Fix construction of interval when mixing real and complex arguments (#611)

With the update it treats the real argument as having imaginary part
zero. The previous behaviour was to only consider the imaginary part
of the complex argument.

Author: Joel-Dahne

Diff for: src/intervals/construction.jl

@@ -481,9 +481,9 @@ end
 _interval_infsup(::Type{T}, a::Complex, b::Complex, d::Decoration = com) where {T<:NumTypes} =
     complex(_interval_infsup(T, real(a), real(b), d), _interval_infsup(T, imag(a), imag(b), d))
 _interval_infsup(::Type{T}, a::Complex, b, d::Decoration = com) where {T<:NumTypes} =
-    complex(_interval_infsup(T, real(a), b, d), _interval_infsup(T, imag(a), imag(a), d))
+    complex(_interval_infsup(T, real(a), real(b), d), _interval_infsup(T, imag(a), imag(b), d))
 _interval_infsup(::Type{T}, a, b::Complex, d::Decoration = com) where {T<:NumTypes} =
-    complex(_interval_infsup(T, a, real(b), d), _interval_infsup(T, imag(b), imag(b), d))
+    complex(_interval_infsup(T, real(a), real(b), d), _interval_infsup(T, imag(a), imag(b), d))
 
 # midpoint constructors
 

Diff for: test/interval_tests/complex.jl

@@ -20,6 +20,9 @@
     @test isequal_interval(intersect_interval(c, hull(a, b)), complex(interval(0, 3), interval(1, 2)))
     @test isempty_interval(intersect_interval(a, b))
     @test isdisjoint_interval(a, b)
+
+    @test isequal_interval(interval(-1 - im, 0), interval(-1 - im, 0 + 0im))
+    @test isequal_interval(interval(0, 1 + im), interval(0 + 0im, 1 + im))
 end
 
 @testset "Inverse roots of unity" begin