feat: copyto! compile (#937)

Author: avik-pal

src/ConcreteRArray.jl

@@ -381,6 +381,19 @@ function Base.copyto!(dest::AbstractConcreteArray, src::AbstractConcreteArray)
     return dest
 end
 
+function mycopyto!(dest, src)
+    dest .= src # use broadcasting instead of copyto!
+    return nothing
+end
+
+function Base.copyto!(
+    dest::Union{AnyConcreteIFRTArray,AnyConcretePJRTArray}, src::AbstractConcreteArray
+)
+    fn = compile(mycopyto!, (dest, src))
+    fn(dest, src)
+    return dest
+end
+
 for aType in (:ConcretePJRTArray, :ConcreteIFRTArray)
     @eval begin
         function Base.copyto!(

test/basic.jl

@@ -1006,3 +1006,11 @@ mulpi(x) = π * x
     y = @jit mulpi(x)
     @test all(Array(y) .≈ π)
 end
+
+@testset "copyto! ConcreteArray" begin
+    x_ra = Reactant.to_rarray(ones(4, 4))
+    y_ra = Reactant.to_rarray(zeros(2, 2))
+    copyto!(view(x_ra, 1:2, 1:2), y_ra)
+    @test Array(x_ra) ==
+        [0.0 0.0 1.0 1.0; 0.0 0.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0]
+end