[julia] Allow ::Nothing for REPL AST transformations.

.julia/config/startup.jl

@@ -1,8 +1,8 @@
 if Base.isinteractive() &&
    (REPL = get(Base.loaded_modules, Base.PkgId(Base.UUID("3fa0cd96-eef1-5676-8a61-b3b8758bbffb"), "REPL"), nothing); REPL !== nothing)
 
-   # Exit Julia with :q
+    # Exit Julia with :q
-    pushfirst!(REPL.repl_ast_transforms, function(ast::Expr)
+    pushfirst!(REPL.repl_ast_transforms, function(ast::Union{Expr,Nothing})
         if Meta.isexpr(ast, :toplevel, 2) && ast.args[2] === QuoteNode(:q)
             exit()
         end
@@ -10,7 +10,7 @@ if Base.isinteractive() &&
     end)
 
     # Automatically load Debugger.jl when encountering @enter
-    pushfirst!(REPL.repl_ast_transforms, function(ast::Expr)
+    pushfirst!(REPL.repl_ast_transforms, function(ast::Union{Expr,Nothing})
         if Meta.isexpr(ast, :toplevel, 2) && Meta.isexpr(ast.args[2], :macrocall) &&
            ast.args[2].args[1] === Symbol("@enter") && !isdefined(Main, Symbol("@enter"))
            @info "Loading Debugger..."