error: expected one of `>`, const, identifier, lifetime, or type, found `,` --> $DIR/issue-20616-7.rs:30:22 | LL | type Type_7 = Box<(),,>; //~ error: expected one of `>`, const, identifier, lifetime, or type, found `,` | ^ expected one of `>`, const, identifier, lifetime, or type here error: aborting due to previous error