Enforce cypclass method overloading rules

Cython/Compiler/Builtin.py

@@ -581,7 +581,7 @@ def inject_acthon_interfaces(self):
     queue_is_empty_type = PyrexTypes.CFuncType(PyrexTypes.c_bint_type, [], nogil = 1)
     queue_is_empty_type.is_const_method = 1
     queue_is_empty_entry = queue_scope.declare("is_empty", "is_empty",
-        queue_activate_type, None, "extern")
+        queue_is_empty_type, None, "extern")
     queue_is_empty_entry.is_cfunction = 1
     queue_is_empty_entry.is_variable = 1
     queue_scope.var_entries.append(queue_is_empty_entry)

Cython/Compiler/PyrexTypes.py

@@ -2958,18 +2958,17 @@ class CFuncType(CType):
             return 0
         return 1
 
-    def compatible_signature_with(self, other_type, as_cmethod = 0, ignore_return_type=0):
-        return self.compatible_signature_with_resolved_type(other_type.resolve(), as_cmethod, ignore_return_type)
+    def compatible_arguments_with(self, other_type, as_cmethod=0):
+        return self.compatible_arguments_with_resolved_type(other_type.resolve(), as_cmethod)
 
-    def compatible_signature_with_resolved_type(self, other_type, as_cmethod, ignore_return_type=0):
-        #print "CFuncType.same_c_signature_as_resolved_type:", \
-        #    self, other_type, "as_cmethod =", as_cmethod ###
+    def compatible_arguments_with_resolved_type(self, other_type, as_cmethod):
         if other_type is error_type:
             return 1
         if not other_type.is_cfunction:
             return 0
-        if not self.is_overridable and other_type.is_overridable:
-            return 0
+        return self.__compatible_arguments_with_resolved_type(other_type, as_cmethod)
+
+    def __compatible_arguments_with_resolved_type(self, other_type, as_cmethod):
         nargs = len(self.args)
         if nargs - self.optional_arg_count != len(other_type.args) - other_type.optional_arg_count:
             return 0
@@ -2984,7 +2983,22 @@ class CFuncType(CType):
                 return 0
         if self.has_varargs != other_type.has_varargs:
             return 0
-        if not ignore_return_type:
+        return 1
+
+    def compatible_signature_with(self, other_type, as_cmethod = 0, skip_args=0, skip_return=0):
+        return self.compatible_signature_with_resolved_type(other_type.resolve(), as_cmethod, skip_args, skip_return)
+
+    def compatible_signature_with_resolved_type(self, other_type, as_cmethod, skip_args=0, skip_return=0):
+        #print "CFuncType.same_c_signature_as_resolved_type:", \
+        #    self, other_type, "as_cmethod =", as_cmethod ###
+        if other_type is error_type:
+            return 1
+        if not other_type.is_cfunction:
+            return 0
+        if not self.is_overridable and other_type.is_overridable:
+            return 0
+        if not skip_args and not self.compatible_arguments_with_resolved_type(other_type, as_cmethod):
+            return 0
         if not self.return_type.subtype_of_resolved_type(other_type.return_type):
             return 0
         if not self.same_calling_convention_as(other_type):
@@ -3010,14 +3024,17 @@ class CFuncType(CType):
                 return 0
         return 1
 
-    def narrower_c_signature_than(self, other_type, as_cmethod = 0):
-        return self.narrower_c_signature_than_resolved_type(other_type.resolve(), as_cmethod)
+    def narrower_arguments_than(self, other_type, as_cmethod = 0):
+        return self.narrower_arguments_than_resolved_type(other_type.resolve(), as_cmethod)
 
-    def narrower_c_signature_than_resolved_type(self, other_type, as_cmethod):
+    def narrower_arguments_than_resolved_type(self, other_type, as_cmethod):
         if other_type is error_type:
             return 1
         if not other_type.is_cfunction:
             return 0
+        return self.__narrower_arguments_than_resolved_type(other_type, as_cmethod)
+
+    def __narrower_arguments_than_resolved_type(self, other_type, as_cmethod):
         nargs = len(self.args)
         if nargs != len(other_type.args):
             return 0
@@ -3031,6 +3048,18 @@ class CFuncType(CType):
             return 0
         if self.optional_arg_count != other_type.optional_arg_count:
             return 0
+        return 1
+
+    def narrower_c_signature_than(self, other_type, as_cmethod = 0, skip_args=0):
+        return self.narrower_c_signature_than_resolved_type(other_type.resolve(), as_cmethod)
+
+    def narrower_c_signature_than_resolved_type(self, other_type, as_cmethod, skip_args=0):
+        if other_type is error_type:
+            return 1
+        if not other_type.is_cfunction:
+            return 0
+        if not skip_args and not self.__narrower_arguments_than_resolved_type(other_type, as_cmethod):
+            return 0
         if not self.return_type.subtype_of_resolved_type(other_type.return_type):
             return 0
         if not self.exception_check and other_type.exception_check:
@@ -3966,6 +3995,9 @@ class CppClassType(CType):
             base_code = public_decl(base_code, dll_linkage)
         return self.base_declaration_code(base_code, entity_code)
 
+    def subtype_of_resolved_type(self, other_type):
+        return self.is_subclass(other_type)
+
     def is_subclass(self, other_type):
         if self.same_as_resolved_type(other_type):
             return 1

Cython/Compiler/Symtab.py

@@ -537,11 +537,13 @@ class Scope(object):
                 cpp_override_allowed = True
                 for index, alt_entry in enumerate(old_entry.all_alternatives()):
                     # in a cypclass, a method can hide a method inherited from a different class
-                    # regardless of their return types
-                    ignore_return_type = (self.is_cyp_class_scope
-                                          and alt_entry.is_inherited
-                                          and alt_entry.from_type is not from_type)
-                    if type.compatible_signature_with(alt_entry.type, ignore_return_type=ignore_return_type):
+                    # based only on their argument types
+                    if self.is_cyp_class_scope:
+                        might_redeclare_or_override = type.compatible_arguments_with
+                    else:
+                        might_redeclare_or_override = type.compatible_signature_with
+
+                    if might_redeclare_or_override(alt_entry.type):
 
                         cpp_override_allowed = False
 
@@ -555,10 +557,36 @@ class Scope(object):
                         # Any inherited method is visible
                         # until overloaded by a method with the same signature
                         if alt_entry.is_inherited:
+
+                            # in a cypclass, if the arguments are compatible
+                            # then the whole signature must also be compatible
+                            if self.is_cyp_class_scope:
+                                if not type.compatible_signature_with(alt_entry.type, skip_args=1):
+                                    error(pos, "Cypclass overriding method with incompatible return type")
+                                    if alt_entry.pos is not None:
+                                        error(alt_entry.pos, "Overriden method is defined here")
+
+                                # 'CFuncType.compatible_signature_with' doesn't compare constness, so we're doing it here.
+                                # TODO: Maybe it should.
+                                elif (type.is_const_method and not alt_entry.type.is_const_method
+                                      or not type.is_const_method and alt_entry.type.is_const_method):
+                                    print(type.is_const_method)
+                                    print(alt_entry.type.is_const_method)
+                                    error(pos, "Cypclass overriding method with conflicting constness")
+                                    if alt_entry.pos is not None:
+                                        error(alt_entry.pos, "Overriden method is defined here")
+
                             previous_alternative_indices.append(index)
                             cpp_override_allowed = True
                             continue
 
+                    elif self.is_cyp_class_scope:
+                        if (type.narrower_arguments_than(alt_entry.type)
+                            or alt_entry.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")
+
             if cpp_override_allowed:
                 # C++ function/method overrides with different signatures are ok.
                 pass

tests/run/cypclass_inplace_operator_inference.pyx

@@ -14,29 +14,28 @@ cdef cypclass B(A) nolock:
     B __iadd__(self, A other):
         self.val += (other.val + 10)
     
-    B __iadd__(self, B other):
-        self.val += (other.val + 100)
+    int is_inferred_as_B(self):
+        return 1
 
 def test_inplace_operator_inference():
     """
     >>> test_inplace_operator_inference()
-    111
+    (11, 1)
     """
     a = A(0)
-    b0 = B(0)
-    b1 = B(0)
+    b = B(0)
 
     # at this point, the types are unambiguous and the following assignments should not cause them to infer as another type.
 
-    a += b0 # should add 1
+    a += b  # should add 1
 
-    # before it being fixed, 'b0 += a' where 'a' is of type A caused 'b0' to be inferred as type A instead of B.
+    # before it being fixed, 'b += a' where 'a' is of type A caused 'b' to be inferred as type A instead of B.
     
-    b0 += a # should add 10
+    b += a  # should add 10
 
-    # since all cypclass methods are virtual, 'b0' being erroneously inferred as type A would cause 
-    # 'b0 += b1' to call 'B __iadd__(self, A other)' instead of 'B __iadd__(self, B other)'.
+    # since all cypclass methods are virtual, 'b' being erroneously inferred as type A would cause a compilation error
+    # when calling 'b.is_inferred_as_B()'.
 
-    b0 += b1 # should add 100
+    r = b.is_inferred_as_B()
 
-    return b0.val
+    return b.val, r