While I was modifying test_trace, it threw an exception when I accidentally
made it try to set the line number from the trace callback for a 'call' event.
This patch makes the error message a little more helpful in that case, and
makes it a little less likely that a future editor will make the same mistake
in test_trace.
diff --git a/Objects/frameobject.c b/Objects/frameobject.c
index 7a9d40d..5e54585 100644
--- a/Objects/frameobject.c
+++ b/Objects/frameobject.c
@@ -127,7 +127,8 @@
if (!f->f_trace)
{
PyErr_Format(PyExc_ValueError,
- "f_lineno can only be set by a trace function");
+ "f_lineno can only be set by a"
+ " line trace function");
return -1;
}