--- a/genshi/template/directives.py
+++ b/genshi/template/directives.py
@@ -22,7 +22,7 @@
 from genshi.core import QName, Stream
 from genshi.path import Path
 from genshi.template.base import TemplateRuntimeError, TemplateSyntaxError, \
-                                 EXPR, _apply_directives
+                                 EXPR, _apply_directives, _ctxt2dict
 from genshi.template.eval import Expression, Suite, ExpressionASTTransformer, \
                                  _parse
 
@@ -725,7 +725,7 @@
     def __call__(self, stream, ctxt, directives):
         frame = {}
         ctxt.push(frame)
-        self.suite.execute(ctxt)
+        self.suite.execute(_ctxt2dict(ctxt))
         for event in _apply_directives(stream, ctxt, directives):
             yield event
         ctxt.pop()

--- a/genshi/template/eval.py
+++ b/genshi/template/eval.py
@@ -439,7 +439,8 @@
         node = node.__class__(*args)
         if lineno is not None:
             node.lineno = lineno
-        if isinstance(node, (ast.Class, ast.Function, ast.GenExpr, ast.Lambda)):
+        if isinstance(node, (ast.Class, ast.Function, ast.Lambda)) or \
+                sys.version_info > (2, 4) and isinstance(node, ast.GenExpr):
             node.filename = '<string>' # workaround for bug in pycodegen
         return node