c-types-proto.lisp (canonify-qualifiers): Delete `nil' entries.

[sod] / src / c-types-proto.lisp

diff --git a/src/c-types-proto.lisp b/src/c-types-proto.lisp
index 43824da3e50f89ef2c0aa0844d59832d30fddddb..0ce2cf35fa73daa2adb91e4536e3ae4966a0d96b 100644 (file)
--- a/src/c-types-proto.lisp
+++ b/src/c-types-proto.lisp
@@ -46,8 +46,11 @@ (defclass qualifiable-c-type (c-type)
 
 (export 'canonify-qualifiers)
 (defun canonify-qualifiers (qualifiers)
-  "Return a canonical list of qualifiers."
-  (delete-duplicates (sort (copy-list qualifiers) #'string<)))
+  "Return a canonical list of qualifiers.
+
+   Duplicates and `nil' entries are deleted, and the remaining entries are
+   sorted."
+  (sort (delete-duplicates (delete nil (copy-list qualifiers))) #'string<))
 
 (export 'qualify-c-type)
 (defgeneric qualify-c-type (type qualifiers)