Simple Reduce Statement Fails to Compile Inside Module

The following code snippet runs just fine in Julia 1.2, unless it's put into a module.
```
module DebugModule

using ForceImport
@force using Reduce.Algebra
using ReduceLinAlg

f(a,b) = (:x - a) * (:x - b)
g(a,b) = int( f(a,b), :x)

# comment this out and the module loads, or simply copy and paste the code
# and it works
g0 = g(:a,:b) - sub( (:(x=b), ), g(:a,:b))

end # module
```
Now see what happens when I try to use this module.
```
julia> using DebugModule
[ Info: Recompiling stale cache file /home/matt/.julia/compiled/v1.2/DebugModule.ji for DebugModule [top-level]
ERROR: LoadError: Base.Meta.ParseError("invalid operator \"--\"")
Stacktrace:
[1] #parse#1(::Bool, ::Bool, ::Bool, ::typeof(Base.Meta.parse), ::String, ::Int64) at ./meta.jl:129
[2] #parse at ./tuple.jl:0 [inlined]
[3] #parse#4(::Bool, ::Bool, ::typeof(Base.Meta.parse), ::String) at ./meta.jl:160
[4] parse at ./meta.jl:160 [inlined]
[5] |>(::String, ::typeof(Base.Meta.parse)) at ./operators.jl:854
[6] #parse_expr#46(::Int64, ::typeof(Reduce.parse_expr), ::String, ::Reduce.RExpr) at /home/matt/.julia/packages/Reduce/4dmwd/src/parser.jl:317
[7] (::getfield(Reduce, Symbol("#kw##parse_expr")))(::NamedTuple{(:be,),Tuple{Int64}}, ::typeof(Reduce.parse_expr), ::String, ::Reduce.RExpr) at ./none:0
[8] #parse#76(::Int64, ::typeof(parse), ::Reduce.RExpr) at /home/matt/.julia/packages/Reduce/4dmwd/src/parser.jl:438
[9] parse at /home/matt/.julia/packages/Reduce/4dmwd/src/parser.jl:438 [inlined]
[10] convert at /home/matt/.julia/packages/Reduce/4dmwd/src/rexpr.jl:414 [inlined]
[11] unfold_expr_force(::Symbol, ::Symbol, ::Expr, ::Symbol) at /home/matt/.julia/packages/Reduce/4dmwd/src/parser.jl:847
[12] #unfold_expr#77(::Bool, ::typeof(Reduce.unfold_expr), ::Symbol, ::Symbol, ::Expr, ::Symbol) at /home/matt/.julia/packages/Reduce/4dmwd/src/parser.jl:806
[13] unfold_expr(::Symbol, ::Symbol, ::Expr, ::Symbol) at /home/matt/.julia/packages/Reduce/4dmwd/src/parser.jl:801
[14] unfold(::Symbol, ::Symbol, ::Expr, ::Symbol) at /home/matt/.julia/packages/Reduce/4dmwd/src/parser.jl:863
[15] int(::Expr, ::Symbol) at /home/matt/.julia/packages/Reduce/4dmwd/src/parser.jl:793
[16] g(::Symbol, ::Symbol) at /mnt/WorkSpace/projects/Maestro/GlucoseSource/DebugModule.jl:10
[17] top-level scope at /mnt/WorkSpace/projects/Maestro/GlucoseSource/DebugModule.jl:14
[18] include at ./boot.jl:328 [inlined]
[19] include_relative(::Module, ::String) at ./loading.jl:1094
[20] include(::Module, ::String) at ./Base.jl:31
[21] top-level scope at none:2
[22] eval at ./boot.jl:330 [inlined]
[23] eval(::Expr) at ./client.jl:432
[24] top-level scope at ./none:3
in expression starting at /mnt/WorkSpace/projects/Maestro/GlucoseSource/DebugModule.jl:14
ERROR: Failed to precompile DebugModule [top-level] to /home/matt/.julia/compiled/v1.2/DebugModule.ji.
Stacktrace:
[1] compilecache(::Base.PkgId, ::String) at ./loading.jl:1253
[2] _require(::Base.PkgId) at ./loading.jl:1013
[3] require(::Base.PkgId) at ./loading.jl:911
[4] require(::Module, ::Symbol) at ./loading.jl:906

julia>
```
If I copy and paste the code into the julia REPL it works fine and the module loads if the last line,
`g0 = g(:a,:b) - sub( (:(x=b), ), g(:a,:b))` is commented out. This looks like a bug to me.