modelize_class: Remove the `useless-bound` warning

[nit.git] / src / modelize / modelize_class.nit

# This file is part of NIT ( http://www.nitlanguage.org ).
#
# Copyright 2012 Jean Privat <jean@pryen.org>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# Analysis and verification of class definitions to instantiate model element
module modelize_class

import modelbuilder

redef class ToolContext
        # Run `AModule::build_classes` on each module
        var modelize_class_phase: Phase = new ModelizeClassPhase(self, null)
end

private class ModelizeClassPhase
        super Phase

        redef fun process_nmodule(nmodule)
        do
                toolcontext.modelbuilder.build_classes(nmodule)
        end
end

redef class ModelBuilder
        # Visit the AST and create the `MClass` objects
        private fun build_a_mclass(nmodule: AModule, nclassdef: AClassdef)
        do
                var mmodule = nmodule.mmodule.as(not null)

                var name: String
                var nkind: nullable AClasskind
                var mkind: MClassKind
                var nvisibility: nullable AVisibility
                var mvisibility: nullable MVisibility
                var arity = 0
                var names = new Array[String]
                var mclass
                if nclassdef isa AStdClassdef then
                        var qid = nclassdef.n_qid
                        assert qid != null
                        name = qid.n_id.text
                        nkind = nclassdef.n_classkind
                        mkind = nkind.mkind
                        nvisibility = nclassdef.n_visibility
                        mvisibility = nvisibility.mvisibility
                        arity = nclassdef.n_formaldefs.length
                        if mvisibility == protected_visibility then
                                error(nvisibility, "Error: only properties can be protected.")
                                return
                        else if mvisibility == intrude_visibility then
                                error(nvisibility, "Error: intrude is not a legal visibility for classes.")
                                return
                        end
                        # Collect formal parameter names
                        for i in [0..arity[ do
                                var nfd = nclassdef.n_formaldefs[i]
                                var ptname = nfd.n_id.text
                                if names.has(ptname) then
                                        error(nfd, "Error: a formal parameter type `{ptname}` already exists.")
                                        return
                                end
                                for c in ptname.chars do if c >= 'a' and c<= 'z' then
                                        warning(nfd, "formal-type-name", "Warning: lowercase in the formal parameter type `{ptname}`.")
                                        break
                                end
                                names.add(ptname)
                        end
                        mclass = try_get_mclass_by_qid(qid, mmodule)
                        if mclass == null and (qid.n_qualified != null or nclassdef.n_kwredef != null) then
                                class_not_found(qid, mmodule)
                                nclassdef.is_broken = true
                                return
                        end

                else if nclassdef isa ATopClassdef and nclassdef.n_propdefs.first.as(AMethPropdef).n_methid.collect_text == "sys" then
                        # Special case to keep `sys` in object.
                        # Needed to keep working bootstrap and a working java FFI together.
                        # TODO: remove once safe to remove
                        name = "Object"
                        nkind = null
                        mkind = interface_kind
                        nvisibility = null
                        mvisibility = public_visibility
                        mclass = try_get_mclass_by_name(nclassdef, mmodule, name)
                else
                        name = "Sys"
                        nkind = null
                        mkind = concrete_kind
                        nvisibility = null
                        mvisibility = public_visibility
                        mclass = try_get_mclass_by_name(nclassdef, mmodule, name)
                end

                if mclass == null then
                        # Check for conflicting class full-names in the package
                        if mmodule.mgroup != null and mvisibility >= protected_visibility then
                                var mclasses = model.get_mclasses_by_name(name)
                                if mclasses != null then for other in mclasses do
                                        if other.intro_mmodule.mgroup != null and other.intro_mmodule.mgroup.mpackage == mmodule.mgroup.mpackage then
                                                # Skip classes that are buggy
                                                if other.try_intro == null then continue
                                                warning(nclassdef, "full-name-conflict", "Error: a class named `{other.full_name}` is already defined in module `{other.intro_mmodule}` at {other.intro.location}.")
                                                break
                                        end
                                end
                        end

                        mclass = new MClass(mmodule, name, nclassdef.location, names, mkind, mvisibility)
                        #print "new class {mclass}"
                else if nclassdef isa AStdClassdef and nmodule.mclass2nclassdef.has_key(mclass) then
                        error(nclassdef, "Error: a class `{name}` is already defined at line {nmodule.mclass2nclassdef[mclass].location.line_start}.")
                        mclass.is_broken = true
                        return
                else if nclassdef isa AStdClassdef and nclassdef.n_kwredef == null then
                        error(nclassdef, "Redef Error: `{name}` is an imported class. Add the `redef` keyword to refine it.")
                        mclass.is_broken = true
                        return
                else if arity != 0 and mclass.arity != arity then
                        error(nclassdef, "Redef Error: expected {mclass.arity} formal parameter(s) for {mclass.signature_to_s}; got {arity}.")
                        mclass.is_broken = true
                        return
                else if nkind != null and mkind != concrete_kind and mclass.kind != mkind then
                        error(nkind, "Redef Error: refinement changed the kind from `{mclass.kind}` to `{mkind}`.")
                else if nvisibility != null and mvisibility != public_visibility and mclass.visibility != mvisibility then
                        error(nvisibility, "Redef Error: refinement changed the visibility from `{mclass.visibility}` to `{mvisibility}`")
                end
                nclassdef.mclass = mclass
                if not nmodule.mclass2nclassdef.has_key(mclass) then
                        nmodule.mclass2nclassdef[mclass] = nclassdef
                        nclassdef.all_defs = [nclassdef]
                else
                        nmodule.mclass2nclassdef[mclass].all_defs.add(nclassdef)
                end
        end

        # Visit the AST and create the `MClassDef` objects
        private fun build_a_mclassdef(nmodule: AModule, nclassdef: AClassdef)
        do
                var mmodule = nmodule.mmodule.as(not null)
                var objectclass = try_get_mclass_by_name(nmodule, mmodule, "Object")
                var mclass = nclassdef.mclass
                if mclass == null then return # Skip error

                # In case of non-standard AClassdef, try to attach to an already existing mclassdef
                var other_nclassdef = nmodule.mclass2nclassdef[mclass]
                if other_nclassdef != nclassdef then
                        assert not nclassdef isa AStdClassdef
                        nclassdef.mclassdef = other_nclassdef.mclassdef
                        return
                end

                var bounds = new Array[MType]
                if nclassdef isa AStdClassdef and mclass.arity > 0 then
                        # Revolve bound for formal parameters
                        for i in [0..mclass.arity[ do
                                if nclassdef.n_formaldefs.is_empty then
                                        # Inherit the bound
                                        var bound = mclass.intro.bound_mtype.arguments[i]
                                        bounds.add(bound)
                                        continue
                                end

                                var nfd = nclassdef.n_formaldefs[i]
                                var pname = mclass.mparameters[i].name
                                if nfd.n_id.text != pname then
                                        error(nfd.n_id, "Error: formal parameter type #{i} `{nfd.n_id.text}` must be named `{pname}` as in the original definition in module `{mclass.intro.mmodule}`.")
                                end
                                var nfdt = nfd.n_type
                                if nfdt != null then
                                        var bound = resolve_mtype_unchecked(mmodule, null, nfdt, false)
                                        if bound == null then return # Forward error
                                        if bound.need_anchor then
                                                # No F-bounds!
                                                error(nfd, "Error: formal parameter type `{pname}` bounded with a formal parameter type.")
                                        else
                                                bounds.add(bound)
                                                nfd.bound = bound
                                        end
                                else if mclass.mclassdefs.is_empty then
                                        if objectclass == null then
                                                error(nfd, "Error: formal parameter type `{pname}` unbounded but no `Object` class exists.")
                                                return
                                        end
                                        # No bound, then implicitely bound by nullable Object
                                        var bound = objectclass.mclass_type.as_nullable
                                        bounds.add(bound)
                                        nfd.bound = bound
                                else
                                        # Inherit the bound
                                        var bound = mclass.intro.bound_mtype.arguments[i]
                                        bounds.add(bound)
                                        nfd.bound = bound
                                end
                        end
                end

                var bound_mtype = mclass.get_mtype(bounds)
                var mclassdef = new MClassDef(mmodule, bound_mtype, nclassdef.location)
                nclassdef.mclassdef = mclassdef
                self.mclassdef2nclassdef[mclassdef] = nclassdef

                if nclassdef isa AStdClassdef then
                        var ndoc = nclassdef.n_doc
                        if ndoc != null then
                                var mdoc = ndoc.to_mdoc
                                mclassdef.mdoc = mdoc
                                mdoc.original_mentity = mclassdef
                        else if mclassdef.is_intro and mclass.visibility >= public_visibility then
                                advice(nclassdef, "missing-doc", "Documentation warning: Undocumented public class `{mclass}`")
                        end
                end

                if mclassdef.is_intro then
                        self.toolcontext.info("{mclassdef} introduces new {mclass.kind} {mclass.full_name}", 3)
                else
                        self.toolcontext.info("{mclassdef} refines {mclass.kind} {mclass.full_name}", 3)
                end
        end

        # Visit the AST and set the super-types of the `MClassDef` objects
        private fun collect_a_mclassdef_inheritance(nmodule: AModule, nclassdef: AClassdef)
        do
                var mmodule = nmodule.mmodule
                if mmodule == null then return
                var objectclass = try_get_mclass_by_name(nmodule, mmodule, "Object")
                var pointerclass = try_get_mclass_by_name(nmodule, mmodule, "Pointer")
                var mclass = nclassdef.mclass
                if mclass == null then return
                var mclassdef = nclassdef.mclassdef
                if mclassdef == null then return

                # Do we need to specify Object as a super class?
                var specobject = true

                # Do we need to specify Pointer as a super class? (is only valid
                # if `nclassdef` is an extern class)
                var specpointer = true

                var supertypes = new Array[MClassType]
                if nclassdef isa AStdClassdef then
                        for nsc in nclassdef.n_superclasses do
                                specobject = false
                                var ntype = nsc.n_type
                                var mtype = resolve_mtype_unchecked(mmodule, mclassdef, ntype, false)
                                if mtype == null then continue # Skip because of error
                                if not mtype isa MClassType then
                                        error(ntype, "Error: supertypes cannot be a formal type.")
                                        return
                                end
                                if not mclass.kind.can_specialize(mtype.mclass.kind) then
                                        error(ntype, "Error: {mclass.kind} `{mclass}` cannot specialize {mtype.mclass.kind} `{mtype.mclass}`.")
                                end
                                supertypes.add mtype
                                #print "new super : {mclass} < {mtype}"
                                if mtype.mclass.kind == extern_kind then specpointer = false
                        end
                end

                if mclassdef.is_intro and objectclass != null then
                        if mclass.kind == extern_kind and mclass.name != "Pointer" then
                                # it is an extern class, but not a Pointer
                                if pointerclass == null then
                                        error(nclassdef, "Error: `Pointer` must be defined first.")
                                        return
                                end
                                if specpointer then supertypes.add pointerclass.mclass_type
                        else if specobject then
                                if mclass.name != "Object" then
                                        # it is a standard class without super class (but is not Object)
                                        supertypes.add objectclass.mclass_type
                                else if mclass.kind != interface_kind then
                                        error(nclassdef, "Error: `Object` must be an {interface_kind}.")
                                        return
                                end
                        end
                end

                mclassdef.set_supertypes(supertypes)
                if not supertypes.is_empty then self.toolcontext.info("{mclassdef} new super-types: {supertypes.join(", ")}", 3)
        end

        # Check the validity of the specialization heirarchy
        private fun check_supertypes(nmodule: AModule, nclassdef: AClassdef)
        do
                var mmodule = nmodule.mmodule
                if mmodule == null then return
                var mclass = nclassdef.mclass
                if mclass == null then return
                var mclassdef = nclassdef.mclassdef
                if mclassdef == null then return

                for s in mclassdef.supertypes do
                        if s.is_subtype(mmodule, mclassdef.bound_mtype, mclassdef.bound_mtype) then
                                error(nclassdef, "Error: inheritance loop for class `{mclass}` with type `{s}`.")
                        end
                end
        end

        # Build the classes of the module `nmodule`.
        private fun build_classes(nmodule: AModule)
        do
                # Force building recursively
                if nmodule.build_classes_is_done then return
                nmodule.build_classes_is_done = true
                var mmodule = nmodule.mmodule
                if mmodule == null then return
                for imp in mmodule.in_importation.direct_greaters do
                        var nimp = mmodule2node(imp)
                        if nimp != null then build_classes(nimp)
                end

                # Create all classes
                # process AStdClassdef before so that non-AStdClassdef classes can be attached to existing ones, if any
                for nclassdef in nmodule.n_classdefs do
                        if not nclassdef isa AStdClassdef then continue
                        self.build_a_mclass(nmodule, nclassdef)
                end
                for nclassdef in nmodule.n_classdefs do
                        if nclassdef isa AStdClassdef then continue
                        self.build_a_mclass(nmodule, nclassdef)
                end

                # Create all classdefs
                for nclassdef in nmodule.n_classdefs do
                        if not nclassdef isa AStdClassdef then continue
                        self.build_a_mclassdef(nmodule, nclassdef)
                end
                for nclassdef in nmodule.n_classdefs do
                        if nclassdef isa AStdClassdef then continue
                        self.build_a_mclassdef(nmodule, nclassdef)
                end

                # Create inheritance on all classdefs
                for nclassdef in nmodule.n_classdefs do
                        self.collect_a_mclassdef_inheritance(nmodule, nclassdef)
                end

                # Create the mclassdef hierarchy
                for mclassdef in mmodule.mclassdefs do
                        mclassdef.add_in_hierarchy
                end

                # Check inheritance
                for nclassdef in nmodule.n_classdefs do
                        self.check_supertypes(nmodule, nclassdef)
                end

                # Check unchecked ntypes
                for nclassdef in nmodule.n_classdefs do
                        if nclassdef isa AStdClassdef then
                                var mclassdef = nclassdef.mclassdef
                                # check bound of formal parameter
                                for nfd in  nclassdef.n_formaldefs do
                                        var nfdt = nfd.n_type
                                        if nfdt != null and nfdt.mtype != null then
                                                var bound = resolve_mtype(mmodule, mclassdef, nfdt)
                                                if bound == null then return # Forward error
                                        end
                                end
                                # check declared super types
                                for nsc in nclassdef.n_superclasses do
                                        var ntype = nsc.n_type
                                        if ntype.mtype != null then
                                                var mtype = resolve_mtype(mmodule, mclassdef, ntype)
                                                if mtype == null then return # Forward error
                                        end
                                end
                        end
                end

                # Check clash of ancestors
                for nclassdef in nmodule.n_classdefs do
                        var mclassdef = nclassdef.mclassdef
                        if mclassdef == null then continue
                        var superclasses = new HashMap[MClass, MClassType]
                        for scd in mclassdef.in_hierarchy.greaters do
                                for st in scd.supertypes do
                                        if not superclasses.has_key(st.mclass) then
                                                superclasses[st.mclass] = st
                                        else if superclasses[st.mclass] != st then
                                                var st1 = superclasses[st.mclass].resolve_for(mclassdef.mclass.mclass_type, mclassdef.bound_mtype, mmodule, false)
                                                var st2 = st.resolve_for(mclassdef.mclass.mclass_type, mclassdef.bound_mtype, mmodule, false)
                                                if st1 != st2 then
                                                        error(nclassdef, "Error: incompatible ancestors for `{mclassdef.mclass}`; conflict: `{st1}` and `{st2}`")
                                                end
                                        end
                                end
                        end
                end

                # TODO: Check that the super-class is not intrusive

                # Check that the superclasses are not already known (by transitivity)
                for nclassdef in nmodule.n_classdefs do
                        if not nclassdef isa AStdClassdef or nclassdef.is_broken then continue
                        var mclassdef = nclassdef.mclassdef
                        if mclassdef == null then continue

                        # Get the direct superclasses
                        # Since we are a mclassdef, just look at the mclassdef hierarchy
                        var parents = new Array[MClass]
                        for sup in mclassdef.in_hierarchy.direct_greaters do
                                parents.add(sup.mclass)
                        end

                        # Used to track duplicates of superclasses
                        var seen_parents = new ArrayMap[MClass, AType]

                        # The Object class
                        var objectclass = try_get_mclass_by_name(nmodule, mmodule, "Object")

                        # Check each declared superclass to see if it belong to the direct superclass
                        for nsc in nclassdef.n_superclasses do
                                var ntype = nsc.n_type
                                var mtype = ntype.mtype
                                if mtype == null then continue
                                assert mtype isa MClassType
                                var sc = mtype.mclass
                                if not parents.has(sc) or sc == objectclass then
                                        # Skip the warning on generated code
                                        if ntype.location.file != null and not ntype.location.file.filename.is_empty then
                                                warning(ntype, "useless-superclass", "Warning: superfluous super-class `{mtype}` in class `{mclassdef.mclass}`.")
                                        end
                                else if not seen_parents.has_key(sc) then
                                        seen_parents[sc] = ntype
                                else
                                        warning(ntype, "useless-superclass", "Warning: duplicated super-class `{mtype}` in class `{mclassdef.mclass}`.")
                                end
                        end
                end
        end

        # Registration of the nclassdef associated to each mclassdef
        private var mclassdef2nclassdef = new HashMap[MClassDef, AClassdef]

        # Retrieve the associated AST node of a mclassdef.
        #
        # This method is used to associate model entity with syntactic entities.
        # If the class definition is not associated with a node, returns `null`.
        fun mclassdef2node(mclassdef: MClassDef): nullable AClassdef do
                return mclassdef2nclassdef.get_or_null(mclassdef)
        end
end

redef class AModule
        # Flag that indicate if the class building is already completed
        var build_classes_is_done: Bool = false
        # What is the AClassdef associated to a `MClass`?
        # Used to check multiple definition of a class.
        var mclass2nclassdef: Map[MClass, AClassdef] = new HashMap[MClass, AClassdef]
end

redef class AClassdef
        # The associated MClass once build by a `ModelBuilder`
        var mclass: nullable MClass
        # The associated MClassDef once build by a `ModelBuilder`
        var mclassdef: nullable MClassDef
        # All (self and other) definitions for the same mclassdef
        var all_defs: nullable Array[AClassdef]
end

redef class AClasskind
        # The class kind associated with the AST node class
        private fun mkind: MClassKind is abstract
end
redef class AConcreteClasskind
        redef fun mkind do return concrete_kind
end
redef class AAbstractClasskind
        redef fun mkind do return abstract_kind
end
redef class AInterfaceClasskind
        redef fun mkind do return interface_kind
end
redef class AEnumClasskind
        redef fun mkind do return enum_kind
end
redef class AExternClasskind
        redef fun mkind do return extern_kind
end

redef class AFormaldef
        # The associated parameter type
        var mtype: nullable MParameterType = null

        # The associated bound
        var bound: nullable MType = null
end