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Require nonlocal names to be bound in an outer scope.

This commit is contained in:
whitequark 2015-05-30 08:06:19 +03:00
parent 56d1a9bc57
commit f979a76c7c
1 changed files with 16 additions and 2 deletions

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@ -4,8 +4,9 @@ from . import asttyped, types
# This visitor will be called for every node with a scope,
# i.e.: class, function, comprehension, lambda
class LocalExtractor(algorithm.Visitor):
def __init__(self, engine):
def __init__(self, env_stack, engine):
super().__init__()
self.env_stack = env_stack
self.engine = engine
self.in_root = False
@ -103,6 +104,19 @@ class LocalExtractor(algorithm.Visitor):
for name, loc in zip(node.names, node.name_locs):
self._check_not_in(name, self.global_, 'global', 'nonlocal', loc)
self._check_not_in(name, self.params, 'a parameter', 'nonlocal', loc)
found = False
for outer_env in reversed(self.env_stack):
if name in outer_env:
found = True
break
if not found:
diag = diagnostic.Diagnostic('fatal',
"can't declare name '{name}' as nonlocal: it is not bound in any outer scope",
{"name": name},
loc, [node.keyword_loc])
self.engine.process(diag)
self.nonlocal_.add(name)
def visit_ExceptHandler(self, node):
@ -146,7 +160,7 @@ class Inferencer(algorithm.Transformer):
self.engine.process(diag)
def visit_FunctionDef(self, node):
extractor = LocalExtractor(engine=self.engine)
extractor = LocalExtractor(env_stack=self.env_stack, engine=self.engine)
extractor.visit(node)
self.env_stack.append(extractor.typing_env)