Wrong type inferred for closure when returned from function

[veddan]

fn make_adder(x: int) -> @fn(int) -> int { |y| x + y }

The above function gives a compile error:
mismatched types: expected @fn(int) -> int but found &fn(int) -> int (expected @ closure, found & closure)

If I change the expression syntax into an explicit return:

fn make_adder(x: int) -> @fn(int) -> int { return |y| x + y; }

the code compiler (and runs) without error.

[catamorphism]

Re-nominating for milestone 5 (production-ready).

[emberian]

Fixed; can be closed pending #8209

[graydon]

accepted for production-ready milestone