🐛 Bug Reports

This is different to issue 246.

🌍 Environment

• Your operating system and version: 4.15.0-50-generic Add PyDict::iter #54-Ubuntu SMP
• Your python version: Python 3.6.8
• How did you install python (e.g. apt or pyenv)? Did you use a virtualenv?: Anaconda 64bit
• Your rust version (rustc --version): rustc 1.34.0-nightly (e1c6d0057 2019-02-22)
• Are you using the latest pyo3 version? Have you tried using latest master (replace version = "0.x.y" with git = "https://github.com/PyO3/pyo3")? version: 0.7.0

💥 Reproducing

When using a struct with lifetime as follow:

use pyo3::prelude::*;

#[pyclass]
struct MyClass<'a> {
    r: &'a u32,
}

results in the compiler error:

error[E0106]: missing lifetime specifier
--> pycore/src/trace.rs:114:8
|
114 | struct MyClass<'a> {
| ^^^^^^^ expected lifetime parameter
error: aborting due to previous error

Using dependency:

[dependencies]
pyo3 = {version = "0.7.0", features = ["extension-module"]}