Problem Using `@isdefined` Inside a `@resumable` Function
wontfixerror messages
I'm having a problem using `@isdefined` inside a `@resumable`
function (https://github.com/JuliaDynamics/ResumableFunctions.jl).
```
function foo(x)
local y
@isdefined y
end
```
works, but
```
@resumable function foo(x)
local y
@isdefined y
end
```
gets the error
```
ERROR: LoadError: MethodError: no method matching var"@isdefined"(::LineNumberNode, ::Module, ::Expr)
Closest candidates are:
var"@isdefined"(::LineNumberNode, ::Module, !Matched::Symbol)
@ Base essentials.jl:177
```
When I try to macroexpand the same definition I get the same
error.
@macroexpand @resumable function foo(x)
local y
y
end
```
The problem appears to be because `@resumable` replaces local
variables in the function body with struct property references:
```
using MacroTools
prewalk(rmlines,
@macroexpand @resumable function foo(x)
local y
y
end
)
quote
mutable struct var"##foo_FSMI#307"{var"##y#308" <: Any, var"##x#309" <: Any} <: ResumableFunctions.FiniteStateMachineIterator{Any}
_state::UInt8
y::var"##y#308"
x::var"##x#309"
function var"##foo_FSMI#307"{var"##y#308", var"##x#309"}(; ) where {var"##y#308" <: Any, var"##x#309" <: Any}
fsmi = new()
fsmi._state = 0x00
fsmi
end
function var"##foo_FSMI#307"(; )
var"##foo_FSMI#307"{Any, Any}()
end
end
function (_fsmi::var"##foo_FSMI#307")(_arg::Any = nothing; )
_fsmi._state === 0x00 && $(Expr(:symbolicgoto, :_STATE_0))
error("@resumable function has stopped!")
$(Expr(:symboliclabel, :_STATE_0))
_fsmi._state = 0xff
_arg isa Exception && throw(_arg)
local _fsmi.y
_fsmi.y
end
begin
$(Expr(:meta, :doc))
function foo(x::Any; )
fsmi = ResumableFunctions.typed_fsmi(var"##foo_FSMI#307", var"##306", x)
fsmi.x = x
fsmi
end
end
end
```
I don't see an obvioous fix for this, but feel it should be noted as
the error message doesn't clearly point to the problem.
4 条评论