No excess properties error on function return type

[mgiedrius]

TypeScript Version: Nightly, 3.7.5

Search Terms: excess property, computed property

Code

const a = <T>(shape: T | (() => T)): T => {
    return shape instanceof Function ? shape() : shape;
}
        
//Case 1
a<{ x: string }>(() => ({ x: '', o: '' })); // I expect this to fail

//Case 2
a<{ x: string }>({ x: '', o: '' }); // Fails as expected

Expected behavior:
I expect Case 1 to show error similar to Case 2 because returned object contains more properties than described in generic type.

Actual behavior:
Case 1 is a valid typescript

Playground Link: Playground Link

[IllusionMH]

Duplicate of #12632 which requires #241

(Sorry if couple of comments were posted - GH had issues with API)

[typescript-bot]

This issue has been marked as a 'Duplicate' and has seen no recent activity. It has been automatically closed for house-keeping purposes.