Handle nested required arguments

Handle arguments of type
    [].each do |one, (two, three)|
    end
when declaring arguments

Author: vinistock

lib/syntax_tree/visitor/with_environment.rb

@@ -67,9 +67,7 @@ def visit_def_endless(node)
     # Visit for keeping track of local arguments, such as method and block
     # arguments
     def visit_params(node)
-      node.requireds.each do |param|
-        current_environment.add_local_definition(param, :argument)
-      end
+      add_argument_definitions(node.requireds)
 
       node.posts.each do |param|
         current_environment.add_local_definition(param, :argument)
@@ -134,5 +132,17 @@ def visit_var_ref(node)
 
       super
     end
+
+    private
+
+    def add_argument_definitions(list)
+      list.each do |param|
+        if param.is_a?(SyntaxTree::MLHSParen)
+          add_argument_definitions(param.contents.parts)
+        else
+          current_environment.add_local_definition(param, :argument)
+        end
+      end
+    end
   end
 end

test/visitor_with_environment_test.rb

@@ -533,5 +533,87 @@ def test_double_aref_on_method_call
       assert_equal(2, argument.definitions[0].start_line)
       assert_equal(2, argument.usages[0].start_line)
     end
+
+    def test_nested_arguments
+      tree = SyntaxTree.parse(<<~RUBY)
+        [[1, [2, 3]]].each do |one, (two, three)|
+          one
+          two
+          three
+        end
+      RUBY
+
+      visitor = Collector.new
+      visitor.visit(tree)
+
+      assert_equal(3, visitor.arguments.length)
+      assert_equal(0, visitor.variables.length)
+
+      argument = visitor.arguments["one"]
+      assert_equal(1, argument.definitions.length)
+      assert_equal(1, argument.usages.length)
+
+      assert_equal(1, argument.definitions[0].start_line)
+      assert_equal(2, argument.usages[0].start_line)
+
+      argument = visitor.arguments["two"]
+      assert_equal(1, argument.definitions.length)
+      assert_equal(1, argument.usages.length)
+
+      assert_equal(1, argument.definitions[0].start_line)
+      assert_equal(3, argument.usages[0].start_line)
+
+      argument = visitor.arguments["three"]
+      assert_equal(1, argument.definitions.length)
+      assert_equal(1, argument.usages.length)
+
+      assert_equal(1, argument.definitions[0].start_line)
+      assert_equal(4, argument.usages[0].start_line)
+    end
+
+    def test_double_nested_arguments
+      tree = SyntaxTree.parse(<<~RUBY)
+        [[1, [2, 3]]].each do |one, (two, (three, four))|
+          one
+          two
+          three
+          four
+        end
+      RUBY
+
+      visitor = Collector.new
+      visitor.visit(tree)
+
+      assert_equal(4, visitor.arguments.length)
+      assert_equal(0, visitor.variables.length)
+
+      argument = visitor.arguments["one"]
+      assert_equal(1, argument.definitions.length)
+      assert_equal(1, argument.usages.length)
+
+      assert_equal(1, argument.definitions[0].start_line)
+      assert_equal(2, argument.usages[0].start_line)
+
+      argument = visitor.arguments["two"]
+      assert_equal(1, argument.definitions.length)
+      assert_equal(1, argument.usages.length)
+
+      assert_equal(1, argument.definitions[0].start_line)
+      assert_equal(3, argument.usages[0].start_line)
+
+      argument = visitor.arguments["three"]
+      assert_equal(1, argument.definitions.length)
+      assert_equal(1, argument.usages.length)
+
+      assert_equal(1, argument.definitions[0].start_line)
+      assert_equal(4, argument.usages[0].start_line)
+
+      argument = visitor.arguments["four"]
+      assert_equal(1, argument.definitions.length)
+      assert_equal(1, argument.usages.length)
+
+      assert_equal(1, argument.definitions[0].start_line)
+      assert_equal(5, argument.usages[0].start_line)
+    end
   end
 end