Relax Location#source to be optional

lib/prism/parse_result.rb

@@ -168,13 +168,13 @@ def inspect
 
     # The source code that this location represents.
     def slice
-      source.slice(start_offset, length)
+      source!.slice(start_offset, length)
     end
 
     # The character offset from the beginning of the source where this location
     # starts.
     def start_character_offset
-      source.character_offset(start_offset)
+      source!.character_offset(start_offset)
     end
 
     # The offset from the start of the file in code units of the given encoding.
@@ -190,7 +190,7 @@ def end_offset
     # The character offset from the beginning of the source where this location
     # ends.
     def end_character_offset
-      source.character_offset(end_offset)
+      source!.character_offset(end_offset)
     end
 
     # The offset from the start of the file in code units of the given encoding.
@@ -200,30 +200,30 @@ def end_code_units_offset(encoding = Encoding::UTF_16LE)
 
     # The line number where this location starts.
     def start_line
-      source.line(start_offset)
+      source!.line(start_offset)
     end
 
     # The content of the line where this location starts before this location.
     def start_line_slice
-      offset = source.line_start(start_offset)
-      source.slice(offset, start_offset - offset)
+      offset = source!.line_start(start_offset)
+      source!.slice(offset, start_offset - offset)
     end
 
     # The line number where this location ends.
     def end_line
-      source.line(end_offset)
+      source!.line(end_offset)
     end
 
     # The column number in bytes where this location starts from the start of
     # the line.
     def start_column
-      source.column(start_offset)
+      source!.column(start_offset)
     end
 
     # The column number in characters where this location ends from the start of
     # the line.
     def start_character_column
-      source.character_column(start_offset)
+      source!.character_column(start_offset)
     end
 
     # The column number in code units of the given encoding where this location
@@ -235,13 +235,13 @@ def start_code_units_column(encoding = Encoding::UTF_16LE)
     # The column number in bytes where this location ends from the start of the
     # line.
     def end_column
-      source.column(end_offset)
+      source!.column(end_offset)
     end
 
     # The column number in characters where this location ends from the start of
     # the line.
     def end_character_column
-      source.character_column(end_offset)
+      source!.character_column(end_offset)
     end
 
     # The column number in code units of the given encoding where this location
@@ -281,8 +281,13 @@ def join(other)
     # the beginning of the file. Useful for when you want a location object but
     # do not care where it points.
     def self.null
-      source = nil #: Source
-      new(source, 0, 0)
+      new(nil, 0, 0)
+    end
+
+    private
+
+    def source!
+      source or raise "Missing source"
     end
   end
 

sig/prism/_private/parse_result.rbs

@@ -6,6 +6,12 @@ module Prism
     def compute_offsets: (String) -> Array[Integer]
   end
 
+  class Location
+    private
+
+    def source!: () -> Source
+  end
+
   class ParseResult[out T]
     def attach_comments!: () -> void
     def mark_newlines!: () -> untyped

sig/prism/parse_result.rbs

@@ -15,13 +15,13 @@ module Prism
   end
 
   class Location
-    attr_reader source: Source
+    attr_reader source: Source?
     attr_reader start_offset: Integer
     attr_reader length: Integer
     attr_reader comments: Array[comment]
 
-    def initialize: (Source source, Integer start_offset, Integer length) -> void
-    def copy: (?source: Source, ?start_offset: Integer, ?length: Integer) -> Location
+    def initialize: (Source? source, Integer start_offset, Integer length) -> void
+    def copy: (?source: Source?, ?start_offset: Integer, ?length: Integer) -> Location
     def slice: () -> String
     def start_character_offset: () -> Integer
     def end_offset: () -> Integer

templates/lib/prism/dsl.rb.erb

@@ -36,7 +36,6 @@ module Prism
 
     # Create a new Location object
     def Location(source = nil, start_offset = 0, length = 0)
-      # @type var source: Source
       Location.new(source, start_offset, length)
     end
     <%- nodes.each do |node| -%>