Add deprecation warning to ENV.index

Author: bjfish

CHANGELOG.md

@@ -63,6 +63,7 @@ Bug fixes:
 * Fixed `printf` should raise error when not enough arguments for positional argument.
 * Removed "shadowing outer local variable" warning.
 * Fixed parameter conversion to `String` in ENV methods.
+* Fixed deprecation warning when `ENV.index` is called.
 
 Compatibility:
 

spec/tags/core/env/index_tags.txt

@@ -201,19 +201,20 @@ def values_at(*params)
   end
 
   def index(value)
-    value = StringValue(value);
-    each do |k, v|
-      return k if v == value
-    end
-    nil
+    warn 'warning: ENV.index is deprecated; use ENV.key'
+    key(value)
   end
 
   def invert
     to_hash.invert
   end
 
   def key(value)
-    index(value)
+    value = StringValue(value);
+    each do |k, v|
+      return k if v == value
+    end
+    nil
   end
 
   def keys
@@ -311,7 +312,7 @@ def assoc(key)
   def rassoc(value)
     value = Truffle::Type.rb_check_convert_type(value, String, :to_str)
     return nil if value.nil?
-    key = index(value)
+    key = key(value)
     key ? [key, value] : nil
   end