Translation request for 1268

[yarongon]

Error Text

An index signature parameter type must be 'string', 'number', 'symbol', or a template literal type.

Supporting Information

Please provide other information that led to this error and any specific questions you have about it: Here's a minimal example:

type MyType = {
    a: string
}

let mapMyTypeToNum: { [key: MyType]: number} = {}