parameter func should be able to return explicit parametric literal

[proppy]

It seems that attempting to return an explicit foreign parametric type literal from a parametric func:

import apfloat;

fn some_apfloat<F_EXP_SZ: u32, F_FRACTION_SZ: u32> () -> apfloat::APFloat<F_EXP_SZ, F_FRACTION_SZ> {
  apfloat::APFloat<F_EXP_SZ, F_FRACTION_SZ>{ sign: u1:1, bexp: uN[F_EXP_SZ]:2, fraction: uN[F_FRACTION_SZ]:3 }
}

currently trigger the following error:

0006:   apfloat::APFloat<F_EXP_SZ, F_FRACTION_SZ>{ sign: u1:1, bexp: uN[F_EXP_SZ]:2, fraction: uN[F_FRACTION_SZ]:3 }
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^ ParseError: Expected '(', got '{': Expected a '(' after parametrics for function invocation.

This can be worked around by introducing an intermediate type alias:

fn some_apfloat<F_EXP_SZ: u32, F_FRACTION_SZ: u32> () -> apfloat::APFloat<F_EXP_SZ, F_FRACTION_SZ> {
  type F = apfloat::APFloat<F_EXP_SZ, F_FRACTION_SZ>;
  F{ sign: u1:1, bexp: uN[F_EXP_SZ]:2, fraction: uN[F_FRACTION_SZ]:3 }
}

or dropping the type parameters from the literal altogether:

fn some_apfloat<F_EXP_SZ: u32, F_FRACTION_SZ: u32> () -> apfloat::APFloat<F_EXP_SZ, F_FRACTION_SZ> {
  apfloat::APFloat{ sign: u1:1, bexp: uN[F_EXP_SZ]:2, fraction: uN[F_FRACTION_SZ]:3 }
}