Backtrace: comparison errors report line containing first error statement in function

[timholy]

function testline()
    strdata = "Hi there".data
    if isempty(strdata)
        error("It's empty")
    end
    if strdata[1:5] == "Hello"
        println("Makes no sense")
    end
end

julia> load("linenumber.jl")

julia> testline()
Not defined. Try .== or isequal.
 in testline at /tmp/linenumber.jl:4  # should be 6

If you comment out the if isempty block, then the line number for the error is correct.

It doesn't depend on referencing, as this too gets the line number wrong:

function testline()
    strdata = "Hi there".data
    if isempty(strdata)
        error("It's empty")
    end
    if strdata == 6
        println("Makes no sense")
    end
end

However, this doesn't:

function testline()
    strdata = "Hi there".data
    if isempty(strdata)
        error("It's empty")
    end
    foo(strdata)
end

With a few further tests I concluded that it seems to report the line number of the first error statement in the function.

[JeffBezanson]

Wow, then the problem in #922 is worse than I thought. LLVM will merge two calls to error even when they have different arguments. The problem goes away if CFGSimplificationPass is disabled.

[JeffBezanson]

Fortunately, adding a superfluous second argument continues to successfully game the system.

[timholy]

Game away! Many thanks.