When in function argument, array of union produces different type error to when in instantiation of same type

[yseymour]

Mild title gore, sorry.

TypeScript Version: 3.2.0-dev.201xxxxx

Search Terms: array union type error

Code

type Foo = 'A' | 'B';
const foo_list: Foo[] = ['A', 'X'];  // Error: Type '"X"' is not assignable to type 'Foo'
declare function bar(x: Foo[]);
bar(['A', 'X']); // Error (x2): Type 'string' is not assignable to type 'Foo'

Expected behavior:
Same error on line 4 as on line 2

Actual behavior:
All elements of the array are highlighted as errors instead, making it difficult to spot which one is wrong.

Playground Link: http://www.typescriptlang.org/play/#src=type%20Foo%20%3D%20'A'%20%7C%20'B'%3B%0Aconst%20foo_list%3A%20Foo%5B%5D%20%3D%20%5B'A'%2C%20'X'%5D%3B%0Adeclare%20function%20bar(x%3A%20Foo%5B%5D)%3B%0Abar(%5B'A'%2C%20'X'%5D)%3B%0A

Related Issues: Probably #26077 or one of its constituents

[yseymour]

This is a bit old, but I'm happy to report it appears to be fixed.