Merge: Not null types
[nit.git] / src / modelize / modelize_property.nit
index 5d93adf..c224b29 100644 (file)
@@ -86,7 +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
@@ -102,6 +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
@@ -181,6 +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
@@ -190,6 +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
@@ -202,9 +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
@@ -218,39 +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
@@ -286,7 +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
@@ -295,6 +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
@@ -323,6 +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
@@ -533,7 +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)
@@ -550,7 +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
 
@@ -558,24 +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
 
@@ -671,6 +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
@@ -799,6 +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)
@@ -811,6 +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
@@ -821,6 +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
 
@@ -832,6 +998,7 @@ 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: Wrong type for parameter `{mysignature.mparameters[i].name}'. found {myt}, expected {prt} as in {mpropdef.mproperty.intro}.")
+                                               self.mpropdef.msignature = null
                                        end
                                end
                        end
@@ -844,6 +1011,7 @@ 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: Wrong return type. found {ret_type}, expected {precursor_ret_type} as in {mpropdef.mproperty.intro}.")
+                                       self.mpropdef.msignature = null
                                end
                        end
                end
@@ -887,32 +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)
@@ -923,15 +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
@@ -949,6 +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
@@ -985,7 +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
@@ -997,28 +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
@@ -1033,7 +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
@@ -1053,14 +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
@@ -1068,13 +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
@@ -1102,6 +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
@@ -1233,7 +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
@@ -1245,7 +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)
@@ -1254,25 +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