Conditional type breaks generic inference on jsx in 2.9

[Kukkimonsuta]

In code below constructing generic jsx element el1 works in 2.8.3, but breaks on 2.9.0-dev.20180512. Constructing el2 in 2.9.0-dev.20180512 works fine - shouldn't these be completely equivalent?

TypeScript Version: 2.9.0-dev.20180512

Search Terms: jsx conditional

Code

type FunctionPropertyNames<T> = { [K in keyof T]: T[K] extends Function ? K : never }[keyof T];
class TestObject {
 a: string = '';
 b: number = 1;
 c: () => void = () => { };
}
interface TestProps<T> {
 model: T;
 foo: FunctionPropertyNames<T>;
}
function Test<T>(props: TestProps<T>) { return <></>; }
const model = new TestObject();

const el1 = <Test model={model} foo="c" />;
const el2 = <Test<TestObject> model={model} foo="c" />;

Expected behavior:
Compilation passes without errors.

Actual behavior:

test.tsx:14:33 - error TS2326: Types of property 'foo' are incompatible.
 Type 'string' is not assignable to type '"c"'.

14 const el1 = <Test model={model} foo="c" />;
 ~~~~~~~

Playground Link:
n/a since playground doesn't support jsx

Related Issues:
Possibly related to #23724