Description
TypeScript Version: 2.4
Code
Example 0
ERROR: error TS2536: Type '"prop"' cannot be used to index type 'T'.
ERROR: error TS2339: Property 'prop' does not exist on type 'T'.
/**
* Example 0
* @class GenericClass
* @template T
*/
class GenericClass<T extends { prop: string }> { // Doesn't work
public insert(arg: T): T['prop'] {
return arg.prop;
}
}Example 1
Works fine
/**
* Example 1
* @class OtherGenericClass
*/
class OtherGenericClass<T extends { prop: string }> { // Works
public insert(arg: T): T['prop'] {
return arg.prop;
}
}Example 2
ERROR: error TS2536: Type '"prop"' cannot be used to index type 'T'.
ERROR: error TS2339: Property 'prop' does not exist on type 'T'.
/**
* Example 2
* @template T
* @param {T} arg
* @returns {T['prop']}
*/
function myFunc<T extends { prop: string }> (arg: T): T['prop'] { // Doesn't work
return arg.prop;
}Example 3
Works fine
/**
* Example 3
* @param {R} arg
* @returns {R['prop']}
*/
function myOtherFunc<R extends { prop: string }> (arg: R): R['prop'] { // Works
return arg.prop;
}Expected behavior:
Template declaration in JSDoc comments should not supersede the in-code template declarations.
Actual behavior:
In example 0 and 2 above, the generic type T is not found to properly extend { prop: string } when the JSDoc comment exists presumably because the JSDoc comment supersedes the type defined inline. This should never be the case where a non-code element takes precedence over the code contents.