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

diff --git a/src/modelize/modelize_property.nit b/src/modelize/modelize_property.nit
index f270c8d..c224b29 100644
--- a/src/modelize/modelize_property.nit
+++ b/src/modelize/modelize_property.nit
@@ -21,6 +21,7 @@ intrude import modelize_class
 private import annotation
 
 redef class ToolContext
+	# Run `AClassdef::build_property` on the classdefs of each module
 	var modelize_property_phase: Phase = new ModelizePropertyPhase(self, [modelize_class_phase])
 end
 
@@ -85,7 +86,8 @@ redef class ModelBuilder
 		# Force building recursively
 		if nclassdef.build_properties_is_done then return
 		nclassdef.build_properties_is_done = true
-		var mclassdef = nclassdef.mclassdef.as(not null)
+		var mclassdef = nclassdef.mclassdef
+		if mclassdef == null then return # skip error
 		if mclassdef.in_hierarchy == null then return # Skip error
 		for superclassdef in mclassdef.in_hierarchy.direct_greaters do
 			if not mclassdef2nclassdef.has_key(superclassdef) then continue
@@ -101,6 +103,24 @@ redef class ModelBuilder
 				npropdef.build_signature(self)
 			end
 			for npropdef in nclassdef2.n_propdefs do
+				if not npropdef isa ATypePropdef then continue
+				# Check circularity
+				var mpropdef = npropdef.mpropdef
+				if mpropdef == null then continue
+				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
+				end
+			end
+			for npropdef in nclassdef2.n_propdefs do
+				# Check ATypePropdef first since they may be required for the other properties
+				if not npropdef isa ATypePropdef then continue
+				npropdef.check_signature(self)
+			end
+
+			for npropdef in nclassdef2.n_propdefs do
+				if npropdef isa ATypePropdef then continue
 				npropdef.check_signature(self)
 			end
 		end
@@ -180,6 +200,7 @@ redef class ModelBuilder
 					mparameters.add(mparameter)
 				end
 				initializers.add(npropdef.mpropdef.mproperty)
+				npropdef.mpropdef.mproperty.is_autoinit = true
 			end
 			if npropdef isa AAttrPropdef then
 				if npropdef.mpropdef == null then return # Skip broken attribute
@@ -189,6 +210,7 @@ redef class ModelBuilder
 					# For autoinit attributes, call the reader to force
 					# the lazy initialization of the attribute.
 					initializers.add(npropdef.mreadpropdef.mproperty)
+					npropdef.mreadpropdef.mproperty.is_autoinit = true
 					continue
 				end
 				if npropdef.has_value then continue
@@ -201,9 +223,11 @@ redef class ModelBuilder
 				if msetter == null then
 					# No setter, it is a old-style attribute, so just add it
 					initializers.add(npropdef.mpropdef.mproperty)
+					npropdef.mpropdef.mproperty.is_autoinit = true
 				else
 					# Add the setter to the list
 					initializers.add(msetter.mproperty)
+					msetter.mproperty.is_autoinit = true
 				end
 			end
 		end
@@ -217,39 +241,100 @@ redef class ModelBuilder
 			return
 		end
 
-		# Search the longest-one and checks for conflict
-		var longest = spropdefs.first
-		if spropdefs.length > 1 then
-			# Check for conflict in the order of initializers
-			# Each initializer list must me a prefix of the longest list
-			# part 1. find the longest list
-			for spd in spropdefs do
-				if spd.initializers.length > longest.initializers.length then longest = spd
-			end
-			# part 2. compare
-			for spd in spropdefs do
-				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(", ")})")
-						return
+		# Look at the autoinit class-annotation
+		var autoinit = nclassdef.get_single_annotation("autoinit", self)
+		var noautoinit = nclassdef.get_single_annotation("noautoinit", self)
+		if autoinit != null then
+			# Just throws the collected initializers
+			mparameters.clear
+			initializers.clear
+
+			if noautoinit != null then
+				error(autoinit, "Error: `autoinit` and `noautoinit` are incompatible.")
+			end
+
+			if autoinit.n_args.is_empty then
+				error(autoinit, "Syntax error: `autoinit` expects method identifiers, use `noautoinit` to clear all autoinits.")
+			end
+
+			# Get and check each argument
+			for narg in autoinit.n_args do
+				var id = narg.as_id
+				if id == null then
+					error(narg, "Syntax error: `autoinit` expects method identifiers.")
+					return
+				end
+
+				# Search the property.
+				# To avoid bad surprises, try to get the setter first.
+				var p = try_get_mproperty_by_name(narg, mclassdef, id + "=")
+				if p == null then
+					p = try_get_mproperty_by_name(narg, mclassdef, id)
+				end
+				if p == null then
+					error(narg, "Error: unknown method `{id}`")
+					return
+				end
+				if not p.is_autoinit then
+					error(narg, "Error: `{p}` is not an autoinit method")
+					return
+				end
+
+				# Register the initializer and the parameters
+				initializers.add(p)
+				var pd = p.intro
+				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)
+					mparameters.add_all sig.mparameters
+				else
+					# TODO attributes?
+					abort
+				end
+			end
+		else if noautoinit != null then
+			if initializers.is_empty then
+				warning(noautoinit, "useless-noautoinit", "Warning: the list of autoinit is already empty.")
+			end
+			# Just clear initializers
+			mparameters.clear
+			initializers.clear
+		else
+			# Search the longest-one and checks for conflict
+			var longest = spropdefs.first
+			if spropdefs.length > 1 then
+				# Check for conflict in the order of initializers
+				# Each initializer list must me a prefix of the longest list
+				# part 1. find the longest list
+				for spd in spropdefs do
+					if spd.initializers.length > longest.initializers.length then longest = spd
+				end
+				# part 2. compare
+				for spd in spropdefs do
+					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(", ")})")
+							# TODO: invalidate the initializer to avoid more errors
+							return
+						end
+						i += 1
 					end
-					i += 1
 				end
 			end
-		end
 
-		# Can we just inherit?
-		if spropdefs.length == 1 and mparameters.is_empty and defined_init == null then
-			self.toolcontext.info("{mclassdef} inherits the basic constructor {longest}", 3)
-			mclassdef.mclass.root_init = longest
-			return
-		end
+			# Can we just inherit?
+			if spropdefs.length == 1 and mparameters.is_empty and defined_init == null then
+				self.toolcontext.info("{mclassdef} inherits the basic constructor {longest}", 3)
+				mclassdef.mclass.root_init = longest
+				return
+			end
 
-		# Combine the inherited list to what is collected
-		if longest.initializers.length > 0 then
-			mparameters.prepend longest.new_msignature.mparameters
-			initializers.prepend longest.initializers
+			# Combine the inherited list to what is collected
+			if longest.initializers.length > 0 then
+				mparameters.prepend longest.new_msignature.mparameters
+				initializers.prepend longest.initializers
+			end
 		end
 
 		# If we already have a basic init definition, then setup its initializers
@@ -285,7 +370,7 @@ redef class ModelBuilder
 		# It is a case-by case
 		var vis_type: nullable MVisibility = null # The own visibility of the type
 		var mmodule_type: nullable MModule = null # The original module of the type
-		mtype = mtype.as_notnullable
+		mtype = mtype.undecorate
 		if mtype isa MClassType then
 			vis_type = mtype.mclass.visibility
 			mmodule_type = mtype.mclass.intro.mmodule
@@ -294,6 +379,8 @@ redef class ModelBuilder
 			mmodule_type = mtype.mproperty.intro_mclassdef.mmodule
 		else if mtype isa MParameterType then
 			# nothing, always visible
+		else if mtype isa MNullType then
+			# nothing to do.
 		else
 			node.debug "Unexpected type {mtype}"
 			abort
@@ -322,6 +409,72 @@ redef class ModelBuilder
 			for t in mtype.arguments do check_visibility(node, t, mpropdef)
 		end
 	end
+
+	# Detect circularity errors for virtual types.
+	fun check_virtual_types_circularity(node: ANode, mproperty: MVirtualTypeProp, recv: MType, mmodule: MModule): Bool
+	do
+		# Check circularity
+		# Slow case: progress on each resolution until we visit all without getting a loop
+
+		# The graph used to detect loops
+		var mtype = mproperty.mvirtualtype
+		var poset = new POSet[MType]
+
+		# The work-list of types to resolve
+		var todo = new List[MType]
+		todo.add mtype
+
+		while not todo.is_empty do
+			# The visited type
+			var t = todo.pop
+
+			if not t.need_anchor then continue
+
+			# Get the types derived of `t` (subtypes and bounds)
+			var nexts
+			if t isa MNullableType then
+				nexts = [t.mtype]
+			else if t isa MGenericType then
+				nexts = t.arguments
+			else if t isa MVirtualType then
+				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
+				nexts = new Array[MType]
+				for d in defs do
+					var next = defs.first.bound
+					if next == null then return false
+					nexts.add next
+				end
+			else if t isa MClassType then
+				# Basic type, nothing to to
+				continue
+			else if t isa MParameterType then
+				# Parameter types cannot depend on virtual types, so nothing to do
+				continue
+			else
+				abort
+			end
+
+			# For each one
+			for next in nexts do
+				if poset.has_edge(next, t) then
+					if mtype == next then
+						error(node, "Error: circularity of virtual type definition: {next} <-> {t}")
+					else
+						error(node, "Error: circularity of virtual type definition: {mtype} -> {next} <-> {t}")
+					end
+					return false
+				else
+					poset.add_edge(t, next)
+					todo.add next
+				end
+			end
+		end
+		return true
+	end
 end
 
 redef class MPropDef
@@ -331,7 +484,8 @@ redef class MPropDef
 end
 
 redef class AClassdef
-	var build_properties_is_done = false
+	# 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
@@ -403,9 +557,9 @@ redef class APropdef
 	# The associated propdef once build by a `ModelBuilder`
 	var mpropdef: nullable MPROPDEF is writable
 
-	private fun build_property(modelbuilder: ModelBuilder, mclassdef: MClassDef) is abstract
-	private fun build_signature(modelbuilder: ModelBuilder) is abstract
-	private fun check_signature(modelbuilder: ModelBuilder) is abstract
+	private fun build_property(modelbuilder: ModelBuilder, mclassdef: MClassDef) do end
+	private fun build_signature(modelbuilder: ModelBuilder) do end
+	private fun check_signature(modelbuilder: ModelBuilder) do end
 	private fun new_property_visibility(modelbuilder: ModelBuilder, mclassdef: MClassDef, nvisibility: nullable AVisibility): MVisibility
 	do
 		var mvisibility = public_visibility
@@ -483,6 +637,18 @@ redef class APropdef
 				modelbuilder.error(self, "Redef error: {mclassdef.mclass}::{mprop.name} is an inherited property. To redefine it, add the redef keyword.")
 				return false
 			end
+
+			# Check for full-name conflicts in the project.
+			# A public property should have a unique qualified name `project::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
+						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
+				end
+			end
 		else
 			if not need_redef then
 				modelbuilder.error(self, "Error: No property {mclassdef.mclass}::{mprop.name} is inherited. Remove the redef keyword to define a new property.")
@@ -519,7 +685,7 @@ redef class ASignature
 			param_names.add(np.n_id.text)
 			var ntype = np.n_type
 			if ntype != null then
-				var mtype = modelbuilder.resolve_mtype(mmodule, mclassdef, ntype)
+				var mtype = modelbuilder.resolve_mtype_unchecked(mmodule, 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)
@@ -536,7 +702,7 @@ redef class ASignature
 		end
 		var ntype = self.n_type
 		if ntype != null then
-			self.ret_type = modelbuilder.resolve_mtype(mmodule, mclassdef, ntype)
+			self.ret_type = modelbuilder.resolve_mtype_unchecked(mmodule, mclassdef, ntype, true)
 			if self.ret_type == null then return false # Skip error
 		end
 
@@ -544,24 +710,24 @@ redef class ASignature
 		return true
 	end
 
-	# Build a visited signature
-	fun build_signature(modelbuilder: ModelBuilder): nullable MSignature
+	private fun check_signature(modelbuilder: ModelBuilder, mclassdef: MClassDef): Bool
 	do
-		if param_names.length != param_types.length then
-			# Some parameters are typed, other parameters are not typed.
-			modelbuilder.error(self.n_params[param_types.length], "Error: Untyped parameter `{param_names[param_types.length]}'.")
-			return null
+		var res = true
+		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
+					res = false
+				end
+			end
 		end
-
-		var mparameters = new Array[MParameter]
-		for i in [0..param_names.length[ do
-			var mparameter = new MParameter(param_names[i], param_types[i], i == vararg_rank)
-			self.n_params[i].mparameter = mparameter
-			mparameters.add(mparameter)
+		var ntype = self.n_type
+		if ntype != null then
+			if modelbuilder.resolve_mtype(mclassdef.mmodule, mclassdef, ntype) == null then
+				res = false
+			end
 		end
-
-		var msignature = new MSignature(mparameters, ret_type)
-		return msignature
+		return res
 	end
 end
 
@@ -657,6 +823,7 @@ redef class AMethPropdef
 			end
 			mprop.is_init = is_init
 			mprop.is_new = n_kwnew != null
+			if mprop.is_new then mclassdef.mclass.has_new_factory = true
 			if parent isa ATopClassdef then mprop.is_toplevel = true
 			self.check_redef_keyword(modelbuilder, mclassdef, n_kwredef, false, mprop)
 		else
@@ -785,6 +952,10 @@ redef class AMethPropdef
 		mpropdef.is_abstract = self.get_single_annotation("abstract", modelbuilder) != null
 		mpropdef.is_intern = self.get_single_annotation("intern", modelbuilder) != null
 		mpropdef.is_extern = self.n_extern_code_block != null or self.get_single_annotation("extern", modelbuilder) != null
+
+		# 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.")
 	end
 
 	redef fun check_signature(modelbuilder)
@@ -797,6 +968,14 @@ redef class AMethPropdef
 		var mysignature = self.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
+				return # Forward error
+			end
+		end
+
 		# Lookup for signature in the precursor
 		# FIXME all precursors should be considered
 		if not mpropdef.is_intro then
@@ -807,6 +986,7 @@ redef class AMethPropdef
 			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
 				return
 			end
 
@@ -815,18 +995,23 @@ redef class AMethPropdef
 				for i in [0..mysignature.arity[ do
 					var myt = mysignature.mparameters[i].mtype
 					var prt = msignature.mparameters[i].mtype
-					if not myt.is_subtype(mmodule, mclassdef.bound_mtype, prt) or
-							not prt.is_subtype(mmodule, mclassdef.bound_mtype, myt) then
-						modelbuilder.error(nsig.n_params[i], "Redef Error: Wrong type for parameter `{mysignature.mparameters[i].name}'. found {myt}, expected {prt} as in {mpropdef.mproperty.intro}.")
+					var node = nsig.n_params[i]
+					if not modelbuilder.check_sametype(node, mmodule, mclassdef.bound_mtype, myt, prt) then
+						modelbuilder.error(node, "Redef Error: Wrong type for parameter `{mysignature.mparameters[i].name}'. found {myt}, expected {prt} as in {mpropdef.mproperty.intro}.")
+						self.mpropdef.msignature = null
 					end
 				end
 			end
 			if precursor_ret_type != null then
+				var node: nullable ANode = null
+				if nsig != null then node = nsig.n_type
+				if node == null then node = self
 				if ret_type == null then
 					# Inherit the return type
 					ret_type = precursor_ret_type
-				else if not ret_type.is_subtype(mmodule, mclassdef.bound_mtype, precursor_ret_type) then
-					modelbuilder.error(nsig.n_type.as(not null), "Redef Error: Wrong return type. found {ret_type}, expected {precursor_ret_type} as in {mpropdef.mproperty.intro}.")
+				else if not modelbuilder.check_subtype(node, mmodule, mclassdef.bound_mtype, ret_type, precursor_ret_type) then
+					modelbuilder.error(node, "Redef Error: Wrong return type. found {ret_type}, expected {precursor_ret_type} as in {mpropdef.mproperty.intro}.")
+					self.mpropdef.msignature = null
 				end
 			end
 		end
@@ -870,32 +1055,31 @@ redef class AAttrPropdef
 	redef fun build_property(modelbuilder, mclassdef)
 	do
 		var mclass = mclassdef.mclass
+		var nid2 = n_id2
+		var name = nid2.text
+
+		var atabstract = self.get_single_annotation("abstract", modelbuilder)
+		if atabstract == null then
+			if mclass.kind == interface_kind then
+				modelbuilder.error(self, "Error: Attempt to define attribute {name} in the interface {mclass}.")
+			else if mclass.kind == enum_kind then
+				modelbuilder.error(self, "Error: Attempt to define attribute {name} in the enum class {mclass}.")
+			else if mclass.kind == extern_kind then
+				modelbuilder.error(self, "Error: Attempt to define attribute {name} in the extern class {mclass}.")
+			end
 
-		var name: String
-		name = self.n_id2.text
-
-		if mclass.kind == interface_kind or mclassdef.mclass.kind == enum_kind then
-			modelbuilder.error(self, "Error: Attempt to define attribute {name} in the interface {mclass}.")
-		else if mclass.kind == enum_kind then
-			modelbuilder.error(self, "Error: Attempt to define attribute {name} in the enum class {mclass}.")
-		else if mclass.kind == extern_kind then
-			modelbuilder.error(self, "Error: Attempt to define attribute {name} in the extern class {mclass}.")
+			var mprop = new MAttribute(mclassdef, "_" + name, private_visibility)
+			var mpropdef = new MAttributeDef(mclassdef, mprop, self.location)
+			self.mpropdef = mpropdef
+			modelbuilder.mpropdef2npropdef[mpropdef] = self
 		end
 
-		# New attribute style
-		var nid2 = self.n_id2
-		var mprop = new MAttribute(mclassdef, "_" + name, private_visibility)
-		var mpropdef = new MAttributeDef(mclassdef, mprop, self.location)
-		self.mpropdef = mpropdef
-		modelbuilder.mpropdef2npropdef[mpropdef] = self
-
 		var readname = name
 		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.deprecation = mprop.deprecation
 		else
 			if not self.check_redef_keyword(modelbuilder, mclassdef, n_kwredef, true, mreadprop) then return
 			check_redef_property_visibility(modelbuilder, self.n_visibility, mreadprop)
@@ -906,15 +1090,26 @@ redef class AAttrPropdef
 		self.mreadpropdef = mreadpropdef
 		modelbuilder.mpropdef2npropdef[mreadpropdef] = self
 		set_doc(mreadpropdef, modelbuilder)
-		mpropdef.mdoc = mreadpropdef.mdoc
+		if mpropdef != null then mpropdef.mdoc = mreadpropdef.mdoc
+		if atabstract != null then mreadpropdef.is_abstract = true
 
 		has_value = n_expr != null or n_block != null
 
+		if atabstract != null and has_value then
+			modelbuilder.error(atabstract, "Error: `abstract` attributes cannot have an initial value")
+			return
+		end
+
 		var atnoinit = self.get_single_annotation("noinit", modelbuilder)
+		if atnoinit == null then atnoinit = self.get_single_annotation("noautoinit", modelbuilder)
 		if atnoinit != null then
 			noinit = true
 			if has_value then
-				modelbuilder.error(atnoinit, "Error: `noinit` attributes cannot have an initial value")
+				modelbuilder.error(atnoinit, "Error: `noautoinit` attributes cannot have an initial value")
+				return
+			end
+			if atabstract != null then
+				modelbuilder.error(atnoinit, "Error: `noautoinit` attributes cannot be abstract")
 				return
 			end
 		end
@@ -932,6 +1127,7 @@ redef class AAttrPropdef
 				else if atautoinit != null then
 					modelbuilder.error(atautoinit, "Error: a autoinit attribute needs a value")
 				end
+				has_value = true
 				return
 			end
 			is_lazy = true
@@ -968,7 +1164,7 @@ redef class AAttrPropdef
 			end
 			mwriteprop = new MMethod(mclassdef, writename, mvisibility)
 			if not self.check_redef_keyword(modelbuilder, mclassdef, nwkwredef, false, mwriteprop) then return
-			mwriteprop.deprecation = mprop.deprecation
+			mwriteprop.deprecation = mreadprop.deprecation
 		else
 			if not self.check_redef_keyword(modelbuilder, mclassdef, nwkwredef or else n_kwredef, true, mwriteprop) then return
 			if atwritable != null then
@@ -980,28 +1176,29 @@ redef class AAttrPropdef
 		var mwritepropdef = new MMethodDef(mclassdef, mwriteprop, self.location)
 		self.mwritepropdef = mwritepropdef
 		modelbuilder.mpropdef2npropdef[mwritepropdef] = self
-		mwritepropdef.mdoc = mpropdef.mdoc
+		mwritepropdef.mdoc = mreadpropdef.mdoc
+		if atabstract != null then mwritepropdef.is_abstract = true
 	end
 
 	redef fun build_signature(modelbuilder)
 	do
+		var mreadpropdef = self.mreadpropdef
 		var mpropdef = self.mpropdef
-		if mpropdef == null then return # Error thus skipped
-		var mclassdef = mpropdef.mclassdef
+		if mreadpropdef == null then return # Error thus skipped
+		var mclassdef = mreadpropdef.mclassdef
 		var mmodule = mclassdef.mmodule
 		var mtype: nullable MType = null
 
-		var mreadpropdef = self.mreadpropdef
 
 		var ntype = self.n_type
 		if ntype != null then
-			mtype = modelbuilder.resolve_mtype(mmodule, mclassdef, ntype)
+			mtype = modelbuilder.resolve_mtype_unchecked(mmodule, mclassdef, ntype, true)
 			if mtype == null then return
 		end
 
 		var inherited_type: nullable MType = null
 		# Inherit the type from the getter (usually an abstract getter)
-		if mreadpropdef != null and not mreadpropdef.is_intro then
+		if not mreadpropdef.is_intro then
 			var msignature = mreadpropdef.mproperty.intro.msignature
 			if msignature == null then return # Error, thus skipped
 			inherited_type = msignature.return_mtype
@@ -1016,7 +1213,7 @@ redef class AAttrPropdef
 		if mtype == null then
 			if nexpr != null then
 				if nexpr isa ANewExpr then
-					mtype = modelbuilder.resolve_mtype(mmodule, mclassdef, nexpr.n_type)
+					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
@@ -1036,14 +1233,14 @@ redef class AAttrPropdef
 					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 {mpropdef}. Implicit typing allowed only for literals and new.")
+					modelbuilder.error(self, "Error: Untyped attribute {mreadpropdef}. Implicit typing allowed only for literals and new.")
 				end
 
 				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(mmodule, mclassdef, nexpr.n_type)
+				var xmtype = modelbuilder.resolve_mtype_unchecked(mmodule, mclassdef, nexpr.n_type, true)
 				if xmtype == mtype then
 					modelbuilder.advice(ntype, "useless-type", "Warning: useless type definition")
 				end
@@ -1051,13 +1248,15 @@ redef class AAttrPropdef
 		end
 
 		if mtype == null then
-			modelbuilder.error(self, "Error: Untyped attribute {mpropdef}")
+			modelbuilder.error(self, "Error: Untyped attribute {mreadpropdef}")
 			return
 		end
 
-		mpropdef.static_mtype = mtype
+		if mpropdef != null then
+			mpropdef.static_mtype = mtype
+		end
 
-		if mreadpropdef != null then
+		do
 			var msignature = new MSignature(new Array[MParameter], mtype)
 			mreadpropdef.msignature = msignature
 		end
@@ -1085,6 +1284,18 @@ redef class AAttrPropdef
 		var mtype = self.mpropdef.static_mtype
 		if mtype == null then return # Error thus skipped
 
+		var mclassdef = mpropdef.mclassdef
+		var mmodule = mclassdef.mmodule
+
+		# Check types
+		if ntype != null then
+			if modelbuilder.resolve_mtype(mmodule, 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
+		end
+
 		# Lookup for signature in the precursor
 		# FIXME all precursors should be considered
 		if not mpropdef.is_intro then
@@ -1148,21 +1359,20 @@ redef class AAttrPropdef
 				for i in [0..mysignature.arity[ do
 					var myt = mysignature.mparameters[i].mtype
 					var prt = msignature.mparameters[i].mtype
-					if not myt.is_subtype(mmodule, mclassdef.bound_mtype, prt) or
-							not prt.is_subtype(mmodule, mclassdef.bound_mtype, myt) then
-						var node: ANode
-						if nsig != null then node = nsig else node = self
+					var node: ANode
+					if nsig != null then node = nsig else node = self
+					if not modelbuilder.check_sametype(node, mmodule, mclassdef.bound_mtype, myt, prt) then
 						modelbuilder.error(node, "Redef Error: Wrong type for parameter `{mysignature.mparameters[i].name}'. found {myt}, expected {prt}.")
 					end
 				end
 			end
 			if precursor_ret_type != null then
+				var node: ANode
+				if nsig != null then node = nsig else node = self
 				if ret_type == null then
 					# Inherit the return type
 					ret_type = precursor_ret_type
-				else if not ret_type.is_subtype(mmodule, mclassdef.bound_mtype, precursor_ret_type) then
-					var node: ANode
-					if nsig != null then node = nsig else node = self
+				else if not modelbuilder.check_subtype(node, mmodule, mclassdef.bound_mtype, ret_type, precursor_ret_type) then
 					modelbuilder.error(node, "Redef Error: Wrong return type. found {ret_type}, expected {precursor_ret_type}.")
 				end
 			end
@@ -1217,7 +1427,7 @@ redef class ATypePropdef
 		var mtype: nullable MType = null
 
 		var ntype = self.n_type
-		mtype = modelbuilder.resolve_mtype(mmodule, mclassdef, ntype)
+		mtype = modelbuilder.resolve_mtype_unchecked(mmodule, mclassdef, ntype, true)
 		if mtype == null then return
 
 		mpropdef.bound = mtype
@@ -1229,7 +1439,7 @@ redef class ATypePropdef
 		var mpropdef = self.mpropdef
 		if mpropdef == null then return # Error thus skipped
 
-		var bound = self.mpropdef.bound
+		var bound = mpropdef.bound
 		if bound == null then return # Error thus skipped
 
 		modelbuilder.check_visibility(n_type, bound, mpropdef)
@@ -1238,25 +1448,13 @@ redef class ATypePropdef
 		var mmodule = mclassdef.mmodule
 		var anchor = mclassdef.bound_mtype
 
-		# Check circularity
-		if bound isa MVirtualType then
-			# Slow case: progress on each resolution until: (i) we loop, or (ii) we found a non formal type
-			var seen = [self.mpropdef.mproperty.mvirtualtype]
-			loop
-				if seen.has(bound) then
-					seen.add(bound)
-					modelbuilder.error(self, "Error: circularity of virtual type definition: {seen.join(" -> ")}")
-					return
-				end
-				seen.add(bound)
-				var next = bound.lookup_bound(mmodule, anchor)
-				if not next isa MVirtualType then break
-				bound = next
-			end
+		var ntype = self.n_type
+		if modelbuilder.resolve_mtype(mmodule, mclassdef, ntype) == null then
+			mpropdef.bound = null
+			return
 		end
 
 		# Check redefinitions
-		bound = mpropdef.bound.as(not null)
 		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
@@ -1269,7 +1467,7 @@ redef class ATypePropdef
 				modelbuilder.warning(n_type, "refine-type", "Redef Error: a virtual type cannot be refined.")
 				break
 			end
-			if not bound.is_subtype(mmodule, anchor, supbound) then
+			if not modelbuilder.check_subtype(n_type, mmodule, anchor, bound, supbound) then
 				modelbuilder.error(n_type, "Redef Error: Wrong bound type. Found {bound}, expected a subtype of {supbound}, as in {p}.")
 				break
 			end