Can't do type creation inside macro when templating is used

[dlfivefifty]

The following throws the error "ERROR: error compiling anonymous: type definition not allowed inside a local scope":

module FooModule
     macro foo(Typ,Abs)
     return esc(quote
           abstract $Abs{T}
           immutable $Typ{T} <: $Abs{T} end
           end
           )
       end
    @foo(FooTyp,FooAbs)
end

The following without the templated abstract type doesn't throw an error:

module FooModule2
     macro foo(Typ,Abs)
     return esc(quote
           abstract $Abs
           immutable $Typ{T} <: $Abs end
           end
           )
       end
    @foo(FooTyp,FooAbs)
end

[@ivarne- edited to add quoting]

[vchuravy]

Which julia version are you using? On 0.3.3 your first example works for me.

[dlfivefifty]

This is a bug in 0.4 I think

Sent from my iPhone

On 11 Dec 2014, at 9:55 am, Valentin Churavy notifications@github.com wrote:

Which julia version are you using? On 0.3.3 your first example works for me.

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[ihnorton]

Not yet sure why this changed. See also #2586.

[ihnorton]

@dlfivefifty here is a (possible) work-around:

macro foo(Typ,Abs)
            return esc(quote
                  abstract $Abs{T}
                  immutable $Typ{S} <: $Abs{S} end
                  end
                  )
              end

Since @JeffBezanson seems to be on right now -- if you see this, can you comment on whether this is more than a dupe of #2586 (and #4893)? I looked at the lowering for Sheehan's examples as well as the code below (which works):

julia> macro foo(AbsSup)
           esc(quote abstract $AbsSup{T} end)
       end

julia> @foo(Sup)

julia> macro bar(AbsSub,AbsSup)
           esc(quote immutable $AbsSub{T} <: $AbsSup{T} end end)
       end

julia> @bar(Sub, Sup)

[edit - copied from the wrong REPL]

From what I can tell the difference is that there is a lambda capture in Sheehan's example, and I believe what is happening is that T is being incorrectly (?) classified as a local variable when it should only be a TypeVar for both declarations. (therefore the code goes through the compiler and hits this error message).

[dlfivefifty]

That seems to fix the toy example, thanks! I can't test the real example in 0.4 because the code is also hit by #9378

[yuyichao]

Probably related (the "local T declare twice" error)

try
    @eval begin
        abstract A1{T}
        abstract B1{T} <: A1{T}
    end
catch e
    println(e)
end

abstract A2{T}
abstract B2{T} <: A2{T}

try
    @eval begin
        abstract A3{T}
        type B3{T} <: A3{T}
        end
    end
catch e
    println(e)
end

abstract A4{T}
type B4{T} <: A4{T}
end

Output

ErrorException("syntax: local \"T\" declared twice")
ErrorException("error compiling anonymous: type definition not allowed inside a local scope")

[JeffBezanson]

Just tried this and it seems to be fixed.