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

diff --git a/src/model/model.nit b/src/model/model.nit
index 4d8ddc4..3841daf 100644
--- a/src/model/model.nit
+++ b/src/model/model.nit
@@ -74,11 +74,7 @@ redef class Model
 	# Visibility or modules are not considered
 	fun get_mclasses_by_name(name: String): nullable Array[MClass]
 	do
-		if mclasses_by_name.has_key(name) then
-			return mclasses_by_name[name]
-		else
-			return null
-		end
+		return mclasses_by_name.get_or_null(name)
 	end
 
 	# Collections of properties grouped by their short name
@@ -92,11 +88,7 @@ redef class Model
 	# Visibility or modules are not considered
 	fun get_mproperties_by_name(name: String): nullable Array[MProperty]
 	do
-		if not mproperties_by_name.has_key(name) then
-			return null
-		else
-			return mproperties_by_name[name]
-		end
+		return mproperties_by_name.get_or_null(name)
 	end
 
 	# The only null type
@@ -203,31 +195,58 @@ redef class MModule
 	private var flatten_mclass_hierarchy_cache: nullable POSet[MClass] = null
 
 	# The primitive type `Object`, the root of the class hierarchy
-	fun object_type: MClassType
-	do
-		var res = self.object_type_cache
-		if res != null then return res
-		res = self.get_primitive_class("Object").mclass_type
-		self.object_type_cache = res
-		return res
-	end
-
-	private var object_type_cache: nullable MClassType
+	var object_type: MClassType = self.get_primitive_class("Object").mclass_type is lazy
 
 	# The type `Pointer`, super class to all extern classes
 	var pointer_type: MClassType = self.get_primitive_class("Pointer").mclass_type is lazy
 
 	# The primitive type `Bool`
-	fun bool_type: MClassType
-	do
-		var res = self.bool_type_cache
-		if res != null then return res
-		res = self.get_primitive_class("Bool").mclass_type
-		self.bool_type_cache = res
-		return res
-	end
+	var bool_type: MClassType = self.get_primitive_class("Bool").mclass_type is lazy
+
+	# 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
+
+	# The primitive type `Float`
+	var float_type: MClassType = self.get_primitive_class("Float").mclass_type is lazy
+
+	# The primitive type `String`
+	var string_type: MClassType = self.get_primitive_class("String").mclass_type is lazy
 
-	private var bool_type_cache: nullable MClassType
+	# The primitive type `NativeString`
+	var native_string_type: MClassType = self.get_primitive_class("NativeString").mclass_type is lazy
+
+	# A primitive type of `Array`
+	fun array_type(elt_type: MType): MClassType do return array_class.get_mtype([elt_type])
+
+	# The primitive class `Array`
+	var array_class: MClass = self.get_primitive_class("Array") is lazy
+
+	# A primitive type of `NativeArray`
+	fun native_array_type(elt_type: MType): MClassType do return native_array_class.get_mtype([elt_type])
+
+	# The primitive class `NativeArray`
+	var native_array_class: MClass = self.get_primitive_class("NativeArray") is lazy
 
 	# The primitive type `Sys`, the main type of the program, if any
 	fun sys_type: nullable MClassType
@@ -250,7 +269,9 @@ redef class MModule
 	fun get_primitive_class(name: String): MClass
 	do
 		var cla = self.model.get_mclasses_by_name(name)
-		if cla == null then
+		# Filter classes by introducing module
+		if cla != null then cla = [for c in cla do if self.in_importation <= c.intro_mmodule then c]
+		if cla == null or cla.is_empty then
 			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.
@@ -260,11 +281,12 @@ redef class MModule
 				cladef.add_in_hierarchy
 				return c
 			end
-			print("Fatal Error: no primitive class {name}")
+			print("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}:"
+			var msg = "Fatal Error: more than one primitive class {name} in {self}:"
 			for c in cla do msg += " {c.full_name}"
 			print msg
 			#exit(1)
@@ -361,9 +383,13 @@ class MClass
 	#
 	# It is the name of the class prefixed by the full_name of the `intro_mmodule`
 	# Example: `"owner::module::MyClass"`
-	redef var full_name is lazy do return "{self.intro_mmodule.full_name}::{name}"
+	redef var full_name is lazy do
+		return "{self.intro_mmodule.namespace_for(visibility)}::{name}"
+	end
 
-	redef var c_name is lazy do return "{intro_mmodule.c_name}__{name.to_cmangle}"
+	redef var c_name is lazy do
+		return "{intro_mmodule.c_namespace_for(visibility)}__{name.to_cmangle}"
+	end
 
 	# The number of generic formal parameters
 	# 0 if the class is not generic
@@ -373,6 +399,29 @@ class MClass
 	# is empty if the class is not generic
 	var mparameters = new Array[MParameterType]
 
+	# A string version of the signature a generic class.
+	#
+	# eg. `Map[K: nullable Object, V: nullable Object]`
+	#
+	# If the class in non generic the name is just given.
+	#
+	# eg. `Object`
+	fun signature_to_s: String
+	do
+		if arity == 0 then return name
+		var res = new FlatBuffer
+		res.append name
+		res.append "["
+		for i in [0..arity[ do
+			if i > 0 then res.append ", "
+			res.append mparameters[i].name
+			res.append ": "
+			res.append intro.bound_mtype.arguments[i].to_s
+		end
+		res.append "]"
+		return res.to_s
+	end
+
 	# Initialize `mparameters` from their names.
 	protected fun setup_parameter_names(parameter_names: nullable Array[String]) is
 		autoinit
@@ -428,8 +477,17 @@ class MClass
 	#
 	# Warning: such a definition may not exist in the early life of the object.
 	# In this case, the method will abort.
+	#
+	# Use `try_intro` instead
 	var intro: MClassDef is noinit
 
+	# The definition that introduces the class or null if not yet known.
+	#
+	# See `intro`
+	fun try_intro: nullable MClassDef do
+		if isset _intro then return _intro else return null
+	end
+
 	# Return the class `self` in the class hierarchy of the module `mmodule`.
 	#
 	# SEE: `MModule::flatten_mclass_hierarchy`
@@ -472,6 +530,21 @@ class MClass
 	end
 
 	private var get_mtype_cache = new HashMap[Array[MType], MGenericType]
+
+	# Is there a `new` factory to allow the pseudo instantiation?
+	var has_new_factory = false is writable
+
+	# Is `self` a standard or abstract class kind?
+	var is_class: Bool is lazy do return kind == concrete_kind or kind == abstract_kind
+
+	# Is `self` an interface kind?
+	var is_interface: Bool is lazy do return kind == interface_kind
+
+	# Is `self` an enum kind?
+	var is_enum: Bool is lazy do return kind == enum_kind
+
+	# Is `self` and abstract class?
+	var is_abstract: Bool is lazy do return kind == abstract_kind
 end
 
 
@@ -539,17 +612,29 @@ class MClassDef
 	# 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.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}"
 		else
-			return "{mmodule.full_name}#{mclass.full_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 mclass.c_name
+			return "{mmodule.c_namespace_for(mclass.visibility)}___{mclass.c_name}"
+		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.to_cmangle}"
+			return "{mmodule.c_name}___{mclass.c_name}"
 		end
 	end
 
@@ -607,7 +692,7 @@ class MClassDef
 	var in_hierarchy: nullable POSetElement[MClassDef] = null
 
 	# Is the definition the one that introduced `mclass`?
-	fun is_intro: Bool do return mclass.intro == self
+	fun is_intro: Bool do return isset mclass._intro and mclass.intro == self
 
 	# All properties introduced by the classdef
 	var intro_mproperties = new Array[MProperty]
@@ -677,6 +762,8 @@ abstract class MType
 		if sup isa MNullableType then
 			sup_accept_null = true
 			sup = sup.mtype
+		else if sup isa MNotNullType then
+			sup = sup.mtype
 		else if sup isa MNullType then
 			sup_accept_null = true
 		end
@@ -684,16 +771,20 @@ abstract class MType
 		# Can `sub` provide null or not?
 		# Thus we can match with `sup_accept_null`
 		# Also discard the nullable marker if it exists
+		var sub_reject_null = false
 		if sub isa MNullableType then
 			if not sup_accept_null then return false
 			sub = sub.mtype
+		else if sub isa MNotNullType then
+			sub_reject_null = true
+			sub = sub.mtype
 		else if sub isa MNullType then
 			return sup_accept_null
 		end
 		# Now the case of direct null and nullable is over.
 
 		# If `sub` is a formal type, then it is accepted if its bound is accepted
-		while sub isa MParameterType or sub isa MVirtualType do
+		while sub isa MFormalType do
 			#print "3.is {sub} a {sup}?"
 
 			# A unfixed formal type can only accept itself
@@ -701,12 +792,16 @@ abstract class MType
 
 			assert anchor != null
 			sub = sub.lookup_bound(mmodule, anchor)
+			if sub_reject_null then sub = sub.as_notnull
 
 			#print "3.is {sub} a {sup}?"
 
 			# Manage the second layer of null/nullable
 			if sub isa MNullableType then
-				if not sup_accept_null then return false
+				if not sup_accept_null and not sub_reject_null then return false
+				sub = sub.mtype
+			else if sub isa MNotNullType then
+				sub_reject_null = true
 				sub = sub.mtype
 			else if sub isa MNullType then
 				return sup_accept_null
@@ -714,10 +809,10 @@ abstract class MType
 		end
 		#print "4.is {sub} a {sup}? <- no more resolution"
 
-		assert sub isa MClassType # It is the only remaining type
+		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 MParameterType or sup isa MVirtualType then
+		if sup isa MFormalType then
 			return false
 		end
 
@@ -968,16 +1063,25 @@ abstract class MType
 		return res
 	end
 
-	# Return the not nullable version of the type
-	# Is the type is already not nullable, then self is returned.
+	# Remove the base type of a decorated (proxy) type.
+	# Is the type is not decorated, then self is returned.
 	#
-	# Note: this just remove the `nullable` notation, but the result can still contains null.
+	# Most of the time it is used to return the not nullable version of a nullable type.
+	# In this case, this just remove the `nullable` notation, but the result can still contains null.
 	# For instance if `self isa MNullType` or self is a formal type bounded by a nullable type.
-	fun as_notnullable: MType
+	# If you really want to exclude the `null` value, then use `as_notnull`
+	fun undecorate: MType
 	do
 		return self
 	end
 
+	# Returns the not null version of the type.
+	# That is `self` minus the `null` value.
+	#
+	# For most types, this return `self`.
+	# For formal types, this returns a special `MNotNullType`
+	fun as_notnull: MType do return self
+
 	private var as_nullable_cache: nullable MType = null
 
 
@@ -1177,13 +1281,13 @@ class MGenericType
 	redef var to_s: String 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
 			args.add t.full_name
 		end
-		return "{mclass.full_name}[{args.join(", ")}]}"
+		return "{mclass.full_name}[{args.join(", ")}]"
 	end
 
 	redef var c_name is lazy do
@@ -1239,9 +1343,19 @@ class MGenericType
 	end
 end
 
+# A formal type (either virtual of parametric).
+#
+# The main issue with formal types is that they offer very little information on their own
+# and need a context (anchor and mmodule) to be useful.
+abstract class MFormalType
+	super MType
+
+	redef var as_notnull = new MNotNullType(self) is lazy
+end
+
 # A virtual formal type.
 class MVirtualType
-	super MType
+	super MFormalType
 
 	# The property associated with the type.
 	# Its the definitions of this property that determine the bound or the virtual type.
@@ -1282,7 +1396,7 @@ class MVirtualType
 	redef fun lookup_fixed(mmodule: MModule, resolved_receiver: MType): MType
 	do
 		assert not resolved_receiver.need_anchor
-		resolved_receiver = resolved_receiver.as_notnullable
+		resolved_receiver = resolved_receiver.undecorate
 		assert resolved_receiver isa MClassType # It is the only remaining type
 
 		var prop = lookup_single_definition(mmodule, resolved_receiver)
@@ -1369,7 +1483,7 @@ end
 # Note that parameter types are shared among class refinements.
 # Therefore parameter only have an internal name (see `to_s` for details).
 class MParameterType
-	super MType
+	super MFormalType
 
 	# The generic class where the parameter belong
 	var mclass: MClass
@@ -1391,7 +1505,7 @@ class MParameterType
 	redef fun lookup_bound(mmodule: MModule, resolved_receiver: MType): MType
 	do
 		assert not resolved_receiver.need_anchor
-		resolved_receiver = resolved_receiver.as_notnullable
+		resolved_receiver = resolved_receiver.undecorate
 		assert resolved_receiver isa MClassType # It is the only remaining type
 		var goalclass = self.mclass
 		if resolved_receiver.mclass == goalclass then
@@ -1419,7 +1533,7 @@ class MParameterType
 	redef fun lookup_fixed(mmodule: MModule, resolved_receiver: MType): MType
 	do
 		assert not resolved_receiver.need_anchor
-		resolved_receiver = resolved_receiver.as_notnullable
+		resolved_receiver = resolved_receiver.undecorate
 		assert resolved_receiver isa MClassType # It is the only remaining type
 		var res = self.resolve_for(resolved_receiver.mclass.mclass_type, resolved_receiver, mmodule, false)
 		return res
@@ -1453,6 +1567,7 @@ 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
@@ -1491,33 +1606,24 @@ class MParameterType
 	end
 end
 
-# A type prefixed with "nullable"
-class MNullableType
+# A type that decorates another type.
+#
+# The point of this class is to provide a common implementation of sevices that just forward to the original type.
+# Specific decorator are expected to redefine (or to extend) the default implementation as this suit them.
+abstract class MProxyType
 	super MType
-
-	# The base type of the nullable type
+	# The base type
 	var mtype: MType
 
 	redef fun model do return self.mtype.model
-
-	init
-	do
-		self.to_s = "nullable {mtype}"
-	end
-
-	redef var to_s: String is noinit
-
-	redef var full_name is lazy do return "nullable {mtype.full_name}"
-
-	redef var c_name is lazy do return "nullable__{mtype.c_name}"
-
 	redef fun need_anchor do return mtype.need_anchor
-	redef fun as_nullable do return self
-	redef fun as_notnullable do return mtype
+	redef fun as_nullable do return mtype.as_nullable
+	redef fun as_notnull do return mtype.as_notnull
+	redef fun undecorate do return mtype.undecorate
 	redef fun resolve_for(mtype, anchor, mmodule, cleanup_virtual)
 	do
 		var res = self.mtype.resolve_for(mtype, anchor, mmodule, cleanup_virtual)
-		return res.as_nullable
+		return res
 	end
 
 	redef fun can_resolve_for(mtype, anchor, mmodule)
@@ -1525,12 +1631,10 @@ class MNullableType
 		return self.mtype.can_resolve_for(mtype, anchor, mmodule)
 	end
 
-	# Efficiently returns `mtype.lookup_fixed(mmodule, resolved_receiver).as_nullable`
 	redef fun lookup_fixed(mmodule, resolved_receiver)
 	do
 		var t = mtype.lookup_fixed(mmodule, resolved_receiver)
-		if t == mtype then return self
-		return t.as_nullable
+		return t
 	end
 
 	redef fun depth do return self.mtype.depth
@@ -1556,6 +1660,64 @@ class MNullableType
 	end
 end
 
+# A type prefixed with "nullable"
+class MNullableType
+	super MProxyType
+
+	init
+	do
+		self.to_s = "nullable {mtype}"
+	end
+
+	redef var to_s: String is noinit
+
+	redef var full_name is lazy do return "nullable {mtype.full_name}"
+
+	redef var c_name is lazy do return "nullable__{mtype.c_name}"
+
+	redef fun as_nullable do return self
+	redef fun resolve_for(mtype, anchor, mmodule, cleanup_virtual)
+	do
+		var res = super
+		return res.as_nullable
+	end
+
+	# Efficiently returns `mtype.lookup_fixed(mmodule, resolved_receiver).as_nullable`
+	redef fun lookup_fixed(mmodule, resolved_receiver)
+	do
+		var t = super
+		if t == mtype then return self
+		return t.as_nullable
+	end
+end
+
+# A non-null version of a formal type.
+#
+# When a formal type in bounded to a nullable type, this is the type of the not null version of it.
+class MNotNullType
+	super MProxyType
+
+	redef fun to_s do return "not null {mtype}"
+	redef var full_name is lazy do return "not null {mtype.full_name}"
+	redef var c_name is lazy do return "notnull__{mtype.c_name}"
+
+	redef fun as_notnull do return self
+
+	redef fun resolve_for(mtype, anchor, mmodule, cleanup_virtual)
+	do
+		var res = super
+		return res.as_notnull
+	end
+
+	# Efficiently returns `mtype.lookup_fixed(mmodule, resolved_receiver).as_notnull`
+	redef fun lookup_fixed(mmodule, resolved_receiver)
+	do
+		var t = super
+		if t == mtype then return self
+		return t.as_notnull
+	end
+end
+
 # The type of the only value null
 #
 # The is only one null type per model, see `MModel::null_type`.
@@ -1566,6 +1728,33 @@ class MNullType
 	redef fun full_name do return "null"
 	redef fun c_name do return "null"
 	redef fun as_nullable do return self
+
+	redef var as_notnull = new MBottomType(model) is lazy
+	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
+
+# 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.
+#
+# Semantically it is the singleton `null.as_notnull`.
+class MBottomType
+	super MType
+	redef var model: Model
+	redef fun to_s do return "bottom"
+	redef fun full_name do return "bottom"
+	redef fun c_name do return "bottom"
+	redef fun as_nullable do return model.null_type
+	redef fun as_notnull do return self
 	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
@@ -1584,6 +1773,15 @@ class MSignature
 	# The each parameter (in order)
 	var mparameters: Array[MParameter]
 
+	# Returns a parameter named `name`, if any.
+	fun mparameter_by_name(name: String): nullable MParameter
+	do
+		for p in mparameters do
+			if p.name == name then return p
+		end
+		return null
+	end
+
 	# The return type (null for a procedure)
 	var return_mtype: nullable MType
 
@@ -1629,7 +1827,7 @@ class MSignature
 	# Example: for "(a: Int, b: Bool..., c: Char)" #-> vararg_rank=1
 	var vararg_rank: Int is noinit
 
-	# The number or parameters
+	# The number of parameters
 	fun arity: Int do return mparameters.length
 
 	redef fun to_s
@@ -1736,18 +1934,22 @@ abstract class MProperty
 	# 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"
+	# Example: "my_package::my_module::MyClass::my_method"
 	redef var full_name is lazy do
-		return "{intro_mclassdef.mmodule.full_name}::{intro_mclassdef.mclass.name}::{name}"
+		return "{intro_mclassdef.mmodule.namespace_for(visibility)}::{intro_mclassdef.mclass.name}::{name}"
 	end
 
 	redef var c_name is lazy do
-		return "{intro_mclassdef.mmodule.c_name}__{intro_mclassdef.mclass.c_name}__{name.to_cmangle}"
+		# FIXME use `namespace_for`
+		return "{intro_mclassdef.mmodule.c_name}__{intro_mclassdef.mclass.name.to_cmangle}__{name.to_cmangle}"
 	end
 
 	# The visibility of the property
 	var visibility: MVisibility
 
+	# Is the property usable as an initializer?
+	var is_autoinit = false is writable
+
 	init
 	do
 		intro_mclassdef.intro_mproperties.add(self)
@@ -1778,10 +1980,13 @@ abstract class MProperty
 	# If mtype does not know mproperty then an empty array is returned.
 	#
 	# If you want the really most specific property, then look at `lookup_first_definition`
+	#
+	# REQUIRE: `not mtype.need_anchor` to simplify the API (no `anchor` parameter)
+	# ENSURE: `not mtype.has_mproperty(mmodule, self) == result.is_empty`
 	fun lookup_definitions(mmodule: MModule, mtype: MType): Array[MPROPDEF]
 	do
 		assert not mtype.need_anchor
-		mtype = mtype.as_notnullable
+		mtype = mtype.undecorate
 
 		var cache = self.lookup_definitions_cache[mmodule, mtype]
 		if cache != null then return cache
@@ -1816,11 +2021,12 @@ abstract class MProperty
 	#
 	# If you want the really most specific property, then look at `lookup_next_definition`
 	#
-	# FIXME: Move to `MPropDef`?
+	# REQUIRE: `not mtype.need_anchor` to simplify the API (no `anchor` parameter)
+	# ENSURE: `not mtype.has_mproperty(mmodule, self) implies result.is_empty`
 	fun lookup_super_definitions(mmodule: MModule, mtype: MType): Array[MPROPDEF]
 	do
 		assert not mtype.need_anchor
-		mtype = mtype.as_notnullable
+		mtype = mtype.undecorate
 
 		# First, select all candidates
 		var candidates = new Array[MPROPDEF]
@@ -1884,24 +2090,28 @@ abstract class MProperty
 	#
 	# FIXME: the linearization is still unspecified
 	#
-	# REQUIRE: `not mtype.need_anchor`
+	# REQUIRE: `not mtype.need_anchor` to simplify the API (no `anchor` parameter)
 	# REQUIRE: `mtype.has_mproperty(mmodule, self)`
 	fun lookup_first_definition(mmodule: MModule, mtype: MType): MPROPDEF
 	do
-		assert mtype.has_mproperty(mmodule, self)
 		return lookup_all_definitions(mmodule, mtype).first
 	end
 
 	# Return all definitions in a linearization order
 	# Most specific first, most general last
+	#
+	# REQUIRE: `not mtype.need_anchor` to simplify the API (no `anchor` parameter)
+	# REQUIRE: `mtype.has_mproperty(mmodule, self)`
 	fun lookup_all_definitions(mmodule: MModule, mtype: MType): Array[MPROPDEF]
 	do
-		assert not mtype.need_anchor
-		mtype = mtype.as_notnullable
+		mtype = mtype.undecorate
 
 		var cache = self.lookup_all_definitions_cache[mmodule, mtype]
 		if cache != null then return cache
 
+		assert not mtype.need_anchor
+		assert mtype.has_mproperty(mmodule, self)
+
 		#print "select prop {mproperty} for {mtype} in {self}"
 		# First, select all candidates
 		var candidates = new Array[MPROPDEF]
@@ -1956,6 +2166,10 @@ 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
@@ -2018,42 +2232,66 @@ abstract class MPropDef
 	# Therefore the combination of identifiers is awful,
 	# the worst case being
 	#
-	# ~~~nitish
-	# "{mclassdef.mmodule.full_name}#{mclassdef.mclass.intro_mmodule.full_name}::{mclassdef.name}#{mproperty.intro_mclassdef.mmodule.full_name}::{mproperty.intro_mclassdef.name}::{name}"
-	# ~~~
+	#  * 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"
 	#
 	# Fortunately, the full-name is simplified when entities are repeated.
-	# The simplest form is "my_module#MyClass#my_property".
+	# For the previous case, the simplest form is "p#A#x".
 	redef var full_name is lazy do
 		var res = new FlatBuffer
-		res.append mclassdef.mmodule.full_name
-		res.append "#"
-		if not mclassdef.is_intro then
-			res.append mclassdef.mclass.intro_mmodule.full_name
-			res.append "::"
-		end
-		res.append mclassdef.name
+
+		# The first part is the mclassdef. Worst case is "r::o#q::n::B"
+		res.append mclassdef.full_name
+
 		res.append "#"
-		if mproperty.intro_mclassdef.mmodule != mclassdef.mmodule then
-			res.append mproperty.intro_mclassdef.mmodule.full_name
-			res.append "::"
-		end
-		if mclassdef.mclass != mproperty.intro_mclassdef.mclass then
-			res.append mproperty.intro_mclassdef.mclass.name
-			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.mpackage != mproperty.intro_mclassdef.mmodule.mpackage then
+				# precise "p::m" only if "p" != "r"
+				res.append mproperty.intro_mclassdef.mmodule.full_name
+				res.append "::"
+			else if mproperty.visibility <= private_visibility then
+				# 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.mpackage then
+					res.append "::"
+					res.append mproperty.intro_mclassdef.mmodule.name
+					res.append "::"
+				end
+			end
+			if mclassdef.mclass != mproperty.intro_mclassdef.mclass then
+				# precise "B" only if not the same class than "A"
+				res.append mproperty.intro_mclassdef.name
+				res.append "::"
+			end
+			# Always use the property name "x"
+			res.append mproperty.name
 		end
-		res.append name
 		return res.to_s
 	end
 
 	redef var c_name is lazy do
 		var res = new FlatBuffer
 		res.append mclassdef.c_name
-		res.append "__"
-		if is_intro then
+		res.append "___"
+		if mclassdef.mclass == mproperty.intro_mclassdef.mclass then
 			res.append name.to_cmangle
 		else
-			res.append mproperty.c_name.to_cmangle
+			if mclassdef.mmodule != mproperty.intro_mclassdef.mmodule then
+				res.append mproperty.intro_mclassdef.mmodule.c_name
+				res.append "__"
+			end
+			if mclassdef.mclass != mproperty.intro_mclassdef.mclass then
+				res.append mproperty.intro_mclassdef.name.to_cmangle
+				res.append "__"
+			end
+			res.append mproperty.name.to_cmangle
 		end
 		return res.to_s
 	end
@@ -2065,7 +2303,7 @@ abstract class MPropDef
 	redef var to_s: String 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`.
 	#