tests/cases/compiler/nonexistentPropertyOnUnion.ts(2,7): error TS2339: Property 'toLowerCase' does not exist on type 'string | Promise<string>'.
  Property 'toLowerCase' does not exist on type 'Promise<string>'.


==== tests/cases/compiler/nonexistentPropertyOnUnion.ts (1 errors) ====
    function f(x: string | Promise<string>) {
        x.toLowerCase();
          ~~~~~~~~~~~
!!! error TS2339: Property 'toLowerCase' does not exist on type 'string | Promise<string>'.
!!! error TS2339:   Property 'toLowerCase' does not exist on type 'Promise<string>'.
    }
    