Inference not working as expected

[sledorze]

TypeScript Version: 1.9.0-dev.20160523-1.0

Code

// A self-contained demonstration of the problem follows...

class Foo {

  identity<T>(x: T): T {
    return x
  }

  compose<A, B, C>(f: (b: B) => C, g: (a: A) => B) : (a:A) => C {
    return (a: A) => f(g(a))
  }

  constructor()  {
    let value = this.compose((a : number) => a, this.identity)
  }
}

Expected behavior:

value should have type (a: number) => number
OR
it should issue an error as the tsconfig.json has "noImplicitAny" defined to true.

Actual behavior:

value has type (a: {}) => number
AND
no error from the compiler.

[mhegazy]

duplicate of #5254

[sledorze]

@mhegazy why has it been closed? I see that the duplicate issue is still open..

[mhegazy]

why has it been closed? I see that the duplicate issue is still open..

We like to keep on report to track an issue. no need to have multiple open reports. Duplicate reports are closed with a link to the main report.

[sledorze]

thanks @mhegazy for the clarification, I understand your need to reduce the 'noise' :)