ast: Allow lookup of the instance parameter by name

This will be used by the doctool to properly identify the
instance parameter.

1 files changed, 1 insertions, 1 deletions

diff --git a/giscanner/ast.py b/giscanner/ast.py
index 3092d67a..aae9ee2e 100644
--- a/giscanner/ast.py
+++ b/giscanner/ast.py
@@ -597,7 +597,7 @@ class Callable(Node):
         raise ValueError("Unknown argument %s" % (name, ))
 
     def get_parameter(self, name):
-        for parameter in self.parameters:
+        for parameter in self.all_parameters:
             if parameter.argname == name:
                 return parameter
         raise ValueError("Unknown argument %s" % (name, ))