src/vs/workbench/contrib/tasks/browser/terminalTaskSystem.ts/TerminalTaskSystem/collectDefinitionVariables
class TerminalTaskSystem:	private collectDefinitionVariables(variables: Set<string>, definition: any): void {
		if (Types.isString(definition)) {
			this.collectVariables(variables, definition);
		} else if (Types.isArray(definition)) {
			definition.forEach((element: any) => this.collectDefinitionVariables(variables, element));
		} else if (Types.isObject(definition)) {
			for (const key in definition) {
				this.collectDefinitionVariables(variables, definition[key]);
			}
		}
	}