Add support for regexp locals

Co-authored-by: Kevin Newton <kddnewton@users.noreply.github.com>

lib/syntax_tree/with_scope.rb

@@ -217,6 +217,63 @@ def visit_var_ref(node)
       super
     end
 
+    # When using regex named capture groups, vcalls might actually be a variable
+    def visit_vcall(node)
+      value = node.value
+      definition = current_scope.find_local(value.value)
+      current_scope.add_local_usage(value, definition.type) if definition
+
+      super
+    end
+
+    # Visit for capturing local variables defined in regex named capture groups
+    def visit_binary(node)
+      if node.operator == :=~
+        left = node.left
+
+        if left.is_a?(RegexpLiteral) && left.parts.length == 1 &&
+             left.parts.first.is_a?(TStringContent)
+          content = left.parts.first
+
+          value = content.value
+          location = content.location
+          start_line = location.start_line
+
+          Regexp
+            .new(value, Regexp::FIXEDENCODING)
+            .names
+            .each do |name|
+              offset = value.index(/\(\?<#{Regexp.escape(name)}>/)
+              line = start_line + value[0...offset].count("\n")
+
+              # We need to add 3 to account for these three characters
+              # prefixing a named capture (?<
+              column = location.start_column + offset + 3
+              if value[0...offset].include?("\n")
+                column =
+                  value[0...offset].length - value[0...offset].rindex("\n") +
+                    3 - 1
+              end
+
+              ident_location =
+                Location.new(
+                  start_line: line,
+                  start_char: location.start_char + offset,
+                  start_column: column,
+                  end_line: line,
+                  end_char: location.start_char + offset + name.length,
+                  end_column: column + name.length
+                )
+
+              identifier = Ident.new(value: name, location: ident_location)
+              current_scope.add_local_definition(identifier, :variable)
+            end
+        end
+      end
+
+      super
+    end
+
     private
 
     def add_argument_definitions(list)

test/with_scope_test.rb

@@ -39,6 +39,13 @@ def visit_label(node)
             arguments[[current_scope.id, value]] = node
           end
         end
+
+        def visit_vcall(node)
+          local = current_scope.find_local(node.value)
+          variables[[current_scope.id, value]] = local if local
+
+          super
+        end
       end
     end
 
@@ -349,6 +356,37 @@ def test_double_nested_arguments
       assert_argument(collector, "four", definitions: [1], usages: [5])
     end
 
+    def test_regex_named_capture_groups
+      collector = Collector.collect(<<~RUBY)
+        if /(?<one>\\w+)-(?<two>\\w+)/ =~ "something-else"
+          one
+          two
+        end
+      RUBY
+
+      assert_equal(2, collector.variables.length)
+
+      assert_variable(collector, "one", definitions: [1], usages: [2])
+      assert_variable(collector, "two", definitions: [1], usages: [3])
+    end
+
+    def test_multiline_regex_named_capture_groups
+      collector = Collector.collect(<<~RUBY)
+        if %r{
+          (?<one>\\w+)-
+          (?<two>\\w+)
+        } =~ "something-else"
+          one
+          two
+        end
+      RUBY
+
+      assert_equal(2, collector.variables.length)
+
+      assert_variable(collector, "one", definitions: [2], usages: [5])
+      assert_variable(collector, "two", definitions: [3], usages: [6])
+    end
+
     class Resolver < Visitor
       prepend WithScope