[ruby/prism] Move location to second position for node initializers

https://github.com/ruby/prism/commit/4cc0eda4ca

lib/prism/desugar_compiler.rb

@@ -2,11 +2,13 @@
 
 module Prism
   class DesugarAndWriteNode # :nodoc:
-    attr_reader :node, :source, :read_class, :write_class, :arguments
+    include DSL
 
-    def initialize(node, source, read_class, write_class, *arguments)
+    attr_reader :node, :default_source, :read_class, :write_class, :arguments
+
+    def initialize(node, default_source, read_class, write_class, **arguments)
       @node = node
-      @source = source
+      @default_source = default_source
       @read_class = read_class
       @write_class = write_class
       @arguments = arguments
@@ -14,22 +16,30 @@ module Prism
 
     # Desugar `x &&= y` to `x && x = y`
     def compile
-      AndNode.new(
-        source,
-        read_class.new(source, *arguments, node.name_loc),
-        write_class.new(source, *arguments, node.name_loc, node.value, node.operator_loc, node.location),
-        node.operator_loc,
-        node.location
+      and_node(
+        location: node.location,
+        left: public_send(read_class, location: node.name_loc, **arguments),
+        right: public_send(
+          write_class,
+          location: node.location,
+          **arguments,
+          name_loc: node.name_loc,
+          value: node.value,
+          operator_loc: node.operator_loc
+        ),
+        operator_loc: node.operator_loc
       )
     end
   end
 
   class DesugarOrWriteDefinedNode # :nodoc:
-    attr_reader :node, :source, :read_class, :write_class, :arguments
+    include DSL
 
-    def initialize(node, source, read_class, write_class, *arguments)
+    attr_reader :node, :default_source, :read_class, :write_class, :arguments
+
+    def initialize(node, default_source, read_class, write_class, **arguments)
       @node = node
-      @source = source
+      @default_source = default_source
       @read_class = read_class
       @write_class = write_class
       @arguments = arguments
@@ -37,35 +47,50 @@ module Prism
 
     # Desugar `x ||= y` to `defined?(x) ? x : x = y`
     def compile
-      IfNode.new(
-        source,
-        node.operator_loc,
-        DefinedNode.new(source, nil, read_class.new(source, *arguments, node.name_loc), nil, node.operator_loc, node.name_loc),
-        node.operator_loc,
-        StatementsNode.new(source, [read_class.new(source, *arguments, node.name_loc)], node.location),
-        ElseNode.new(
-          source,
-          node.operator_loc,
-          StatementsNode.new(
-            source,
-            [write_class.new(source, *arguments, node.name_loc, node.value, node.operator_loc, node.location)],
-            node.location
+      if_node(
+        location: node.location,
+        if_keyword_loc: node.operator_loc,
+        predicate: defined_node(
+          location: node.name_loc,
+          value: public_send(read_class, location: node.name_loc, **arguments),
+          keyword_loc: node.operator_loc
         ),
-          node.operator_loc,
-          node.location
+        then_keyword_loc: node.operator_loc,
+        statements: statements_node(
+          location: node.location,
+          body: [public_send(read_class, location: node.name_loc, **arguments)]
         ),
-        node.operator_loc,
-        node.location
+        consequent: else_node(
+          location: node.location,
+          else_keyword_loc: node.operator_loc,
+          statements: statements_node(
+            location: node.location,
+            body: [
+              public_send(
+                write_class,
+                location: node.location,
+                **arguments,
+                name_loc: node.name_loc,
+                value: node.value,
+                operator_loc: node.operator_loc
+              )
+            ]
+          ),
+          end_keyword_loc: node.operator_loc
+        ),
+        end_keyword_loc: node.operator_loc
       )
     end
   end
 
   class DesugarOperatorWriteNode # :nodoc:
-    attr_reader :node, :source, :read_class, :write_class, :arguments
+    include DSL
 
-    def initialize(node, source, read_class, write_class, *arguments)
+    attr_reader :node, :default_source, :read_class, :write_class, :arguments
+
+    def initialize(node, default_source, read_class, write_class, **arguments)
       @node = node
-      @source = source
+      @default_source = default_source
       @read_class = read_class
       @write_class = write_class
       @arguments = arguments
@@ -75,35 +100,41 @@ module Prism
     def compile
       binary_operator_loc = node.binary_operator_loc.chop
 
-      write_class.new(
-        source,
-        *arguments,
-        node.name_loc,
-        CallNode.new(
-          source,
-          0,
-          read_class.new(source, *arguments, node.name_loc),
-          nil,
-          binary_operator_loc.slice.to_sym,
-          binary_operator_loc,
-          nil,
-          ArgumentsNode.new(source, 0, [node.value], node.value.location),
-          nil,
-          nil,
-          node.location
+      public_send(
+        write_class,
+        location: node.location,
+        **arguments,
+        name_loc: node.name_loc,
+        value: call_node(
+          location: node.location,
+          receiver: public_send(
+            read_class,
+            location: node.name_loc,
+            **arguments
           ),
-        node.binary_operator_loc.copy(start_offset: node.binary_operator_loc.end_offset - 1, length: 1),
-        node.location
+          name: binary_operator_loc.slice.to_sym,
+          message_loc: binary_operator_loc,
+          arguments: arguments_node(
+            location: node.value.location,
+            arguments: [node.value]
+          )
+        ),
+        operator_loc: node.binary_operator_loc.copy(
+          start_offset: node.binary_operator_loc.end_offset - 1,
+          length: 1
+        )
       )
     end
   end
 
   class DesugarOrWriteNode # :nodoc:
-    attr_reader :node, :source, :read_class, :write_class, :arguments
+    include DSL
 
-    def initialize(node, source, read_class, write_class, *arguments)
+    attr_reader :node, :default_source, :read_class, :write_class, :arguments
+
+    def initialize(node, default_source, read_class, write_class, **arguments)
       @node = node
-      @source = source
+      @default_source = default_source
       @read_class = read_class
       @write_class = write_class
       @arguments = arguments
@@ -111,12 +142,18 @@ module Prism
 
     # Desugar `x ||= y` to `x || x = y`
     def compile
-      OrNode.new(
-        source,
-        read_class.new(source, *arguments, node.name_loc),
-        write_class.new(source, *arguments, node.name_loc, node.value, node.operator_loc, node.location),
-        node.operator_loc,
-        node.location
+      or_node(
+        location: node.location,
+        left: public_send(read_class, location: node.name_loc, **arguments),
+        right: public_send(
+          write_class,
+          location: node.location,
+          **arguments,
+          name_loc: node.name_loc,
+          value: node.value,
+          operator_loc: node.operator_loc
+        ),
+        operator_loc: node.operator_loc
       )
     end
   end
@@ -125,91 +162,91 @@ module Prism
 
   class ClassVariableAndWriteNode
     def desugar # :nodoc:
-      DesugarAndWriteNode.new(self, source, ClassVariableReadNode, ClassVariableWriteNode, name).compile
+      DesugarAndWriteNode.new(self, source, :class_variable_read_node, :class_variable_write_node, name: name).compile
     end
   end
 
   class ClassVariableOrWriteNode
     def desugar # :nodoc:
-      DesugarOrWriteDefinedNode.new(self, source, ClassVariableReadNode, ClassVariableWriteNode, name).compile
+      DesugarOrWriteDefinedNode.new(self, source, :class_variable_read_node, :class_variable_write_node, name: name).compile
     end
   end
 
   class ClassVariableOperatorWriteNode
     def desugar # :nodoc:
-      DesugarOperatorWriteNode.new(self, source, ClassVariableReadNode, ClassVariableWriteNode, name).compile
+      DesugarOperatorWriteNode.new(self, source, :class_variable_read_node, :class_variable_write_node, name: name).compile
     end
   end
 
   class ConstantAndWriteNode
     def desugar # :nodoc:
-      DesugarAndWriteNode.new(self, source, ConstantReadNode, ConstantWriteNode, name).compile
+      DesugarAndWriteNode.new(self, source, :constant_read_node, :constant_write_node, name: name).compile
     end
   end
 
   class ConstantOrWriteNode
     def desugar # :nodoc:
-      DesugarOrWriteDefinedNode.new(self, source, ConstantReadNode, ConstantWriteNode, name).compile
+      DesugarOrWriteDefinedNode.new(self, source, :constant_read_node, :constant_write_node, name: name).compile
     end
   end
 
   class ConstantOperatorWriteNode
     def desugar # :nodoc:
-      DesugarOperatorWriteNode.new(self, source, ConstantReadNode, ConstantWriteNode, name).compile
+      DesugarOperatorWriteNode.new(self, source, :constant_read_node, :constant_write_node, name: name).compile
     end
   end
 
   class GlobalVariableAndWriteNode
     def desugar # :nodoc:
-      DesugarAndWriteNode.new(self, source, GlobalVariableReadNode, GlobalVariableWriteNode, name).compile
+      DesugarAndWriteNode.new(self, source, :global_variable_read_node, :global_variable_write_node, name: name).compile
     end
   end
 
   class GlobalVariableOrWriteNode
     def desugar # :nodoc:
-      DesugarOrWriteDefinedNode.new(self, source, GlobalVariableReadNode, GlobalVariableWriteNode, name).compile
+      DesugarOrWriteDefinedNode.new(self, source, :global_variable_read_node, :global_variable_write_node, name: name).compile
     end
   end
 
   class GlobalVariableOperatorWriteNode
     def desugar # :nodoc:
-      DesugarOperatorWriteNode.new(self, source, GlobalVariableReadNode, GlobalVariableWriteNode, name).compile
+      DesugarOperatorWriteNode.new(self, source, :global_variable_read_node, :global_variable_write_node, name: name).compile
     end
   end
 
   class InstanceVariableAndWriteNode
     def desugar # :nodoc:
-      DesugarAndWriteNode.new(self, source, InstanceVariableReadNode, InstanceVariableWriteNode, name).compile
+      DesugarAndWriteNode.new(self, source, :instance_variable_read_node, :instance_variable_write_node, name: name).compile
     end
   end
 
   class InstanceVariableOrWriteNode
     def desugar # :nodoc:
-      DesugarOrWriteNode.new(self, source, InstanceVariableReadNode, InstanceVariableWriteNode, name).compile
+      DesugarOrWriteNode.new(self, source, :instance_variable_read_node, :instance_variable_write_node, name: name).compile
     end
   end
 
   class InstanceVariableOperatorWriteNode
     def desugar # :nodoc:
-      DesugarOperatorWriteNode.new(self, source, InstanceVariableReadNode, InstanceVariableWriteNode, name).compile
+      DesugarOperatorWriteNode.new(self, source, :instance_variable_read_node, :instance_variable_write_node, name: name).compile
     end
   end
 
   class LocalVariableAndWriteNode
     def desugar # :nodoc:
-      DesugarAndWriteNode.new(self, source, LocalVariableReadNode, LocalVariableWriteNode, name, depth).compile
+      DesugarAndWriteNode.new(self, source, :local_variable_read_node, :local_variable_write_node, name: name, depth: depth).compile
     end
   end
 
   class LocalVariableOrWriteNode
     def desugar # :nodoc:
-      DesugarOrWriteNode.new(self, source, LocalVariableReadNode, LocalVariableWriteNode, name, depth).compile
+      DesugarOrWriteNode.new(self, source, :local_variable_read_node, :local_variable_write_node, name: name, depth: depth).compile
     end
   end
 
   class LocalVariableOperatorWriteNode
     def desugar # :nodoc:
-      DesugarOperatorWriteNode.new(self, source, LocalVariableReadNode, LocalVariableWriteNode, name, depth).compile
+      DesugarOperatorWriteNode.new(self, source, :local_variable_read_node, :local_variable_write_node, name: name, depth: depth).compile
     end
   end
 

lib/prism/node_ext.rb

@@ -69,11 +69,11 @@ module Prism
     def to_interpolated
       InterpolatedStringNode.new(
         source,
+        location,
         frozen? ? InterpolatedStringNodeFlags::FROZEN : 0,
         opening_loc,
-        [copy(opening_loc: nil, closing_loc: nil, location: content_loc)],
-        closing_loc,
-        location
+        [copy(location: content_loc, opening_loc: nil, closing_loc: nil)],
+        closing_loc
       )
     end
   end
@@ -86,10 +86,10 @@ module Prism
     def to_interpolated
       InterpolatedXStringNode.new(
         source,
+        location,
         opening_loc,
-        [StringNode.new(source, 0, nil, content_loc, nil, unescaped, content_loc)],
-        closing_loc,
-        location
+        [StringNode.new(source, content_loc, 0, nil, content_loc, nil, unescaped)],
+        closing_loc
       )
     end
   end
@@ -115,9 +115,9 @@ module Prism
       deprecated("value", "numerator", "denominator")
 
       if denominator == 1
-        IntegerNode.new(source, flags, numerator, location.chop)
+        IntegerNode.new(source, location.chop, flags, numerator)
       else
-        FloatNode.new(source, numerator.to_f / denominator, location.chop)
+        FloatNode.new(source, location.chop, numerator.to_f / denominator)
       end
     end
   end
@@ -195,7 +195,7 @@ module Prism
     # continue to supply that API.
     def child
       deprecated("name", "name_loc")
-      name ? ConstantReadNode.new(source, name, name_loc) : MissingNode.new(source, location)
+      name ? ConstantReadNode.new(source, name_loc, name) : MissingNode.new(source, location)
     end
   end
 
@@ -231,7 +231,7 @@ module Prism
     # continue to supply that API.
     def child
       deprecated("name", "name_loc")
-      name ? ConstantReadNode.new(source, name, name_loc) : MissingNode.new(source, location)
+      name ? ConstantReadNode.new(source, name_loc, name) : MissingNode.new(source, location)
     end
   end
 

lib/prism/parse_result.rb

@@ -10,7 +10,11 @@ module Prism
     # specialized and more performant `ASCIISource` if no multibyte characters
     # are present in the source code.
     def self.for(source, start_line = 1, offsets = [])
-      source.ascii_only? ? ASCIISource.new(source, start_line, offsets): new(source, start_line, offsets)
+      if source.ascii_only?
+        ASCIISource.new(source, start_line, offsets)
+      else
+        new(source, start_line, offsets)
+      end
     end
 
     # The source code that this source object represents.
@@ -87,7 +91,12 @@ module Prism
     # encodings, it is not captured here.
     def code_units_offset(byte_offset, encoding)
       byteslice = (source.byteslice(0, byte_offset) or raise).encode(encoding)
-      (encoding == Encoding::UTF_16LE || encoding == Encoding::UTF_16BE) ? (byteslice.bytesize / 2) : byteslice.length
+
+      if encoding == Encoding::UTF_16LE || encoding == Encoding::UTF_16BE
+        byteslice.bytesize / 2
+      else
+        byteslice.length
+      end
     end
 
     # Returns the column number in code units for the given encoding for the

lib/prism/parse_result/errors.rb

@@ -4,13 +4,18 @@ require "stringio"
 
 module Prism
   class ParseResult < Result
+    # An object to represent the set of errors on a parse result. This object
+    # can be used to format the errors in a human-readable way.
     class Errors
+      # The parse result that contains the errors.
       attr_reader :parse_result
 
+      # Initialize a new set of errors from the given parse result.
       def initialize(parse_result)
         @parse_result = parse_result
       end
 
+      # Formats the errors in a human-readable way and return them as a string.
       def format
         error_lines = {}
         parse_result.errors.each do |error|

prism/templates/ext/prism/api_node.c.erb

@@ -177,7 +177,10 @@ pm_ast_new(const pm_parser_t *parser, const pm_node_t *node, rb_encoding *encodi
 
                     // source
                     argv[0] = source;
-                    <%- node.fields.each.with_index(1) do |field, index| -%>
+
+                    // location
+                    argv[1] = pm_location_new(parser, node->location.start, node->location.end);
+                    <%- node.fields.each.with_index(2) do |field, index| -%>
 
                     // <%= field.name %>
                     <%- case field -%>
@@ -232,9 +235,6 @@ pm_ast_new(const pm_parser_t *parser, const pm_node_t *node, rb_encoding *encodi
                     <%- end -%>
                     <%- end -%>
 
-                    // location
-                    argv[<%= node.fields.length + 1 %>] = pm_location_new(parser, node->location.start, node->location.end);
-
                     rb_ary_push(value_stack, rb_class_new_instance(<%= node.fields.length + 2 %>, argv, rb_cPrism<%= node.name %>));
                     break;
                 }

prism/templates/lib/prism/dsl.rb.erb

@@ -5,45 +5,118 @@ module Prism
   #     source = Prism::Source.for("[1]")
   #
   #     Prism::ArrayNode.new(
+  #       source,
+  #       Prism::Location.new(source, 0, 3),
+  #       0,
   #       [
   #         Prism::IntegerNode.new(
-  #           Prism::IntegerBaseFlags::DECIMAL,
-  #           1,
+  #           source,
   #           Prism::Location.new(source, 1, 1),
-  #           source
+  #           Prism::IntegerBaseFlags::DECIMAL,
+  #           1
   #         )
   #       ],
   #       Prism::Location.new(source, 0, 1),
-  #       Prism::Location.new(source, 2, 1),
-  #       source
+  #       Prism::Location.new(source, 2, 1)
   #     )
   #
   # you could instead write:
   #
-  #     source = Prism::Source.for("[1]")
+  #     class Builder
+  #       include Prism::DSL
   #
-  #     ArrayNode(
-  #       IntegerNode(Prism::IntegerBaseFlags::DECIMAL, 1, Location(source, 1, 1)), source),
-  #       Location(source, 0, 1),
-  #       Location(source, 2, 1),
-  #       source
+  #       attr_reader :default_source
+  #
+  #       def initialize
+  #         @default_source = source("[1]")
+  #       end
+  #
+  #       def build
+  #         array_node(
+  #           location: location(start_offset: 0, length: 3),
+  #           elements: [
+  #             integer_node(
+  #               location: location(start_offset: 1, length: 1),
+  #               flags: integer_base_flag(:decimal),
+  #               value: 1
   #             )
+  #           ],
+  #           opening_loc: location(start_offset: 0, length: 1),
+  #           closing_loc: location(start_offset: 2, length: 1)
+  #         )
+  #       end
+  #     end
   #
-  # This is mostly helpful in the context of writing tests, but can also be used
-  # to generate trees programmatically.
+  # This is mostly helpful in the context of generating trees programmatically.
   module DSL
-    private
+    # Provide all of these methods as module methods as well, to allow for
+    # building nodes like Prism::DSL.nil_node.
+    extend self
 
-    # Create a new Location object
-    def Location(source = nil, start_offset = 0, length = 0)
-      Location.new(source, start_offset, length) # steep:ignore
+    # Create a new Source object.
+    def source(string)
+      Source.for(string)
+    end
+
+    # Create a new Location object.
+    def location(source: default_source, start_offset: 0, length: 0)
+      Location.new(source, start_offset, length)
     end
     <%- nodes.each do |node| -%>
 
-    # Create a new <%= node.name %> node
-    def <%= node.name %>(<%= (node.fields.map(&:name) + ["source = nil, location = Location()"]).join(", ") %>)
-      <%= node.name %>.new(<%= ["source", *node.fields.map(&:name), "location"].join(", ") %>)
+    # Create a new <%= node.name %> node.
+    def <%= node.human %>(<%= ["source: default_source", "location: default_location", *node.fields.map { |field|
+      case field
+      when Prism::Template::NodeField, Prism::Template::ConstantField
+        "#{field.name}: default_node(source, location)"
+      when Prism::Template::OptionalNodeField, Prism::Template::OptionalConstantField, Prism::Template::OptionalLocationField
+        "#{field.name}: nil"
+      when Prism::Template::NodeListField, Prism::Template::ConstantListField
+        "#{field.name}: []"
+      when Prism::Template::StringField
+        "#{field.name}: \"\""
+      when Prism::Template::LocationField
+        "#{field.name}: location"
+      when Prism::Template::UInt8Field, Prism::Template::UInt32Field, Prism::Template::FlagsField, Prism::Template::IntegerField, Prism::Template::DoubleField
+        "#{field.name}: 0"
+      else
+        raise
+      end
+    }].join(", ") %>)
+      <%= node.name %>.new(<%= ["source", "location", *node.fields.map(&:name)].join(", ") %>)
     end
     <%- end -%>
+    <%- flags.each do |flag| -%>
+
+    # Retrieve the value of one of the <%= flag.name %> flags.
+    def <%= flag.human.chomp("s") %>(name)
+      case name
+      <%- flag.values.each do |value| -%>
+      when :<%= value.name.downcase %> then <%= flag.name %>::<%= value.name %>
+      <%- end -%>
+      else raise ArgumentError, "invalid <%= flag.name %> flag: #{name.inspect}"
+      end
+    end
+    <%- end -%>
+
+    private
+
+    # The default source object that gets attached to nodes and locations if no
+    # source is specified.
+    def default_source
+      Source.for("")
+    end
+
+    # The default location object that gets attached to nodes if no location is
+    # specified, which uses the given source.
+    def default_location
+      Location.new(default_source, 0, 0)
+    end
+
+    # The default node that gets attached to nodes if no node is specified for a
+    # required node field.
+    def default_node(source, location)
+      MissingNode.new(source, location)
+    end
   end
 end

prism/templates/lib/prism/node.rb.erb

@@ -166,8 +166,8 @@ module Prism
   #<%= line %>
   <%- end -%>
   class <%= node.name -%> < Node
-    # def initialize: (<%= (node.fields.map { |field| "#{field.rbs_class} #{field.name}" } + ["Location location"]).join(", ") %>) -> void
-    def initialize(source, <%= (node.fields.map(&:name) + ["location"]).join(", ") %>)
+    # Initialize a new <%= node.name %> node.
+    def initialize(<%= ["source", "location", *node.fields.map(&:name)].join(", ") %>)
       @source = source
       @location = location
       <%- node.fields.each do |field| -%>
@@ -228,9 +228,9 @@ module Prism
       }.compact.join(", ") %>] #: Array[Prism::node | Location]
     end
 
-    # def copy: (<%= (node.fields.map { |field| "?#{field.name}: #{field.rbs_class}" } + ["?location: Location"]).join(", ") %>) -> <%= node.name %>
-    def copy(<%= (node.fields.map(&:name) + ["location"]).map { |field| "#{field}: self.#{field}" }.join(", ") %>)
-      <%= node.name %>.new(<%= ["source", *node.fields.map(&:name), "location"].join(", ") %>)
+    # def copy: (<%= (["?location: Location"] + node.fields.map { |field| "?#{field.name}: #{field.rbs_class}" }).join(", ") %>) -> <%= node.name %>
+    def copy(<%= (["location"] + node.fields.map(&:name)).map { |field| "#{field}: self.#{field}" }.join(", ") %>)
+      <%= node.name %>.new(<%= ["source", "location", *node.fields.map(&:name)].join(", ") %>)
     end
 
     # def deconstruct: () -> Array[nil | Node]

prism/templates/lib/prism/serialize.rb.erb

@@ -319,7 +319,7 @@ module Prism
         end
       end
 
-      if RUBY_ENGINE == 'ruby'
+      if RUBY_ENGINE == "ruby"
         def load_node
           type = io.getbyte
           location = load_location
@@ -330,8 +330,7 @@ module Prism
             <%- if node.needs_serialized_length? -%>
             load_uint32
             <%- end -%>
-            <%= node.name %>.new(
-              source, <%= (node.fields.map { |field|
+            <%= node.name %>.new(<%= ["source", "location", *node.fields.map { |field|
               case field
               when Prism::Template::NodeField then "load_node"
               when Prism::Template::OptionalNodeField then "load_optional_node"
@@ -348,7 +347,7 @@ module Prism
               when Prism::Template::DoubleField then "load_double"
               else raise
               end
-            } + ["location"]).join(", ") -%>)
+            }].join(", ") -%>)
             <%- end -%>
           end
         end
@@ -367,8 +366,7 @@ module Prism
               <%- if node.needs_serialized_length? -%>
               load_uint32
               <%- end -%>
-              <%= node.name %>.new(
-                source, <%= (node.fields.map { |field|
+              <%= node.name %>.new(<%= ["source", "location", *node.fields.map { |field|
                 case field
                 when Prism::Template::NodeField then "load_node"
                 when Prism::Template::OptionalNodeField then "load_optional_node"
@@ -385,7 +383,7 @@ module Prism
                 when Prism::Template::DoubleField then "load_double"
                 else raise
                 end
-              } + ["location"]).join(", ") -%>)
+              }].join(", ") -%>)
             },
             <%- end -%>
           ]

test/prism/errors/content_after_unterminated_heredoc.txt

@@ -1,2 +1,4 @@
 <<~FOO.foo
    ^~~ unterminated heredoc; can't find string "FOO" anywhere before EOF
+   ^~~ unterminated heredoc; can't find string "FOO" anywhere before EOF
+

test/prism/snapshots/patterns.txt

@@ -1,8 +1,8 @@
-@ ProgramNode (location: (1,0)-(217,5))
-├── locals: [:bar, :baz, :qux, :b, :a, :foo, :x]
+@ ProgramNode (location: (1,0)-(220,31))
+├── locals: [:bar, :baz, :qux, :b, :a, :foo, :x, :_a]
 └── statements:
-    @ StatementsNode (location: (1,0)-(217,5))
-    └── body: (length: 180)
+    @ StatementsNode (location: (1,0)-(220,31))
+    └── body: (length: 182)
         ├── @ MatchRequiredNode (location: (1,0)-(1,10))
         │   ├── value:
         │   │   @ CallNode (location: (1,0)-(1,3))
@@ -4883,27 +4883,115 @@
         │       │           └── operator_loc: (212,11)-(212,13) = "in"
         │       ├── opening_loc: (212,7)-(212,8) = "{"
         │       └── closing_loc: (212,18)-(212,19) = "}"
-        └── @ MultiWriteNode (location: (214,0)-(217,5))
-            ├── lefts: (length: 2)
-            │   ├── @ LocalVariableTargetNode (location: (215,2)-(215,3))
-            │   │   ├── name: :a
+        ├── @ MultiWriteNode (location: (214,0)-(217,5))
+        │   ├── lefts: (length: 2)
+        │   │   ├── @ LocalVariableTargetNode (location: (215,2)-(215,3))
+        │   │   │   ├── name: :a
+        │   │   │   └── depth: 0
+        │   │   └── @ LocalVariableTargetNode (location: (216,2)-(216,3))
+        │   │       ├── name: :b
         │   │       └── depth: 0
-            │   └── @ LocalVariableTargetNode (location: (216,2)-(216,3))
-            │       ├── name: :b
-            │       └── depth: 0
-            ├── rest: ∅
-            ├── rights: (length: 0)
-            ├── lparen_loc: (214,0)-(214,1) = "("
-            ├── rparen_loc: (217,0)-(217,1) = ")"
-            ├── operator_loc: (217,2)-(217,3) = "="
-            └── value:
-                @ CallNode (location: (217,4)-(217,5))
-                ├── flags: variable_call, ignore_visibility
-                ├── receiver: ∅
-                ├── call_operator_loc: ∅
-                ├── name: :c
-                ├── message_loc: (217,4)-(217,5) = "c"
-                ├── opening_loc: ∅
-                ├── arguments: ∅
-                ├── closing_loc: ∅
-                └── block: ∅
+        │   ├── rest: ∅
+        │   ├── rights: (length: 0)
+        │   ├── lparen_loc: (214,0)-(214,1) = "("
+        │   ├── rparen_loc: (217,0)-(217,1) = ")"
+        │   ├── operator_loc: (217,2)-(217,3) = "="
+        │   └── value:
+        │       @ CallNode (location: (217,4)-(217,5))
+        │       ├── flags: variable_call, ignore_visibility
+        │       ├── receiver: ∅
+        │       ├── call_operator_loc: ∅
+        │       ├── name: :c
+        │       ├── message_loc: (217,4)-(217,5) = "c"
+        │       ├── opening_loc: ∅
+        │       ├── arguments: ∅
+        │       ├── closing_loc: ∅
+        │       └── block: ∅
+        ├── @ CaseMatchNode (location: (219,0)-(219,25))
+        │   ├── predicate:
+        │   │   @ ParenthesesNode (location: (219,5)-(219,7))
+        │   │   ├── body: ∅
+        │   │   ├── opening_loc: (219,5)-(219,6) = "("
+        │   │   └── closing_loc: (219,6)-(219,7) = ")"
+        │   ├── conditions: (length: 1)
+        │   │   └── @ InNode (location: (219,9)-(219,20))
+        │   │       ├── pattern:
+        │   │       │   @ ArrayPatternNode (location: (219,12)-(219,20))
+        │   │       │   ├── constant: ∅
+        │   │       │   ├── requireds: (length: 2)
+        │   │       │   │   ├── @ LocalVariableTargetNode (location: (219,13)-(219,15))
+        │   │       │   │   │   ├── name: :_a
+        │   │       │   │   │   └── depth: 0
+        │   │       │   │   └── @ LocalVariableTargetNode (location: (219,17)-(219,19))
+        │   │       │   │       ├── name: :_a
+        │   │       │   │       └── depth: 0
+        │   │       │   ├── rest: ∅
+        │   │       │   ├── posts: (length: 0)
+        │   │       │   ├── opening_loc: (219,12)-(219,13) = "["
+        │   │       │   └── closing_loc: (219,19)-(219,20) = "]"
+        │   │       ├── statements: ∅
+        │   │       ├── in_loc: (219,9)-(219,11) = "in"
+        │   │       └── then_loc: ∅
+        │   ├── consequent: ∅
+        │   ├── case_keyword_loc: (219,0)-(219,4) = "case"
+        │   └── end_keyword_loc: (219,22)-(219,25) = "end"
+        └── @ CaseMatchNode (location: (220,0)-(220,31))
+            ├── predicate:
+            │   @ ParenthesesNode (location: (220,5)-(220,7))
+            │   ├── body: ∅
+            │   ├── opening_loc: (220,5)-(220,6) = "("
+            │   └── closing_loc: (220,6)-(220,7) = ")"
+            ├── conditions: (length: 1)
+            │   └── @ InNode (location: (220,9)-(220,26))
+            │       ├── pattern:
+            │       │   @ ArrayPatternNode (location: (220,12)-(220,26))
+            │       │   ├── constant: ∅
+            │       │   ├── requireds: (length: 2)
+            │       │   │   ├── @ HashPatternNode (location: (220,13)-(220,18))
+            │       │   │   │   ├── constant: ∅
+            │       │   │   │   ├── elements: (length: 1)
+            │       │   │   │   │   └── @ AssocNode (location: (220,14)-(220,17))
+            │       │   │   │   │       ├── key:
+            │       │   │   │   │       │   @ SymbolNode (location: (220,14)-(220,16))
+            │       │   │   │   │       │   ├── flags: forced_us_ascii_encoding
+            │       │   │   │   │       │   ├── opening_loc: ∅
+            │       │   │   │   │       │   ├── value_loc: (220,14)-(220,15) = "a"
+            │       │   │   │   │       │   ├── closing_loc: (220,15)-(220,16) = ":"
+            │       │   │   │   │       │   └── unescaped: "a"
+            │       │   │   │   │       ├── value:
+            │       │   │   │   │       │   @ IntegerNode (location: (220,16)-(220,17))
+            │       │   │   │   │       │   ├── flags: decimal
+            │       │   │   │   │       │   └── value: 1
+            │       │   │   │   │       └── operator_loc: ∅
+            │       │   │   │   ├── rest: ∅
+            │       │   │   │   ├── opening_loc: (220,13)-(220,14) = "{"
+            │       │   │   │   └── closing_loc: (220,17)-(220,18) = "}"
+            │       │   │   └── @ HashPatternNode (location: (220,20)-(220,25))
+            │       │   │       ├── constant: ∅
+            │       │   │       ├── elements: (length: 1)
+            │       │   │       │   └── @ AssocNode (location: (220,21)-(220,24))
+            │       │   │       │       ├── key:
+            │       │   │       │       │   @ SymbolNode (location: (220,21)-(220,23))
+            │       │   │       │       │   ├── flags: forced_us_ascii_encoding
+            │       │   │       │       │   ├── opening_loc: ∅
+            │       │   │       │       │   ├── value_loc: (220,21)-(220,22) = "a"
+            │       │   │       │       │   ├── closing_loc: (220,22)-(220,23) = ":"
+            │       │   │       │       │   └── unescaped: "a"
+            │       │   │       │       ├── value:
+            │       │   │       │       │   @ IntegerNode (location: (220,23)-(220,24))
+            │       │   │       │       │   ├── flags: decimal
+            │       │   │       │       │   └── value: 2
+            │       │   │       │       └── operator_loc: ∅
+            │       │   │       ├── rest: ∅
+            │       │   │       ├── opening_loc: (220,20)-(220,21) = "{"
+            │       │   │       └── closing_loc: (220,24)-(220,25) = "}"
+            │       │   ├── rest: ∅
+            │       │   ├── posts: (length: 0)
+            │       │   ├── opening_loc: (220,12)-(220,13) = "["
+            │       │   └── closing_loc: (220,25)-(220,26) = "]"
+            │       ├── statements: ∅
+            │       ├── in_loc: (220,9)-(220,11) = "in"
+            │       └── then_loc: ∅
+            ├── consequent: ∅
+            ├── case_keyword_loc: (220,0)-(220,4) = "case"
+            └── end_keyword_loc: (220,28)-(220,31) = "end"