# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1479071879 -3600
# Node ID fc5056a50cba44ef4520aa1f5c0413f6642287d5
# Parent  052e4264d8b7c34aa196e152bc5a70c3036ac07d
Prevent redefinition of imported names and attempt to reference them correctly.

diff -r 052e4264d8b7 -r fc5056a50cba inspector.py
--- a/inspector.py	Sat Nov 12 23:29:32 2016 +0100
+++ b/inspector.py	Sun Nov 13 22:17:59 2016 +0100
@@ -343,9 +343,15 @@
         # Names and attributes are assigned the entire expression.
 
         if isinstance(n, compiler.ast.AssName):
-            if n.name == "self":
+
+            # Prevent redefinition of certain names.
+
+            if self.in_class and self.in_function and n.name == "self":
                 raise InspectError("Redefinition of self is not allowed.", self.get_namespace_path(), n)
 
+            if self.have_imported_name(n.name):
+                raise InspectError("Redefinition of an imported name is not allowed.", self.get_namespace_path(), n)
+
             name_ref = expr and self.process_structure_node(expr)
 
             # Name assignments populate either function namespaces or the
@@ -480,6 +486,11 @@
 
         path = self.get_namespace_path()
 
+        # Prevent redefinition of imported names.
+
+        if self.have_imported_name(n.name):
+            raise InspectError("Redefinition of an imported name is not allowed.", self.get_namespace_path(), n)
+
         # To avoid notions of class "versions" where the same definition
         # might be parameterised with different state and be referenced
         # elsewhere (as base classes, for example), classes in functions or
@@ -576,6 +587,11 @@
 
         is_lambda = isinstance(n, compiler.ast.Lambda)
 
+        # Prevent redefinition of imported names.
+
+        if not is_lambda and self.have_imported_name(name):
+            raise InspectError("Redefinition of an imported name is not allowed.", self.get_namespace_path(), n)
+
         # Where a function is declared conditionally, use a separate name for
         # the definition, and assign the definition to the stated name.
 
@@ -728,6 +744,11 @@
             if name == self.name:
                 raise InspectError("Cannot import the current module.", path, n)
 
+            # Prevent redefinition of imported names.
+
+            if self.have_imported_name(alias or name):
+                raise InspectError("Redefinition of an imported name is not allowed.", self.get_namespace_path(), n)
+
             self.set_module(alias or name.split(".")[-1], name)
             self.queue_module(name, True)
 
diff -r 052e4264d8b7 -r fc5056a50cba modules.py
--- a/modules.py	Sat Nov 12 23:29:32 2016 +0100
+++ b/modules.py	Sun Nov 13 22:17:59 2016 +0100
@@ -92,7 +92,7 @@
 
         # Name resolution details.
 
-        self.name_references = {} # references to globals
+        self.name_references = {} # references to globals and imported names
 
         # Initialisation-related details.
 
@@ -352,6 +352,13 @@
         global_path = self.get_global_path(name)
         return self.imported.get(path) or self.imported.get(global_path)
 
+    def have_imported_name(self, name):
+
+        "Return whether 'name' has been imported into the current namespace."
+
+        path = self.get_object_path(name)
+        return self.imported.has_key(path)
+
     def set_imported_name(self, name, ref):
 
         "Establish a reference for 'name' given by 'ref'."
diff -r 052e4264d8b7 -r fc5056a50cba translator.py
--- a/translator.py	Sat Nov 12 23:29:32 2016 +0100
+++ b/translator.py	Sun Nov 13 22:17:59 2016 +0100
@@ -625,7 +625,7 @@
         # the complete access.
 
         name_ref = attr_expr and attr_expr.is_name() and attr_expr
-        name = name_ref and self.get_name_for_tracking(name_ref.name, name_ref and name_ref.final()) or None
+        name = name_ref and self.get_name_for_tracking(name_ref.name, name_ref and name_ref.final() or name_ref.get_name()) or None
 
         location = self.get_access_location(name)
         refs = self.get_referenced_attributes(location)