self.name == other.name
-                and self._start_pos == other._start_pos)
+        return (self.path == other.path and self.name == other.name and
+                self._start_pos == other._start_pos)
 
     def __ne__(self, other):
         return not self.__eq__(other)
@@ -77,23 +77,19 @@ class Warning(Error):
     pass
 
 
-def add(evaluator, name, jedi_obj, message=None, typ=Error, payload=None):
+def add(context, name, jedi_name, message=None, typ=Error, payload=None):
     return
-    from jedi.evaluate.iterable import MergedNodes
-    while isinstance(jedi_obj, MergedNodes):
-        if len(jedi_obj) != 1:
-            # TODO is this kosher?
-            return
-        jedi_obj = list(jedi_obj)[0]
-
+    from jedi.evaluate import Evaluator
+    if isinstance(context, Evaluator):
+        raise 1
     exception = CODES[name][1]
-    if _check_for_exception_catch(evaluator, jedi_obj, exception, payload):
+    if _check_for_exception_catch(context, jedi_name, exception, payload):
         return
 
-    module_path = jedi_obj.get_parent_until().path
-    instance = typ(name, module_path, jedi_obj.start_pos, message)
+    module_path = jedi_name.get_root_node().path
+    instance = typ(name, module_path, jedi_name.start_pos, message)
     debug.warning(str(instance), format=False)
-    evaluator.analysis.append(instance)
+    context.evaluator.analysis.append(instance)
 
 
 def _check_for_setattr(instance):
@@ -114,25 +110,29 @@ def _check_for_setattr(instance):
                for stmt in stmts)
 
 
-def add_attribute_error(evaluator, scope, name):
-    message = ('AttributeError: %s has no attribute %s.' % (scope, name))
-    from jedi.evaluate.instance import AbstractInstanceContext
+def add_attribute_error(context, name):
+    message = ('AttributeError: %s has no attribute %s.' % (context, name))
+    from jedi.evaluate.instance import AbstractInstanceContext, CompiledInstanceName
     # Check for __getattr__/__getattribute__ existance and issue a warning
     # instead of an error, if that happens.
-    if isinstance(scope, AbstractInstanceContext):
-        typ = Warning
-        if not (scope.get_function_slot_names('__getattr__') or
-                scope.get_function_slot_names('__getattribute__')):
-            if not _check_for_setattr(scope):
-                typ = Error
-    else:
-        typ = Error
+    typ = Error
+    if isinstance(context, AbstractInstanceContext):
+        slot_names = context.get_function_slot_names('__getattr__') + \
+            context.get_function_slot_names('__getattribute__')
+        for n in slot_names:
+            if isinstance(name, CompiledInstanceName) and \
+                    n.parent_context.obj == object:
+                typ = Warning
+                break
 
-    payload = scope, name
-    add(evaluator, 'attribute-error', name, message, typ, payload)
+        if _check_for_setattr(context):
+            typ = Warning
+
+    payload = context, name
+    add(context, 'attribute-error', name, message, typ, payload)
 
 
-def _check_for_exception_catch(evaluator, jedi_obj, exception, payload=None):
+def _check_for_exception_catch(context, jedi_name, exception, payload=None):
     """
     Checks if a jedi object (e.g. `Statement`) sits inside a try/catch and
     doesn't count as an error (if equal to `exception`).
@@ -153,17 +153,18 @@ def _check_for_exception_catch(evaluator, jedi_obj, exception, payload=None):
             colon = next(iterator)
             suite = next(iterator)
             if branch_type == 'try' \
-                    and not (branch_type.start_pos < jedi_obj.start_pos <= suite.end_pos):
+                    and not (branch_type.start_pos < jedi_name.start_pos <= suite.end_pos):
                 return False
 
         for node in obj.except_clauses():
             if node is None:
                 return True  # An exception block that catches everything.
             else:
-                except_classes = evaluator.eval_element(node)
+                except_classes = context.eval_node(node)
                 for cls in except_classes:
                     from jedi.evaluate import iterable
-                    if isinstance(cls, iterable.Array) and cls.type == 'tuple':
+                    if isinstance(cls, iterable.AbstractSequence) and \
+                            cls.array_type == 'tuple':
                         # multiple exceptions
                         for typ in unite(cls.py__iter__()):
                             if check_match(typ, exception):
@@ -174,7 +175,7 @@ def _check_for_exception_catch(evaluator, jedi_obj, exception, payload=None):
 
     def check_hasattr(node, suite):
         try:
-            assert suite.start_pos <= jedi_obj.start_pos < suite.end_pos
+            assert suite.start_pos <= jedi_name.start_pos < suite.end_pos
             assert node.type in ('power', 'atom_expr')
             base = node.children[0]
             assert base.type == 'name' and base.value == 'hasattr'
@@ -183,28 +184,28 @@ def _check_for_exception_catch(evaluator, jedi_obj, exception, payload=None):
             arglist = trailer.children[1]
             assert arglist.type == 'arglist'
             from jedi.evaluate.param import Arguments
-            args = list(Arguments(evaluator, arglist).unpack())
+            args = list(Arguments(context, arglist).unpack())
             # Arguments should be very simple
             assert len(args) == 2
 
             # Check name
             key, values = args[1]
             assert len(values) == 1
-            names = list(evaluator.eval_element(values[0]))
+            names = list(context.eval_node(values[0]))
             assert len(names) == 1 and isinstance(names[0], CompiledObject)
             assert names[0].obj == str(payload[1])
 
             # Check objects
             key, values = args[0]
             assert len(values) == 1
-            objects = evaluator.eval_element(values[0])
+            objects = context.eval_node(values[0])
             return payload[0] in objects
         except AssertionError:
             return False
 
-    obj = jedi_obj
-    while obj is not None and not obj.isinstance(tree.Function, tree.Class):
-        if obj.isinstance(tree.Flow):
+    obj = jedi_name
+    while obj is not None and not isinstance(obj, (tree.Function, tree.Class)):
+        if isinstance(obj, tree.Flow):
             # try/except catch check
             if obj.isinstance(tree.TryStmt) and check_try_for_except(obj, exception):
                 return True
diff --git a/jedi/evaluate/finder.py b/jedi/evaluate/finder.py
index 2fbe7f48..18987de6 100644
--- a/jedi/evaluate/finder.py
+++ b/jedi/evaluate/finder.py
@@ -14,9 +14,7 @@ would check whether a flow has the form of ``if isinstance(a, type_or_tuple)``.
 Unfortunately every other thing is being ignored (e.g. a == '' would be easy to
 check for -> a is a string). There's big potential in these checks.
 """
-from itertools import chain
 
-from jedi._compatibility import unicode
 from jedi.parser import tree
 from jedi import debug
 from jedi.common import unite
@@ -33,9 +31,7 @@ from jedi.evaluate import analysis
 from jedi.evaluate import flow_analysis
 from jedi.evaluate import param
 from jedi.evaluate import helpers
-from jedi.evaluate.context import TreeContext
-from jedi.evaluate.cache import memoize_default
-from jedi.evaluate.filters import get_global_filters, ContextName
+from jedi.evaluate.filters import get_global_filters, TreeNameDefinition
 
 
 def filter_after_position(names, position, origin=None):
@@ -128,22 +124,22 @@ class NameFinder(object):
                          isinstance(self._name.parent.parent, tree.Param)):
             if isinstance(self._name, tree.Name):
                 if attribute_lookup:
-                    analysis.add_attribute_error(self._evaluator,
-                                                 self._context, self._name)
+                    analysis.add_attribute_error(self._context, self._name)
                 else:
                     message = ("NameError: name '%s' is not defined."
                                % self._string_name)
-                    analysis.add(self._evaluator, 'name-error', self._name,
-                                 message)
+                    analysis.add(self._context, 'name-error', self._name, message)
 
         return types
 
-    def get_filters(self, search_global=False):
+    def _get_origin_scope(self):
         if isinstance(self._name, tree.Name):
-            origin_scope = self._name.get_parent_until(tree.Scope, reverse=True)
+            return self._name.get_parent_until(tree.Scope, reverse=True)
         else:
-            origin_scope = None
+            return None
 
+    def get_filters(self, search_global=False):
+        origin_scope = self._get_origin_scope()
         if search_global:
             return get_global_filters(self._evaluator, self._context, self._position, origin_scope)
         else:
@@ -321,15 +317,17 @@ class NameFinder(object):
         # Add isinstance and other if/assert knowledge.
         if not types and isinstance(self._name, tree.Name) and \
                 not isinstance(self._name_context, AbstractInstanceContext):
-            # Ignore FunctionExecution parents for now.
             flow_scope = self._name
+            base_node = self._name_context.get_node()
+            if base_node.type == 'comp_for':
+                return types
             while True:
                 flow_scope = flow_scope.get_parent_scope(include_flows=True)
                 n = _check_flow_information(self._name_context, flow_scope,
                                             self._name, self._position)
                 if n is not None:
                     return n
-                if flow_scope == self._name_context.get_node():
+                if flow_scope == base_node:
                     break
         return types
 
diff --git a/jedi/evaluate/flow_analysis.py b/jedi/evaluate/flow_analysis.py
index 2bdd5ab5..a20843db 100644
--- a/jedi/evaluate/flow_analysis.py
+++ b/jedi/evaluate/flow_analysis.py
@@ -1,6 +1,3 @@
-from jedi.parser import tree
-
-
 class Status(object):
     lookup_table = {}
 
diff --git a/jedi/evaluate/imports.py b/jedi/evaluate/imports.py
index d7c8efa7..a4798d90 100644
--- a/jedi/evaluate/imports.py
+++ b/jedi/evaluate/imports.py
@@ -147,10 +147,10 @@ class NestedImportModule(tree.Module):
                                    self._nested_import)
 
 
-def _add_error(evaluator, name, message=None):
+def _add_error(context, name, message=None):
+    # Should be a name, not a string!
     if hasattr(name, 'parent'):
-        # Should be a name, not a string!
-        analysis.add(evaluator, 'import-error', name, message)
+        analysis.add(context, 'import-error', name, message)
 
 
 def get_init_path(directory_path):
@@ -168,25 +168,21 @@ def get_init_path(directory_path):
 class ImportName(AbstractNameDefinition):
     start_pos = (1, 0)
 
-    def __init__(self, parent_module, string_name):
-        self.parent_module = parent_module
+    def __init__(self, parent_context, string_name):
+        self.parent_context = parent_context
         self.string_name = string_name
 
     def infer(self):
         return Importer(
-            self.parent_module.evaluator,
+            self.parent_context.evaluator,
             [self.string_name],
-            self.parent_module,
+            self.parent_context,
         ).follow()
 
     def get_root_context(self):
         # Not sure if this is correct.
         return self.parent_context.get_root_context()
 
-    @property
-    def parent_context(self):
-        return self.parent_module
-
     @property
     def api_type(self):
         return 'module'
@@ -195,18 +191,12 @@ class ImportName(AbstractNameDefinition):
 class SubModuleName(ImportName):
     def infer(self):
         return Importer(
-            self.parent_module.evaluator,
+            self.parent_context.evaluator,
             [self.string_name],
-            self.parent_module,
+            self.parent_context,
             level=1
         ).follow()
 
-    @property
-    def parent_context(self):
-        # This is a bit of a special case. But it seems like it's working well.
-        # Since a SubModuleName is basically a lazy name to a module
-        return next(iter(self.infer()))
-
 
 class Importer(object):
     def __init__(self, evaluator, import_path, module_context, level=0):
@@ -249,7 +239,7 @@ class Importer(object):
                     if dir_name:
                         import_path.insert(0, dir_name)
                     else:
-                        _add_error(self._evaluator, import_path[-1])
+                        _add_error(module_context, import_path[-1])
                         import_path = []
                         # TODO add import error.
                         debug.warning('Attempted relative import beyond top-level package.')
@@ -336,7 +326,7 @@ class Importer(object):
                 method = parent_module.py__path__
             except AttributeError:
                 # The module is not a package.
-                _add_error(self._evaluator, import_path[-1])
+                _add_error(parent_module, import_path[-1])
                 return set()
             else:
                 paths = method()
@@ -351,7 +341,7 @@ class Importer(object):
                     except ImportError:
                         module_path = None
                 if module_path is None:
-                    _add_error(self._evaluator, import_path[-1])
+                    _add_error(parent_module, import_path[-1])
                     return set()
         else:
             parent_module = None
@@ -367,7 +357,7 @@ class Importer(object):
                     sys.path = temp
             except ImportError:
                 # The module is not a package.
-                _add_error(self._evaluator, import_path[-1])
+                _add_error(parent_module, import_path[-1])
                 return set()
 
         source = None
diff --git a/jedi/evaluate/param.py b/jedi/evaluate/param.py
index 5534a4a2..347895e3 100644
--- a/jedi/evaluate/param.py
+++ b/jedi/evaluate/param.py
@@ -63,11 +63,9 @@ class AbstractArguments():
         Evaluates all arguments as a support for static analysis
         (normally Jedi).
         """
-        raise DeprecationWarning
-        for key, element_values in self.unpack():
-            for element in element_values:
-                types = self._evaluator.eval_element(self.context, element)
-                try_iter_content(types)
+        for key, lazy_context in self.unpack():
+            types = lazy_context.infer()
+            try_iter_content(types)
 
 
 class TreeArguments(AbstractArguments):
@@ -260,7 +258,7 @@ def get_params(evaluator, parent_context, func, var_args):
                          % (func.name, key))
                     calling_va = _get_calling_var_args(evaluator, var_args)
                     if calling_va is not None:
-                        analysis.add(evaluator, 'type-error-multiple-values',
+                        analysis.add(parent_context, 'type-error-multiple-values',
                                      calling_va, message=m)
                 else:
                     keys_used[key] = ExecutedParam(parent_context, key_param, var_args, argument)
@@ -302,7 +300,7 @@ def get_params(evaluator, parent_context, func, var_args):
                     calling_va = var_args.get_calling_var_args()
                     if calling_va is not None:
                         m = _error_argument_count(func, len(unpacked_va))
-                        analysis.add(evaluator, 'type-error-too-few-arguments',
+                        analysis.add(parent_context, 'type-error-too-few-arguments',
                                      calling_va, message=m)
             else:
                 result_arg = argument
@@ -323,13 +321,13 @@ def get_params(evaluator, parent_context, func, var_args):
                 calling_va = _get_calling_var_args(evaluator, var_args)
                 if calling_va is not None:
                     m = _error_argument_count(func, len(unpacked_va))
-                    analysis.add(evaluator, 'type-error-too-few-arguments',
+                    analysis.add(parent_context, 'type-error-too-few-arguments',
                                  calling_va, message=m)
 
     for key, argument in non_matching_keys.items():
         m = "TypeError: %s() got an unexpected keyword argument '%s'." \
             % (func.name, key)
-        analysis.add(evaluator, 'type-error-keyword-argument', argument.whatever, message=m)
+        analysis.add(parent_context, 'type-error-keyword-argument', argument.whatever, message=m)
 
     remaining_arguments = list(var_arg_iterator)
     if remaining_arguments:
@@ -354,7 +352,7 @@ def get_params(evaluator, parent_context, func, var_args):
                     # print('\t\tnonkw', non_kw_param.parent.var_args.argument_node, )
                     if origin_args not in [f.parent.parent for f in first_values]:
                         continue
-            analysis.add(evaluator, 'type-error-too-many-arguments',
+            analysis.add(parent_context, 'type-error-too-many-arguments',
                          v, message=m)
     return result_params
 
diff --git a/jedi/evaluate/precedence.py b/jedi/evaluate/precedence.py
index ae8e274f..51c5c94c 100644
--- a/jedi/evaluate/precedence.py
+++ b/jedi/evaluate/precedence.py
@@ -59,13 +59,13 @@ def calculate_children(evaluator, context, children):
                     types = context.eval_node(right)
             # Otherwise continue, because of uncertainty.
         else:
-            types = calculate(evaluator, types, operator,
+            types = calculate(evaluator, context, types, operator,
                               context.eval_node(right))
     debug.dbg('calculate_children types %s', types)
     return types
 
 
-def calculate(evaluator, left_result, operator, right_result):
+def calculate(evaluator, context, left_result, operator, right_result):
     result = set()
     if not left_result or not right_result:
         # illegal slices e.g. cause left/right_result to be None
@@ -80,7 +80,7 @@ def calculate(evaluator, left_result, operator, right_result):
         else:
             for left in left_result:
                 for right in right_result:
-                    result |= _element_calculate(evaluator, left, operator, right)
+                    result |= _element_calculate(evaluator, context, left, operator, right)
     return result
 
 
@@ -125,7 +125,7 @@ def _is_list(obj):
     return isinstance(obj, iterable.AbstractSequence) and obj.array_type == 'list'
 
 
-def _element_calculate(evaluator, left, operator, right):
+def _element_calculate(evaluator, context, left, operator, right):
     from jedi.evaluate import iterable, instance
     l_is_num = _is_number(left)
     r_is_num = _is_number(right)
@@ -173,7 +173,7 @@ def _element_calculate(evaluator, left, operator, right):
     if operator in ('+', '-') and l_is_num != r_is_num \
             and not (check(left) or check(right)):
         message = "TypeError: unsupported operand type(s) for +: %s and %s"
-        analysis.add(evaluator, 'type-error-operation', operator,
+        analysis.add(context, 'type-error-operation', operator,
                      message % (left, right))
 
     return set([left, right])
diff --git a/jedi/evaluate/stdlib.py b/jedi/evaluate/stdlib.py
index cfe8dee9..6617049d 100644
--- a/jedi/evaluate/stdlib.py
+++ b/jedi/evaluate/stdlib.py
@@ -58,11 +58,11 @@ def execute(evaluator, obj, arguments):
 
 def _follow_param(evaluator, arguments, index):
     try:
-        key, values = list(arguments.unpack())[index]
+        key, lazy_context = list(arguments.unpack())[index]
     except IndexError:
         return set()
     else:
-        return unite(evaluator.eval_element(v) for v in values)
+        return lazy_context.infer()
 
 
 def argument_clinic(string, want_obj=False, want_context=False, want_arguments=False):
@@ -219,7 +219,7 @@ def builtins_isinstance(evaluator, objects, types, arguments):
                 message = 'TypeError: isinstance() arg 2 must be a ' \
                           'class, type, or tuple of classes and types, ' \
                           'not %s.' % cls_or_tup
-                analysis.add(evaluator, 'type-error-isinstance', node, message)
+                analysis.add(cls_or_tup, 'type-error-isinstance', node, message)
 
     return set(compiled.create(evaluator, x) for x in bool_results)
 
@@ -244,11 +244,12 @@ def collections_namedtuple(evaluator, obj, arguments):
     _fields = list(_follow_param(evaluator, arguments, 1))[0]
     if isinstance(_fields, compiled.CompiledObject):
         fields = _fields.obj.replace(',', ' ').split()
-    elif isinstance(_fields, iterable.Array):
-        try:
-            fields = [v.obj for v in unite(_fields.py__iter__())]
-        except AttributeError:
-            return set()
+    elif isinstance(_fields, iterable.AbstractSequence):
+        fields = [
+            v.obj
+            for lazy_context in _fields.py__iter__()
+            for v in lazy_context.infer() if hasattr(v, 'obj')
+        ]
     else:
         return set()
 
@@ -265,7 +266,7 @@ def collections_namedtuple(evaluator, obj, arguments):
 
     # Parse source
     generated_class = ParserWithRecovery(evaluator.grammar, unicode(source)).module.subscopes[0]
-    return set([er.Class(evaluator, generated_class)])
+    return set([er.ClassContext(evaluator, generated_class, evaluator.BUILTINS)])
 
 
 @argument_clinic('first, /')
diff --git a/test/conftest.py b/test/conftest.py
index ac04e268..56193a7d 100644
--- a/test/conftest.py
+++ b/test/conftest.py
@@ -71,9 +71,12 @@ def pytest_generate_tests(metafunc):
 
     if 'static_analysis_case' in metafunc.fixturenames:
         base_dir = os.path.join(os.path.dirname(__file__), 'static_analysis')
+        cases = list(collect_static_analysis_tests(base_dir, test_files))
         metafunc.parametrize(
             'static_analysis_case',
-            collect_static_analysis_tests(base_dir, test_files))
+            cases,
+            ids=[c.name for c in cases]
+        )
 
 
 def collect_static_analysis_tests(base_dir, test_files):
@@ -91,6 +94,7 @@ class StaticAnalysisCase(object):
     """
     def __init__(self, path):
         self._path = path
+        self.name = os.path.basename(path)
         with open(path) as f:
             self._source = f.read()
 
@@ -98,7 +102,6 @@ class StaticAnalysisCase(object):
         for line in self._source.splitlines():
             self.skip = self.skip or run.skip_python_version(line)
 
-
     def collect_comparison(self):
         cases = []
         for line_nr, line in enumerate(self._source.splitlines(), 1):