regression in codegen of array constructors

[JeffBezanson]

julia> @code_typed ones(1)
1-element Array{Any,1}:
 :($(Expr(:lambda, Any[symbol("#self#"),:(dims::Any...)], Any[Any[Any[symbol("#self#"),Base.#ones,0],Any[:dims,Tuple{Int64},0]],Any[],Any[Any]], :(begin  # array.jl, line 169: # boot.jl, line 345: # boot.jl, line 331:
        GenSym(0) = (Core.convert)(Core.Int,(top(getfield))(dims::Tuple{Int64},1)::Int64)
        return (Base.fill!)((top(ccall))(:jl_alloc_array_1d,(top(apply_type))(Core.Array,Float64,1)::Type{Array{Float64,1}},(top(svec))(Core.Any,Core.Int)::SimpleVector,Array{Float64,1},0,(top(unsafe_convert))(Core.Int,GenSym(0))::Int64,GenSym(0))::Array{Float64,1},(Base.box)(Float64,(Base.sitofp)(Float64,1)))::Array{Float64,1}
    end::Array{Float64,1}))))

Although we infer the type OK, there is still a call to Core.convert and we generate a call to jl_apply_generic. Most likely a bootstrap artifact due to moving some array constructors to Core.

[mbauman]

Looks like I just need to rebase #14441.

[vtjnash]

I suspect this is because Inference is prohibited from inferring code in Core (unless it has sparams). as such, the following works around the issue. afaict, there is no downside either?

diff --git a/base/boot.jl b/base/boot.jl
index d60941b..cb8e21f 100644
--- a/base/boot.jl
+++ b/base/boot.jl
@@ -322,7 +322,7 @@ Task(f::ANY) = ccall(:jl_new_task, Any, (Any, Int), f, 0)::Task
 # so the methods and ccall's in Core aren't permitted to use convert
 convert(::Type{Any}, x::ANY) = x
 convert{T}(::Type{T}, x::T) = x
-cconvert(T::Type, x) = convert(T, x)
+cconvert{T}(::Type{T}, x) = convert(T, x)
 unsafe_convert{T}(::Type{T}, x::T) = x

 # primitive array constructors