Class CoalescingOperandParenthesesOrError

java.lang.Object
org.ek9lang.compiler.phase1.CoalescingOperandParenthesesOrError
All Implemented Interfaces:
Consumer<EK9Parser.ExpressionContext>
final class CoalescingOperandParenthesesOrError extends Object implements Consumer<EK9Parser.ExpressionContext>
E08269 (Steve, D6, 2026-10-07): a coalescing operator - the null coalescing ??, the Elvis ?: and the comparison coalescing family <? <=? >? >=? - may not be an UNPARENTHESISED operand of a DIFFERENT binary operator, nor take one as an operand.

These operators share ONE level that binds tighter than arithmetic, comparison and logic (PRECEDENCE (5), 2026-10-07), so a + b ?: c is a + (b ?: c): when a is unset the whole result is unset and the fallback was never a fallback for the sum. Rather than document a precedence nobody guesses, the mix is a compile error and the parentheses say which reading is meant. A chain of the SAME operator (a ?: b ?: c, a ?? b ?? c, a <? b <? c) reads one way only and stays legal. ?? joined the rule on 2026-10-07 (P3): a ?? b ^ c had changed reading silently when the coalescing level moved below ^.

Purely syntactic, so it runs in phase 1 over the parse tree (see BinaryExpressions).