1 files changed, 1 insertions, 1 deletions
diff --git a/lib/puppet/parser/ast/branch.rb b/lib/puppet/parser/ast/branch.rb
index 0c481ffe6..c0fa0da30 100644
--- a/lib/puppet/parser/ast/branch.rb
+++ b/lib/puppet/parser/ast/branch.rb
@@ -31,7 +31,7 @@ class Puppet::Parser::AST
             @children.each { |child|
                 unless child.is_a?(AST)
                     raise Puppet::DevError,
-                        "child %s is a %s instead of ast" % [child, child.class]
+                        "child #{child} is a #{child.class} instead of ast"
                 end
             }
         end