Compiler crashes if type includes self by value

[stepancheg]

pub struct DescriptorProto {
    nested_type: Option<DescriptorProto>,
}

fn foo() -> Option<DescriptorProto> {
    None
}

fn main() {}

Seems to crash with stack overflow. Should print nice message and gracefully shutdown.

[jdm]

Dup of #4363.