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Automatically infer return type of NoneType for no return statements.

This commit is contained in:
whitequark 2015-07-04 00:58:48 +03:00
parent bfabca494b
commit ee0990cb5e
1 changed files with 13 additions and 0 deletions
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13
artiq/compiler/transforms/inferencer.py
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@ -20,6 +20,7 @@ class Inferencer(algorithm.Visitor):
self.engine = engine self.engine = engine
self.function = None # currently visited function, for Return inference self.function = None # currently visited function, for Return inference
self.in_loop = False self.in_loop = False
self.has_return = False
def _unify(self, typea, typeb, loca, locb, makenotes=None): def _unify(self, typea, typeb, loca, locb, makenotes=None):
try: try:
@ -768,9 +769,11 @@ class Inferencer(algorithm.Visitor):
def visit_FunctionDefT(self, node): def visit_FunctionDefT(self, node):
old_function, self.function = self.function, node old_function, self.function = self.function, node
old_in_loop, self.in_loop = self.in_loop, False old_in_loop, self.in_loop = self.in_loop, False
old_has_return, self.has_return = self.has_return, False
self.generic_visit(node) self.generic_visit(node)
self.function = old_function self.function = old_function
self.in_loop = old_in_loop self.in_loop = old_in_loop
self.has_return = old_has_return
if any(node.decorator_list): if any(node.decorator_list):
diag = diagnostic.Diagnostic("error", diag = diagnostic.Diagnostic("error",
@ -779,6 +782,14 @@ class Inferencer(algorithm.Visitor):
self.engine.process(diag) self.engine.process(diag)
return return
# Lack of return statements is not the only case where the return
# type cannot be inferred. The other one is infinite (possibly mutual)
# recursion. Since Python functions don't have to return a value,
# we ignore that one.
if not self.has_return:
self._unify(node.return_type, builtins.TNone(),
node.name_loc, None)
signature_type = self._type_from_arguments(node.args, node.return_type) signature_type = self._type_from_arguments(node.args, node.return_type)
if signature_type: if signature_type:
self._unify(node.signature_type, signature_type, self._unify(node.signature_type, signature_type,
@ -792,6 +803,8 @@ class Inferencer(algorithm.Visitor):
self.engine.process(diag) self.engine.process(diag)
return return
self.has_return = True
self.generic_visit(node) self.generic_visit(node)
def makenotes(printer, typea, typeb, loca, locb): def makenotes(printer, typea, typeb, loca, locb):
return [ return [