[GROOVY-3421] Expression underlying a spread map expression is evaluated twice

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.7-beta-1, 2.2.0-beta-1, 2.4.3
• Fix Version/s: 4.0.0-beta-1, 3.0.9, 2.5.16
• Component/s: Compiler
• Assignee: Eric Milles
• Reporter: Peter Niederwieser
• Created: 20/Mar/09 21:07
• Updated: 25/Feb/22 18:37
• Resolved: 06/Jun/21 22:29

Description

class SpreadMapBug extends GroovyTestCase {
    void test() {
        def x = 0
        assertEquals([a:1, b:1], [a:1, *:[b:++x]]) // fails; actual value: [a:1, b:2]
    }
}

Maybe this bug is related to the (strange) AST representation for a spread map expression (at least that's how I found the bug):
"*:[b:++x]" is a MapEntryExpression whose

• key is a SpreadMapExpression whose expression is a MapExpression representing "[b:++x]"
• value is a MapExpression representing "[b:++x]".

That makes two MapExpressionS...