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Commit 6ba13637 authored by Xavier Thompson's avatar Xavier Thompson
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Improve the 'illegal implicit conversion overloads' rule for cypclasses

parent 7a94ec2c
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Showing with 99 additions and 41 deletions
Cython/Compiler/Nodes.py
View file @ 6ba13637
......@@ -1583,6 +1583,7 @@ class CppClassNode(CStructOrUnionDefNode, BlockNode):
if not cyobject_base:
base_class_types.append(cy_object_type)
# declare this class
self.entry = env.declare_cpp_class(
self.name, scope, self.pos,
self.cname, base_class_types, visibility=self.visibility, templates=template_types,
......@@ -1592,6 +1593,8 @@ class CppClassNode(CStructOrUnionDefNode, BlockNode):
self.entry.is_cpp_class = 1
if scope is not None:
scope.type = self.entry.type
# analyse the sub-declarations
defined_funcs = []
def func_attributes(attributes):
for attr in attributes:
......@@ -1616,6 +1619,40 @@ class CppClassNode(CStructOrUnionDefNode, BlockNode):
func.template_declaration = "template <typename %s>" % ", typename ".join(template_names)
self.body = StatListNode(self.pos, stats=defined_funcs)
# check for illegal implicit conversion paths between method arguments
if self.cypclass and scope is not None:
for method_entry in scope.entries.values():
if method_entry.is_cfunction:
from_type = method_entry.from_type
for alt_entry in method_entry.all_alternatives():
alt_type = alt_entry.type
for other_entry in method_entry.all_alternatives():
if alt_entry is other_entry:
continue
other_type = other_entry.type
# if there is a conversion path from one method to another
# the set of classes that define the first must be a superset
# of the set of base classes that define the second method
if alt_type.convertible_arguments_to(other_type):
# since the classes are MRO-ordered, a subset is actually the same as a subsequence
def is_subsequence(s, seq):
return all(e in iter(seq) for e in s)
if not is_subsequence(other_entry.defining_classes, alt_entry.defining_classes):
error(
alt_entry.pos, (
"Illegal implicit conversion path between cypclass methods:\n"
"Cypclass method\n"
">> %s\n"
"has argument types implicitely convertible to method\n"
">> %s\n"
"but some superclasses of '%s' only declare the second method\n"
% (alt_type.declaration_code(alt_entry.name, for_display = 1).strip(),
other_type.declaration_code(alt_entry.name, for_display = 1).strip(),
self.name)
)
)
# analyse the subclasses that were waiting for this class (their base) to be analysed
for thunk in self.entry.type.deferred_declarations:
thunk()
......
Cython/Compiler/PyrexTypes.py
View file @ 6ba13637
......@@ -2956,22 +2956,25 @@ class CFuncType(CType):
return 0
return 1
def convertible_arguments_with(self, other_type):
return self.convertible_arguments_with_resolved_type(other_type.resolve())
def convertible_arguments_to(self, other_type):
return self.convertible_arguments_to_resolved_type(other_type.resolve())
def convertible_arguments_with_resolved_type(self, other_type):
def convertible_arguments_to_resolved_type(self, other_type):
if other_type is error_type:
return 1
if not other_type.is_cfunction:
return 0
if len(self.args) - self.optional_arg_count != len(other_type.args) - other_type.optional_arg_count:
return 0
if self.has_varargs != other_type.has_varargs:
return 0
arg_type_pairs = ((arg.type, other_arg.type) for arg, other_arg in zip(self.args, other_type.args))
if (all((arg.assignable_from(other) for arg, other in arg_type_pairs))
or
all((other.assignable_from(arg) for arg, other in arg_type_pairs))):
self_minargs = len(self.args) - self.optional_arg_count
if self_minargs > len(other_type.args):
return 0
other_minargs = len(other_type.args) - other_type.optional_arg_count
if other_minargs > len(self.args):
return 0
minargs = max(self_minargs, other_minargs)
arg_type_pairs = ((arg.type, o_arg.type) for arg, o_arg in zip(self.args[:minargs], other_type.args))
if all( (o_arg.assignable_from(arg) for arg, o_arg in arg_type_pairs) ):
return 1
return 0
......
Cython/Compiler/Symtab.py
View file @ 6ba13637
......@@ -172,6 +172,10 @@ class Entry(object):
#
# mro_index integer The index of the type where this entry was originally
# declared in the mro of the cypclass where it is now
#
# defining_classes [CypClassType or CppClassType or CStructOrUnionType]
# All the base classes that define an entry that this entry
# overrides, if this entry represents a cypclass method
# TODO: utility_code and utility_code_definition serves the same purpose...
......@@ -248,6 +252,8 @@ class Entry(object):
needs_rlock = False
needs_wlock = False
is_default = False
mro_index = 0
from_type = None
def __init__(self, name, cname, type, pos = None, init = None):
self.name = name
......@@ -260,8 +266,7 @@ class Entry(object):
self.cf_references = []
self.inner_entries = []
self.defining_entry = self
self.mro_index = 0
self.from_type = None
self.defining_classes = []
def __repr__(self):
return "%s(<%x>, name=%s, type=%s)" % (type(self).__name__, id(self), self.name, self.type)
......@@ -526,6 +531,9 @@ class Scope(object):
entries = self.entries
if from_type is None and self.is_cyp_class_scope:
from_type = self.parent_type
# The indices of all previous overloaded alternatives that this declaration will hide.
previous_alternative_indices = []
......@@ -541,7 +549,7 @@ class Scope(object):
for index, alt_entry in enumerate(old_entry.all_alternatives()):
alt_type = alt_entry.type
if type.convertible_arguments_with(alt_type):
if type.compatible_arguments_with(alt_type):
cpp_override_allowed = False
# allow default constructor or __alloc__ to be redeclared by user
......@@ -550,26 +558,27 @@ class Scope(object):
cpp_override_allowed = True
continue
# enforce cypclass overloading rules
elif alt_entry.is_inherited:
# if the arguments are compatible, then the signatures need to actually be the
# same so that this method actually overrides the other in the virtual table
alt_declarator_str = alt_type.declarator_code(name, for_display = 1).strip()
new_declarator_str = type.declarator_code(name, for_display = 1).strip()
if new_declarator_str != alt_declarator_str:
error(pos, ("Cypclass methods have conflicting signatures:\n"
error(pos, ("Fallacious override:\n"
"Cypclass method\n"
">> %s\n"
"has implicitly convertible arguments from or to:\n"
"has compatible arguments with inherited method\n"
">> %s\n"
"but their signatures are not exactly the same"
"but their signatures are not exactly the same\n"
% (type.declaration_code(name, for_display = 1).strip(),
alt_type.declaration_code(name, for_display = 1).strip()))
)
if alt_entry.pos is not None:
error(alt_entry.pos, "Conflicting method is defined here")
elif alt_entry.is_inherited:
# the return type must be covariant
if not type.return_type.subtype_of_resolved_type(alt_type.return_type):
elif not type.return_type.subtype_of_resolved_type(alt_type.return_type):
error(pos, "Cypclass method overrides another with incompatible return type")
if alt_entry.pos is not None:
error(alt_entry.pos, "Conflicting method is defined here")
......@@ -581,6 +590,13 @@ class Scope(object):
# stop if cpp_override_allowed is False for the current alternative
break
# if an overloaded alternative has narrower argument types than another, then the method
# actually called will depend on the static type of the arguments
elif type.narrower_arguments_than(alt_type) or alt_type.narrower_arguments_than(type):
error(pos, "Cypclass overloaded method with narrower arguments")
if alt_entry.pos is not None:
error(alt_entry.pos, "Conflicting method is defined here")
# normal cpp case
else:
for index, alt_entry in enumerate(old_entry.all_alternatives()):
......@@ -622,6 +638,7 @@ class Scope(object):
if from_type and self.is_cyp_class_scope:
entry.mro_index = self.parent_type.mro().index(from_type)
entry.from_type = from_type
entry.defining_classes.append(from_type)
entry.in_cinclude = self.in_cinclude
entry.create_wrapper = create_wrapper
......@@ -634,26 +651,27 @@ class Scope(object):
# give all alternative entries access to all overloaded alternatives
entry.overloaded_alternatives = entries[name].overloaded_alternatives
# sort the indices in decreasing order
previous_alternative_indices.reverse()
# remplace the first hidden entry with the new entry
# remplace the overriden entry with the new entry
if previous_alternative_indices:
first_index = previous_alternative_indices.pop()
entries[name].overloaded_alternatives[first_index] = entry
# there should never be more than one entry that this entry can override
assert(len(previous_alternative_indices) == 1)
index = previous_alternative_indices[0]
if self.is_cyp_class_scope:
# remember all the bases from which this entry was overridden
overridden_entry = entries[name].overloaded_alternatives[index]
entry.defining_classes = overridden_entry.defining_classes
entry.defining_classes.append(from_type)
entries[name].overloaded_alternatives[index] = entry
# the overloaded entry at index 0 is always the one in the scope dict
if first_index == 0:
if index == 0:
entries[name] = entry
# if no entries are hidden by the new entry, just add it to the alternatives
else:
entries[name].overloaded_alternatives.append(entry)
# outright remove the entries for the remaining indices (in decreasing order)
for index in previous_alternative_indices:
del entries[name].overloaded_alternatives[index]
else:
# this is the first entry with this name
entries[name] = entry
......
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