stack! macro cannot deal with matrix size in some situation

[kazuki0824]

stack! macro sometimes fails to create block matrices in the situation where

1. one of the input matrices is statically sized with generics
2. horizontal stack + row size bound with generics

use nalgebra::{stack, Const, DMatrix, DVector, Dyn, OMatrix, SMatrix, SVector};

fn calc<const D: usize>() -> OMatrix<f64, Const<{ D }>, Dyn> {
    let mat_a: SMatrix<f64, D, D> = SMatrix::from_element(1.0);
    let mat_b: SVector<f64, D> = SVector::from_element(1.0);

    let ret = stack![mat_a, mat_b];
    ret
}

fn calc_dyn1<const D: usize>() -> OMatrix<f64, Const<{ D }>, Dyn> {
    let mat_a: SMatrix<f64, D, D> = SMatrix::from_element(1.0);
    let mat_b: DVector<f64> = DVector::from_element(D, 1.0);

    let ret = stack![mat_a, mat_b];
    ret
}

fn calc_dyn2<const D: usize>() -> OMatrix<f64, Const<{ D }>, Dyn> {
    let mat_a: SMatrix<f64, D, D> = SMatrix::from_element(1.0);
    let mat_b: DVector<f64> = DVector::from_element(D, 1.0);

    let ret = stack![mat_b, mat_a];
    ret
}

fn calc_dyn3<const D: usize>() -> OMatrix<f64, Const<{ D }>, Dyn> {
    let mat_a = DMatrix::from_element(D, D, 1.0);
    let mat_b: SVector<f64, D> = SVector::from_element(1.0);

    let ret = stack![mat_a, mat_b];
    ret
}


fn main() {
    println!("Hello, world!");
    println!("{}", calc::<3>());        // invalid
    println!("{}", calc_dyn1::<3>());   // invalid
    println!("{}", calc_dyn2::<3>());   // invalid
    println!("{}", calc_dyn3::<3>());   // valid
}