[GR-20430] Fix enumeration issue in ENV.{select, filter} when no block is given.

PullRequest: truffleruby/1239

Author: eregon

CHANGELOG.md

@@ -58,6 +58,7 @@ Bug fixes:
 * Fixed `Struct#hash` for `keyword_init: true` `Struct`.
 * Fixed `String#{upcase!,downcase!,swapcase!}(:ascii)` for non-ASCII-compatible encodings like UTF-16.
 * Fixed `String#capitalize!` for strings that weren't full ASCII.
+* Fixed enumeration issue in `ENV.{select, filter}`.
 
 Compatibility:
 

spec/tags/core/env/filter_tags.txt

@@ -240,7 +240,7 @@ def replace(other)
   end
 
   def select(&blk)
-    return to_enum { size } unless block_given?
+    return to_enum(:select) { size } unless block_given?
     to_hash.select(&blk)
   end
   alias_method :filter, :select