the given string is not compatible to the expected encoding "US_ASCII"

[gogainda]

given code:

puts      [49, 46, 50].pack('c*').encode("us-ascii")
          .encode(xml: :text)
          .gsub("\u{000D}", '
') # Carriage Return
          .gsub("\u{000A}", '
') # Line Feed
          .gsub("\u{0085}", '…') # Next Line
          .gsub("\u{2028}", '
') #

fails with:

the given string is not compatible to the expected encoding "US_ASCII", did you forget to convert it? (java.lang.IllegalArgumentException)
	from com.oracle.truffle.api.strings.InternalErrors.wrongEncoding(InternalErrors.java:91)
	from com.oracle.truffle.api.strings.AbstractTruffleString.looseCheckEncoding(AbstractTruffleString.java:354)
	from com.oracle.truffle.api.strings.TruffleString$ByteIndexOfStringNode.indexOfString(TruffleString.java:3876)
	from com.oracle.truffle.api.strings.TruffleStringFactory$ByteIndexOfStringNodeGen.execute(TruffleStringFactory.java:3488)
	from com.oracle.truffle.api.strings.TruffleString$ByteIndexOfStringNode.execute(TruffleString.java:3841)
	from org.truffleruby.core.string.StringNodes$StringByteIndexNode.stringByteIndex(StringNodes.java:3878)
	from org.truffleruby.core.string.StringNodesFactory$StringByteIndexNodeFactory$StringByteIndexNodeGen.execute(StringNodesFactory.java:12579)
	from org.truffleruby.language.control.SequenceNode.execute(SequenceNode.java:37)
	from org.truffleruby.language.control.IfElseNode.execute(IfElseNode.java:45)
	from org.truffleruby.language.control.IfElseNode.execute(IfElseNode.java:45)
	from org.truffleruby.language.control.SequenceNode.execute(SequenceNode.java:37)
	from org.truffleruby.language.RubyMethodRootNode.execute(RubyMethodRootNode.java:65)
<internal:core> core/truffle/string_operations.rb:288:in `byte_index'
	from <internal:core> core/truffle/string_operations.rb:108:in `gsub_string_matches'
	from <internal:core> core/truffle/string_operations.rb:74:in `gsub_internal_matches'
	from <internal:core> core/string.rb:850:in `gsub'
	from test-str.rb:1:in `<main>'

[eregon]

Thanks for the report.
Here is a slightly clearer repro:

s = [49, 46, 50].pack('c*').encode("us-ascii")
s = s.encode(xml: :text)
s = s.gsub("\u{000D}", '
') # OK
s = s.gsub("\u{000A}", '
') # OK
s = s.gsub("\u{0085}", '…') # fails
s = s.gsub("\u{2028}", '
') # fails
puts s

It fails on line 5 and 6.