#450: potentially escape index letters; _ needs to be.

sphinx/writers/latex.py

@@ -266,7 +266,8 @@ class LaTeXTranslator(nodes.NodeVisitor):
             for i, (letter, entries) in enumerate(content):
                 if i > 0:
                     ret.append('\\indexspace\n')
-                ret.append('\\bigletter{%s}\n' % letter)
+                ret.append('\\bigletter{%s}\n' %
+                           letter.translate(tex_escape_map))
                 for entry in entries:
                     if not entry[3]:
                         continue