Use custom deep_clone for Sexp

slightly faster and probably uses less memory

lib/brakeman/processors/alias_processor.rb

@@ -63,7 +63,7 @@ class Brakeman::AliasProcessor < Brakeman::SexpProcessor
 
     #Generic replace
     if replacement = env[exp] and not duplicate? replacement
-      result = set_line replacement.deep_clone, exp.line
+      result = replacement.deep_clone(exp.line)
     else
       result = exp
     end
@@ -580,20 +580,6 @@ class Brakeman::AliasProcessor < Brakeman::SexpProcessor
     meth_env
   end
 
-  #Set line nunber for +exp+ and every Sexp it contains. Used when replacing
-  #expressions, so warnings indicate the correct line.
-  def set_line exp, line_number
-    if sexp? exp
-      exp.original_line(exp.original_line || exp.line)
-      exp.line line_number
-      exp.each do |e|
-        set_line e, line_number
-      end
-    end
-
-    exp
-  end
-
   #Finds the inner most call target which is not the target of a call to <<
   def find_push_target exp
     if call? exp and exp.method == :<<

lib/ruby_parser/bm_sexp.rb

@@ -14,6 +14,30 @@ class Sexp
     raise NoMethodError.new("No method '#{name}' for Sexp", name, args)
   end
 
+  #Create clone of Sexp and nested Sexps but not their non-Sexp contents.
+  #If a line number is provided, also sets line/original_line on all Sexps.
+  def deep_clone line = nil
+    s = Sexp.new
+
+    self.each do |e|
+      if e.is_a? Sexp
+        s << e.deep_clone(line)
+      else
+        s << e
+      end
+    end
+
+    if line
+      s.original_line(self.original_line || self.line)
+      s.line(line)
+    else
+      s.original_line(self.original_line)
+      s.line(self.line)
+    end
+
+    s
+  end
+
   def paren
     @paren ||= false
   end