X-Git-Url: http://nitlanguage.org

diff --git a/src/model/model.nit b/src/model/model.nit
index 999e7f1..030cca9 100644
--- a/src/model/model.nit
+++ b/src/model/model.nit
@@ -30,6 +30,15 @@ import mdoc
 import ordered_tree
 private import more_collections
 
+redef class MEntity
+	# The visibility of the MEntity.
+	#
+	# MPackages, MGroups and MModules are always public.
+	# The visibility of `MClass` and `MProperty` is defined by the keyword used.
+	# `MClassDef` and `MPropDef` return the visibility of `MClass` and `MProperty`.
+	fun visibility: MVisibility do return public_visibility
+end
+
 redef class Model
 	# All known classes
 	var mclasses = new Array[MClass]
@@ -66,7 +75,7 @@ redef class Model
 	# Collections of classes grouped by their short name
 	private var mclasses_by_name = new MultiHashMap[String, MClass]
 
-	# Return all class named `name`.
+	# Return all classes named `name`.
 	#
 	# If such a class does not exist, null is returned
 	# (instead of an empty array)
@@ -119,7 +128,17 @@ redef class Model
 	end
 end
 
-# An OrderedTree that can be easily refined for display purposes
+# An OrderedTree bound to MEntity.
+#
+# We introduce a new class so it can be easily refined by tools working
+# with a Model.
+class MEntityTree
+	super OrderedTree[MEntity]
+end
+
+# A MEntityTree borned to MConcern.
+#
+# TODO remove when nitdoc is fully merged with model_collect
 class ConcernsTree
 	super OrderedTree[MConcern]
 end
@@ -140,7 +159,7 @@ redef class MModule
 		return self.in_importation <= mclass.intro_mmodule
 	end
 
-	# Full hierarchy of introduced ans imported classes.
+	# Full hierarchy of introduced and imported classes.
 	#
 	# Create a new hierarchy got by flattening the classes for the module
 	# and its imported modules.
@@ -206,6 +225,24 @@ redef class MModule
 	# The primitive type `Int`
 	var int_type: MClassType = self.get_primitive_class("Int").mclass_type is lazy
 
+	# The primitive type `Byte`
+	var byte_type: MClassType = self.get_primitive_class("Byte").mclass_type is lazy
+
+	# The primitive type `Int8`
+	var int8_type: MClassType = self.get_primitive_class("Int8").mclass_type is lazy
+
+	# The primitive type `Int16`
+	var int16_type: MClassType = self.get_primitive_class("Int16").mclass_type is lazy
+
+	# The primitive type `UInt16`
+	var uint16_type: MClassType = self.get_primitive_class("UInt16").mclass_type is lazy
+
+	# The primitive type `Int32`
+	var int32_type: MClassType = self.get_primitive_class("Int32").mclass_type is lazy
+
+	# The primitive type `UInt32`
+	var uint32_type: MClassType = self.get_primitive_class("UInt32").mclass_type is lazy
+
 	# The primitive type `Char`
 	var char_type: MClassType = self.get_primitive_class("Char").mclass_type is lazy
 
@@ -215,8 +252,8 @@ redef class MModule
 	# The primitive type `String`
 	var string_type: MClassType = self.get_primitive_class("String").mclass_type is lazy
 
-	# The primitive type `NativeString`
-	var native_string_type: MClassType = self.get_primitive_class("NativeString").mclass_type is lazy
+	# The primitive type `CString`
+	var native_string_type: MClassType = self.get_primitive_class("CString").mclass_type is lazy
 
 	# A primitive type of `Array`
 	fun array_type(elt_type: MType): MClassType do return array_class.get_mtype([elt_type])
@@ -257,19 +294,21 @@ redef class MModule
 			if name == "Bool" and self.model.get_mclasses_by_name("Object") != null then
 				# Bool is injected because it is needed by engine to code the result
 				# of the implicit casts.
-				var c = new MClass(self, name, null, enum_kind, public_visibility)
-				var cladef = new MClassDef(self, c.mclass_type, new Location(null, 0,0,0,0))
+				var loc = model.no_location
+				var c = new MClass(self, name, loc, null, enum_kind, public_visibility)
+				var cladef = new MClassDef(self, c.mclass_type, loc)
 				cladef.set_supertypes([object_type])
 				cladef.add_in_hierarchy
 				return c
 			end
-			print("Fatal Error: no primitive class {name} in {self}")
+			print_error("Fatal Error: no primitive class {name} in {self}")
 			exit(1)
+			abort
 		end
 		if cla.length != 1 then
 			var msg = "Fatal Error: more than one primitive class {name} in {self}:"
 			for c in cla do msg += " {c.full_name}"
-			print msg
+			print_error msg
 			#exit(1)
 		end
 		return cla.first
@@ -281,18 +320,15 @@ redef class MModule
 		var props = self.model.get_mproperties_by_name(name)
 		if props == null then return null
 		var res: nullable MMethod = null
+		var recvtype = recv.intro.bound_mtype
 		for mprop in props do
 			assert mprop isa MMethod
-			var intro = mprop.intro_mclassdef
-			for mclassdef in recv.mclassdefs do
-				if not self.in_importation.greaters.has(mclassdef.mmodule) then continue
-				if not mclassdef.in_hierarchy.greaters.has(intro) then continue
-				if res == null then
-					res = mprop
-				else if res != mprop then
-					print("Fatal Error: ambigous property name '{name}'; conflict between {mprop.full_name} and {res.full_name}")
-					abort
-				end
+			if not recvtype.has_mproperty(self, mprop) then continue
+			if res == null then
+				res = mprop
+			else if res != mprop then
+				print_error("Fatal Error: ambigous property name '{name}'; conflict between {mprop.full_name} and {res.full_name}")
+				abort
 			end
 		end
 		return res
@@ -352,13 +388,16 @@ class MClass
 	super MEntity
 
 	# The module that introduce the class
+	#
 	# While classes are not bound to a specific module,
-	# the introducing module is used for naming an visibility
+	# the introducing module is used for naming and visibility.
 	var intro_mmodule: MModule
 
 	# The short name of the class
 	# In Nit, the name of a class cannot evolve in refinements
-	redef var name: String
+	redef var name
+
+	redef var location
 
 	# The canonical name of the class
 	#
@@ -436,7 +475,7 @@ class MClass
 
 	# The visibility of the class
 	# In Nit, the visibility of a class cannot evolve in refinements
-	var visibility: MVisibility
+	redef var visibility
 
 	init
 	do
@@ -480,12 +519,12 @@ class MClass
 
 	# The principal static type of the class.
 	#
-	# For non-generic class, mclass_type is the only `MClassType` based
+	# For non-generic class, `mclass_type` is the only `MClassType` based
 	# on self.
 	#
 	# For a generic class, the arguments are the formal parameters.
-	# i.e.: for the class Array[E:Object], the `mclass_type` is Array[E].
-	# If you want Array[Object] the see `MClassDef::bound_mtype`
+	# i.e.: for the class `Array[E:Object]`, the `mclass_type` is `Array[E]`.
+	# If you want `Array[Object]`, see `MClassDef::bound_mtype`.
 	#
 	# For generic classes, the mclass_type is also the way to get a formal
 	# generic parameter type.
@@ -526,6 +565,8 @@ class MClass
 
 	# Is `self` and abstract class?
 	var is_abstract: Bool is lazy do return kind == abstract_kind
+
+	redef fun mdoc_or_fallback do return intro.mdoc_or_fallback
 end
 
 
@@ -562,12 +603,13 @@ class MClassDef
 	# ENSURE: `bound_mtype.mclass == self.mclass`
 	var bound_mtype: MClassType
 
-	# The origin of the definition
-	var location: Location
+	redef var location
+
+	redef fun visibility do return mclass.visibility
 
 	# Internal name combining the module and the class
-	# Example: "mymodule#MyClass"
-	redef var to_s: String is noinit
+	# Example: "mymodule$MyClass"
+	redef var to_s is noinit
 
 	init
 	do
@@ -578,41 +620,41 @@ class MClassDef
 			assert not isset mclass._intro
 			mclass.intro = self
 		end
-		self.to_s = "{mmodule}#{mclass}"
+		self.to_s = "{mmodule}${mclass}"
 	end
 
 	# Actually the name of the `mclass`
 	redef fun name do return mclass.name
 
-	# The module and class name separated by a '#'.
+	# The module and class name separated by a '$'.
 	#
 	# The short-name of the class is used for introduction.
-	# Example: "my_module#MyClass"
+	# Example: "my_module$MyClass"
 	#
 	# The full-name of the class is used for refinement.
-	# Example: "my_module#intro_module::MyClass"
+	# Example: "my_module$intro_module::MyClass"
 	redef var full_name is lazy do
 		if is_intro then
-			# public gives 'p#A'
-			# private gives 'p::m#A'
-			return "{mmodule.namespace_for(mclass.visibility)}#{mclass.name}"
-		else if mclass.intro_mmodule.mproject != mmodule.mproject then
-			# public gives 'q::n#p::A'
-			# private gives 'q::n#p::m::A'
-			return "{mmodule.full_name}#{mclass.full_name}"
+			# public gives 'p$A'
+			# private gives 'p::m$A'
+			return "{mmodule.namespace_for(mclass.visibility)}${mclass.name}"
+		else if mclass.intro_mmodule.mpackage != mmodule.mpackage then
+			# public gives 'q::n$p::A'
+			# private gives 'q::n$p::m::A'
+			return "{mmodule.full_name}${mclass.full_name}"
 		else if mclass.visibility > private_visibility then
-			# public gives 'p::n#A'
-			return "{mmodule.full_name}#{mclass.name}"
+			# public gives 'p::n$A'
+			return "{mmodule.full_name}${mclass.name}"
 		else
-			# private gives 'p::n#::m::A' (redundant p is omitted)
-			return "{mmodule.full_name}#::{mclass.intro_mmodule.name}::{mclass.name}"
+			# private gives 'p::n$::m::A' (redundant p is omitted)
+			return "{mmodule.full_name}$::{mclass.intro_mmodule.name}::{mclass.name}"
 		end
 	end
 
 	redef var c_name is lazy do
 		if is_intro then
 			return "{mmodule.c_namespace_for(mclass.visibility)}___{mclass.c_name}"
-		else if mclass.intro_mmodule.mproject == mmodule.mproject and mclass.visibility > private_visibility then
+		else if mclass.intro_mmodule.mpackage == mmodule.mpackage and mclass.visibility > private_visibility then
 			return "{mmodule.c_name}___{mclass.name.to_cmangle}"
 		else
 			return "{mmodule.c_name}___{mclass.c_name}"
@@ -678,8 +720,11 @@ class MClassDef
 	# All properties introduced by the classdef
 	var intro_mproperties = new Array[MProperty]
 
-	# All property definitions in the class (introductions and redefinitions)
+	# All property introductions and redefinitions in `self` (not inheritance).
 	var mpropdefs = new Array[MPropDef]
+
+	# All property introductions and redefinitions (not inheritance) in `self` by its associated property.
+	var mpropdefs_by_property = new HashMap[MProperty, MPropDef]
 end
 
 # A global static type
@@ -790,19 +835,19 @@ abstract class MType
 		end
 		#print "4.is {sub} a {sup}? <- no more resolution"
 
-		assert sub isa MClassType else print "{sub} <? {sub}" # It is the only remaining type
-
-		# A unfixed formal type can only accept itself
-		if sup isa MFormalType then
-			return false
+		if sub isa MBottomType or sub isa MErrorType then
+			return true
 		end
 
-		if sup isa MNullType then
-			# `sup` accepts only null
+		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 or sup isa MErrorType then
+			# These types are not super-types of Class-based types.
 			return false
 		end
 
-		assert sup isa MClassType # It is the only remaining type
+		assert sup isa MClassType else print_error "got {sup} {sub.inspect}" # It is the only remaining type
 
 		# Now both are MClassType, we need to dig
 
@@ -991,7 +1036,7 @@ abstract class MType
 	# The result is returned exactly as declared in the "type" property (verbatim).
 	# So it could be another formal type.
 	#
-	# In case of conflict, the method aborts.
+	# 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.
@@ -1005,8 +1050,25 @@ abstract class MType
 	#
 	# 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 `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.
@@ -1137,6 +1199,8 @@ class MClassType
 
 	redef fun model do return self.mclass.intro_mmodule.model
 
+	redef fun location do return mclass.location
+
 	# TODO: private init because strongly bounded to its mclass. see `mclass.mclass_type`
 
 	# The formal arguments of the type
@@ -1259,10 +1323,10 @@ class MGenericType
 
 	# The short-name of the class, then the full-name of each type arguments within brackets.
 	# Example: `"Map[String, List[Int]]"`
-	redef var to_s: String is noinit
+	redef var to_s is noinit
 
 	# The full-name of the class, then the full-name of each type arguments within brackets.
-	# Example: `"standard::Map[standard::String, standard::List[standard::Int]]"`
+	# Example: `"core::Map[core::String, core::List[core::Int]]"`
 	redef var full_name is lazy do
 		var args = new Array[String]
 		for t in arguments do
@@ -1281,7 +1345,7 @@ class MGenericType
 		return res.to_s
 	end
 
-	redef var need_anchor: Bool is noinit
+	redef var need_anchor is noinit
 
 	redef fun resolve_for(mtype, anchor, mmodule, cleanup_virtual)
 	do
@@ -1303,6 +1367,24 @@ class MGenericType
 		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
@@ -1342,11 +1424,15 @@ class MVirtualType
 	# Its the definitions of this property that determine the bound or the virtual type.
 	var mproperty: MVirtualTypeProp
 
+	redef fun location do return mproperty.location
+
 	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.as(not null)
+		# 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
@@ -1381,7 +1467,8 @@ class MVirtualType
 		assert resolved_receiver isa MClassType # It is the only remaining type
 
 		var prop = lookup_single_definition(mmodule, resolved_receiver)
-		var res = prop.bound.as(not null)
+		var res = prop.bound
+		if res == null then return new MErrorType(model)
 
 		# Recursively lookup the fixed result
 		res = res.lookup_fixed(mmodule, resolved_receiver)
@@ -1402,6 +1489,9 @@ class MVirtualType
 	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
@@ -1471,6 +1561,8 @@ class MParameterType
 
 	redef fun model do return self.mclass.intro_mmodule.model
 
+	redef fun location do return mclass.location
+
 	# The position of the parameter (0 for the first parameter)
 	# FIXME: is `position` a better name?
 	var rank: Int
@@ -1501,7 +1593,8 @@ class MParameterType
 				return res
 			end
 		end
-		abort
+		# Cannot found `self` in `resolved_receiver`
+		return new MErrorType(model)
 	end
 
 	# A PT is fixed when:
@@ -1548,6 +1641,7 @@ class MParameterType
 		end
 		if resolved_receiver isa MNullableType then resolved_receiver = resolved_receiver.mtype
 		if resolved_receiver isa MParameterType then
+			assert anchor != null
 			assert resolved_receiver.mclass == anchor.mclass
 			resolved_receiver = anchor.arguments[resolved_receiver.rank]
 			if resolved_receiver isa MNullableType then resolved_receiver = resolved_receiver.mtype
@@ -1595,6 +1689,8 @@ abstract class MProxyType
 	# The base type
 	var mtype: MType
 
+	redef fun location do return mtype.location
+
 	redef fun model do return self.mtype.model
 	redef fun need_anchor do return mtype.need_anchor
 	redef fun as_nullable do return mtype.as_nullable
@@ -1611,6 +1707,10 @@ abstract class MProxyType
 		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)
@@ -1649,7 +1749,7 @@ class MNullableType
 		self.to_s = "nullable {mtype}"
 	end
 
-	redef var to_s: String is noinit
+	redef var to_s is noinit
 
 	redef var full_name is lazy do return "nullable {mtype.full_name}"
 
@@ -1703,7 +1803,7 @@ end
 # The is only one null type per model, see `MModel::null_type`.
 class MNullType
 	super MType
-	redef var model: Model
+	redef var model
 	redef fun to_s do return "null"
 	redef fun full_name do return "null"
 	redef fun c_name do return "null"
@@ -1724,12 +1824,13 @@ end
 # 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: Model
+	redef var model
 	redef fun to_s do return "bottom"
 	redef fun full_name do return "bottom"
 	redef fun c_name do return "bottom"
@@ -1746,6 +1847,31 @@ class MBottomType
 	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
@@ -1795,37 +1921,31 @@ class MSignature
 		for i in [0..mparameters.length[ do
 			var parameter = mparameters[i]
 			if parameter.is_vararg then
-				assert vararg_rank == -1
+				if vararg_rank >= 0 then
+					# If there is more than one vararg,
+					# consider that additional arguments cannot be mapped.
+					vararg_rank = -1
+					break
+				end
 				vararg_rank = i
 			end
 		end
 		self.vararg_rank = vararg_rank
 	end
 
-	# The rank of the ellipsis (`...`) for vararg (starting from 0).
+	# The rank of the main ellipsis (`...`) for vararg (starting from 0).
 	# value is -1 if there is no vararg.
 	# Example: for "(a: Int, b: Bool..., c: Char)" #-> vararg_rank=1
+	#
+	# From a model POV, a signature can contain more than one vararg parameter,
+	# the `vararg_rank` just indicates the one that will receive the additional arguments.
+	# However, currently, if there is more that one vararg parameter, no one will be the main one,
+	# and additional arguments will be refused.
 	var vararg_rank: Int is noinit
 
 	# The number of parameters
 	fun arity: Int do return mparameters.length
 
-	# The number of non-default parameters
-	#
-	# The number of default parameters is then `arity-min_arity`.
-	#
-	# Note that there cannot be both varargs and default prameters, thus
-	# if `vararg_rank != -1` then `min_arity` == `arity`
-	fun min_arity: Int
-	do
-		if vararg_rank != -1 then return arity
-		var res = 0
-		for p in mparameters do
-			if not p.is_default then res += 1
-		end
-		return res
-	end
-
 	redef fun to_s
 	do
 		var b = new FlatBuffer
@@ -1871,7 +1991,7 @@ class MParameter
 	super MEntity
 
 	# The name of the parameter
-	redef var name: String
+	redef var name
 
 	# The static type of the parameter
 	var mtype: MType
@@ -1879,9 +1999,6 @@ class MParameter
 	# Is the parameter a vararg?
 	var is_vararg: Bool
 
-	# Is the parameter a default one?
-	var is_default: Bool
-
 	redef fun to_s
 	do
 		if is_vararg then
@@ -1897,7 +2014,7 @@ class MParameter
 	do
 		if not self.mtype.need_anchor then return self
 		var newtype = self.mtype.resolve_for(mtype, anchor, mmodule, cleanup_virtual)
-		var res = new MParameter(self.name, newtype, self.is_vararg, self.is_default)
+		var res = new MParameter(self.name, newtype, self.is_vararg)
 		return res
 	end
 
@@ -1928,14 +2045,29 @@ abstract class MProperty
 	var intro_mclassdef: MClassDef
 
 	# The (short) name of the property
-	redef var name: String
+	redef var name
+
+	redef var location
+
+	redef fun mdoc_or_fallback do return intro.mdoc_or_fallback
 
 	# The canonical name of the property.
 	#
-	# It is the short-`name` prefixed by the short-name of the class and the full-name of the module.
-	# Example: "my_project::my_module::MyClass::my_method"
+	# It is currently the short-`name` prefixed by the short-name of the class and the full-name of the module.
+	# Example: "my_package::my_module::MyClass::my_method"
+	#
+	# The full-name of the module is needed because two distinct modules of the same package can
+	# still refine the same class and introduce homonym properties.
+	#
+	# For public properties not introduced by refinement, the module name is not used.
+	#
+	# Example: `my_package::MyClass::My_method`
 	redef var full_name is lazy do
-		return "{intro_mclassdef.mmodule.namespace_for(visibility)}::{intro_mclassdef.mclass.name}::{name}"
+		if intro_mclassdef.is_intro then
+			return "{intro_mclassdef.mmodule.namespace_for(visibility)}::{intro_mclassdef.mclass.name}::{name}"
+		else
+			return "{intro_mclassdef.mmodule.full_name}::{intro_mclassdef.mclass.name}::{name}"
+		end
 	end
 
 	redef var c_name is lazy do
@@ -1944,7 +2076,7 @@ abstract class MProperty
 	end
 
 	# The visibility of the property
-	var visibility: MVisibility
+	redef var visibility
 
 	# Is the property usable as an initializer?
 	var is_autoinit = false is writable
@@ -1993,14 +2125,27 @@ abstract class MProperty
 		#print "select prop {mproperty} for {mtype} in {self}"
 		# First, select all candidates
 		var candidates = new Array[MPROPDEF]
-		for mpropdef in self.mpropdefs do
-			# If the definition is not imported by the module, then skip
-			if not mmodule.in_importation <= mpropdef.mclassdef.mmodule then continue
-			# If the definition is not inherited by the type, then skip
-			if not mtype.is_subtype(mmodule, null, mpropdef.mclassdef.bound_mtype) then continue
-			# Else, we keep it
-			candidates.add(mpropdef)
+
+		# Here we have two strategies: iterate propdefs or iterate classdefs.
+		var mpropdefs = self.mpropdefs
+		if mpropdefs.length <= 1 or mpropdefs.length < mtype.collect_mclassdefs(mmodule).length then
+			# Iterate on all definitions of `self`, keep only those inherited by `mtype` in `mmodule`
+			for mpropdef in mpropdefs do
+				# If the definition is not imported by the module, then skip
+				if not mmodule.in_importation <= mpropdef.mclassdef.mmodule then continue
+				# If the definition is not inherited by the type, then skip
+				if not mtype.is_subtype(mmodule, null, mpropdef.mclassdef.bound_mtype) then continue
+				# Else, we keep it
+				candidates.add(mpropdef)
+			end
+		else
+			# Iterate on all super-classdefs of `mtype`, keep only the definitions of `self`, if any.
+			for mclassdef in mtype.collect_mclassdefs(mmodule) do
+				var p = mclassdef.mpropdefs_by_property.get_or_null(self)
+				if p != null then candidates.add p
+			end
 		end
+
 		# Fast track for only one candidate
 		if candidates.length <= 1 then
 			self.lookup_definitions_cache[mmodule, mtype] = candidates
@@ -2076,7 +2221,7 @@ abstract class MProperty
 			end
 		end
 		if res.is_empty then
-			print "All lost! {candidates.join(", ")}"
+			print_error "All lost! {candidates.join(", ")}"
 			# FIXME: should be abort!
 		end
 		return res
@@ -2165,6 +2310,10 @@ class MMethod
 	do
 		return self.is_init
 	end
+
+	# A specific method that is safe to call on null.
+	# Currently, only `==`, `!=` and `is_same_instance` are safe
+	fun is_null_safe: Bool do return name == "==" or name == "!=" or name == "is_same_instance"
 end
 
 # A global attribute
@@ -2183,6 +2332,9 @@ class MVirtualTypeProp
 
 	# 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)
@@ -2205,18 +2357,20 @@ abstract class MPropDef
 	# The associated global property
 	var mproperty: MPROPERTY
 
-	# The origin of the definition
-	var location: Location
+	redef var location: Location
+
+	redef fun visibility do return mproperty.visibility
 
 	init
 	do
 		mclassdef.mpropdefs.add(self)
 		mproperty.mpropdefs.add(self)
+		mclassdef.mpropdefs_by_property[mproperty] = self
 		if mproperty.intro_mclassdef == mclassdef then
 			assert not isset mproperty._intro
 			mproperty.intro = self
 		end
-		self.to_s = "{mclassdef}#{mproperty}"
+		self.to_s = "{mclassdef}${mproperty}"
 	end
 
 	# Actually the name of the `mproperty`
@@ -2230,31 +2384,31 @@ abstract class MPropDef
 	#  * a property "p::m::A::x"
 	#  * redefined in a refinement of a class "q::n::B"
 	#  * in a module "r::o"
-	#  * so "r::o#q::n::B#p::m::A::x"
+	#  * so "r::o$q::n::B$p::m::A::x"
 	#
 	# Fortunately, the full-name is simplified when entities are repeated.
-	# For the previous case, the simplest form is "p#A#x".
+	# For the previous case, the simplest form is "p$A$x".
 	redef var full_name is lazy do
 		var res = new FlatBuffer
 
-		# The first part is the mclassdef. Worst case is "r::o#q::n::B"
+		# The first part is the mclassdef. Worst case is "r::o$q::n::B"
 		res.append mclassdef.full_name
 
-		res.append "#"
+		res.append "$"
 
 		if mclassdef.mclass == mproperty.intro_mclassdef.mclass then
 			# intro are unambiguous in a class
 			res.append name
 		else
 			# Just try to simplify each part
-			if mclassdef.mmodule.mproject != mproperty.intro_mclassdef.mmodule.mproject then
+			if mclassdef.mmodule.mpackage != mproperty.intro_mclassdef.mmodule.mpackage then
 				# precise "p::m" only if "p" != "r"
-				res.append mproperty.intro_mclassdef.mmodule.full_name
+				res.append mproperty.intro_mclassdef.mmodule.namespace_for(mproperty.visibility)
 				res.append "::"
 			else if mproperty.visibility <= private_visibility then
-				# Same project ("p"=="q"), but private visibility,
+				# Same package ("p"=="q"), but private visibility,
 				# does the module part ("::m") need to be displayed
-				if mclassdef.mmodule.namespace_for(mclassdef.mclass.visibility) != mproperty.intro_mclassdef.mmodule.mproject then
+				if mclassdef.mmodule.namespace_for(mclassdef.mclass.visibility) != mproperty.intro_mclassdef.mmodule.mpackage then
 					res.append "::"
 					res.append mproperty.intro_mclassdef.mmodule.name
 					res.append "::"
@@ -2294,11 +2448,11 @@ abstract class MPropDef
 	redef fun model do return mclassdef.model
 
 	# Internal name combining the module, the class and the property
-	# Example: "mymodule#MyClass#mymethod"
-	redef var to_s: String is noinit
+	# Example: "mymodule$MyClass$mymethod"
+	redef var to_s is noinit
 
 	# Is self the definition that introduce the property?
-	fun is_intro: Bool do return mproperty.intro == self
+	fun is_intro: Bool do return isset mproperty._intro and mproperty.intro == self
 
 	# Return the next definition in linearization of `mtype`.
 	#
@@ -2398,7 +2552,7 @@ end
 # Note this class is basically an enum.
 # FIXME: use a real enum once user-defined enums are available
 class MClassKind
-	redef var to_s: String
+	redef var to_s
 
 	# Is a constructor required?
 	var need_init: Bool