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Conditional type breaks generic inference on jsx in 2.9 #24080
Description
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
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