@mihailik noted in #6932 that ECMA web site

12.2.6 Object Initializer
NOTE 1 An object initializer is an expression describing the initialization of an Object, written in a form resembling a literal. It is a list of zero or more pairs of property keys and associated values, enclosed in curly brackets. The values need not be literals; they are evaluated each time the object initializer is evaluated.

https://github.com/Microsoft/TypeScript/blob/331d26f40271c7a21c6fa74ffac633b45f653dda/src/compiler/checker.ts#L7284
Should probably be revisited:

       // This is motivated by ECMA-262 sections 9.3.1, 9.8.1, 11.1.5, and 11.2.1.