@ ProgramNode (location: (1,0)-(58,2))
├── flags: ∅
├── locals: [:foo, :ab, :abc, :a]
└── statements:
    @ StatementsNode (location: (1,0)-(58,2))
    ├── flags: ∅
    └── body: (length: 28)
        ├── @ CallNode (location: (1,0)-(1,9))
        │   ├── flags: newline, ignore_visibility
        │   ├── receiver: ∅
        │   ├── call_operator_loc: ∅
        │   ├── name: :foo
        │   ├── message_loc: (1,0)-(1,3) = "foo"
        │   ├── opening_loc: ∅
        │   ├── arguments:
        │   │   @ ArgumentsNode (location: (1,4)-(1,9))
        │   │   ├── flags: ∅
        │   │   └── arguments: (length: 1)
        │   │       └── @ RegularExpressionNode (location: (1,4)-(1,9))
        │   │           ├── flags: static_literal, forced_us_ascii_encoding
        │   │           ├── opening_loc: (1,4)-(1,5) = "/"
        │   │           ├── content_loc: (1,5)-(1,8) = "bar"
        │   │           ├── closing_loc: (1,8)-(1,9) = "/"
        │   │           └── unescaped: "bar"
        │   ├── closing_loc: ∅
        │   └── block: ∅
        ├── @ RegularExpressionNode (location: (3,0)-(3,8))
        │   ├── flags: newline, static_literal, ignore_case, forced_us_ascii_encoding
        │   ├── opening_loc: (3,0)-(3,3) = "%r{"
        │   ├── content_loc: (3,3)-(3,6) = "abc"
        │   ├── closing_loc: (3,6)-(3,8) = "}i"
        │   └── unescaped: "abc"
        ├── @ RegularExpressionNode (location: (5,0)-(5,5))
        │   ├── flags: newline, static_literal, forced_us_ascii_encoding
        │   ├── opening_loc: (5,0)-(5,1) = "/"
        │   ├── content_loc: (5,1)-(5,4) = "a\\b"
        │   ├── closing_loc: (5,4)-(5,5) = "/"
        │   └── unescaped: "a\\b"
        ├── @ InterpolatedRegularExpressionNode (location: (7,0)-(7,11))
        │   ├── flags: newline
        │   ├── opening_loc: (7,0)-(7,1) = "/"
        │   ├── parts: (length: 2)
        │   │   ├── @ StringNode (location: (7,1)-(7,5))
        │   │   │   ├── flags: static_literal, frozen
        │   │   │   ├── opening_loc: ∅
        │   │   │   ├── content_loc: (7,1)-(7,5) = "aaa "
        │   │   │   ├── closing_loc: ∅
        │   │   │   └── unescaped: "aaa "
        │   │   └── @ EmbeddedVariableNode (location: (7,5)-(7,10))
        │   │       ├── flags: ∅
        │   │       ├── operator_loc: (7,5)-(7,6) = "#"
        │   │       └── variable:
        │   │           @ GlobalVariableReadNode (location: (7,6)-(7,10))
        │   │           ├── flags: ∅
        │   │           └── name: :$bbb
        │   └── closing_loc: (7,10)-(7,11) = "/"
        ├── @ InterpolatedRegularExpressionNode (location: (9,0)-(9,16))
        │   ├── flags: newline
        │   ├── opening_loc: (9,0)-(9,1) = "/"
        │   ├── parts: (length: 3)
        │   │   ├── @ StringNode (location: (9,1)-(9,5))
        │   │   │   ├── flags: static_literal, frozen
        │   │   │   ├── opening_loc: ∅
        │   │   │   ├── content_loc: (9,1)-(9,5) = "aaa "
        │   │   │   ├── closing_loc: ∅
        │   │   │   └── unescaped: "aaa "
        │   │   ├── @ EmbeddedStatementsNode (location: (9,5)-(9,11))
        │   │   │   ├── flags: ∅
        │   │   │   ├── opening_loc: (9,5)-(9,7) = "\#{"
        │   │   │   ├── statements:
        │   │   │   │   @ StatementsNode (location: (9,7)-(9,10))
        │   │   │   │   ├── flags: ∅
        │   │   │   │   └── body: (length: 1)
        │   │   │   │       └── @ CallNode (location: (9,7)-(9,10))
        │   │   │   │           ├── flags: variable_call, ignore_visibility
        │   │   │   │           ├── receiver: ∅
        │   │   │   │           ├── call_operator_loc: ∅
        │   │   │   │           ├── name: :bbb
        │   │   │   │           ├── message_loc: (9,7)-(9,10) = "bbb"
        │   │   │   │           ├── opening_loc: ∅
        │   │   │   │           ├── arguments: ∅
        │   │   │   │           ├── closing_loc: ∅
        │   │   │   │           └── block: ∅
        │   │   │   └── closing_loc: (9,10)-(9,11) = "}"
        │   │   └── @ StringNode (location: (9,11)-(9,15))
        │   │       ├── flags: static_literal, frozen
        │   │       ├── opening_loc: ∅
        │   │       ├── content_loc: (9,11)-(9,15) = " ccc"
        │   │       ├── closing_loc: ∅
        │   │       └── unescaped: " ccc"
        │   └── closing_loc: (9,15)-(9,16) = "/"
        ├── @ ArrayNode (location: (11,0)-(11,27))
        │   ├── flags: newline
        │   ├── elements: (length: 2)
        │   │   ├── @ MatchWriteNode (location: (11,1)-(11,21))
        │   │   │   ├── flags: ∅
        │   │   │   ├── call:
        │   │   │   │   @ CallNode (location: (11,1)-(11,21))
        │   │   │   │   ├── flags: ∅
        │   │   │   │   ├── receiver:
        │   │   │   │   │   @ RegularExpressionNode (location: (11,1)-(11,14))
        │   │   │   │   │   ├── flags: static_literal, forced_us_ascii_encoding
        │   │   │   │   │   ├── opening_loc: (11,1)-(11,2) = "/"
        │   │   │   │   │   ├── content_loc: (11,2)-(11,13) = "(?<foo>bar)"
        │   │   │   │   │   ├── closing_loc: (11,13)-(11,14) = "/"
        │   │   │   │   │   └── unescaped: "(?<foo>bar)"
        │   │   │   │   ├── call_operator_loc: ∅
        │   │   │   │   ├── name: :=~
        │   │   │   │   ├── message_loc: (11,15)-(11,17) = "=~"
        │   │   │   │   ├── opening_loc: ∅
        │   │   │   │   ├── arguments:
        │   │   │   │   │   @ ArgumentsNode (location: (11,18)-(11,21))
        │   │   │   │   │   ├── flags: ∅
        │   │   │   │   │   └── arguments: (length: 1)
        │   │   │   │   │       └── @ CallNode (location: (11,18)-(11,21))
        │   │   │   │   │           ├── flags: variable_call, ignore_visibility
        │   │   │   │   │           ├── receiver: ∅
        │   │   │   │   │           ├── call_operator_loc: ∅
        │   │   │   │   │           ├── name: :baz
        │   │   │   │   │           ├── message_loc: (11,18)-(11,21) = "baz"
        │   │   │   │   │           ├── opening_loc: ∅
        │   │   │   │   │           ├── arguments: ∅
        │   │   │   │   │           ├── closing_loc: ∅
        │   │   │   │   │           └── block: ∅
        │   │   │   │   ├── closing_loc: ∅
        │   │   │   │   └── block: ∅
        │   │   │   └── targets: (length: 1)
        │   │   │       └── @ LocalVariableTargetNode (location: (11,5)-(11,8))
        │   │   │           ├── flags: ∅
        │   │   │           ├── name: :foo
        │   │   │           └── depth: 0
        │   │   └── @ LocalVariableReadNode (location: (11,23)-(11,26))
        │   │       ├── flags: ∅
        │   │       ├── name: :foo
        │   │       └── depth: 0
        │   ├── opening_loc: (11,0)-(11,1) = "["
        │   └── closing_loc: (11,26)-(11,27) = "]"
        ├── @ RegularExpressionNode (location: (13,0)-(13,6))
        │   ├── flags: newline, static_literal, ignore_case, forced_us_ascii_encoding
        │   ├── opening_loc: (13,0)-(13,1) = "/"
        │   ├── content_loc: (13,1)-(13,4) = "abc"
        │   ├── closing_loc: (13,4)-(13,6) = "/i"
        │   └── unescaped: "abc"
        ├── @ RegularExpressionNode (location: (15,0)-(15,26))
        │   ├── flags: newline, static_literal, ignore_case, forced_us_ascii_encoding
        │   ├── opening_loc: (15,0)-(15,3) = "%r/"
        │   ├── content_loc: (15,3)-(15,24) = "[a-z$._?][\\w$.?\#@~]*:"
        │   ├── closing_loc: (15,24)-(15,26) = "/i"
        │   └── unescaped: "[a-z$._?][\\w$.?\#@~]*:"
        ├── @ RegularExpressionNode (location: (17,0)-(17,37))
        │   ├── flags: newline, static_literal, ignore_case, forced_us_ascii_encoding
        │   ├── opening_loc: (17,0)-(17,3) = "%r/"
        │   ├── content_loc: (17,3)-(17,35) = "([a-z$._?][\\w$.?\#@~]*)(\\s+)(equ)"
        │   ├── closing_loc: (17,35)-(17,37) = "/i"
        │   └── unescaped: "([a-z$._?][\\w$.?\#@~]*)(\\s+)(equ)"
        ├── @ RegularExpressionNode (location: (19,0)-(19,25))
        │   ├── flags: newline, static_literal, ignore_case, forced_us_ascii_encoding
        │   ├── opening_loc: (19,0)-(19,3) = "%r/"
        │   ├── content_loc: (19,3)-(19,23) = "[a-z$._?][\\w$.?\#@~]*"
        │   ├── closing_loc: (19,23)-(19,25) = "/i"
        │   └── unescaped: "[a-z$._?][\\w$.?\#@~]*"
        ├── @ RegularExpressionNode (location: (21,0)-(24,1))
        │   ├── flags: newline, static_literal, forced_us_ascii_encoding
        │   ├── opening_loc: (21,0)-(21,3) = "%r("
        │   ├── content_loc: (21,3)-(24,0) = "\n(?:[\#$%_']|\\(\\)|\\(,\\)|\\[\\]|[0-9])*\n  (?:[\#$%_']+)\n"
        │   ├── closing_loc: (24,0)-(24,1) = ")"
        │   └── unescaped: "\n(?:[\#$%_']|\\(\\)|\\(,\\)|\\[\\]|[0-9])*\n  (?:[\#$%_']+)\n"
        ├── @ CallNode (location: (26,0)-(26,16))
        │   ├── flags: newline
        │   ├── receiver:
        │   │   @ RegularExpressionNode (location: (26,0)-(26,8))
        │   │   ├── flags: static_literal, forced_us_ascii_encoding
        │   │   ├── opening_loc: (26,0)-(26,1) = "/"
        │   │   ├── content_loc: (26,1)-(26,7) = "(?#\\))"
        │   │   ├── closing_loc: (26,7)-(26,8) = "/"
        │   │   └── unescaped: "(?#\\))"
        │   ├── call_operator_loc: ∅
        │   ├── name: :=~
        │   ├── message_loc: (26,9)-(26,11) = "=~"
        │   ├── opening_loc: ∅
        │   ├── arguments:
        │   │   @ ArgumentsNode (location: (26,12)-(26,16))
        │   │   ├── flags: ∅
        │   │   └── arguments: (length: 1)
        │   │       └── @ StringNode (location: (26,12)-(26,16))
        │   │           ├── flags: ∅
        │   │           ├── opening_loc: (26,12)-(26,13) = "\""
        │   │           ├── content_loc: (26,13)-(26,15) = "hi"
        │   │           ├── closing_loc: (26,15)-(26,16) = "\""
        │   │           └── unescaped: "hi"
        │   ├── closing_loc: ∅
        │   └── block: ∅
        ├── @ RegularExpressionNode (location: (28,0)-(28,9))
        │   ├── flags: newline, static_literal, forced_us_ascii_encoding
        │   ├── opening_loc: (28,0)-(28,3) = "%r#"
        │   ├── content_loc: (28,3)-(28,8) = "pound"
        │   ├── closing_loc: (28,8)-(28,9) = "#"
        │   └── unescaped: "pound"
        ├── @ InterpolatedRegularExpressionNode (location: (30,0)-(30,13))
        │   ├── flags: newline, once
        │   ├── opening_loc: (30,0)-(30,1) = "/"
        │   ├── parts: (length: 2)
        │   │   ├── @ StringNode (location: (30,1)-(30,5))
        │   │   │   ├── flags: static_literal, frozen
        │   │   │   ├── opening_loc: ∅
        │   │   │   ├── content_loc: (30,1)-(30,5) = "aaa "
        │   │   │   ├── closing_loc: ∅
        │   │   │   └── unescaped: "aaa "
        │   │   └── @ EmbeddedStatementsNode (location: (30,5)-(30,11))
        │   │       ├── flags: ∅
        │   │       ├── opening_loc: (30,5)-(30,7) = "\#{"
        │   │       ├── statements:
        │   │       │   @ StatementsNode (location: (30,7)-(30,10))
        │   │       │   ├── flags: ∅
        │   │       │   └── body: (length: 1)
        │   │       │       └── @ CallNode (location: (30,7)-(30,10))
        │   │       │           ├── flags: variable_call, ignore_visibility
        │   │       │           ├── receiver: ∅
        │   │       │           ├── call_operator_loc: ∅
        │   │       │           ├── name: :bbb
        │   │       │           ├── message_loc: (30,7)-(30,10) = "bbb"
        │   │       │           ├── opening_loc: ∅
        │   │       │           ├── arguments: ∅
        │   │       │           ├── closing_loc: ∅
        │   │       │           └── block: ∅
        │   │       └── closing_loc: (30,10)-(30,11) = "}"
        │   └── closing_loc: (30,11)-(30,13) = "/o"
        ├── @ MatchWriteNode (location: (32,0)-(33,10))
        │   ├── flags: newline
        │   ├── call:
        │   │   @ CallNode (location: (32,0)-(33,10))
        │   │   ├── flags: ∅
        │   │   ├── receiver:
        │   │   │   @ RegularExpressionNode (location: (32,0)-(33,4))
        │   │   │   ├── flags: static_literal, forced_us_ascii_encoding
        │   │   │   ├── opening_loc: (32,0)-(32,1) = "/"
        │   │   │   ├── content_loc: (32,1)-(33,3) = "(?<a\\\nb>)"
        │   │   │   ├── closing_loc: (33,3)-(33,4) = "/"
        │   │   │   └── unescaped: "(?<ab>)"
        │   │   ├── call_operator_loc: ∅
        │   │   ├── name: :=~
        │   │   ├── message_loc: (33,5)-(33,7) = "=~"
        │   │   ├── opening_loc: ∅
        │   │   ├── arguments:
        │   │   │   @ ArgumentsNode (location: (33,8)-(33,10))
        │   │   │   ├── flags: ∅
        │   │   │   └── arguments: (length: 1)
        │   │   │       └── @ StringNode (location: (33,8)-(33,10))
        │   │   │           ├── flags: ∅
        │   │   │           ├── opening_loc: (33,8)-(33,9) = "\""
        │   │   │           ├── content_loc: (33,9)-(33,9) = ""
        │   │   │           ├── closing_loc: (33,9)-(33,10) = "\""
        │   │   │           └── unescaped: ""
        │   │   ├── closing_loc: ∅
        │   │   └── block: ∅
        │   └── targets: (length: 1)
        │       └── @ LocalVariableTargetNode (location: (32,0)-(33,4))
        │           ├── flags: ∅
        │           ├── name: :ab
        │           └── depth: 0
        ├── @ LocalVariableReadNode (location: (33,12)-(33,14))
        │   ├── flags: newline
        │   ├── name: :ab
        │   └── depth: 0
        ├── @ MatchWriteNode (location: (35,0)-(35,24))
        │   ├── flags: newline
        │   ├── call:
        │   │   @ CallNode (location: (35,0)-(35,24))
        │   │   ├── flags: ∅
        │   │   ├── receiver:
        │   │   │   @ RegularExpressionNode (location: (35,0)-(35,18))
        │   │   │   ├── flags: static_literal, forced_us_ascii_encoding
        │   │   │   ├── opening_loc: (35,0)-(35,1) = "/"
        │   │   │   ├── content_loc: (35,1)-(35,17) = "(?<abc>)(?<abc>)"
        │   │   │   ├── closing_loc: (35,17)-(35,18) = "/"
        │   │   │   └── unescaped: "(?<abc>)(?<abc>)"
        │   │   ├── call_operator_loc: ∅
        │   │   ├── name: :=~
        │   │   ├── message_loc: (35,19)-(35,21) = "=~"
        │   │   ├── opening_loc: ∅
        │   │   ├── arguments:
        │   │   │   @ ArgumentsNode (location: (35,22)-(35,24))
        │   │   │   ├── flags: ∅
        │   │   │   └── arguments: (length: 1)
        │   │   │       └── @ StringNode (location: (35,22)-(35,24))
        │   │   │           ├── flags: ∅
        │   │   │           ├── opening_loc: (35,22)-(35,23) = "\""
        │   │   │           ├── content_loc: (35,23)-(35,23) = ""
        │   │   │           ├── closing_loc: (35,23)-(35,24) = "\""
        │   │   │           └── unescaped: ""
        │   │   ├── closing_loc: ∅
        │   │   └── block: ∅
        │   └── targets: (length: 1)
        │       └── @ LocalVariableTargetNode (location: (35,4)-(35,7))
        │           ├── flags: ∅
        │           ├── name: :abc
        │           └── depth: 0
        ├── @ LocalVariableReadNode (location: (35,26)-(35,29))
        │   ├── flags: newline
        │   ├── name: :abc
        │   └── depth: 0
        ├── @ CallNode (location: (37,0)-(37,16))
        │   ├── flags: newline
        │   ├── receiver:
        │   │   @ RegularExpressionNode (location: (37,0)-(37,10))
        │   │   ├── flags: static_literal, forced_us_ascii_encoding
        │   │   ├── opening_loc: (37,0)-(37,1) = "/"
        │   │   ├── content_loc: (37,1)-(37,9) = "(?<a b>)"
        │   │   ├── closing_loc: (37,9)-(37,10) = "/"
        │   │   └── unescaped: "(?<a b>)"
        │   ├── call_operator_loc: ∅
        │   ├── name: :=~
        │   ├── message_loc: (37,11)-(37,13) = "=~"
        │   ├── opening_loc: ∅
        │   ├── arguments:
        │   │   @ ArgumentsNode (location: (37,14)-(37,16))
        │   │   ├── flags: ∅
        │   │   └── arguments: (length: 1)
        │   │       └── @ StringNode (location: (37,14)-(37,16))
        │   │           ├── flags: ∅
        │   │           ├── opening_loc: (37,14)-(37,15) = "\""
        │   │           ├── content_loc: (37,15)-(37,15) = ""
        │   │           ├── closing_loc: (37,15)-(37,16) = "\""
        │   │           └── unescaped: ""
        │   ├── closing_loc: ∅
        │   └── block: ∅
        ├── @ LocalVariableWriteNode (location: (39,0)-(39,5))
        │   ├── flags: newline
        │   ├── name: :a
        │   ├── depth: 0
        │   ├── name_loc: (39,0)-(39,1) = "a"
        │   ├── value:
        │   │   @ IntegerNode (location: (39,4)-(39,5))
        │   │   ├── flags: static_literal, decimal
        │   │   └── value: 1
        │   └── operator_loc: (39,2)-(39,3) = "="
        ├── @ CallNode (location: (40,0)-(40,24))
        │   ├── flags: newline, ignore_visibility
        │   ├── receiver: ∅
        │   ├── call_operator_loc: ∅
        │   ├── name: :tap
        │   ├── message_loc: (40,0)-(40,3) = "tap"
        │   ├── opening_loc: ∅
        │   ├── arguments: ∅
        │   ├── closing_loc: ∅
        │   └── block:
        │       @ BlockNode (location: (40,4)-(40,24))
        │       ├── flags: ∅
        │       ├── locals: []
        │       ├── parameters: ∅
        │       ├── body:
        │       │   @ StatementsNode (location: (40,6)-(40,22))
        │       │   ├── flags: ∅
        │       │   └── body: (length: 1)
        │       │       └── @ MatchWriteNode (location: (40,6)-(40,22))
        │       │           ├── flags: newline
        │       │           ├── call:
        │       │           │   @ CallNode (location: (40,6)-(40,22))
        │       │           │   ├── flags: ∅
        │       │           │   ├── receiver:
        │       │           │   │   @ RegularExpressionNode (location: (40,6)-(40,14))
        │       │           │   │   ├── flags: static_literal, forced_us_ascii_encoding
        │       │           │   │   ├── opening_loc: (40,6)-(40,7) = "/"
        │       │           │   │   ├── content_loc: (40,7)-(40,13) = "(?<a>)"
        │       │           │   │   ├── closing_loc: (40,13)-(40,14) = "/"
        │       │           │   │   └── unescaped: "(?<a>)"
        │       │           │   ├── call_operator_loc: ∅
        │       │           │   ├── name: :=~
        │       │           │   ├── message_loc: (40,15)-(40,17) = "=~"
        │       │           │   ├── opening_loc: ∅
        │       │           │   ├── arguments:
        │       │           │   │   @ ArgumentsNode (location: (40,18)-(40,22))
        │       │           │   │   ├── flags: ∅
        │       │           │   │   └── arguments: (length: 1)
        │       │           │   │       └── @ CallNode (location: (40,18)-(40,22))
        │       │           │   │           ├── flags: variable_call, ignore_visibility
        │       │           │   │           ├── receiver: ∅
        │       │           │   │           ├── call_operator_loc: ∅
        │       │           │   │           ├── name: :to_s
        │       │           │   │           ├── message_loc: (40,18)-(40,22) = "to_s"
        │       │           │   │           ├── opening_loc: ∅
        │       │           │   │           ├── arguments: ∅
        │       │           │   │           ├── closing_loc: ∅
        │       │           │   │           └── block: ∅
        │       │           │   ├── closing_loc: ∅
        │       │           │   └── block: ∅
        │       │           └── targets: (length: 1)
        │       │               └── @ LocalVariableTargetNode (location: (40,10)-(40,11))
        │       │                   ├── flags: ∅
        │       │                   ├── name: :a
        │       │                   └── depth: 1
        │       ├── opening_loc: (40,4)-(40,5) = "{"
        │       └── closing_loc: (40,23)-(40,24) = "}"
        ├── @ MatchWriteNode (location: (42,0)-(42,16))
        │   ├── flags: newline
        │   ├── call:
        │   │   @ CallNode (location: (42,0)-(42,16))
        │   │   ├── flags: ∅
        │   │   ├── receiver:
        │   │   │   @ RegularExpressionNode (location: (42,0)-(42,10))
        │   │   │   ├── flags: static_literal, forced_us_ascii_encoding
        │   │   │   ├── opening_loc: (42,0)-(42,1) = "/"
        │   │   │   ├── content_loc: (42,1)-(42,9) = "(?<foo>)"
        │   │   │   ├── closing_loc: (42,9)-(42,10) = "/"
        │   │   │   └── unescaped: "(?<foo>)"
        │   │   ├── call_operator_loc: ∅
        │   │   ├── name: :=~
        │   │   ├── message_loc: (42,11)-(42,13) = "=~"
        │   │   ├── opening_loc: ∅
        │   │   ├── arguments:
        │   │   │   @ ArgumentsNode (location: (42,14)-(42,16))
        │   │   │   ├── flags: ∅
        │   │   │   └── arguments: (length: 1)
        │   │   │       └── @ StringNode (location: (42,14)-(42,16))
        │   │   │           ├── flags: ∅
        │   │   │           ├── opening_loc: (42,14)-(42,15) = "\""
        │   │   │           ├── content_loc: (42,15)-(42,15) = ""
        │   │   │           ├── closing_loc: (42,15)-(42,16) = "\""
        │   │   │           └── unescaped: ""
        │   │   ├── closing_loc: ∅
        │   │   └── block: ∅
        │   └── targets: (length: 1)
        │       └── @ LocalVariableTargetNode (location: (42,4)-(42,7))
        │           ├── flags: ∅
        │           ├── name: :foo
        │           └── depth: 0
        ├── @ CallNode (location: (43,0)-(43,16))
        │   ├── flags: newline
        │   ├── receiver:
        │   │   @ RegularExpressionNode (location: (43,0)-(43,10))
        │   │   ├── flags: static_literal, forced_us_ascii_encoding
        │   │   ├── opening_loc: (43,0)-(43,1) = "/"
        │   │   ├── content_loc: (43,1)-(43,9) = "(?<Foo>)"
        │   │   ├── closing_loc: (43,9)-(43,10) = "/"
        │   │   └── unescaped: "(?<Foo>)"
        │   ├── call_operator_loc: ∅
        │   ├── name: :=~
        │   ├── message_loc: (43,11)-(43,13) = "=~"
        │   ├── opening_loc: ∅
        │   ├── arguments:
        │   │   @ ArgumentsNode (location: (43,14)-(43,16))
        │   │   ├── flags: ∅
        │   │   └── arguments: (length: 1)
        │   │       └── @ StringNode (location: (43,14)-(43,16))
        │   │           ├── flags: ∅
        │   │           ├── opening_loc: (43,14)-(43,15) = "\""
        │   │           ├── content_loc: (43,15)-(43,15) = ""
        │   │           ├── closing_loc: (43,15)-(43,16) = "\""
        │   │           └── unescaped: ""
        │   ├── closing_loc: ∅
        │   └── block: ∅
        ├── @ CallNode (location: (45,0)-(45,16))
        │   ├── flags: newline
        │   ├── receiver:
        │   │   @ RegularExpressionNode (location: (45,0)-(45,10))
        │   │   ├── flags: static_literal, forced_us_ascii_encoding
        │   │   ├── opening_loc: (45,0)-(45,1) = "/"
        │   │   ├── content_loc: (45,1)-(45,9) = "(?<nil>)"
        │   │   ├── closing_loc: (45,9)-(45,10) = "/"
        │   │   └── unescaped: "(?<nil>)"
        │   ├── call_operator_loc: ∅
        │   ├── name: :=~
        │   ├── message_loc: (45,11)-(45,13) = "=~"
        │   ├── opening_loc: ∅
        │   ├── arguments:
        │   │   @ ArgumentsNode (location: (45,14)-(45,16))
        │   │   ├── flags: ∅
        │   │   └── arguments: (length: 1)
        │   │       └── @ StringNode (location: (45,14)-(45,16))
        │   │           ├── flags: ∅
        │   │           ├── opening_loc: (45,14)-(45,15) = "\""
        │   │           ├── content_loc: (45,15)-(45,15) = ""
        │   │           ├── closing_loc: (45,15)-(45,16) = "\""
        │   │           └── unescaped: ""
        │   ├── closing_loc: ∅
        │   └── block: ∅
        ├── @ DefNode (location: (46,0)-(46,32))
        │   ├── flags: newline
        │   ├── name: :foo
        │   ├── name_loc: (46,4)-(46,7) = "foo"
        │   ├── receiver: ∅
        │   ├── parameters:
        │   │   @ ParametersNode (location: (46,8)-(46,12))
        │   │   ├── flags: ∅
        │   │   ├── requireds: (length: 0)
        │   │   ├── optionals: (length: 0)
        │   │   ├── rest: ∅
        │   │   ├── posts: (length: 0)
        │   │   ├── keywords: (length: 1)
        │   │   │   └── @ RequiredKeywordParameterNode (location: (46,8)-(46,12))
        │   │   │       ├── flags: ∅
        │   │   │       ├── name: :nil
        │   │   │       └── name_loc: (46,8)-(46,12) = "nil:"
        │   │   ├── keyword_rest: ∅
        │   │   └── block: ∅
        │   ├── body:
        │   │   @ StatementsNode (location: (46,16)-(46,32))
        │   │   ├── flags: ∅
        │   │   └── body: (length: 1)
        │   │       └── @ MatchWriteNode (location: (46,16)-(46,32))
        │   │           ├── flags: ∅
        │   │           ├── call:
        │   │           │   @ CallNode (location: (46,16)-(46,32))
        │   │           │   ├── flags: ∅
        │   │           │   ├── receiver:
        │   │           │   │   @ RegularExpressionNode (location: (46,16)-(46,26))
        │   │           │   │   ├── flags: static_literal, forced_us_ascii_encoding
        │   │           │   │   ├── opening_loc: (46,16)-(46,17) = "/"
        │   │           │   │   ├── content_loc: (46,17)-(46,25) = "(?<nil>)"
        │   │           │   │   ├── closing_loc: (46,25)-(46,26) = "/"
        │   │           │   │   └── unescaped: "(?<nil>)"
        │   │           │   ├── call_operator_loc: ∅
        │   │           │   ├── name: :=~
        │   │           │   ├── message_loc: (46,27)-(46,29) = "=~"
        │   │           │   ├── opening_loc: ∅
        │   │           │   ├── arguments:
        │   │           │   │   @ ArgumentsNode (location: (46,30)-(46,32))
        │   │           │   │   ├── flags: ∅
        │   │           │   │   └── arguments: (length: 1)
        │   │           │   │       └── @ StringNode (location: (46,30)-(46,32))
        │   │           │   │           ├── flags: ∅
        │   │           │   │           ├── opening_loc: (46,30)-(46,31) = "\""
        │   │           │   │           ├── content_loc: (46,31)-(46,31) = ""
        │   │           │   │           ├── closing_loc: (46,31)-(46,32) = "\""
        │   │           │   │           └── unescaped: ""
        │   │           │   ├── closing_loc: ∅
        │   │           │   └── block: ∅
        │   │           └── targets: (length: 1)
        │   │               └── @ LocalVariableTargetNode (location: (46,20)-(46,23))
        │   │                   ├── flags: ∅
        │   │                   ├── name: :nil
        │   │                   └── depth: 0
        │   ├── locals: [:nil]
        │   ├── def_keyword_loc: (46,0)-(46,3) = "def"
        │   ├── operator_loc: ∅
        │   ├── lparen_loc: (46,7)-(46,8) = "("
        │   ├── rparen_loc: (46,12)-(46,13) = ")"
        │   ├── equal_loc: (46,14)-(46,15) = "="
        │   └── end_keyword_loc: ∅
        ├── @ RegularExpressionNode (location: (48,0)-(48,10))
        │   ├── flags: newline, static_literal, extended, forced_us_ascii_encoding
        │   ├── opening_loc: (48,0)-(48,1) = "/"
        │   ├── content_loc: (48,1)-(48,8) = "(?-x:#)"
        │   ├── closing_loc: (48,8)-(48,10) = "/x"
        │   └── unescaped: "(?-x:#)"
        ├── @ RegularExpressionNode (location: (50,0)-(56,1))
        │   ├── flags: newline, static_literal, forced_us_ascii_encoding
        │   ├── opening_loc: (50,0)-(50,1) = "/"
        │   ├── content_loc: (50,1)-(56,0) = "a\nb\\\nc\\\nd\\\\\\\ne\\\\\nf\\\n"
        │   ├── closing_loc: (56,0)-(56,1) = "/"
        │   └── unescaped: "a\nbcd\\\\e\\\\\nf"
        └── @ RegularExpressionNode (location: (58,0)-(58,2))
            ├── flags: newline, static_literal, forced_us_ascii_encoding
            ├── opening_loc: (58,0)-(58,1) = "/"
            ├── content_loc: (58,1)-(58,1) = ""
            ├── closing_loc: (58,1)-(58,2) = "/"
            └── unescaped: ""
