Support an unless guard in a pattern - #483
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AST.create_pattern_node routed a guard to IfPatternNode only for :if_node, so `in pat unless cond` raised "unknown pattern node type: unless_node". IfPatternNode reads only the predicate and the guarded pattern, so an unless guard needs no node of its own; only the sanity check differs, because Prism names the else slot `subsequent` on IfNode and `else_clause` on UnlessNode.
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Motivation / Background
This Pull Request has been created because an
unlessguard in a pattern aborts the analysis:An
ifguard has always worked. ruby/ruby usesunlessguards intest/ruby/test_pattern_matching.rbandspec/ruby/language/pattern_matching_spec.rb.Detail
IfPatternNodereads only the predicate and the guarded pattern, and the truth value of a guard is never used to narrow the subject, soifandunlessneed no separate nodes. A guard never has an else part either way, so the same sanity check covers both.🤖 Generated with Claude Code