Puppet 4 lexer fails to parse multiple heredocs on the same line

notice({ @(foo) => @(bar) })

hello

-foo

world

-bar

$ puppet apply foo.pp

Error: Could not parse for environment production: undefined local variable or method `lexing_context' for #<Puppet::Pops::Parser::Lexer2:0x007faadd1551a0> on node peterhu-osx

$ puppet apply foo.pp

Notice: Scope(Class[main]): {hello => world}

Notice: Compiled catalog for peterhu-osx in environment production in 1.18 seconds

Notice: Applied catalog in 0.08 seconds