end
#print "4.is {sub} a {sup}? <- no more resolution"
- if sub isa MBottomType then
+ if sub isa MBottomType or sub isa MErrorType then
return true
end
assert sub isa MClassType else print_error "{sub} <? {sup}" # It is the only remaining type
# Handle sup-type when the sub-type is class-based (other cases must have be identified before).
- if sup isa MFormalType or sup isa MNullType or sup isa MBottomType then
+ if sup isa MFormalType or sup isa MNullType or sup isa MBottomType or sup isa MErrorType then
# These types are not super-types of Class-based types.
return false
end
# The result is returned exactly as declared in the "type" property (verbatim).
# So it could be another formal type.
#
- # In case of conflicts or inconsistencies in the model, the method returns a `MBottomType`.
+ # In case of conflicts or inconsistencies in the model, the method returns a `MErrorType`.
fun lookup_bound(mmodule: MModule, resolved_receiver: MType): MType do return self
# Resolve the formal type to its simplest equivalent form.
# By default, return self.
# See the redefinitions for specific behavior in each kind of type.
#
- # In case of conflicts or inconsistencies in the model, the method returns a `MBottomType`.
+ # In case of conflicts or inconsistencies in the model, the method returns a `MErrorType`.
fun lookup_fixed(mmodule: MModule, resolved_receiver: MType): MType do return self
+ # Is the type a `MErrorType` or contains an `MErrorType`?
+ #
+ # `MErrorType` are used in result with conflict or inconsistencies.
+ #
+ # See `is_legal_in` to check conformity with generic bounds.
+ fun is_ok: Bool do return true
+
+ # Is the type legal in a given `mmodule` (with an optional `anchor`)?
+ #
+ # A type is valid if:
+ #
+ # * it does not contain a `MErrorType` (see `is_ok`).
+ # * its generic formal arguments are within their bounds.
+ fun is_legal_in(mmodule: MModule, anchor: nullable MClassType): Bool do return is_ok
+
# Can the type be resolved?
#
# In order to resolve open types, the formal types must make sence.
return true
end
+ redef fun is_ok
+ do
+ for t in arguments do if not t.is_ok then return false
+ return super
+ end
+
+ redef fun is_legal_in(mmodule, anchor)
+ do
+ var mtype
+ if need_anchor then
+ assert anchor != null
+ mtype = anchor_to(mmodule, anchor)
+ else
+ mtype = self
+ end
+ if not mtype.is_ok then return false
+ return mtype.is_subtype(mmodule, null, mtype.mclass.intro.bound_mtype)
+ end
redef fun depth
do
redef fun model do return self.mproperty.intro_mclassdef.mmodule.model
- redef fun lookup_bound(mmodule: MModule, resolved_receiver: MType): MType
+ redef fun lookup_bound(mmodule, resolved_receiver)
do
- return lookup_single_definition(mmodule, resolved_receiver).bound or else new MBottomType(model)
+ # There is two possible invalid cases: the vt does not exists in resolved_receiver or the bound is broken
+ if not resolved_receiver.has_mproperty(mmodule, mproperty) then return new MErrorType(model)
+ return lookup_single_definition(mmodule, resolved_receiver).bound or else new MErrorType(model)
end
private fun lookup_single_definition(mmodule: MModule, resolved_receiver: MType): MVirtualTypeDef
var prop = lookup_single_definition(mmodule, resolved_receiver)
var res = prop.bound
- if res == null then return new MBottomType(model)
+ if res == null then return new MErrorType(model)
# Recursively lookup the fixed result
res = res.lookup_fixed(mmodule, resolved_receiver)
do
if not cleanup_virtual then return self
assert can_resolve_for(mtype, anchor, mmodule)
+
+ if mproperty.is_selftype then return mtype
+
# self is a virtual type declared (or inherited) in mtype
# The point of the function it to get the bound of the virtual type that make sense for mtype
# But because mtype is maybe a virtual/formal type, we need to get a real receiver first
return res
end
end
- abort
+ # Cannot found `self` in `resolved_receiver`
+ return new MErrorType(model)
end
# A PT is fixed when:
return self.mtype.can_resolve_for(mtype, anchor, mmodule)
end
+ redef fun is_ok do return mtype.is_ok
+
+ redef fun is_legal_in(mmodule, anchor) do return mtype.is_legal_in(mmodule, anchor)
+
redef fun lookup_fixed(mmodule, resolved_receiver)
do
var t = mtype.lookup_fixed(mmodule, resolved_receiver)
# The special universal most specific type.
#
# This type is intended to be only used internally for type computation or analysis and should not be exposed to the user.
-# The bottom type can de used to denote things that are absurd, dead, or the absence of knowledge.
+# The bottom type can de used to denote things that are dead (no instance).
#
# Semantically it is the singleton `null.as_notnull`.
+# Is also means that `self.as_nullable == null`.
class MBottomType
super MType
redef var model
redef fun collect_mtypes(mmodule) do return new HashSet[MClassType]
end
+# A special type used as a silent error marker when building types.
+#
+# This type is intended to be only used internally for type operation and should not be exposed to the user.
+# The error type can de used to denote things that are conflicting or inconsistent.
+#
+# Some methods on types can return a `MErrorType` to denote a broken or a conflicting result.
+# Use `is_ok` to check if a type is (or contains) a `MErrorType` .
+class MErrorType
+ super MType
+ redef var model
+ redef fun to_s do return "error"
+ redef fun full_name do return "error"
+ redef fun c_name do return "error"
+ redef fun need_anchor do return false
+ redef fun resolve_for(mtype, anchor, mmodule, cleanup_virtual) do return self
+ redef fun can_resolve_for(mtype, anchor, mmodule) do return true
+ redef fun is_ok do return false
+
+ redef fun collect_mclassdefs(mmodule) do return new HashSet[MClassDef]
+
+ redef fun collect_mclasses(mmodule) do return new HashSet[MClass]
+
+ redef fun collect_mtypes(mmodule) do return new HashSet[MClassType]
+end
+
# A signature of a method
class MSignature
super MType
# The formal type associated to the virtual type property
var mvirtualtype = new MVirtualType(self)
+
+ # Is `self` the special virtual type `SELF`?
+ var is_selftype: Bool is lazy do return name == "SELF"
end
# A definition of a property (local property)