[GROOVY-9360] += and -= no longer rejected in assertion statement in Groovy 3

• Type: Question
• Status: Closed
• Priority: Minor
• Resolution: Not A Problem
• Affects Version/s: 3.0.0-rc-2
• Component/s: parser-antlr4
• Assignee: Unassigned
• Reporter: Marcin Zajaczkowski
• Created: 08/Jan/20 18:50
• Updated: 16/Aug/22 21:30
• Resolved: 15/Aug/22 15:55

Description

Playing with the failures which Groovy 3 brought to Spock tests itself,
I noticed that Groovy 3 no longer rejects += and -= if used in an
assertion statement:

//Groovy 3-rc2
def a = 1
assert a += 1 //passes
assert a == 2 //passes

While it behaves consistently, I wonder if that change was introduced purposely (it was failing in Groovy 2) and should be documented or the check should be enhanced?

//Groovy 2.5
startup failed:
Script1.groovy: 3: unexpected token: += @ line 1, column 10.
   assert a += 1
            ^1 error

https://github.com/apache/groovy/commit/a17b9eb85835a5eaa306a893a0a8bcd51a49e299#diff-05fe8708ce3207739a2cb39a97426e8dR345

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