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3.5 regression: return type forced more restrictive than needed
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**TypeScript Version:** 3.5.0-dev.20190508
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**Search Terms:** restrictive return type
**Code**
```ts
class Box<A> {
constructor(public val: A) {}
}
interface ContainerFor<A> {
array: Array<A>;
box: Box<A>;
}
function single<T extends keyof ContainerFor<number>>(t: T, x: number): ContainerFor<number>[T] {
switch (t) {
case "array":
return new Array<number>(x);
case "box":
return new Box<number>(x);
}
return new Box<number>(0); // this should not be needed
}
function test() {
let t1 = single("array", 42);
let t2 = single("box", 42);
//let t3 = single("boo", 42);
}
```
**Expected behavior:**
This code worked with 3.4, but had an unsoundness bug in that `single` was allowed to return the wrong type (swap array and box). It was clear that switching over `t` did not increase knowledge about the expected output type and I was forced to have a fallback return which is of course unreachable. But the code itself worked.
The `test` function also shows things work as expected. The types for `t1` and `t2` are inferred correctly and asking for an unknown thing ("boo") is reported as an error.
I would expect this to still work in 3.5, perhaps fixing one of the issues I'm having in the internals of `si…
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