Code locations of iteration with break are incorrect.

[bicycle1885]

I found Debugger.jl points to a wrong code location in the following example:

julia> @enter stringsearch("abra", "abra")
In stringsearch(a, b) at /home/kenta/workspace/JuliaInterpreter/bug.jl:1
 1  function stringsearch(a::String, b::String)
 2      found = true
>3      for i in eachindex(a)
 4          if a[i] != b[i]
 5              found = false
 6              break
 7          end

About to run: (eachindex)("abra")
1|debug> n
In stringsearch(a, b) at /home/kenta/workspace/JuliaInterpreter/bug.jl:1
 1  function stringsearch(a::String, b::String)
 2      found = true
 3      for i in eachindex(a)
>4          if a[i] != b[i]
 5              found = false
 6              break
 7          end
 8      end

About to run: (getindex)("abra", 1)
1|debug>
In stringsearch(a, b) at /home/kenta/workspace/JuliaInterpreter/bug.jl:1
  2      found = true
  3      for i in eachindex(a)
  4          if a[i] != b[i]
  5              found = false
> 6              break  <---- WRONG: it won't break since a[i] == b[i]
  7          end
  8      end
  9      return found
 10  end

About to run: (iterate)(Base.EachStringIndex{String}("abra"), 2)
1|debug>

This is because the current call frame misunderstand that the iteration comes from line 6, not line 3.

function stringsearch(a::String, b::String)
    found = true
    for i in eachindex(a)
        if a[i] != b[i]
            found = false
            break
        end
    end
    return found
end

using JuliaInterpreter
frame = JuliaInterpreter.enter_call(stringsearch, "abra", "abra")
show(IOContext(stdout, :limit => false), frame)

Frame for stringsearch(a::String, b::String) in Main at /home/kenta/workspace/JuliaInterpreter/bug.jl:1
   1 2  1 ─       found = true
   2 3  │   %2  = Base.eachindex(a)
   3 3  │         @_4 = Base.iterate(%2)
   4 3  │   %4  = @_4 === nothing
   5 3  │   %5  = ($(QuoteNode(Core.Intrinsics.not_int)))(%4)
   6 3  └──       goto #6 if not %5
   7 3  2 ┄ %7  = @_4
   8 3  │         i = Core.getfield(%7, 1)
   9 3  │   %9  = Core.getfield(%7, 2)
  10 4  │   %10 = Base.getindex(a, i)
  11 4  │   %11 = Base.getindex(b, i)
  12 4  │   %12 = %10 != %11
  13 4  └──       goto #4 if not %12
  14 5  3 ─       found = false
  15 6  └──       goto #6
  16 6  4 ─       @_4 = Base.iterate(%2, %9)  <---- This originates from line 3, not line 6.
  17 6  │   %17 = @_4 === nothing
  18 6  │   %18 = ($(QuoteNode(Core.Intrinsics.not_int)))(%17)
  19 6  └──       goto #6 if not %18
  20 6  5 ─       goto #2
  21 9  6 ┄       return found
a = "abra"
b = "abra"               _

[pfitzseb]

I'd argue this is an issue with Base inserting the wrong line number node for this function (and probably iteration in general):

julia> Base.uncompressed_ast(first(methods(stringsearch)))
CodeInfo(
    @ REPL[12]:2 within `stringsearch'
1 ─       found = true
│   @ REPL[12]:3 within `stringsearch'
│   %2  = Main.eachindex(a)
│         @_4 = Base.iterate(%2)
│   %4  = @_4 === nothing
│   %5  = Base.not_int(%4)
└──       goto #6 if not %5
2 ┄ %7  = @_4
│         i = Core.getfield(%7, 1)
│   %9  = Core.getfield(%7, 2)
│   @ REPL[12]:4 within `stringsearch'
│   %10 = Base.getindex(a, i)
│   %11 = Base.getindex(b, i)
│   %12 = %10 != %11
└──       goto #4 if not %12
    @ REPL[12]:5 within `stringsearch'
3 ─       found = false
│   @ REPL[12]:6 within `stringsearch'
└──       goto #6
4 ─       @_4 = Base.iterate(%2, %9)
│   %17 = @_4 === nothing
│   %18 = Base.not_int(%17)
└──       goto #6 if not %18
5 ─       goto #2
    @ REPL[12]:9 within `stringsearch'
6 ┄       return found
)

I don't think we can do anything about this here.

[bicycle1885]

Thank you. I'd keep this open until I open an issue upstream.

[simeonschaub]

Closed by JuliaLang/julia#41857