typing: warn `useless-type` for useless type in a local variable

[nit.git] / src / semantize / typing.nit

diff --git a/src/semantize/typing.nit b/src/semantize/typing.nit
index bb66218..cdb8ae8 100644 (file)
--- a/src/semantize/typing.nit
+++ b/src/semantize/typing.nit
@@ -39,10 +39,10 @@ private class TypeVisitor
 
        # The static type of the receiver
        # Mainly used for type tests and type resolutions
-       var anchor: nullable MClassType
+       var anchor: nullable MClassType = null
 
        # The analyzed mclassdef
-       var mclassdef: nullable MClassDef
+       var mclassdef: nullable MClassDef = null
 
        # The analyzed property
        var mpropdef: nullable MPropDef
@@ -54,10 +54,9 @@ private class TypeVisitor
        # * method called on the implicit self must be top-level
        var is_toplevel_context = false
 
-       init(modelbuilder: ModelBuilder, mmodule: MModule, mpropdef: nullable MPropDef)
+       init
        do
-               self.modelbuilder = modelbuilder
-               self.mmodule = mmodule
+               var mpropdef = self.mpropdef
 
                if mpropdef != null then
                        self.mpropdef = mpropdef
@@ -669,7 +668,11 @@ redef class AVardeclExpr
                var nexpr = self.n_expr
                if nexpr != null then
                        if mtype != null then
-                               v.visit_expr_subtype(nexpr, mtype)
+                               var etype = v.visit_expr_subtype(nexpr, mtype)
+                               if etype == mtype then
+                                       assert ntype != null
+                                       v.modelbuilder.advice(ntype, "useless-type", "Warning: useless type definition for variable `{variable.name}`")
+                               end
                        else
                                mtype = v.visit_expr(nexpr)
                                if mtype == null then return # Skip error