In Julia v1.3.0, macros @less and @which don’t seem to work as expected when applied to methods from the standard library:
# This works
@which sin(1)
sin(x::Real) in Base.Math at special/trig.jl:53
# This doesn't
using Dates
@which Date(2019)
Date(y::Int64) in Dates at /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.3/Dates/src/types.jl:222
@less Date(2019)
/buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.3/Dates/src/types.jl: No such file or directory
ERROR: failed process: Process(`less +222g /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.3/Dates/src/types.jl`, ProcessExited(1)) [1]
It seems that the path to the source file contains leftovers from the building process.