gistfile1.txt

> bill = { name = "Gates", age = 57 }
{ name = "Gates", age = 57 } : { age : number, name : String }
> { bill | test = "123" }
-- TYPE MISMATCH --------------------------------------------- repl-temp-000.elm

`bill` is being used in an unexpected way.

4|   { bill | test = "123" }
       ^^^^
Based on its definition, `bill` has this type:

    { age : ..., name : ... }

But you are trying to use it as:

    { b | test : ... }

Hint: The record fields do not match up. One has age and name. The other has
test.