src/vs/workbench/services/configuration/common/configurationEditingService.ts/ConfigurationEditingService/toErrorMessage
class ConfigurationEditingService:	private toErrorMessage(error: ConfigurationEditingErrorCode, target: EditableConfigurationTarget, operation: IConfigurationEditOperation): string {
		switch (error) {

			// API constraints
			case ConfigurationEditingErrorCode.ERROR_UNKNOWN_KEY: return nls.localize('errorUnknownKey', "Unable to write to {0} because {1} is not a registered configuration.", this.stringifyTarget(target), operation.key);
			case ConfigurationEditingErrorCode.ERROR_INVALID_WORKSPACE_CONFIGURATION_APPLICATION: return nls.localize('errorInvalidWorkspaceConfigurationApplication', "Unable to write {0} to Workspace Settings. This setting can be written only into User settings.", operation.key);
			case ConfigurationEditingErrorCode.ERROR_INVALID_WORKSPACE_CONFIGURATION_MACHINE: return nls.localize('errorInvalidWorkspaceConfigurationMachine', "Unable to write {0} to Workspace Settings. This setting can be written only into User settings.", operation.key);
			case ConfigurationEditingErrorCode.ERROR_INVALID_FOLDER_CONFIGURATION: return nls.localize('errorInvalidFolderConfiguration', "Unable to write to Folder Settings because {0} does not support the folder resource scope.", operation.key);
			case ConfigurationEditingErrorCode.ERROR_INVALID_USER_TARGET: return nls.localize('errorInvalidUserTarget', "Unable to write to User Settings because {0} does not support for global scope.", operation.key);
			case ConfigurationEditingErrorCode.ERROR_INVALID_WORKSPACE_TARGET: return nls.localize('errorInvalidWorkspaceTarget', "Unable to write to Workspace Settings because {0} does not support for workspace scope in a multi folder workspace.", operation.key);
			case ConfigurationEditingErrorCode.ERROR_INVALID_FOLDER_TARGET: return nls.localize('errorInvalidFolderTarget', "Unable to write to Folder Settings because no resource is provided.");
			case ConfigurationEditingErrorCode.ERROR_INVALID_RESOURCE_LANGUAGE_CONFIGURATION: return nls.localize('errorInvalidResourceLanguageConfiguration', "Unable to write to Language Settings because {0} is not a resource language setting.", operation.key);
			case ConfigurationEditingErrorCode.ERROR_NO_WORKSPACE_OPENED: return nls.localize('errorNoWorkspaceOpened', "Unable to write to {0} because no workspace is opened. Please open a workspace first and try again.", this.stringifyTarget(target));

			// User issues
			case ConfigurationEditingErrorCode.ERROR_INVALID_CONFIGURATION: {
				if (operation.workspaceStandAloneConfigurationKey === TASKS_CONFIGURATION_KEY) {
					return nls.localize('errorInvalidTaskConfiguration', "Unable to write into the tasks configuration file. Please open it to correct errors/warnings in it and try again.");
				}
				if (operation.workspaceStandAloneConfigurationKey === LAUNCH_CONFIGURATION_KEY) {
					return nls.localize('errorInvalidLaunchConfiguration', "Unable to write into the launch configuration file. Please open it to correct errors/warnings in it and try again.");
				}
				switch (target) {
					case EditableConfigurationTarget.USER_LOCAL:
						return nls.localize('errorInvalidConfiguration', "Unable to write into user settings. Please open the user settings to correct errors/warnings in it and try again.");
					case EditableConfigurationTarget.USER_REMOTE:
						return nls.localize('errorInvalidRemoteConfiguration', "Unable to write into remote user settings. Please open the remote user settings to correct errors/warnings in it and try again.");
					case EditableConfigurationTarget.WORKSPACE:
						return nls.localize('errorInvalidConfigurationWorkspace', "Unable to write into workspace settings. Please open the workspace settings to correct errors/warnings in the file and try again.");
					case EditableConfigurationTarget.WORKSPACE_FOLDER: {
						let workspaceFolderName: string = '<<unknown>>';
						if (operation.resource) {
							const folder = this.contextService.getWorkspaceFolder(operation.resource);
							if (folder) {
								workspaceFolderName = folder.name;
							}
						}
						return nls.localize('errorInvalidConfigurationFolder', "Unable to write into folder settings. Please open the '{0}' folder settings to correct errors/warnings in it and try again.", workspaceFolderName);
					}
					default:
						return '';
				}
			}
			case ConfigurationEditingErrorCode.ERROR_CONFIGURATION_FILE_DIRTY: {
				if (operation.workspaceStandAloneConfigurationKey === TASKS_CONFIGURATION_KEY) {
					return nls.localize('errorTasksConfigurationFileDirty', "Unable to write into tasks configuration file because the file has unsaved changes. Please save it first and then try again.");
				}
				if (operation.workspaceStandAloneConfigurationKey === LAUNCH_CONFIGURATION_KEY) {
					return nls.localize('errorLaunchConfigurationFileDirty', "Unable to write into launch configuration file because the file has unsaved changes. Please save it first and then try again.");
				}
				switch (target) {
					case EditableConfigurationTarget.USER_LOCAL:
						return nls.localize('errorConfigurationFileDirty', "Unable to write into user settings because the file has unsaved changes. Please save the user settings file first and then try again.");
					case EditableConfigurationTarget.USER_REMOTE:
						return nls.localize('errorRemoteConfigurationFileDirty', "Unable to write into remote user settings because the file has unsaved changes. Please save the remote user settings file first and then try again.");
					case EditableConfigurationTarget.WORKSPACE:
						return nls.localize('errorConfigurationFileDirtyWorkspace', "Unable to write into workspace settings because the file has unsaved changes. Please save the workspace settings file first and then try again.");
					case EditableConfigurationTarget.WORKSPACE_FOLDER: {
						let workspaceFolderName: string = '<<unknown>>';
						if (operation.resource) {
							const folder = this.contextService.getWorkspaceFolder(operation.resource);
							if (folder) {
								workspaceFolderName = folder.name;
							}
						}
						return nls.localize('errorConfigurationFileDirtyFolder', "Unable to write into folder settings because the file has unsaved changes. Please save the '{0}' folder settings file first and then try again.", workspaceFolderName);
					}
					default:
						return '';
				}
			}
			case ConfigurationEditingErrorCode.ERROR_CONFIGURATION_FILE_MODIFIED_SINCE:
				if (operation.workspaceStandAloneConfigurationKey === TASKS_CONFIGURATION_KEY) {
					return nls.localize('errorTasksConfigurationFileModifiedSince', "Unable to write into tasks configuration file because the content of the file is newer.");
				}
				if (operation.workspaceStandAloneConfigurationKey === LAUNCH_CONFIGURATION_KEY) {
					return nls.localize('errorLaunchConfigurationFileModifiedSince', "Unable to write into launch configuration file because the content of the file is newer.");
				}
				switch (target) {
					case EditableConfigurationTarget.USER_LOCAL:
						return nls.localize('errorConfigurationFileModifiedSince', "Unable to write into user settings because the content of the file is newer.");
					case EditableConfigurationTarget.USER_REMOTE:
						return nls.localize('errorRemoteConfigurationFileModifiedSince', "Unable to write into remote user settings because the content of the file is newer.");
					case EditableConfigurationTarget.WORKSPACE:
						return nls.localize('errorConfigurationFileModifiedSinceWorkspace', "Unable to write into workspace settings because the content of the file is newer.");
					case EditableConfigurationTarget.WORKSPACE_FOLDER:
						return nls.localize('errorConfigurationFileModifiedSinceFolder', "Unable to write into folder settings because the content of the file is newer.");
				}
			case ConfigurationEditingErrorCode.ERROR_INTERNAL: return nls.localize('errorUnknown', "Unable to write to {0} because of an internal error.", this.stringifyTarget(target));
		}
	}