Incorrectly flattening case statement with in in the in #3710
Description
I have such gist:
require "bundler/inline"
gemfile do
source "https://rubygems.org"
gem "prism"
end
args = [:increased]
context = Data.define(:event).new(:decreased)
result =
case args
in [event]
context.event in ^event
end
puts result
source = <<~RUBY
case args
in [event]
context.event in ^event
end
RUBY
puts Prism.parse(source).inspectRuby prior to 3.4.6 returns false for a result. 3.4.6 and 3.4.7 returns :decreased. It looks like in Ruby 3.4 the inner in is flattened and treated as in in the case statement, see:
Ruby 3.2.2:
#<Prism::ParseResult:0x00007f5c3bd1b868 @value=@ ProgramNode (location: (1,0)-(4,3))
├── flags: ∅
├── locals: [:event]
└── statements:
@ StatementsNode (location: (1,0)-(4,3))
├── flags: ∅
└── body: (length: 1)
└── @ CaseMatchNode (location: (1,0)-(4,3))
├── flags: newline
├── predicate:
│ @ CallNode (location: (1,5)-(1,9))
│ ├── flags: variable_call, ignore_visibility
│ ├── receiver: ∅
│ ├── call_operator_loc: ∅
│ ├── name: :args
│ ├── message_loc: (1,5)-(1,9) = "args"
│ ├── opening_loc: ∅
│ ├── arguments: ∅
│ ├── closing_loc: ∅
│ └── block: ∅
├── conditions: (length: 1)
│ └── @ InNode (location: (2,0)-(3,25))
│ ├── flags: ∅
│ ├── pattern:
│ │ @ ArrayPatternNode (location: (2,3)-(2,10))
│ │ ├── flags: ∅
│ │ ├── constant: ∅
│ │ ├── requireds: (length: 1)
│ │ │ └── @ LocalVariableTargetNode (location: (2,4)-(2,9))
│ │ │ ├── flags: ∅
│ │ │ ├── name: :event
│ │ │ └── depth: 0
│ │ ├── rest: ∅
│ │ ├── posts: (length: 0)
│ │ ├── opening_loc: (2,3)-(2,4) = "["
│ │ └── closing_loc: (2,9)-(2,10) = "]"
│ ├── statements:
│ │ @ StatementsNode (location: (3,2)-(3,25))
│ │ ├── flags: ∅
│ │ └── body: (length: 1)
│ │ └── @ MatchPredicateNode (location: (3,2)-(3,25))
│ │ ├── flags: newline
│ │ ├── value:
│ │ │ @ CallNode (location: (3,2)-(3,15))
│ │ │ ├── flags: ∅
│ │ │ ├── receiver:
│ │ │ │ @ CallNode (location: (3,2)-(3,9))
│ │ │ │ ├── flags: variable_call, ignore_visibility
│ │ │ │ ├── receiver: ∅
│ │ │ │ ├── call_operator_loc: ∅
│ │ │ │ ├── name: :context
│ │ │ │ ├── message_loc: (3,2)-(3,9) = "context"
│ │ │ │ ├── opening_loc: ∅
│ │ │ │ ├── arguments: ∅
│ │ │ │ ├── closing_loc: ∅
│ │ │ │ └── block: ∅
│ │ │ ├── call_operator_loc: (3,9)-(3,10) = "."
│ │ │ ├── name: :event
│ │ │ ├── message_loc: (3,10)-(3,15) = "event"
│ │ │ ├── opening_loc: ∅
│ │ │ ├── arguments: ∅
│ │ │ ├── closing_loc: ∅
│ │ │ └── block: ∅
│ │ ├── pattern:
│ │ │ @ PinnedVariableNode (location: (3,19)-(3,25))
│ │ │ ├── flags: ∅
│ │ │ ├── variable:
│ │ │ │ @ LocalVariableReadNode (location: (3,20)-(3,25))
│ │ │ │ ├── flags: ∅
│ │ │ │ ├── name: :event
│ │ │ │ └── depth: 0
│ │ │ └── operator_loc: (3,19)-(3,20) = "^"
│ │ └── operator_loc: (3,16)-(3,18) = "in"
│ ├── in_loc: (2,0)-(2,2) = "in"
│ └── then_loc: ∅
├── else_clause: ∅
├── case_keyword_loc: (1,0)-(1,4) = "case"
└── end_keyword_loc: (4,0)-(4,3) = "end"
, @comments=[], @magic_comments=[], @data_loc=nil, @errors=[], @warnings=[], @source=#<Prism::ASCIISource:0x00007f5c3bcbd178 @source="case args\nin [event]\n context.event in ^event\nend\n", @start_line=1, @offsets=[0, 10, 21, 47, 51]>>
Ruby 3.4.7:
#<Prism::ParseResult:0x00007f05afebc768 @value=@ ProgramNode (location: (1,0)-(4,3))
├── flags: ∅
├── locals: [:event]
└── statements:
@ StatementsNode (location: (1,0)-(4,3))
├── flags: ∅
└── body: (length: 1)
└── @ CaseMatchNode (location: (1,0)-(4,3))
├── flags: newline
├── predicate:
│ @ CallNode (location: (1,5)-(1,9))
│ ├── flags: variable_call, ignore_visibility
│ ├── receiver: ∅
│ ├── call_operator_loc: ∅
│ ├── name: :args
│ ├── message_loc: (1,5)-(1,9) = "args"
│ ├── opening_loc: ∅
│ ├── arguments: ∅
│ ├── closing_loc: ∅
│ └── block: ∅
├── conditions: (length: 2)
│ ├── @ InNode (location: (2,0)-(3,15))
│ │ ├── flags: ∅
│ │ ├── pattern:
│ │ │ @ ArrayPatternNode (location: (2,3)-(2,10))
│ │ │ ├── flags: ∅
│ │ │ ├── constant: ∅
│ │ │ ├── requireds: (length: 1)
│ │ │ │ └── @ LocalVariableTargetNode (location: (2,4)-(2,9))
│ │ │ │ ├── flags: ∅
│ │ │ │ ├── name: :event
│ │ │ │ └── depth: 0
│ │ │ ├── rest: ∅
│ │ │ ├── posts: (length: 0)
│ │ │ ├── opening_loc: (2,3)-(2,4) = "["
│ │ │ └── closing_loc: (2,9)-(2,10) = "]"
│ │ ├── statements:
│ │ │ @ StatementsNode (location: (3,2)-(3,15))
│ │ │ ├── flags: ∅
│ │ │ └── body: (length: 1)
│ │ │ └── @ CallNode (location: (3,2)-(3,15))
│ │ │ ├── flags: newline
│ │ │ ├── receiver:
│ │ │ │ @ CallNode (location: (3,2)-(3,9))
│ │ │ │ ├── flags: variable_call, ignore_visibility
│ │ │ │ ├── receiver: ∅
│ │ │ │ ├── call_operator_loc: ∅
│ │ │ │ ├── name: :context
│ │ │ │ ├── message_loc: (3,2)-(3,9) = "context"
│ │ │ │ ├── opening_loc: ∅
│ │ │ │ ├── arguments: ∅
│ │ │ │ ├── closing_loc: ∅
│ │ │ │ └── block: ∅
│ │ │ ├── call_operator_loc: (3,9)-(3,10) = "."
│ │ │ ├── name: :event
│ │ │ ├── message_loc: (3,10)-(3,15) = "event"
│ │ │ ├── opening_loc: ∅
│ │ │ ├── arguments: ∅
│ │ │ ├── closing_loc: ∅
│ │ │ └── block: ∅
│ │ ├── in_loc: (2,0)-(2,2) = "in"
│ │ └── then_loc: ∅
│ └── @ InNode (location: (3,16)-(3,25))
│ ├── flags: ∅
│ ├── pattern:
│ │ @ PinnedVariableNode (location: (3,19)-(3,25))
│ │ ├── flags: ∅
│ │ ├── variable:
│ │ │ @ LocalVariableReadNode (location: (3,20)-(3,25))
│ │ │ ├── flags: ∅
│ │ │ ├── name: :event
│ │ │ └── depth: 0
│ │ └── operator_loc: (3,19)-(3,20) = "^"
│ ├── statements: ∅
│ ├── in_loc: (3,16)-(3,18) = "in"
│ └── then_loc: ∅
├── else_clause: ∅
├── case_keyword_loc: (1,0)-(1,4) = "case"
└── end_keyword_loc: (4,0)-(4,3) = "end"
, @comments=[], @magic_comments=[], @data_loc=nil, @errors=[], @warnings=[], @source=#<Prism::ASCIISource:0x00007f05b002ceb8 @source="case args\nin [event]\n context.event in ^event\nend\n", @start_line=1, @offsets=[0, 10, 21, 47, 51]>>
I also tested on 3.4.5 which has the same tree but returns false as expected.
Filled a bug in upstream, not sure where it belongs https://bugs.ruby-lang.org/issues/21674