Remove some unnecessary real specializations for structured matrices (#56083)

The `real(::AbstractArray{<:Rea})` fallback method should handle these
cases correctly.

Author: jishnub

stdlib/LinearAlgebra/src/hessenberg.jl

@@ -70,7 +70,6 @@ Base.dataids(A::UpperHessenberg) = Base.dataids(parent(A))
 Base.unaliascopy(A::UpperHessenberg) = UpperHessenberg(Base.unaliascopy(parent(A)))
 
 copy(H::UpperHessenberg) = UpperHessenberg(copy(H.data))
-real(H::UpperHessenberg{<:Real}) = H
 real(H::UpperHessenberg{<:Complex}) = UpperHessenberg(triu!(real(H.data),-1))
 imag(H::UpperHessenberg) = UpperHessenberg(triu!(imag(H.data),-1))
 

stdlib/LinearAlgebra/src/triangular.jl

@@ -45,7 +45,6 @@ for t in (:LowerTriangular, :UnitLowerTriangular, :UpperTriangular, :UnitUpperTr
         copy(A::$t) = $t(copy(A.data))
         Base.unaliascopy(A::$t) = $t(Base.unaliascopy(A.data))
 
-        real(A::$t{<:Real}) = A
         real(A::$t{<:Complex}) = (B = real(A.data); $t(B))
         real(A::$t{<:Complex, <:StridedMaybeAdjOrTransMat}) = $t(real.(A))
     end