src: use `as_notnullable` in code

[nit.git] / src / typing.nit

diff --git a/src/typing.nit b/src/typing.nit
index edb1c89..d2cc5fa 100644 (file)
--- a/src/typing.nit
+++ b/src/typing.nit
@@ -51,6 +51,11 @@ private class TypeVisitor
 
        var selfvariable: Variable = new Variable("self")
 
+       # Is `self` use restricted?
+       # * no explicit `self`
+       # * method called on the implicit self must be top-level
+       var is_toplevel_context = false
+
        init(modelbuilder: ModelBuilder, mmodule: MModule, mpropdef: nullable MPropDef)
        do
                self.modelbuilder = modelbuilder
@@ -67,6 +72,11 @@ private class TypeVisitor
                        var selfvariable = new Variable("self")
                        self.selfvariable = selfvariable
                        selfvariable.declared_type = mclass.mclass_type
+
+                       var mprop = mpropdef.mproperty
+                       if mprop isa MMethod and mprop.is_toplevel then
+                               is_toplevel_context = true
+                       end
                end
        end
 
@@ -241,6 +251,15 @@ private class TypeVisitor
                end
 
                assert mproperty isa MMethod
+
+               if is_toplevel_context and recv_is_self and not mproperty.is_toplevel and name != "sys" and name != "exit" then
+                       # FIXME named methods are here as a workaround
+                       error(node, "Error: '{name}' is not a top-level method, thus need a receiver.")
+               end
+               if not recv_is_self and mproperty.is_toplevel then
+                       error(node, "Error: cannot call '{name}', a top-level method, with a receiver.")
+               end
+
                if mproperty.visibility == protected_visibility and not recv_is_self and self.mmodule.visibility_for(mproperty.intro_mclassdef.mmodule) < intrude_visibility and not modelbuilder.toolcontext.opt_ignore_visibility.value then
                        self.modelbuilder.error(node, "Error: Method '{name}' is protected and can only acceded by self.")
                        return null
@@ -265,7 +284,7 @@ private class TypeVisitor
                var erasure_cast = false
                var rettype = mpropdef.msignature.return_mtype
                if not recv_is_self and rettype != null then
-                       if rettype isa MNullableType then rettype = rettype.mtype
+                       rettype = rettype.as_notnullable
                        if rettype isa MParameterType then
                                var erased_rettype = msignature.return_mtype
                                assert erased_rettype != null
@@ -833,7 +852,7 @@ redef class AForExpr
                if objcla == null then return
 
                # check iterator method
-               var itdef = v.get_method(self, mtype, "iterator", true)
+               var itdef = v.get_method(self, mtype, "iterator", n_expr isa ASelfExpr)
                if itdef == null then
                        v.error(self, "Type Error: 'for' expects a type providing 'iterator' method, got '{mtype}'.")
                        return
@@ -886,7 +905,7 @@ redef class AForExpr
                # anchor formal and virtual types
                if mtype.need_anchor then mtype = v.anchor_to(mtype)
 
-               if mtype isa MNullableType then mtype = mtype.mtype
+               mtype = mtype.as_notnullable
                self.coltype = mtype.as(MClassType)
 
                # get methods is_ok, next, item
@@ -989,9 +1008,7 @@ redef class AOrElseExpr
                        return # Skip error
                end
 
-               if t1 isa MNullableType then
-                       t1 = t1.mtype
-               end
+               t1 = t1.as_notnullable
 
                var t = v.merge_types(self, [t1, t2])
                if t == null then
@@ -1062,7 +1079,7 @@ redef class ASuperstringExpr
                if mclass == null then return # Forward error
                self.mtype = mclass.mclass_type
                for nexpr in self.n_exprs do
-                       var t = v.visit_expr(nexpr)
+                       v.visit_expr_subtype(nexpr, v.mmodule.object_type)
                end
        end
 end
@@ -1175,6 +1192,8 @@ redef class AAsNotnullExpr
        redef fun accept_typing(v)
        do
                var mtype = v.visit_expr(self.n_expr)
+               if mtype == null then return # Forward error
+
                if mtype isa MNullType then
                        v.error(self, "Type error: as(not null) on null")
                        return
@@ -1183,8 +1202,18 @@ redef class AAsNotnullExpr
                        self.mtype = mtype.mtype
                        return
                end
-               # TODO: warn on useless as not null
                self.mtype = mtype
+
+               if mtype isa MClassType then
+                       v.modelbuilder.warning(self, "Warning: expression is already not null, since it is a `{mtype}`.")
+                       return
+               end
+               assert mtype.need_anchor
+               var u = v.anchor_to(mtype)
+               if not u isa MNullableType then
+                       v.modelbuilder.warning(self, "Warning: expression is already not null, since it is a `{mtype}: {u}`.")
+                       return
+               end
        end
 end
 
@@ -1199,6 +1228,9 @@ redef class ASelfExpr
        redef var its_variable: nullable Variable
        redef fun accept_typing(v)
        do
+               if v.is_toplevel_context and not self isa AImplicitSelfExpr then
+                       v.error(self, "Error: self cannot be used in top-level method.")
+               end
                var variable = v.selfvariable
                self.its_variable = variable
                self.mtype = v.get_variable(self, variable)