Add a useful assertion message if a type gets multiply declared.

diff --git a/src/size.py b/src/size.py
index 8376833..5ead8b2 100755 (executable)
--- a/src/size.py
+++ b/src/size.py
@@ -21,7 +21,7 @@ class AnnotateSize(XMLFilterBase):
        }
        header = []
        def setTypeSize(self, name, size):
-               assert not self.types.has_key(name)
+               assert not self.types.has_key(name), "size of " + name + " declared as both " + str(size) + " and " + str(self.types[name])
                self.types[name] = size
 
        struct = None