Can't compute eigenvalues of Hermitian Diagonal matrix for generic types

[araujoms]

As the title says, the following code fails:

using LinearAlgebra
using GenericLinearAlgebra
m = Hermitian(Diagonal(randn(BigFloat,2)))
eigvals(m)

This is not related to BigFloat, it also fails for Double64 and Float128. I think the underlying issue is the same as JuliaLang/LinearAlgebra.jl#1056, the lack of a universal fallback.

To make life even stranger, after GenericLinearAlgebra is loaded this code starts failing even for Float64. That is,

using LinearAlgebra
m = Hermitian(Diagonal(randn(Float64,2)))
eigvals(m)

works fine, but

using LinearAlgebra
using GenericLinearAlgebra
m = Hermitian(Diagonal(randn(Float64,2)))
eigvals(m)

fails.

I had previously reported this issue under JuliaLang/LinearAlgebra.jl#1070 under the misconception that GenericLinearAlgebra was a standard library, but @aravindh-krishnamoorthy noted that it isn't, and this issue is not caused by LinearAlgebra.

[andreasnoack]

It should be fixed by #140. Longer term, it would probably be good to avoid the piracy somehow. On the other hand, it's pretty useful (when it doesn't break LinearAlgebra).