# Revise 3.13 FieldError

**URL:** <https://discourse.julialang.org/t/revise-3-13-fielderror/135451>\
**Category:** General Usage\
**Tags:** question\
**Created:** [February 4, 2026, 3:24pm UTC](https://discourse.julialang.org/t/revise-3-13-fielderror/135451 "2026-02-04T15:24:48Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![hendri54](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/hendri54/32/9621_2.png) [@hendri54](https://discourse.julialang.org/u/hendri54)\
**Post date:** [February 4, 2026, 3:24pm UTC](https://discourse.julialang.org/t/revise-3-13-fielderror/135451/1 "2026-02-04T15:24:48Z")

</div>

Since updating to Julia 1.12 and Revise 3.13 I have been getting errors that look like this:

```julia-auto
julia> mdl.check_comparison(cmp1)
┌ Error: Failed to revise /Users/lutz/Documents/projects/p2022/mismatch/MismatchMM/src/comparison_check.jl
│ exception =
│ FieldError: type Base.MethodList has no field `mt`, available fields: `ms`, `tn`
│ Stacktrace:
│ [1] top-level scope
│ @ ~/Documents/projects/p2022/mismatch/MismatchMM/src/comparison_check.jl:1
│ Revise evaluation error at /Users/lutz/Documents/projects/p2022/mismatch/MismatchMM/src/comparison_check.jl:1
│
└ @ Revise ~/.julia/packages/Revise/b0dDX/src/packagedef.jl:898

```

The message always contains

```julia-auto
exception =
│ FieldError: type Base.MethodList has no field `mt`, available fields: `ms`

```

The code sometimes runs. At other times, it fails because some `UndefVarError` gets thrown, telling me that a function does not exist (even though it does).  
Restarting the Julia session clears the error and the code runs (for a while).  
Other than downgrading to Julia 1.11, do I have good options?