Add global fallback when lookup fails to find anything in scope chain

Co-authored-by: kwerle <23320+kwerle@users.noreply.github.com>

Author: Copilot

lib/ruby_language_server/project_manager.rb

@@ -280,6 +280,17 @@ def project_definitions_for(name, parent_scopes = [], class_method_filter = nil)
           # Move up to parent scope
           current_scope = current_scope.parent
         end
+        
+        # Fallback: if nothing found in scope chain, search globally
+        if results.empty?
+          all_scopes = RubyLanguageServer::ScopeData::Scope.where(name: name)
+          all_scopes = all_scopes.where(class_method: class_method_filter) unless class_method_filter.nil?
+          results.concat(all_scopes.to_a)
+
+          # Also search for constants/variables globally
+          all_variables = RubyLanguageServer::ScopeData::Variable.where(name: name)
+          results.concat(all_variables.to_a)
+        end
       end
 
       # Return locations for all matching scopes and variables

spec/lib/ruby_language_server/project_manager_spec.rb

@@ -467,5 +467,98 @@ class Baz
         assert_equal 0, results.first[:range][:start][:line]
       end
     end
+
+    describe 'global fallback when not found in scope' do
+      it 'finds constants defined elsewhere when not in local scope' do
+        # Define a class in one file
+        external_file = <<~CODE_FILE
+          class ExternalClass
+            def external_method
+            end
+          end
+        CODE_FILE
+
+        # Reference it from another file in a different scope
+        reference_file = <<~CODE_FILE
+          module MyModule
+            class MyClass
+              def my_method
+                ExternalClass # Not in local scope but exists globally
+              end
+            end
+          end
+        CODE_FILE
+
+        project_manager.update_document_content('external_uri', external_file)
+        project_manager.tags_for_uri('external_uri') # Force load
+
+        project_manager.update_document_content('reference_uri', reference_file)
+        project_manager.tags_for_uri('reference_uri') # Force load
+
+        # Position on "ExternalClass" (line 3, character 8)
+        position = OpenStruct.new(line: 3, character: 8)
+        results = project_manager.possible_definitions('reference_uri', position)
+
+        # Should find the class via global fallback
+        assert_equal 1, results.length
+        assert_equal 'external_uri', results.first[:uri]
+        assert_equal 0, results.first[:range][:start][:line]
+      end
+
+      it 'finds methods defined elsewhere when not in local scope' do
+        # Define a class with a method in one file
+        external_file = <<~CODE_FILE
+          class MyExternalClass
+            def my_external_method
+            end
+          end
+        CODE_FILE
+
+        # Reference the method from another scope
+        reference_file = <<~CODE_FILE
+          module DifferentModule
+            class DifferentClass
+              def some_method
+                # Call method that's not in local scope
+              end
+            end
+          end
+        CODE_FILE
+
+        project_manager.update_document_content('external_uri', external_file)
+        project_manager.tags_for_uri('external_uri')
+
+        project_manager.update_document_content('reference_uri', reference_file)
+        project_manager.tags_for_uri('reference_uri')
+
+        # Note: Testing method fallback would require context parsing
+        # For now, just verify constant fallback doesn't break method lookup
+        position = OpenStruct.new(line: 3, character: 8)
+        results = project_manager.possible_definitions('reference_uri', position)
+        assert_instance_of Array, results
+      end
+
+      it 'returns empty array when nothing exists anywhere' do
+        reference_file = <<~CODE_FILE
+          module MyModule
+            class MyClass
+              def my_method
+                CompletelyNonExistentClass
+              end
+            end
+          end
+        CODE_FILE
+
+        project_manager.update_document_content('reference_uri', reference_file)
+        project_manager.tags_for_uri('reference_uri')
+
+        # Position on "CompletelyNonExistentClass"
+        position = OpenStruct.new(line: 3, character: 8)
+        results = project_manager.possible_definitions('reference_uri', position)
+
+        # Should return empty array as nothing exists
+        assert_equal [], results
+      end
+    end
   end
 end