Mass assignments were being clobbered, make api use consistent

lib/brakeman/checks/check_mass_assignment.rb

@@ -21,7 +21,6 @@ class Brakeman::CheckMassAssignment < Brakeman::BaseCheck
 
     return if models.empty?
 
-    @results = Set.new
 
     Brakeman.debug "Finding possible mass assignment calls on #{models.length} models"
     calls = tracker.find_call :chained => true, :targets => models, :methods => [:new,
@@ -45,7 +44,7 @@ class Brakeman::CheckMassAssignment < Brakeman::BaseCheck
 
     check = check_call call
 
-    if check and not @results.include? call
+    if check and not duplicate? res
       @results << call
 
       model = tracker.models[res[:chain].first]

lib/brakeman/checks/check_without_protection.rb

@@ -23,8 +23,6 @@ class Brakeman::CheckWithoutProtection < Brakeman::BaseCheck
 
     return if models.empty?
 
-    @results = Set.new
-
     Brakeman.debug "Finding all mass assignments"
     calls = tracker.find_call :targets => models, :methods => [:new,
       :attributes=, 
@@ -45,7 +43,7 @@ class Brakeman::CheckWithoutProtection < Brakeman::BaseCheck
     call = res[:call]
     last_arg = call[3][-1]
 
-    if hash? last_arg and not @results.include? call
+    if hash? last_arg and not duplicate? res
 
       hash_iterate(last_arg) do |k,v|
         if symbol? k and k[1] == :without_protection and v[0] == :true