InexactError() when checking if Float StepRange contains NaNs

[daschw]

julia> versioninfo()
Julia Version 0.6.2
Commit d386e40 (2017-12-13 18:08 UTC)
Platform Info:
  OS: Linux (x86_64-pc-linux-gnu)
  CPU: Intel(R) Core(TM) i5-6200U CPU @ 2.30GHz
  WORD_SIZE: 64
  BLAS: libopenblas (DYNAMIC_ARCH NO_AFFINITY Haswell)
  LAPACK: libopenblas
  LIBM: libm
  LLVM: libLLVM-3.9.1 (ORCJIT, skylake)

julia> Inf in 1:10
false

julia> NaN in 1:10
false

julia> Inf in 1.0:10.0
ERROR: InexactError()
Stacktrace:
 [1] in(::Float64, ::StepRangeLen{Float64,Base.TwicePrecision{Float64},Base.TwicePrecision{Float64}}) at ./range.jl:865
 [2] macro expansion at /home/dani/.julia/v0.6/Revise/src/Revise.jl:775 [inlined]
 [3] (::Revise.##17#18{Base.REPL.REPLBackend})() at ./event.jl:73

julia> NaN in 1.0:10.0
ERROR: InexactError()
Stacktrace:
 [1] in(::Float64, ::StepRangeLen{Float64,Base.TwicePrecision{Float64},Base.TwicePrecision{Float64}}) at ./range.jl:865
 [2] macro expansion at /home/dani/.julia/v0.6/Revise/src/Revise.jl:775 [inlined]
 [3] (::Revise.##17#18{Base.REPL.REPLBackend})() at ./event.jl:73