Add completion support for locals

lib/ruby_lsp/document.rb

@@ -117,8 +117,18 @@ def locate(node, char_position, node_types: [])
       parent = T.let(nil, T.nilable(Prism::Node))
       nesting_nodes = T.let(
         [],
-        T::Array[T.any(Prism::ClassNode, Prism::ModuleNode, Prism::SingletonClassNode, Prism::DefNode)],
+        T::Array[T.any(
+          Prism::ClassNode,
+          Prism::ModuleNode,
+          Prism::SingletonClassNode,
+          Prism::DefNode,
+          Prism::BlockNode,
+          Prism::LambdaNode,
+          Prism::ProgramNode,
+        )],
       )
+
+      nesting_nodes << node if node.is_a?(Prism::ProgramNode)
       call_node = T.let(nil, T.nilable(Prism::CallNode))
 
       until queue.empty?
@@ -148,11 +158,8 @@ def locate(node, char_position, node_types: [])
         # Keep track of the nesting where we found the target. This is used to determine the fully qualified name of the
         # target when it is a constant
         case candidate
-        when Prism::ClassNode, Prism::ModuleNode
-          nesting_nodes << candidate
-        when Prism::SingletonClassNode
-          nesting_nodes << candidate
-        when Prism::DefNode
+        when Prism::ClassNode, Prism::ModuleNode, Prism::SingletonClassNode, Prism::DefNode, Prism::BlockNode,
+          Prism::LambdaNode
           nesting_nodes << candidate
         end
 
@@ -193,24 +200,7 @@ def locate(node, char_position, node_types: [])
         end
       end
 
-      nesting = []
-      surrounding_method = T.let(nil, T.nilable(String))
-
-      nesting_nodes.each do |node|
-        case node
-        when Prism::ClassNode, Prism::ModuleNode
-          nesting << node.constant_path.slice
-        when Prism::SingletonClassNode
-          nesting << "<Class:#{nesting.last}>"
-        when Prism::DefNode
-          surrounding_method = node.name.to_s
-          next unless node.receiver.is_a?(Prism::SelfNode)
-
-          nesting << "<Class:#{nesting.last}>"
-        end
-      end
-
-      NodeContext.new(closest, parent, nesting, call_node, surrounding_method)
+      NodeContext.new(closest, parent, nesting_nodes, call_node)
     end
 
     sig { returns(T::Boolean) }

lib/ruby_lsp/listeners/completion.rb

@@ -277,6 +277,8 @@ def complete_require_relative(node)
 
       sig { params(node: Prism::CallNode, name: String).void }
       def complete_methods(node, name)
+        add_local_completions(node, name)
+
         type = @type_inferrer.infer_receiver_type(@node_context)
         return unless type
 
@@ -317,6 +319,28 @@ def complete_methods(node, name)
         # We have not indexed this namespace, so we can't provide any completions
       end
 
+      sig { params(node: Prism::CallNode, name: String).void }
+      def add_local_completions(node, name)
+        return if @global_state.has_type_checker
+
+        range = range_from_location(T.must(node.message_loc))
+
+        @node_context.locals_for_scope.each do |local|
+          local_name = local.to_s
+          next unless local_name.start_with?(name)
+
+          @response_builder << Interface::CompletionItem.new(
+            label: local_name,
+            filter_text: local_name,
+            text_edit: Interface::TextEdit.new(range: range, new_text: local_name),
+            kind: Constant::CompletionItemKind::VARIABLE,
+            data: {
+              skip_resolve: true,
+            },
+          )
+        end
+      end
+
       sig { params(label: String, node: Prism::StringNode).returns(Interface::CompletionItem) }
       def build_completion(label, node)
         # We should use the content location as we only replace the content and not the delimiters of the string

lib/ruby_lsp/node_context.rb

@@ -23,22 +23,82 @@ class NodeContext
       params(
         node: T.nilable(Prism::Node),
         parent: T.nilable(Prism::Node),
-        nesting: T::Array[String],
+        nesting_nodes: T::Array[T.any(
+          Prism::ClassNode,
+          Prism::ModuleNode,
+          Prism::SingletonClassNode,
+          Prism::DefNode,
+          Prism::BlockNode,
+          Prism::LambdaNode,
+          Prism::ProgramNode,
+        )],
         call_node: T.nilable(Prism::CallNode),
-        surrounding_method: T.nilable(String),
       ).void
     end
-    def initialize(node, parent, nesting, call_node, surrounding_method)
+    def initialize(node, parent, nesting_nodes, call_node)
       @node = node
       @parent = parent
-      @nesting = nesting
+      @nesting_nodes = nesting_nodes
       @call_node = call_node
-      @surrounding_method = surrounding_method
+
+      nesting, surrounding_method = handle_nesting_nodes(nesting_nodes)
+      @nesting = T.let(nesting, T::Array[String])
+      @surrounding_method = T.let(surrounding_method, T.nilable(String))
     end
 
     sig { returns(String) }
     def fully_qualified_name
       @fully_qualified_name ||= T.let(@nesting.join("::"), T.nilable(String))
     end
+
+    sig { returns(T::Array[Symbol]) }
+    def locals_for_scope
+      locals = []
+
+      @nesting_nodes.each do |node|
+        if node.is_a?(Prism::ClassNode) || node.is_a?(Prism::ModuleNode) || node.is_a?(Prism::SingletonClassNode) ||
+            node.is_a?(Prism::DefNode)
+          locals.clear
+        end
+
+        locals.concat(node.locals)
+      end
+
+      locals
+    end
+
+    private
+
+    sig do
+      params(nodes: T::Array[T.any(
+        Prism::ClassNode,
+        Prism::ModuleNode,
+        Prism::SingletonClassNode,
+        Prism::DefNode,
+        Prism::BlockNode,
+        Prism::LambdaNode,
+        Prism::ProgramNode,
+      )]).returns([T::Array[String], T.nilable(String)])
+    end
+    def handle_nesting_nodes(nodes)
+      nesting = []
+      surrounding_method = T.let(nil, T.nilable(String))
+
+      @nesting_nodes.each do |node|
+        case node
+        when Prism::ClassNode, Prism::ModuleNode
+          nesting << node.constant_path.slice
+        when Prism::SingletonClassNode
+          nesting << "<Class:#{nesting.last}>"
+        when Prism::DefNode
+          surrounding_method = node.name.to_s
+          next unless node.receiver.is_a?(Prism::SelfNode)
+
+          nesting << "<Class:#{nesting.last}>"
+        end
+      end
+
+      [nesting, surrounding_method]
+    end
   end
 end

lib/ruby_lsp/requests/completion_resolve.rb

@@ -38,6 +38,8 @@ def initialize(global_state, item)
 
       sig { override.returns(T::Hash[Symbol, T.untyped]) }
       def perform
+        return @item if @item.dig(:data, :skip_resolve)
+
         # Based on the spec https://microsoft.github.io/language-server-protocol/specification#textDocument_completion,
         # a completion resolve request must always return the original completion item without modifying ANY fields
         # other than detail and documentation (NOT labelDetails). If we modify anything, the completion behaviour might

test/requests/completion_test.rb

@@ -1076,6 +1076,61 @@ def do_something
     end
   end
 
+  def test_completion_for_locals
+    source = +<<~RUBY
+      class Child
+        abc0 = 42
+
+        def do_something(abc1, abc2, abc3)
+          a
+
+          [].each do |abc4, abc5|
+            a
+          end
+        end
+
+        a
+      end
+
+      abc = 12
+      a
+    RUBY
+
+    with_server(source, stub_no_typechecker: true) do |server, uri|
+      server.process_message(id: 1, method: "textDocument/completion", params: {
+        textDocument: { uri: uri },
+        position: { line: 4, character: 5 },
+      })
+
+      result = server.pop_response.response
+      assert_equal(["abc1", "abc2", "abc3"], result.map(&:label))
+
+      server.process_message(id: 1, method: "textDocument/completion", params: {
+        textDocument: { uri: uri },
+        position: { line: 7, character: 7 },
+      })
+
+      result = server.pop_response.response
+      assert_equal(["abc1", "abc2", "abc3", "abc4", "abc5"], result.map(&:label))
+
+      server.process_message(id: 1, method: "textDocument/completion", params: {
+        textDocument: { uri: uri },
+        position: { line: 11, character: 3 },
+      })
+
+      result = server.pop_response.response
+      assert_equal(["abc0"], result.map(&:label))
+
+      server.process_message(id: 1, method: "textDocument/completion", params: {
+        textDocument: { uri: uri },
+        position: { line: 15, character: 1 },
+      })
+
+      result = server.pop_response.response
+      assert_equal(["abc"], result.map(&:label))
+    end
+  end
+
   private
 
   def with_file_structure(server, &block)