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
# Can the type be resolved?
redef fun lookup_bound(mmodule: MModule, resolved_receiver: MType): MType
do
- return lookup_single_definition(mmodule, resolved_receiver).bound or else new MBottomType(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)
# 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.
+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 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