Use #nil? instead of == nil.

mrbgems/mruby-array-ext/mrblib/array.rb

@@ -217,7 +217,7 @@ class Array
   #    [ "a", "b", "c" ].compact!           #=> nil
   #
   def compact!
-    result = self.select { |e| e != nil }
+    result = self.select { |e| !e.nil? }
     if result.size == self.size
       nil
     else
@@ -262,7 +262,7 @@ class Array
   #
 
   def fetch(n=nil, ifnone=NONE, &block)
-    warn "block supersedes default value argument" if n != nil && ifnone != NONE && block
+    warn "block supersedes default value argument" if !n.nil? && ifnone != NONE && block
 
     idx = n
     if idx < 0
@@ -312,51 +312,51 @@ class Array
   #
 
   def fill(arg0=nil, arg1=nil, arg2=nil, &block)
-    if arg0 == nil && arg1 == nil && arg2 == nil && !block
+    if arg0.nil? && arg1.nil? && arg2.nil? && !block
       raise ArgumentError, "wrong number of arguments (0 for 1..3)"
     end
 
     beg = len = 0
     ary = []
     if block
-      if arg0 == nil && arg1 == nil && arg2 == nil
+      if arg0.nil? && arg1.nil? && arg2.nil?
         # ary.fill { |index| block }                    -> ary
         beg = 0
         len = self.size
-      elsif arg0 != nil && arg0.kind_of?(Range)
+      elsif !arg0.nil? && arg0.kind_of?(Range)
         # ary.fill(range) { |index| block }             -> ary
         beg = arg0.begin
         beg += self.size if beg < 0
         len = arg0.end
         len += self.size if len < 0
         len += 1 unless arg0.exclude_end?
-      elsif arg0 != nil
+      elsif !arg0.nil?
         # ary.fill(start [, length] ) { |index| block } -> ary
         beg = arg0
         beg += self.size if beg < 0
-        if arg1 == nil
+        if arg1.nil?
           len = self.size
         else
           len = arg0 + arg1
         end
       end
     else
-      if arg0 != nil && arg1 == nil && arg2 == nil
+      if !arg0.nil? && arg1.nil? && arg2.nil?
         # ary.fill(obj)                                 -> ary
         beg = 0
         len = self.size
-      elsif arg0 != nil && arg1 != nil && arg1.kind_of?(Range)
+      elsif !arg0.nil? && !arg1.nil? && arg1.kind_of?(Range)
         # ary.fill(obj, range )                         -> ary
         beg = arg1.begin
         beg += self.size if beg < 0
         len = arg1.end
         len += self.size if len < 0
         len += 1 unless arg1.exclude_end?
-      elsif arg0 != nil && arg1 != nil
+      elsif !arg0.nil? && !arg1.nil?
         # ary.fill(obj, start [, length])               -> ary
         beg = arg1
         beg += self.size if beg < 0
-        if arg2 == nil
+        if arg2.nil?
           len = self.size
         else
           len = beg + arg2
@@ -582,7 +582,7 @@ class Array
       elsif v == true
         satisfied = true
         smaller = true
-      elsif v == false || v == nil
+      elsif v == false || v.nil?
         smaller = false
       end
       if smaller

mrbgems/mruby-enum-ext/mrblib/enum.rb

@@ -515,7 +515,7 @@ module Enumerable
   #
 
   def each_with_object(obj=nil, &block)
-    raise ArgumentError, "wrong number of arguments (0 for 1)" if obj == nil
+    raise ArgumentError, "wrong number of arguments (0 for 1)" if obj.nil?
 
     return to_enum(:each_with_object, obj) unless block
 
@@ -574,10 +574,10 @@ module Enumerable
   #
 
   def cycle(n=nil, &block)
-    return to_enum(:cycle, n) if !block && n == nil
+    return to_enum(:cycle, n) if !block && n.nil?
 
     ary = []
-    if n == nil
+    if n.nil?
       self.each do|*val|
         ary.push val
         block.call(*val)

mrbgems/mruby-string-ext/mrblib/string.rb

@@ -164,9 +164,9 @@ class String
   #    string                  #=> "thsa sting"
   #
   def slice!(arg1, arg2=nil)
-    raise "wrong number of arguments (for 1..2)" if arg1 == nil && arg2 == nil
+    raise "wrong number of arguments (for 1..2)" if arg1.nil? && arg2.nil?
 
-    if arg1 != nil && arg2 != nil
+    if !arg1.nil? && !arg2.nil?
       idx = arg1
       idx += self.size if arg1 < 0
       if idx >= 0 && idx <= self.size && arg2 > 0
@@ -196,8 +196,8 @@ class String
         return nil
       end
     end
-    unless str == nil || str == ""
-      if arg1 != nil && arg2 !=nil
+    unless str.nil? || str == ""
+      if !arg1.nil? && !arg2.nil?
         idx = arg1 >= 0 ? arg1 : self.size+arg1
         str2 = self[0...idx] + self[idx+arg2..-1].to_s
       else
@@ -207,13 +207,13 @@ class String
           str2 = self[0...idx] + self[idx2+1..-1].to_s
         elsif arg1.kind_of?(String)
           idx = self.index(arg1)
-          str2 = self[0...idx] + self[idx+arg1.size..-1] unless idx == nil
+          str2 = self[0...idx] + self[idx+arg1.size..-1] unless idx.nil?
         else
           idx = arg1 >= 0 ? arg1 : self.size+arg1
           str2 = self[0...idx] + self[idx+1..-1].to_s
         end
       end
-      self.replace(str2) unless str2 == nil
+      self.replace(str2) unless str2.nil?
     end
     str
   end