Do not import List, Dict, and Set by default (#2863)

Fix #999

This is a straightforward fix: List, Set, and Dict are treated as aliases to their builtins counterparts, therefore they are ignored by remove_imported_names_from_symtable, I fix this by also removing the alias names.

The fix also revealed few places in mypy where imports were missing, and one bug in fastparse.py. Those have been fixed.

The fix also includes a typeshed sync at  python/typeshed#933.

Author: ilevkivskyi

mypy/fastparse.py

@@ -398,7 +398,7 @@ def make_argument(arg: ast3.arg, default: Optional[ast3.expr], kind: int) -> Arg
                 if arg.annotation is not None:
                     arg_type = TypeConverter(self.errors, line=line).visit(arg.annotation)
                 elif arg.type_comment is not None:
-                    arg_type = parse_type_comment(arg.type_comment, arg.lineno, arg.col_offset)
+                    arg_type = parse_type_comment(arg.type_comment, arg.lineno, self.errors)
             return Argument(Var(arg.arg), arg_type, self.visit(default), kind)
 
         new_args = []

mypy/options.py

@@ -2,7 +2,7 @@
 import pprint
 import sys
 
-from typing import Any, Mapping, Optional, Tuple, List, Pattern
+from typing import Any, Mapping, Optional, Tuple, List, Pattern, Dict
 
 from mypy import defaults
 

mypy/semanal.py

@@ -253,6 +253,8 @@ def visit_file(self, file_node: MypyFile, fnam: str, options: Options) -> None:
 
         if self.cur_mod_id == 'builtins':
             remove_imported_names_from_symtable(self.globals, 'builtins')
+            for alias_name in ['List', 'Dict', 'Set']:
+                self.globals.pop(alias_name, None)
 
         if '__all__' in self.globals:
             for name, g in self.globals.items():

mypy/test/testgraph.py

@@ -1,6 +1,6 @@
 """Test cases for graph processing code in build.py."""
 
-from typing import AbstractSet, Dict, Set
+from typing import AbstractSet, Dict, Set, List
 
 from mypy.myunit import Suite, assert_equal
 from mypy.build import BuildManager, State, BuildSourceSet

mypy/typevars.py

@@ -1,4 +1,4 @@
-from typing import Union
+from typing import Union, List
 
 from mypy.nodes import TypeInfo
 

test-data/samples/crawl.py

@@ -16,7 +16,7 @@
 import sys
 import time
 import urllib.parse
-from typing import Any, Generator, IO, Optional, Sequence, Set, Tuple
+from typing import Any, Generator, IO, Optional, Sequence, Set, Tuple, List, Dict
 
 
 ARGS = argparse.ArgumentParser(description="Web crawler")

test-data/samples/crawl2.py

@@ -17,7 +17,7 @@
 import sys
 import time
 import urllib.parse
-from typing import Any, Awaitable, IO, Optional, Sequence, Set, Tuple
+from typing import Any, Awaitable, IO, Optional, Sequence, Set, Tuple, List, Dict
 
 
 ARGS = argparse.ArgumentParser(description="Web crawler")

test-data/unit/pythoneval.test

@@ -1147,7 +1147,7 @@ print(b.x + 1)
 4
 
 [case testInferenceWithLambda]
-from typing import TypeVar, Iterable, Iterator
+from typing import TypeVar, Iterable, Iterator, List
 import itertools
 
 _T = TypeVar('_T')