Special case conj

Co-authored-by: "Shashi Gowda" <gowda@mit.edu>
Co-authored-by: "Yingbo Ma" <mayingbo5@gmail.com>

Author: YingboMa

src/function_registration.jl

@@ -55,6 +55,7 @@ end
 # special cases
 Base.:^(x::Expression,y::T) where T <: Integer = Operation(Base.:^, Expression[x, y])
 Base.:^(x::Expression,y::T) where T <: Rational = Operation(Base.:^, Expression[x, y])
+Base.conj(x::Expression) = Operation(Base.conj, [x])
 Base.muladd(a::Expression, b::Expression, c::Expression) = a * b + c
 
 @register Base.getindex(x,i)

test/direct.jl

@@ -83,3 +83,4 @@ end
 test_worldage()
 
 @test muladd(x, y, z) == x * y + z
+@test_nowarn [x, y, z]'