syntax: error on local variable masking

[nit.git] / src / syntax / control_flow.nit

diff --git a/src/syntax/control_flow.nit b/src/syntax/control_flow.nit
index 4cd879b..4b8d0fc 100644 (file)
--- a/src/syntax/control_flow.nit
+++ b/src/syntax/control_flow.nit
@@ -36,6 +36,10 @@ abstract class VariableContext
        # Register a new variable with its name
        fun add(v: Variable)
        do
+               var old_var = self[v.name]
+               if old_var != null then
+                       _visitor.error(v.decl, "Error: '{v}' already defined at {old_var.decl.location.relative_to(v.decl.location)}.")
+               end
                _dico[v.name] = v
                _all_variables.add(v)
        end