Add Regexp::Expression#loc and #expression to replace `parsed_tre…

…e_expr_loc`

changelog/new_add_regexpregexpexpressionloc_and.md

@@ -0,0 +1 @@
+* [#8960](https://github.com/rubocop-hq/rubocop/pull/8960): Add `Regexp::Expression#loc` and `#expression` to replace `parsed_tree_expr_loc`. ([@marcandre][])

lib/rubocop.rb

@@ -15,6 +15,7 @@
 
 require_relative 'rubocop/ast_aliases'
 require_relative 'rubocop/ext/regexp_node'
+require_relative 'rubocop/ext/regexp_parser'
 
 require_relative 'rubocop/core_ext/string'
 require_relative 'rubocop/ext/processed_source'

lib/rubocop/cop/lint/duplicate_regexp_character_class_element.rb

@@ -43,7 +43,7 @@ def each_repeated_character_class_element_loc(node)
 
               child_source = child.to_s
 
-              yield node.parsed_tree_expr_loc(child) if seen.include?(child_source)
+              yield child.expression if seen.include?(child_source)
 
               seen << child_source
             end
@@ -56,7 +56,7 @@ def each_repeated_character_class_element_loc(node)
         # mark every space (except the first) as duplicate if we do not skip regexp_parser nodes
         # that are within an interpolation.
         def within_interpolation?(node, child)
-          parse_tree_child_loc = node.parsed_tree_expr_loc(child)
+          parse_tree_child_loc = child.expression
 
           interpolation_locs(node).any? { |il| il.overlaps?(parse_tree_child_loc) }
         end

lib/rubocop/ext/regexp_node.rb

@@ -11,6 +11,8 @@ def ANY.==(_)
       private_constant :ANY
 
       # @return [Regexp::Expression::Root, nil]
+      # Note: we extend Regexp nodes to provide `loc` and `expression`
+      # see `ext/regexp_parser`.
       attr_reader :parsed_tree
 
       def assign_properties(*)
@@ -22,6 +24,8 @@ def assign_properties(*)
         rescue StandardError
           nil
         end
+        origin = loc.begin.end
+        @parsed_tree&.each_expression(true) { |e| e.origin = origin }
       end
 
       def each_capture(named: ANY)
@@ -37,11 +41,6 @@ def each_capture(named: ANY)
         self
       end
 
-      # @return [Parser::Source::Range] the range of the parse-tree expression
-      def parsed_tree_expr_loc(expr)
-        loc.begin.end.adjust(begin_pos: expr.ts, end_pos: expr.ts).resize(expr.full_length)
-      end
-
       private
 
       def with_interpolations_blanked

lib/rubocop/ext/regexp_parser.rb

@@ -0,0 +1,77 @@
+# frozen_string_literal: true
+
+module RuboCop
+  module Ext
+    # Extensions for `regexp_parser` gem
+    module RegexpParser
+      # Source map for RegexpParser nodes
+      class Map < ::Parser::Source::Map
+        attr_reader :body, :quantifier, :begin, :end
+
+        def initialize(expression, body:, quantifier: nil, begin_l: nil, end_l: nil)
+          @begin = begin_l
+          @end = end_l
+          @body = body
+          @quantifier = quantifier
+          super(expression)
+        end
+      end
+
+      module Expression
+        # Add `expression` and `loc` to all `regexp_parser` nodes
+        module Base
+          attr_accessor :origin
+
+          # Shortcut to `loc.expression`
+          def expression
+            @expression ||= origin.adjust(begin_pos: ts, end_pos: ts + full_length)
+          end
+
+          # @returns a location map like `parser` does, with:
+          #   - expression: complete expression
+          #   - quantifier: for `+`, `{1,2}`, etc.
+          #   - begin/end: for `[` and `]` (only CharacterSet for now)
+          #
+          # E.g.
+          #     [a-z]{2,}
+          #     ^^^^^^^^^ expression
+          #          ^^^^ quantifier
+          #     ^^^^^     body
+          #     ^         begin
+          #         ^     end
+          #
+          # Please open issue if you need other locations
+          def loc
+            @loc ||= begin
+              Map.new(expression, **build_location)
+            end
+          end
+
+          private
+
+          def build_location
+            return { body: expression } unless (q = quantifier)
+
+            body = expression.adjust(end_pos: -q.text.length)
+            q_loc = expression.with(begin_pos: body.end_pos)
+            { body: body, quantifier: q_loc }
+          end
+        end
+
+        # Provide `CharacterSet` with `begin` and `end` locations.
+        module CharacterSet
+          def build_location
+            h = super
+            body = h[:body]
+            h.merge!(
+              begin_l: body.with(end_pos: body.begin_pos + 1),
+              end_l: body.with(begin_pos: body.end_pos - 1)
+            )
+          end
+        end
+      end
+      ::Regexp::Expression::Base.include Expression::Base
+      ::Regexp::Expression::CharacterSet.include Expression::CharacterSet
+    end
+  end
+end

spec/rubocop/ext/regexp_node_spec.rb

@@ -96,29 +96,23 @@
         expect(tree.to_s).to eq('foobaz')
       end
     end
-  end
 
-  describe '#parsed_node_loc' do
-    let(:source) { '/([a-z]+)\d*\s?(?:foo)/' }
+    context 'with a regexp with subexpressions' do
+      let(:source) { '/([a-z]+)\d*\s?(?:foo)/' }
 
-    it 'returns the correct loc for each node in the parsed_tree' do
-      loc_sources = node.parsed_tree.each_expression.map do |regexp_node|
-        node.parsed_tree_expr_loc(regexp_node).source
-      end
+      it 'has location information' do
+        nodes = node.parsed_tree.each_expression.map { |exp, _index| exp }
+
+        sources = nodes.map { |n| n.loc.expression.source }
 
-      expect(loc_sources).to eq(
-        [
-          '([a-z]+)',
-          '[a-z]+',
-          'a-z',
-          'a',
-          'z',
-          '\d*',
-          '\s?',
-          '(?:foo)',
-          'foo'
-        ]
-      )
+        expect(sources).to eq %w{
+          ([a-z]+) [a-z]+ a-z a z \d* \s? (?:foo) foo
+        }
+
+        loc = nodes[1].loc
+        delim = loc.begin, loc.body, loc.end, loc.quantifier
+        expect(delim.map(&:source)).to eq %w{[ [a-z] ] +}
+      end
     end
   end
 end