Macro hygiene problems with function return type and where

[TotalVerb]

OK:

julia> module Foo
           macro bar()
               :(foo(x) = x; foo(1))
           end
       end
Foo

julia> Foo.@bar
1

julia> macroexpand(:(Foo.@bar))
quote 
    #3#foo(#4#x) = begin  # REPL[1], line 3:
            #4#x
        end
    #3#foo(1)
end

Problem:

julia> module Foo2
           macro bar()
               :(foo(x)::Int = x; foo(1))
           end
       end
Foo2

julia> Foo2.@bar
ERROR: syntax: "Foo2.x" is not a valid function argument name

julia> macroexpand(:(Foo2.@bar))
quote 
    (Foo2.foo)(Foo2.x)::Foo2.Int = Foo2.x
    (Foo2.foo)(1)
end

Related problems manifest in other cases:

julia> global function foo(x)::Int
       end
ERROR: syntax: invalid syntax in "global" declaration

julia> global function foo(x)
       end
foo (generic function with 1 method)

In general I think there are several places that need to be updated for (function (:: ,ex ,rettype) ,body) and (function (where ,ex ,ex2) ,body) syntax.

Some of the sites I identified are

macroexpand.scm

• julia/src/macroexpand.scm

  Line 52 in 2d803f3

  (define vars-introduced-by-patterns

• julia/src/macroexpand.scm

  Line 105 in 2d803f3

  ((and (pair? (cadar binds))

• julia/src/macroexpand.scm

  Line 141 in 2d803f3

  (define keywords-introduced-by-patterns

• julia/src/macroexpand.scm

  Line 255 in 2d803f3

  (if (and (pair? (cadr e)) (eq? (caadr e) 'call))

• julia/src/macroexpand.scm

  Line 305 in 2d803f3

  (define (decl-var* e)

• julia/src/macroexpand.scm

  Line 318 in 2d803f3

  (define (function-def? e)

julia-syntax.scm

• julia/src/julia-syntax.scm

  Line 1319 in 2d803f3

  (define (assigned-name e)

I would make a PR, but I'm a little reluctant to because I don't know if simply adding cases for where and :: to each of the above sites is the best solution.