Bug 18540 – [scope] incorrect "escapes a reference to parameter e, perhaps annotate with return"

cat > bug.d << CODE module interpreter; import std.algorithm.mutation : move; struct S { string s; } struct Interpreter(Engine) { Engine _engine; S s; } Interpreter!Engine interpreter(Engine)(return scope Engine e) @system { return Interpreter!Engine(move(e)); } struct EchoEngine { @disable this(this); } void bug() { auto intp = interpreter(EchoEngine()); } CODE ---- dmd -c bug.d ---- Error: returning Interpreter(move(e), S(null)) escapes a reference to parameter e, perhaps annotate with return

Can this be reduced to an example that doesn't reference Phobos?

Doesn't produce an error for master, with or without -dip1000.