Backported fixes

• Fix expandParam's use of argForParam/isArgPrefixOf. #19412
• Remove ascriptionVarargsUnpacking as we never used it #19399
• Make explicit arguments for context bounds an error from 3.5 #19316
• Avoid generating given definitions that loop #19282
• Turn given loop prevention on for -source future #19392
• Fix algorithm to prevent recursive givens #19411

Contributors

Thank you to all the contributors who made this release possible 🎉

According to git shortlog -sn --no-merges 3.4.0-RC1..3.4.0-RC2 these are:

    15	Martin Odersky
     4	Nicolas Stucki
     3	Paweł Marks
     1	Dale Wijnand
     1	Jan Chyb