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noImplicitAny reports incorrect error? #8546
Description
TypeScript Version:
1.8.10
Code
This code uses the React type definitions via tsd install react-global
Unfortunately I could not reproduce the problem in a simpler setting, such as using a plain base class, without React and TSX.
class Control extends React.Component<any, any> {
render() {
return <button onClick={() => buttonClicked(Control)}>Button</button>;
}
}
function buttonClicked(controlType: typeof React.Component) {
}It is compiled using a tsconfig.json file:
{
"compilerOptions": {
"noImplicitAny": true,
"jsx": "react"
}
}Expected behavior:
No compile errors.
Actual behavior:
Error TS7023: 'render' implicitly has return type 'any' because it does not have a return type annotation and is referenced directly or indirectly in one of its return expressions.
The problem does not happen if the onClick callback is given through an intermediary variable, instead of being inlined.
Activity
mhegazy commentedon May 10, 2016
The compiler tries to figure out the return types of functions from the type of their return expressions. this can depend on figuring out other types. sometimes that could lead to cycles; the compiler breaks these by giving the type
any. this can be solved by adding an explicit type annotation, something likerender(): JSX.Element { .. }.Please see my reply to a similar issue in #1146 (comment)