"cargo test" fails on 1.5.0+

[diwic]

It runs just fine on 1.4.0-nightly, but fails on 1.5.0-stable and 1.7.0-nightly.

src/methoddisp.rs:793:88: 797:6 error: `count` does not live long enough
src/methoddisp.rs:793     let _setme = i.add_p_ref(f.property("setme", 0u8).access(Access::ReadWrite).on_set(|_,_,_| {
src/methoddisp.rs:794         let v: i32 = count.get_value().inner().unwrap();
src/methoddisp.rs:795         count.set_value((v + 1).into()).unwrap();
src/methoddisp.rs:796         Ok(vec!())
src/methoddisp.rs:797     }));
src/methoddisp.rs:787:27: 798:2 note: reference must be valid for the block at 787:26...
src/methoddisp.rs:787 fn prop_lifetime_simple() {
src/methoddisp.rs:788     let count;
src/methoddisp.rs:789     let f = Factory::new_fnmut();
src/methoddisp.rs:790     let mut i = f.interface("com.example.dbus.rs");
src/methoddisp.rs:791     count = i.add_p_ref(f.property("changes", 0i32));
src/methoddisp.rs:792 
                  ...
src/methoddisp.rs:788:15: 798:2 note: ...but borrowed value is only valid for the block suffix following statement 0 at 788:14
src/methoddisp.rs:788     let count;
src/methoddisp.rs:789     let f = Factory::new_fnmut();
src/methoddisp.rs:790     let mut i = f.interface("com.example.dbus.rs");
src/methoddisp.rs:791     count = i.add_p_ref(f.property("changes", 0i32));
src/methoddisp.rs:792 
src/methoddisp.rs:793     let _setme = i.add_p_ref(f.property("setme", 0u8).access(Access::ReadWrite).on_set(|_,_,_| {

[diwic]

In addition, at least the note line looks broken:

src/methoddisp.rs:793:88: 797:6 error: `count` does not live long enough
src/methoddisp.rs:788:34: 798:2 note: reference must be valid for the block suffix following statement 0 at 788:33...
src/methoddisp.rs:789:15: 798:2 note: ...but borrowed value is only valid for the block suffix following statement 1 at 789:14

...but moving let count above let f = Factory::new_fnmut() just moves the error too:

src/methoddisp.rs:793:88: 797:6 error: `count` does not live long enough
src/methoddisp.rs:787:27: 798:2 note: reference must be valid for the block at 787:26...
src/methoddisp.rs:788:15: 798:2 note: ...but borrowed value is only valid for the block suffix following statement 0 at 788:14

Related issue that might have caused this: rust-lang/rust#29106

[diwic]

@apasel422, since you wrote the code for fixing rust-lang/rust#29106 , if it's not too much to ask, would you mind seeing if it's Rust that's overly conservative here? It looks so to me.

[apasel422]

@diwic I'm looking at this now, and don't have a sure answer, but I think it's unlikely that Rust is being overly conservative. I have a hunch that it's variance-related.

[diwic]

Fixed as part of tree rewrite.