typing: look for method in `sys` when they are not in `self`

Signed-off-by: Jean Privat <jean@pryen.org>

diff --git a/src/semantize/typing.nit b/src/semantize/typing.nit
index 38a689a..ce51fa3 100644 (file)
--- a/src/semantize/typing.nit
+++ b/src/semantize/typing.nit
@@ -1441,6 +1441,15 @@ redef class ASelfExpr
        end
 end
 
+redef class AImplicitSelfExpr
+       # Is the implicit receiver `sys`?
+       #
+       # By default, the implicit receiver is `self`.
+       # But when there is not method for `self`, `sys` is used as a fall-back.
+       # Is this case this flag is set to `true`.
+       var is_sys = false
+end
+
 ## MESSAGE SENDING AND PROPERTY
 
 redef class ASendExpr
@@ -1449,13 +1458,38 @@ redef class ASendExpr
 
        redef fun accept_typing(v)
        do
-               var recvtype = v.visit_expr(self.n_expr)
+               var nrecv = self.n_expr
+               var recvtype = v.visit_expr(nrecv)
                var name = self.property_name
 
                if recvtype == null then return # Forward error
 
-               var callsite = v.get_method(self, recvtype, name, self.n_expr isa ASelfExpr)
-               if callsite == null then return
+               var callsite = null
+               var unsafe_type = v.anchor_to(recvtype)
+               var mproperty = v.try_get_mproperty_by_name2(self, unsafe_type, name)
+               if mproperty == null and nrecv isa AImplicitSelfExpr then
+                       # Special fall-back search in `sys` when noting found in the implicit receiver.
+                       var sysclass = v.try_get_mclass(self, "Sys")
+                       if sysclass != null then
+                               var systype = sysclass.mclass_type
+                               mproperty = v.try_get_mproperty_by_name2(self, systype, name)
+                               if mproperty != null then
+                                       callsite = v.get_method(self, systype, name, false)
+                                       if callsite == null then return # Forward error
+                                       # Update information, we are looking at `sys` now, not `self`
+                                       nrecv.is_sys = true
+                                       nrecv.its_variable = null
+                                       nrecv.mtype = systype
+                                       recvtype = systype
+                               end
+                       end
+               end
+               if callsite == null then
+                       # If still nothing, just exit
+                       callsite = v.get_method(self, recvtype, name, nrecv isa ASelfExpr)
+                       if callsite == null then return
+               end
+
                self.callsite = callsite
                var msignature = callsite.msignature