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

diff --git a/src/modelize/modelize_property.nit b/src/modelize/modelize_property.nit
index f1cce80..aabe809 100644
--- a/src/modelize/modelize_property.nit
+++ b/src/modelize/modelize_property.nit
@@ -80,7 +80,6 @@ redef class ModelBuilder
 	end
 
 	# Build the properties of `nclassdef`.
-	# REQUIRE: all superclasses are built.
 	private fun build_properties(nclassdef: AClassdef)
 	do
 		# Force building recursively
@@ -110,7 +109,8 @@ redef class ModelBuilder
 				if mpropdef.bound == null then continue
 				if not check_virtual_types_circularity(npropdef, mpropdef.mproperty, mclassdef.bound_mtype, mclassdef.mmodule) then
 					# Invalidate the bound
-					mpropdef.bound = mclassdef.mmodule.model.null_type
+					mpropdef.is_broken = true
+					mpropdef.bound = new MErrorType(mclassdef.mmodule.model)
 				end
 			end
 			for npropdef in nclassdef2.n_propdefs do
@@ -144,7 +144,7 @@ redef class ModelBuilder
 		# Look for the init in Object, or create it
 		if mclassdef.mclass.name == "Object" and the_root_init_mmethod == null then
 			# Create the implicit root-init method
-			var mprop = new MMethod(mclassdef, "init", mclassdef.mclass.visibility)
+			var mprop = new MMethod(mclassdef, "init", nclassdef.location, mclassdef.mclass.visibility)
 			mprop.is_root_init = true
 			var mpropdef = new MMethodDef(mclassdef, mprop, nclassdef.location)
 			var mparameters = new Array[MParameter]
@@ -152,15 +152,11 @@ redef class ModelBuilder
 			mpropdef.msignature = msignature
 			mpropdef.new_msignature = msignature
 			mprop.is_init = true
-			nclassdef.mfree_init = mpropdef
 			self.toolcontext.info("{mclassdef} gets a free empty constructor {mpropdef}{msignature}", 3)
 			the_root_init_mmethod = mprop
 			return
 		end
 
-		# Is the class forbid constructors?
-		if not mclassdef.mclass.kind.need_init then return
-
 		# Is there already a constructor defined?
 		var defined_init: nullable MMethodDef = null
 		for mpropdef in mclassdef.mpropdefs do
@@ -182,29 +178,21 @@ redef class ModelBuilder
 		var initializers = new Array[MProperty]
 		for npropdef in nclassdef.n_propdefs do
 			if npropdef isa AMethPropdef then
-				if npropdef.mpropdef == null then return # Skip broken method
-				var at = npropdef.get_single_annotation("autoinit", self)
-				if at == null then continue # Skip non tagged init
-
-				var sig = npropdef.mpropdef.msignature
+				if not npropdef.is_autoinit then continue # Skip non tagged autoinit
+				var mpropdef = npropdef.mpropdef
+				if mpropdef == null then return # Skip broken method
+				var sig = mpropdef.msignature
 				if sig == null then continue # Skip broken method
 
-				if not npropdef.mpropdef.is_intro then
-					self.error(at, "Error: `autoinit` cannot be set on redefinitions.")
-					continue
-				end
-
-				for param in sig.mparameters do
-					var ret_type = param.mtype
-					var mparameter = new MParameter(param.name, ret_type, false, ret_type isa MNullableType)
-					mparameters.add(mparameter)
-				end
-				initializers.add(npropdef.mpropdef.mproperty)
-				npropdef.mpropdef.mproperty.is_autoinit = true
+				mparameters.add_all sig.mparameters
+				initializers.add(mpropdef.mproperty)
+				mpropdef.mproperty.is_autoinit = true
 			end
 			if npropdef isa AAttrPropdef then
 				var mreadpropdef = npropdef.mreadpropdef
-				if mreadpropdef == null or mreadpropdef.msignature == null then return # Skip broken attribute
+				if mreadpropdef == null then return # Skip broken attribute
+				var msignature = mreadpropdef.msignature
+				if msignature == null then return # Skip broken attribute
 				if npropdef.noinit then continue # Skip noinit attribute
 				var atlateinit = npropdef.get_single_annotation("lateinit", self)
 				if atlateinit != null then
@@ -214,25 +202,28 @@ redef class ModelBuilder
 					mreadpropdef.mproperty.is_autoinit = true
 					continue
 				end
-				if npropdef.has_value then continue
-				var paramname = mreadpropdef.mproperty.name
-				var ret_type = mreadpropdef.msignature.return_mtype
-				if ret_type == null then return
-				var mparameter = new MParameter(paramname, ret_type, false, ret_type isa MNullableType)
-				mparameters.add(mparameter)
+				if npropdef.has_value and not npropdef.is_optional then continue
 				var msetter = npropdef.mwritepropdef
 				if msetter == null then
 					# No setter, it is a readonly attribute, so just add it
+					var paramname = mreadpropdef.mproperty.name
+					var ret_type = msignature.return_mtype
+					if ret_type == null then return
+					var mparameter = new MParameter(paramname, ret_type, false)
+					mparameters.add(mparameter)
+
 					initializers.add(npropdef.mpropdef.mproperty)
 					npropdef.mpropdef.mproperty.is_autoinit = true
 				else
 					# Add the setter to the list
+					mparameters.add_all msetter.msignature.mparameters
 					initializers.add(msetter.mproperty)
 					msetter.mproperty.is_autoinit = true
 				end
 			end
 		end
 
+		var the_root_init_mmethod = self.the_root_init_mmethod
 		if the_root_init_mmethod == null then return
 
 		# Look for most-specific new-stype init definitions
@@ -287,13 +278,7 @@ redef class ModelBuilder
 				if pd isa MMethodDef then
 					# Get the signature resolved for the current receiver
 					var sig = pd.msignature.resolve_for(mclassdef.mclass.mclass_type, mclassdef.bound_mtype, mclassdef.mmodule, false)
-					# Because the last parameter of setters is never default, try to default them for the autoinit.
-					for param in sig.mparameters do
-						if not param.is_default and param.mtype isa MNullableType then
-							param = new MParameter(param.name, param.mtype, param.is_vararg, true)
-						end
-						mparameters.add(param)
-					end
+					mparameters.add_all(sig.mparameters)
 				else
 					# TODO attributes?
 					abort
@@ -315,7 +300,12 @@ redef class ModelBuilder
 					var i = 0
 					for p in spd.initializers do
 						if p != longest.initializers[i] then
-							self.error(nclassdef, "Error: conflict for inherited inits {spd}({spd.initializers.join(", ")}) and {longest}({longest.initializers.join(", ")})")
+							var proposal = new ArraySet[MProperty]
+							for spd2 in spropdefs do
+								proposal.add_all spd2.initializers
+							end
+							proposal.add_all initializers
+							self.error(nclassdef, "Error: cannot generate automatic init for class {mclassdef.mclass}. Conflict in the order in inherited initializers {spd}({spd.initializers.join(", ")}) and {longest}({longest.initializers.join(", ")}). Use `autoinit` to order initializers. eg `autoinit {proposal.join(", ")}`")
 							# TODO: invalidate the initializer to avoid more errors
 							return
 						end
@@ -359,14 +349,13 @@ redef class ModelBuilder
 		end
 
 		# Else create the local implicit basic init definition
-		var mprop = the_root_init_mmethod.as(not null)
+		var mprop = the_root_init_mmethod
 		var mpropdef = new MMethodDef(mclassdef, mprop, nclassdef.location)
 		mpropdef.has_supercall = true
 		mpropdef.initializers.add_all(initializers)
 		var msignature = new MSignature(mparameters, null)
 		mpropdef.new_msignature = msignature
 		mpropdef.msignature = new MSignature(new Array[MParameter], null) # always an empty real signature
-		nclassdef.mfree_init = mpropdef
 		self.toolcontext.info("{mclassdef} gets a free constructor for attributes {mpropdef}{msignature}", 3)
 		mclassdef.mclass.root_init = mpropdef
 	end
@@ -384,7 +373,7 @@ redef class ModelBuilder
 		mtype = mtype.undecorate
 		if mtype isa MClassType then
 			vis_type = mtype.mclass.visibility
-			mmodule_type = mtype.mclass.intro.mmodule
+			mmodule_type = mtype.mclass.intro_mmodule
 		else if mtype isa MVirtualType then
 			vis_type = mtype.mproperty.visibility
 			mmodule_type = mtype.mproperty.intro_mclassdef.mmodule
@@ -392,6 +381,10 @@ redef class ModelBuilder
 			# nothing, always visible
 		else if mtype isa MNullType then
 			# nothing to do.
+		else if mtype isa MBottomType then
+			# nothing to do.
+		else if mtype isa MErrorType then
+			# nothing to do.
 		else
 			node.debug "Unexpected type {mtype}"
 			abort
@@ -451,8 +444,7 @@ redef class ModelBuilder
 				var vt = t.mproperty
 				# Because `vt` is possibly unchecked, we have to do the bound-lookup manually
 				var defs = vt.lookup_definitions(mmodule, recv)
-				# TODO something to manage correctly bound conflicts
-				assert not defs.is_empty
+				if defs.is_empty then return false
 				nexts = new Array[MType]
 				for d in defs do
 					var next = defs.first.bound
@@ -497,9 +489,6 @@ end
 redef class AClassdef
 	# Marker used in `ModelBuilder::build_properties`
 	private var build_properties_is_done = false
-
-	# The free init (implicitely constructed by the class if required)
-	var mfree_init: nullable MMethodDef = null
 end
 
 redef class MClass
@@ -601,7 +590,7 @@ redef class APropdef
 			var mdoc = ndoc.to_mdoc
 			mpropdef.mdoc = mdoc
 			mdoc.original_mentity = mpropdef
-		else if mpropdef.is_intro and mpropdef.mproperty.visibility >= protected_visibility then
+		else if mpropdef.is_intro and mpropdef.mproperty.visibility >= protected_visibility and mpropdef.name != "new" then
 			modelbuilder.advice(self, "missing-doc", "Documentation warning: Undocumented property `{mpropdef.mproperty}`")
 		end
 
@@ -640,12 +629,12 @@ redef class APropdef
 				return false
 			end
 
-			# Check for full-name conflicts in the project.
-			# A public property should have a unique qualified name `project::class::prop`.
+			# Check for full-name conflicts in the package.
+			# A public property should have a unique qualified name `package::class::prop`.
 			if mprop.intro_mclassdef.mmodule.mgroup != null and mprop.visibility >= protected_visibility then
 				var others = modelbuilder.model.get_mproperties_by_name(mprop.name)
 				if others != null then for other in others do
-					if other != mprop and other.intro_mclassdef.mmodule.mgroup != null and other.intro_mclassdef.mmodule.mgroup.mproject == mprop.intro_mclassdef.mmodule.mgroup.mproject and other.intro_mclassdef.mclass.name == mprop.intro_mclassdef.mclass.name and other.visibility >= protected_visibility then
+					if other != mprop and other.intro_mclassdef.mmodule.mgroup != null and other.intro_mclassdef.mmodule.mgroup.mpackage == mprop.intro_mclassdef.mmodule.mgroup.mpackage and other.intro_mclassdef.mclass.name == mprop.intro_mclassdef.mclass.name and other.visibility >= protected_visibility then
 						modelbuilder.advice(self, "full-name-conflict", "Warning: A property named `{other.full_name}` is already defined in module `{other.intro_mclassdef.mmodule}` for the class `{other.intro_mclassdef.mclass.name}`.")
 						break
 					end
@@ -682,14 +671,13 @@ redef class ASignature
 	# Visit and fill information about a signature
 	private fun visit_signature(modelbuilder: ModelBuilder, mclassdef: MClassDef): Bool
 	do
-		var mmodule = mclassdef.mmodule
 		var param_names = self.param_names
 		var param_types = self.param_types
 		for np in self.n_params do
 			param_names.add(np.n_id.text)
 			var ntype = np.n_type
 			if ntype != null then
-				var mtype = modelbuilder.resolve_mtype_unchecked(mmodule, mclassdef, ntype, true)
+				var mtype = modelbuilder.resolve_mtype_unchecked(mclassdef, ntype, true)
 				if mtype == null then return false # Skip error
 				for i in [0..param_names.length-param_types.length[ do
 					param_types.add(mtype)
@@ -706,7 +694,7 @@ redef class ASignature
 		end
 		var ntype = self.n_type
 		if ntype != null then
-			self.ret_type = modelbuilder.resolve_mtype_unchecked(mmodule, mclassdef, ntype, true)
+			self.ret_type = modelbuilder.resolve_mtype_unchecked(mclassdef, ntype, true)
 			if self.ret_type == null then return false # Skip error
 		end
 
@@ -720,17 +708,18 @@ redef class ASignature
 		for np in self.n_params do
 			var ntype = np.n_type
 			if ntype != null then
-				if modelbuilder.resolve_mtype(mclassdef.mmodule, mclassdef, ntype) == null then
+				if modelbuilder.resolve_mtype(mclassdef, ntype) == null then
 					res = false
 				end
 			end
 		end
 		var ntype = self.n_type
 		if ntype != null then
-			if modelbuilder.resolve_mtype(mclassdef.mmodule, mclassdef, ntype) == null then
+			if modelbuilder.resolve_mtype(mclassdef, ntype) == null then
 				res = false
 			end
 		end
+		if not res then is_broken = true
 		return res
 	end
 end
@@ -743,6 +732,8 @@ end
 redef class AMethPropdef
 	redef type MPROPDEF: MMethodDef
 
+	# Is the method annotated `autoinit`?
+	var is_autoinit = false
 
 	# Can self be used as a root init?
 	private fun look_like_a_root_init(modelbuilder: ModelBuilder, mclassdef: MClassDef): Bool
@@ -778,22 +769,21 @@ redef class AMethPropdef
 	do
 		var n_kwinit = n_kwinit
 		var n_kwnew = n_kwnew
-		var is_init = n_kwinit != null or n_kwnew != null
+		var is_new = n_kwnew != null
+		var is_init = n_kwinit != null or is_new
 		var name: String
 		var amethodid = self.n_methid
 		var name_node: ANode
 		if amethodid == null then
-			if not is_init then
-				name = "main"
-				name_node = self
-			else if n_kwinit != null then
+			if n_kwinit != null then
 				name = "init"
 				name_node = n_kwinit
 			else if n_kwnew != null then
 				name = "new"
 				name_node = n_kwnew
 			else
-				abort
+				name = "main"
+				name_node = self
 			end
 		else if amethodid isa AIdMethid then
 			name = amethodid.n_id.text
@@ -831,17 +821,21 @@ redef class AMethPropdef
 		end
 		if mprop == null then
 			var mvisibility = new_property_visibility(modelbuilder, mclassdef, self.n_visibility)
-			mprop = new MMethod(mclassdef, name, mvisibility)
+			mprop = new MMethod(mclassdef, name, self.location, mvisibility)
 			if look_like_a_root_init and modelbuilder.the_root_init_mmethod == null then
 				modelbuilder.the_root_init_mmethod = mprop
 				mprop.is_root_init = true
 			end
 			mprop.is_init = is_init
-			mprop.is_new = n_kwnew != null
-			if mprop.is_new then mclassdef.mclass.has_new_factory = true
+			mprop.is_new = is_new
+			if is_new then mclassdef.mclass.has_new_factory = true
 			if name == "sys" then mprop.is_toplevel = true # special case for sys allowed in `new` factories
-			self.check_redef_keyword(modelbuilder, mclassdef, n_kwredef, false, mprop)
+			if not self.check_redef_keyword(modelbuilder, mclassdef, n_kwredef, false, mprop) then
+				mprop.is_broken = true
+				return
+			end
 		else
+			if mprop.is_broken then return
 			if not self.check_redef_keyword(modelbuilder, mclassdef, n_kwredef, not self isa AMainMethPropdef, mprop) then return
 			check_redef_property_visibility(modelbuilder, self.n_visibility, mprop)
 		end
@@ -850,7 +844,10 @@ redef class AMethPropdef
 		if is_init then
 			for p, n in mclassdef.mprop2npropdef do
 				if p != mprop and p isa MMethod and p.name == name then
-					check_redef_keyword(modelbuilder, mclassdef, n_kwredef, false, p)
+					if not check_redef_keyword(modelbuilder, mclassdef, n_kwredef, false, p) then
+						mprop.is_broken = true
+						return
+					end
 					break
 				end
 			end
@@ -875,11 +872,12 @@ redef class AMethPropdef
 	do
 		var mpropdef = self.mpropdef
 		if mpropdef == null then return # Error thus skiped
+		var mproperty = mpropdef.mproperty
 		var mclassdef = mpropdef.mclassdef
 		var mmodule = mclassdef.mmodule
 		var nsig = self.n_signature
 
-		if mpropdef.mproperty.is_root_init and not mclassdef.is_intro then
+		if mproperty.is_root_init and not mclassdef.is_intro then
 			var root_init = mclassdef.mclass.root_init
 			if root_init != null then
 				# Inherit the initializers by refinement
@@ -909,7 +907,7 @@ redef class AMethPropdef
 		# FIXME: do not inherit from the intro, but from the most specific
 		var msignature: nullable MSignature = null
 		if not mpropdef.is_intro then
-			msignature = mpropdef.mproperty.intro.msignature
+			msignature = mproperty.intro.msignature
 			if msignature == null then return # Skip error
 
 			# The local signature is adapted to use the local formal types, if any.
@@ -919,14 +917,14 @@ redef class AMethPropdef
 			if param_names.length != msignature.arity then
 				var node: ANode
 				if nsig != null then node = nsig else node = self
-				modelbuilder.error(node, "Redef Error: expected {msignature.arity} parameter(s) for `{mpropdef.mproperty.name}{msignature}`; got {param_names.length}. See introduction at `{mpropdef.mproperty.full_name}`.")
+				modelbuilder.error(node, "Redef Error: expected {msignature.arity} parameter(s) for `{mproperty.name}{msignature}`; got {param_names.length}. See introduction at `{mproperty.full_name}`.")
 				return
 			end
-		else if mpropdef.mproperty.is_init and not mpropdef.mproperty.is_new then
+		else if mproperty.is_init and not mproperty.is_new then
 			# FIXME UGLY: inherit signature from a super-constructor
 			for msupertype in mclassdef.supertypes do
 				msupertype = msupertype.anchor_to(mmodule, mclassdef.bound_mtype)
-				var candidate = modelbuilder.try_get_mproperty_by_name2(self, mmodule, msupertype, mpropdef.mproperty.name)
+				var candidate = modelbuilder.try_get_mproperty_by_name2(self, mmodule, msupertype, mproperty.name)
 				if candidate != null then
 					if msignature == null then
 						msignature = candidate.intro.as(MMethodDef).msignature
@@ -957,26 +955,20 @@ redef class AMethPropdef
 
 		var mparameters = new Array[MParameter]
 		for i in [0..param_names.length[ do
-			var is_default = false
-			if vararg_rank == -1 and param_types[i] isa MNullableType then
-				if i < param_names.length-1 or accept_special_last_parameter then
-					is_default = true
-				end
-			end
-			var mparameter = new MParameter(param_names[i], param_types[i], i == vararg_rank, is_default)
+			var mparameter = new MParameter(param_names[i], param_types[i], i == vararg_rank)
 			if nsig != null then nsig.n_params[i].mparameter = mparameter
 			mparameters.add(mparameter)
 		end
 
 		# In `new`-factories, the return type is by default the classtype.
-		if ret_type == null and mpropdef.mproperty.is_new then ret_type = mclassdef.mclass.mclass_type
+		if ret_type == null and mproperty.is_new then ret_type = mclassdef.mclass.mclass_type
 
 		# Special checks for operator methods
 		if not accept_special_last_parameter and mparameters.not_empty and mparameters.last.is_vararg then
-			modelbuilder.error(self.n_signature.n_params.last, "Error: illegal variadic parameter `{mparameters.last}` for `{mpropdef.mproperty.name}`.")
+			modelbuilder.error(self.n_signature.n_params.last, "Error: illegal variadic parameter `{mparameters.last}` for `{mproperty.name}`.")
 		end
 		if ret_type == null and return_is_mandatory then
-			modelbuilder.error(self.n_methid, "Error: mandatory return type for `{mpropdef.mproperty.name}`.")
+			modelbuilder.error(self.n_methid, "Error: mandatory return type for `{mproperty.name}`.")
 		end
 
 		msignature = new MSignature(mparameters, ret_type)
@@ -988,6 +980,17 @@ redef class AMethPropdef
 		# Check annotations
 		var at = self.get_single_annotation("lazy", modelbuilder)
 		if at != null then modelbuilder.error(at, "Syntax Error: `lazy` must be used on attributes.")
+
+		var atautoinit = self.get_single_annotation("autoinit", modelbuilder)
+		if atautoinit != null then
+			if not mpropdef.is_intro then
+				modelbuilder.error(atautoinit, "Error: `autoinit` cannot be set on redefinitions.")
+			else if not mclassdef.is_intro then
+				modelbuilder.error(atautoinit, "Error: `autoinit` cannot be used in class refinements.")
+			else
+				self.is_autoinit = true
+			end
+		end
 	end
 
 	redef fun check_signature(modelbuilder)
@@ -997,13 +1000,14 @@ redef class AMethPropdef
 		var mclassdef = mpropdef.mclassdef
 		var mmodule = mclassdef.mmodule
 		var nsig = self.n_signature
-		var mysignature = self.mpropdef.msignature
+		var mysignature = mpropdef.msignature
 		if mysignature == null then return # Error thus skiped
 
 		# Check
 		if nsig != null then
 			if not nsig.check_signature(modelbuilder, mclassdef) then
-				self.mpropdef.msignature = null # invalidate
+				mpropdef.msignature = null # invalidate
+				mpropdef.is_broken = true
 				return # Forward error
 			end
 		end
@@ -1017,8 +1021,9 @@ redef class AMethPropdef
 			var precursor_ret_type = msignature.return_mtype
 			var ret_type = mysignature.return_mtype
 			if ret_type != null and precursor_ret_type == null then
-				modelbuilder.error(nsig.n_type.as(not null), "Redef Error: `{mpropdef.mproperty}` is a procedure, not a function.")
-				self.mpropdef.msignature = null
+				modelbuilder.error(nsig.n_type, "Redef Error: `{mpropdef.mproperty}` is a procedure, not a function.")
+				mpropdef.msignature = null
+				mpropdef.is_broken = true
 				return
 			end
 
@@ -1030,7 +1035,8 @@ redef class AMethPropdef
 					var node = nsig.n_params[i]
 					if not modelbuilder.check_sametype(node, mmodule, mclassdef.bound_mtype, myt, prt) then
 						modelbuilder.error(node, "Redef Error: expected `{prt}` for parameter `{mysignature.mparameters[i].name}'; got `{myt}`.")
-						self.mpropdef.msignature = null
+						mpropdef.msignature = null
+						mpropdef.is_broken = true
 					end
 				end
 			end
@@ -1043,12 +1049,13 @@ redef class AMethPropdef
 					ret_type = precursor_ret_type
 				else if not modelbuilder.check_subtype(node, mmodule, mclassdef.bound_mtype, ret_type, precursor_ret_type) then
 					modelbuilder.error(node, "Redef Error: expected `{precursor_ret_type}` for return type; got `{ret_type}`.")
-					self.mpropdef.msignature = null
+					mpropdef.msignature = null
+					mpropdef.is_broken = true
 				end
 			end
 		end
 
-		if mysignature.arity > 0 then
+		if nsig != null then
 			# Check parameters visibility
 			for i in [0..mysignature.arity[ do
 				var nt = nsig.n_params[i].n_type
@@ -1063,6 +1070,8 @@ redef class AMethPropdef
 	# For parameters, type is always useless in a redef.
 	# For return type, type is useless if not covariant with introduction.
 	redef fun check_repeated_types(modelbuilder) do
+		var mpropdef = self.mpropdef
+		if mpropdef == null then return
 		if mpropdef.is_intro or n_signature == null then return
 		# check params
 		for param in n_signature.n_params do
@@ -1135,14 +1144,21 @@ end
 redef class AAttrPropdef
 	redef type MPROPDEF: MAttributeDef
 
+	# The static type of the property (declared, inferred or inherited)
+	# This attribute is also used to check if the property was analyzed and is valid.
+	var mtype: nullable MType
+
 	# Is the node tagged `noinit`?
 	var noinit = false
 
 	# Is the node tagged lazy?
 	var is_lazy = false
 
-	# Has the node a default value?
-	# Could be through `n_expr` or `n_block`
+	# Is the node tagged optional?
+	var is_optional = false
+
+	# Does the node have a default value?
+	# Could be through `n_expr`, `n_block` or `is_lazy`
 	var has_value = false
 
 	# The guard associated to a lazy attribute.
@@ -1168,7 +1184,7 @@ redef class AAttrPropdef
 				modelbuilder.error(self, "Error: attempt to define attribute `{name}` in the {mclass.kind} `{mclass}`.")
 			end
 
-			var mprop = new MAttribute(mclassdef, "_" + name, private_visibility)
+			var mprop = new MAttribute(mclassdef, "_" + name, self.location, private_visibility)
 			var mpropdef = new MAttributeDef(mclassdef, mprop, self.location)
 			self.mpropdef = mpropdef
 			modelbuilder.mpropdef2npropdef[mpropdef] = self
@@ -1178,14 +1194,24 @@ redef class AAttrPropdef
 		var mreadprop = modelbuilder.try_get_mproperty_by_name(nid2, mclassdef, readname).as(nullable MMethod)
 		if mreadprop == null then
 			var mvisibility = new_property_visibility(modelbuilder, mclassdef, self.n_visibility)
-			mreadprop = new MMethod(mclassdef, readname, mvisibility)
-			if not self.check_redef_keyword(modelbuilder, mclassdef, n_kwredef, false, mreadprop) then return
+			mreadprop = new MMethod(mclassdef, readname, self.location, mvisibility)
+			if not self.check_redef_keyword(modelbuilder, mclassdef, n_kwredef, false, mreadprop) then
+				mreadprop.is_broken = true
+				return
+			end
 		else
+			if mreadprop.is_broken then return
 			if not self.check_redef_keyword(modelbuilder, mclassdef, n_kwredef, true, mreadprop) then return
 			check_redef_property_visibility(modelbuilder, self.n_visibility, mreadprop)
 		end
 		mclassdef.mprop2npropdef[mreadprop] = self
 
+		var attr_mpropdef = mpropdef
+		if attr_mpropdef != null then
+			mreadprop.getter_for = attr_mpropdef.mproperty
+			attr_mpropdef.mproperty.getter = mreadprop
+		end
+
 		var mreadpropdef = new MMethodDef(mclassdef, mreadprop, self.location)
 		self.mreadpropdef = mreadpropdef
 		modelbuilder.mpropdef2npropdef[mreadpropdef] = self
@@ -1209,8 +1235,7 @@ redef class AAttrPropdef
 				return
 			end
 			if atabstract != null then
-				modelbuilder.error(atnoinit, "Error: `noautoinit` attributes cannot be abstract.")
-				return
+				modelbuilder.warning(atnoinit, "useless-noautoinit", "Warning: superfluous `noautoinit` on abstract attribute.")
 			end
 		end
 
@@ -1231,11 +1256,21 @@ redef class AAttrPropdef
 				return
 			end
 			is_lazy = true
-			var mlazyprop = new MAttribute(mclassdef, "lazy _" + name, none_visibility)
+			var mlazyprop = new MAttribute(mclassdef, "lazy _" + name, self.location, none_visibility)
+			mlazyprop.is_fictive = true
 			var mlazypropdef = new MAttributeDef(mclassdef, mlazyprop, self.location)
+			mlazypropdef.is_fictive = true
 			self.mlazypropdef = mlazypropdef
 		end
 
+		var atoptional = self.get_single_annotation("optional", modelbuilder)
+		if atoptional != null then
+			if not has_value then
+				modelbuilder.error(atoptional, "Error: `optional` attributes need a default value.")
+			end
+			is_optional = true
+		end
+
 		var atreadonly = self.get_single_annotation("readonly", modelbuilder)
 		if atreadonly != null then
 			if not has_value then
@@ -1245,6 +1280,10 @@ redef class AAttrPropdef
 			return
 		end
 
+		if not mclassdef.is_intro and not has_value and not noinit then
+			modelbuilder.advice(self, "attr-in-refinement", "Warning: attributes in refinement need a value or `noautoinit`.")
+		end
+
 		var writename = name + "="
 		var atwritable = self.get_single_annotation("writable", modelbuilder)
 		if atwritable != null then
@@ -1260,12 +1299,18 @@ redef class AAttrPropdef
 			if atwritable != null then
 				mvisibility = new_property_visibility(modelbuilder, mclassdef, atwritable.n_visibility)
 			else
-				mvisibility = private_visibility
+				mvisibility = mreadprop.visibility
+				# By default, use protected visibility at most
+				if mvisibility > protected_visibility then mvisibility = protected_visibility
+			end
+			mwriteprop = new MMethod(mclassdef, writename, self.location, mvisibility)
+			if not self.check_redef_keyword(modelbuilder, mclassdef, nwkwredef, false, mwriteprop) then
+				mwriteprop.is_broken = true
+				return
 			end
-			mwriteprop = new MMethod(mclassdef, writename, mvisibility)
-			if not self.check_redef_keyword(modelbuilder, mclassdef, nwkwredef, false, mwriteprop) then return
 			mwriteprop.deprecation = mreadprop.deprecation
 		else
+			if mwriteprop.is_broken then return
 			if not self.check_redef_keyword(modelbuilder, mclassdef, nwkwredef or else n_kwredef, true, mwriteprop) then return
 			if atwritable != null then
 				check_redef_property_visibility(modelbuilder, atwritable.n_visibility, mwriteprop)
@@ -1273,11 +1318,32 @@ redef class AAttrPropdef
 		end
 		mclassdef.mprop2npropdef[mwriteprop] = self
 
+		if attr_mpropdef != null then
+			mwriteprop.setter_for = attr_mpropdef.mproperty
+			attr_mpropdef.mproperty.setter = mwriteprop
+		end
+
 		var mwritepropdef = new MMethodDef(mclassdef, mwriteprop, self.location)
 		self.mwritepropdef = mwritepropdef
 		modelbuilder.mpropdef2npropdef[mwritepropdef] = self
 		mwritepropdef.mdoc = mreadpropdef.mdoc
 		if atabstract != null then mwritepropdef.is_abstract = true
+
+		var atautoinit = self.get_single_annotation("autoinit", modelbuilder)
+		if atautoinit != null then
+			if has_value then
+				modelbuilder.error(atautoinit, "Error: `autoinit` attributes cannot have an initial value.")
+			else if not mwritepropdef.is_intro then
+				modelbuilder.error(atautoinit, "Error: `autoinit` attributes cannot be set on redefinitions.")
+			else if not mclassdef.is_intro then
+				modelbuilder.error(atautoinit, "Error: `autoinit` attributes cannot be used in class refinements.")
+			else if atabstract == null then
+				modelbuilder.warning(atautoinit, "useless-autoinit", "Warning: superfluous `autoinit` on attribute.")
+			end
+		else if atabstract != null then
+			# By default, abstract attribute are not autoinit
+			noinit = true
+		end
 	end
 
 	redef fun build_signature(modelbuilder)
@@ -1292,7 +1358,7 @@ redef class AAttrPropdef
 
 		var ntype = self.n_type
 		if ntype != null then
-			mtype = modelbuilder.resolve_mtype_unchecked(mmodule, mclassdef, ntype, true)
+			mtype = modelbuilder.resolve_mtype_unchecked(mclassdef, ntype, true)
 			if mtype == null then return
 		end
 
@@ -1312,35 +1378,12 @@ redef class AAttrPropdef
 		var nexpr = self.n_expr
 		if mtype == null then
 			if nexpr != null then
-				if nexpr isa ANewExpr then
-					mtype = modelbuilder.resolve_mtype_unchecked(mmodule, mclassdef, nexpr.n_type, true)
-				else if nexpr isa AIntExpr then
-					var cla = modelbuilder.try_get_mclass_by_name(nexpr, mmodule, "Int")
-					if cla != null then mtype = cla.mclass_type
-				else if nexpr isa AFloatExpr then
-					var cla = modelbuilder.try_get_mclass_by_name(nexpr, mmodule, "Float")
-					if cla != null then mtype = cla.mclass_type
-				else if nexpr isa ACharExpr then
-					var cla = modelbuilder.try_get_mclass_by_name(nexpr, mmodule, "Char")
-					if cla != null then mtype = cla.mclass_type
-				else if nexpr isa ABoolExpr then
-					var cla = modelbuilder.try_get_mclass_by_name(nexpr, mmodule, "Bool")
-					if cla != null then mtype = cla.mclass_type
-				else if nexpr isa ASuperstringExpr then
-					var cla = modelbuilder.try_get_mclass_by_name(nexpr, mmodule, "String")
-					if cla != null then mtype = cla.mclass_type
-				else if nexpr isa AStringFormExpr then
-					var cla = modelbuilder.try_get_mclass_by_name(nexpr, mmodule, "String")
-					if cla != null then mtype = cla.mclass_type
-				else
-					modelbuilder.error(self, "Error: untyped attribute `{mreadpropdef}`. Implicit typing allowed only for literals and new.")
-				end
-
+				mtype = infer_static_type(modelbuilder, nexpr, mclassdef, mmodule, mreadpropdef)
 				if mtype == null then return
 			end
 		else if ntype != null and inherited_type == mtype then
 			if nexpr isa ANewExpr then
-				var xmtype = modelbuilder.resolve_mtype_unchecked(mmodule, mclassdef, nexpr.n_type, true)
+				var xmtype = modelbuilder.resolve_mtype_unchecked(mclassdef, nexpr.n_type, true)
 				if xmtype == mtype then
 					modelbuilder.advice(ntype, "useless-type", "Warning: useless type definition")
 				end
@@ -1352,6 +1395,8 @@ redef class AAttrPropdef
 			return
 		end
 
+		self.mtype = mtype
+
 		if mpropdef != null then
 			mpropdef.static_mtype = mtype
 		end
@@ -1363,26 +1408,99 @@ redef class AAttrPropdef
 
 		var mwritepropdef = self.mwritepropdef
 		if mwritepropdef != null then
+			var mwritetype = mtype
+			if is_optional then
+				mwritetype = mwritetype.as_nullable
+			end
 			var name: String
 			name = n_id2.text
-			var mparameter = new MParameter(name, mtype, false, false)
+			var mparameter = new MParameter(name, mwritetype, false)
 			var msignature = new MSignature([mparameter], null)
 			mwritepropdef.msignature = msignature
 		end
 
 		var mlazypropdef = self.mlazypropdef
 		if mlazypropdef != null then
-			mlazypropdef.static_mtype = modelbuilder.model.get_mclasses_by_name("Bool").first.mclass_type
+			mlazypropdef.static_mtype = mmodule.bool_type
 		end
 		check_repeated_types(modelbuilder)
 	end
 
+	# Detect the static type from the value assigned to the attribute `self`
+	#
+	# Return the static type if it can be safely inferred.
+	private fun infer_static_type(modelbuilder: ModelBuilder, nexpr: AExpr,
+		mclassdef: MClassDef, mmodule: MModule, mreadpropdef: MPropDef): nullable MType
+	do
+		var mtype = null
+		if nexpr isa ANewExpr then
+			mtype = modelbuilder.resolve_mtype_unchecked(mclassdef, nexpr.n_type, true)
+		else if nexpr isa AAsCastExpr then
+			mtype = modelbuilder.resolve_mtype_unchecked(mclassdef, nexpr.n_type, true)
+		else if nexpr isa AIntegerExpr then
+			var cla: nullable MClass = null
+			if nexpr.value isa Int then
+				cla = modelbuilder.try_get_mclass_by_name(nexpr, mmodule, "Int")
+			else if nexpr.value isa Byte then
+				cla = modelbuilder.try_get_mclass_by_name(nexpr, mmodule, "Byte")
+			else if nexpr.value isa Int8 then
+				cla = modelbuilder.try_get_mclass_by_name(nexpr, mmodule, "Int8")
+			else if nexpr.value isa Int16 then
+				cla = modelbuilder.try_get_mclass_by_name(nexpr, mmodule, "Int16")
+			else if nexpr.value isa UInt16 then
+				cla = modelbuilder.try_get_mclass_by_name(nexpr, mmodule, "UInt16")
+			else if nexpr.value isa Int32 then
+				cla = modelbuilder.try_get_mclass_by_name(nexpr, mmodule, "Int32")
+			else if nexpr.value isa UInt32 then
+				cla = modelbuilder.try_get_mclass_by_name(nexpr, mmodule, "UInt32")
+			else
+				# Should not happen, and should be updated as new types are added
+				abort
+			end
+			if cla != null then mtype = cla.mclass_type
+		else if nexpr isa AFloatExpr then
+			var cla = modelbuilder.try_get_mclass_by_name(nexpr, mmodule, "Float")
+			if cla != null then mtype = cla.mclass_type
+		else if nexpr isa ACharExpr then
+			var cla: nullable MClass
+			if nexpr.is_ascii then
+				cla = modelbuilder.try_get_mclass_by_name(nexpr, mmodule, "Byte")
+			else if nexpr.is_code_point then
+				cla = modelbuilder.try_get_mclass_by_name(nexpr, mmodule, "Int")
+			else
+				cla = modelbuilder.try_get_mclass_by_name(nexpr, mmodule, "Char")
+			end
+			if cla != null then mtype = cla.mclass_type
+		else if nexpr isa ABoolExpr then
+			var cla = modelbuilder.try_get_mclass_by_name(nexpr, mmodule, "Bool")
+			if cla != null then mtype = cla.mclass_type
+		else if nexpr isa ASuperstringExpr then
+			var cla = modelbuilder.try_get_mclass_by_name(nexpr, mmodule, "String")
+			if cla != null then mtype = cla.mclass_type
+		else if nexpr isa AStringFormExpr then
+			var cla: nullable MClass
+			if nexpr.is_bytestring then
+				cla = modelbuilder.try_get_mclass_by_name(nexpr, mmodule, "Bytes")
+			else if nexpr.is_re then
+				cla = modelbuilder.try_get_mclass_by_name(nexpr, mmodule, "Regex")
+			else if nexpr.is_string then
+				cla = modelbuilder.try_get_mclass_by_name(nexpr, mmodule, "String")
+			else
+				abort
+			end
+			if cla != null then mtype = cla.mclass_type
+		else
+			modelbuilder.error(self, "Error: untyped attribute `{mreadpropdef}`. Implicit typing allowed only for literals and new.")
+		end
+		return mtype
+	end
+
 	redef fun check_signature(modelbuilder)
 	do
 		var mpropdef = self.mpropdef
 		if mpropdef == null then return # Error thus skipped
 		var ntype = self.n_type
-		var mtype = self.mpropdef.static_mtype
+		var mtype = self.mtype
 		if mtype == null then return # Error thus skipped
 
 		var mclassdef = mpropdef.mclassdef
@@ -1390,11 +1508,11 @@ redef class AAttrPropdef
 
 		# Check types
 		if ntype != null then
-			if modelbuilder.resolve_mtype(mmodule, mclassdef, ntype) == null then return
+			if modelbuilder.resolve_mtype(mclassdef, ntype) == null then return
 		end
 		var nexpr = n_expr
 		if nexpr isa ANewExpr then
-			if modelbuilder.resolve_mtype(mmodule, mclassdef, nexpr.n_type) == null then return
+			if modelbuilder.resolve_mtype(mclassdef, nexpr.n_type) == null then return
 		end
 
 		# Lookup for signature in the precursor
@@ -1482,6 +1600,8 @@ redef class AAttrPropdef
 
 	# Type is useless if the attribute type is the same thant the intro.
 	redef fun check_repeated_types(modelbuilder) do
+		var mreadpropdef = self.mreadpropdef
+		if mreadpropdef == null then return
 		if mreadpropdef.is_intro or n_type == null then return
 		# get intro
 		var intro = mreadpropdef.mproperty.intro
@@ -1495,7 +1615,7 @@ redef class AAttrPropdef
 			ntype = n_intro.n_type.mtype
 		end
 		# check
-		if ntype ==null or ntype != n_type.mtype then return
+		if ntype == null or ntype != n_type.mtype or mpropdef == null then return
 		modelbuilder.advice(n_type, "useless-signature", "Warning: useless type repetition on redefined attribute `{mpropdef.name}`")
 	end
 end
@@ -1505,31 +1625,33 @@ redef class ATypePropdef
 
 	redef fun build_property(modelbuilder, mclassdef)
 	do
-		var name = self.n_id.text
-		var mprop = modelbuilder.try_get_mproperty_by_name(self.n_id, mclassdef, name)
+		var name = self.n_qid.n_id.text
+		var mprop = modelbuilder.try_get_mproperty_by_name(self.n_qid, mclassdef, name)
 		if mprop == null then
 			var mvisibility = new_property_visibility(modelbuilder, mclassdef, self.n_visibility)
-			mprop = new MVirtualTypeProp(mclassdef, name, mvisibility)
+			mprop = new MVirtualTypeProp(mclassdef, name, self.location, mvisibility)
 			for c in name.chars do if c >= 'a' and c<= 'z' then
-				modelbuilder.warning(n_id, "bad-type-name", "Warning: lowercase in the virtual type `{name}`.")
+				modelbuilder.warning(n_qid, "bad-type-name", "Warning: lowercase in the virtual type `{name}`.")
 				break
 			end
-			if not self.check_redef_keyword(modelbuilder, mclassdef, self.n_kwredef, false, mprop) then return
 		else
-			if not self.check_redef_keyword(modelbuilder, mclassdef, self.n_kwredef, true, mprop) then return
+			if mprop.is_broken then return
 			assert mprop isa MVirtualTypeProp
 			check_redef_property_visibility(modelbuilder, self.n_visibility, mprop)
 		end
-		mclassdef.mprop2npropdef[mprop] = self
 
 		var mpropdef = new MVirtualTypeDef(mclassdef, mprop, self.location)
 		self.mpropdef = mpropdef
-		modelbuilder.mpropdef2npropdef[mpropdef] = self
 		if mpropdef.is_intro then
 			modelbuilder.toolcontext.info("{mpropdef} introduces new type {mprop.full_name}", 4)
 		else
 			modelbuilder.toolcontext.info("{mpropdef} redefines type {mprop.full_name}", 4)
 		end
+		if not self.check_redef_keyword(modelbuilder, mclassdef, self.n_kwredef, not mpropdef.is_intro, mprop) then
+			mpropdef.is_broken =true
+		end
+		mclassdef.mprop2npropdef[mprop] = self
+		modelbuilder.mpropdef2npropdef[mpropdef] = self
 		set_doc(mpropdef, modelbuilder)
 
 		var atfixed = get_single_annotation("fixed", modelbuilder)
@@ -1543,11 +1665,10 @@ redef class ATypePropdef
 		var mpropdef = self.mpropdef
 		if mpropdef == null then return # Error thus skipped
 		var mclassdef = mpropdef.mclassdef
-		var mmodule = mclassdef.mmodule
 		var mtype: nullable MType = null
 
 		var ntype = self.n_type
-		mtype = modelbuilder.resolve_mtype_unchecked(mmodule, mclassdef, ntype, true)
+		mtype = modelbuilder.resolve_mtype_unchecked(mclassdef, ntype, true)
 		if mtype == null then return
 
 		mpropdef.bound = mtype
@@ -1569,7 +1690,7 @@ redef class ATypePropdef
 		var anchor = mclassdef.bound_mtype
 
 		var ntype = self.n_type
-		if modelbuilder.resolve_mtype(mmodule, mclassdef, ntype) == null then
+		if modelbuilder.resolve_mtype(mclassdef, ntype) == null then
 			mpropdef.bound = null
 			return
 		end
@@ -1577,14 +1698,13 @@ redef class ATypePropdef
 		# Check redefinitions
 		for p in mpropdef.mproperty.lookup_super_definitions(mmodule, anchor) do
 			var supbound = p.bound
-			if supbound == null then break # broken super bound, skip error
+			if supbound == null or supbound isa MBottomType or p.is_broken then break # broken super bound, skip error
 			if p.is_fixed then
 				modelbuilder.error(self, "Redef Error: virtual type `{mpropdef.mproperty}` is fixed in super-class `{p.mclassdef.mclass}`.")
 				break
 			end
 			if p.mclassdef.mclass == mclassdef.mclass then
-				# Still a warning to pass existing bad code
-				modelbuilder.warning(n_type, "refine-type", "Redef Error: a virtual type cannot be refined.")
+				modelbuilder.error(n_type, "Redef Error: a virtual type cannot be refined.")
 				break
 			end
 			if not modelbuilder.check_subtype(n_type, mmodule, anchor, bound, supbound) then