doesn't compile with "-Z minimal-versions"

[rlidwka]

I'm trying to test my stuff with oldest possible versions of all libraries to make sure semver ranges are correct.

$ cargo +nightly -Z minimal-versions update ; cargo build

See rust-lang/cargo#5657 for details on the flag.

syntect doesn't compile.

One issue I found is that flate2@1.0.2 and below picks up deprecated gcc crate via transitive miniz-sys dependency.

Thus, I suggest to replace:

flate2 = { version = "1.0", optional = true }

with at least

flate2 = { version = "1.0.3", optional = true }

... where the issue is fixed.

And there is something about older versions of serde that doesn't work right, but I haven't found exact dependency that does it. Let me know if you're interested in fixing that sort of thing, might look in deeper if so.

error[E0432]: unresolved import `std::path::AsPath`
  --> /home/user/.cargo/registry/src/github.com-1ecc6299db9ec823/gcc-0.3.0/src/lib.rs:50:26
   |
50 | use std::path::{PathBuf, AsPath};
   |                          ^^^^^^
   |                          |
   |                          no `AsPath` in `path`
   |                          help: a similar name exists in the module: `Path`

error[E0433]: failed to resolve: could not find `old_io` in `std`
   --> /home/user/.cargo/registry/src/github.com-1ecc6299db9ec823/gcc-0.3.0/src/lib.rs:328:10
    |
328 |     std::old_io::stdio::set_stderr(Box::new(std::old_io::util::NullWriter));
    |          ^^^^^^ could not find `old_io` in `std`

error[E0433]: failed to resolve: could not find `old_io` in `std`
   --> /home/user/.cargo/registry/src/github.com-1ecc6299db9ec823/gcc-0.3.0/src/lib.rs:328:50
    |
328 |     std::old_io::stdio::set_stderr(Box::new(std::old_io::util::NullWriter));
    |                                                  ^^^^^^ could not find `old_io` in `std`

error[E0425]: cannot find function `set_exit_status` in module `env`
   --> /home/user/.cargo/registry/src/github.com-1ecc6299db9ec823/gcc-0.3.0/src/lib.rs:327:10
    |
327 |     env::set_exit_status(1);
    |          ^^^^^^^^^^^^^^^ not found in `env`

error[E0635]: unknown feature `old_io`
  --> /home/user/.cargo/registry/src/github.com-1ecc6299db9ec823/gcc-0.3.0/src/lib.rs:45:12
   |
45 | #![feature(old_io, io, path, env, collections, process, fs)]
   |            ^^^^^^

error[E0635]: unknown feature `io`
  --> /home/user/.cargo/registry/src/github.com-1ecc6299db9ec823/gcc-0.3.0/src/lib.rs:45:20
   |
45 | #![feature(old_io, io, path, env, collections, process, fs)]
   |                    ^^

error[E0635]: unknown feature `path`
  --> /home/user/.cargo/registry/src/github.com-1ecc6299db9ec823/gcc-0.3.0/src/lib.rs:45:24
   |
45 | #![feature(old_io, io, path, env, collections, process, fs)]
   |                        ^^^^

error[E0635]: unknown feature `fs`
  --> /home/user/.cargo/registry/src/github.com-1ecc6299db9ec823/gcc-0.3.0/src/lib.rs:45:57
   |
45 | #![feature(old_io, io, path, env, collections, process, fs)]
   |                                                         ^^

error[E0635]: unknown feature `collections`
  --> /home/user/.cargo/registry/src/github.com-1ecc6299db9ec823/gcc-0.3.0/src/lib.rs:45:35
   |
45 | #![feature(old_io, io, path, env, collections, process, fs)]
   |                                   ^^^^^^^^^^^

Some errors have detailed explanations: E0425, E0432, E0433, E0635.
For more information about an error, try `rustc --explain E0425`.
error: could not compile `gcc` due to 9 previous errors
warning: build failed, waiting for other jobs to finish...
error[E0277]: the trait bound `MapAccessDeserializer<MapDeserializer<'_, std::array::IntoIter<(&str, std::string::String), 1>, _>>: EnumAccess<'de>` is not satisfied
    --> /home/user/.cargo/registry/src/github.com-1ecc6299db9ec823/plist-1.3.0/src/de.rs:136:36
     |
136  |                   visitor.visit_enum(MapAccessDeserializer::new(MapDeserializer::new(
     |  _________________________----------_^
     | |                         |
     | |                         required by a bound introduced by this call
137  | |                     IntoIter::new([(DATE_NEWTYPE_STRUCT_NAME, v.to_rfc3339())]),
138  | |                 )))
     | |__________________^ the trait `EnumAccess<'de>` is not implemented for `MapAccessDeserializer<MapDeserializer<'_, std::array::IntoIter<(&str, std::string::String), 1>, _>>`
     |
     = help: the following other types implement trait `EnumAccess<'de>`:
               &'a mut de::Deserializer<I>
               BorrowedStrDeserializer<'de, E>
               CowStrDeserializer<'a, E>
               StringDeserializer<E>
               U32Deserializer<E>
               serde::de::value::StrDeserializer<'a, E>
note: required by a bound in `visit_enum`
    --> /home/user/.cargo/registry/src/github.com-1ecc6299db9ec823/serde-1.0.27/src/de/mod.rs:1504:12
     |
1504 |         A: EnumAccess<'de>,
     |            ^^^^^^^^^^^^^^^ required by this bound in `visit_enum`

error[E0277]: the trait bound `MapAccessDeserializer<MapDeserializer<'_, std::array::IntoIter<(&str, u64), 1>, _>>: EnumAccess<'de>` is not satisfied
    --> /home/user/.cargo/registry/src/github.com-1ecc6299db9ec823/plist-1.3.0/src/de.rs:152:72
     |
152  |               Event::Uid(v) if self.in_plist_value => visitor.visit_enum(MapAccessDeserializer::new(
     |  _____________________________________________________________----------_^
     | |                                                             |
     | |                                                             required by a bound introduced by this call
153  | |                 MapDeserializer::new(IntoIter::new([(UID_NEWTYPE_STRUCT_NAME, v.get())])),
154  | |             )),
     | |_____________^ the trait `EnumAccess<'de>` is not implemented for `MapAccessDeserializer<MapDeserializer<'_, std::array::IntoIter<(&str, u64), 1>, _>>`
     |
     = help: the following other types implement trait `EnumAccess<'de>`:
               &'a mut de::Deserializer<I>
               BorrowedStrDeserializer<'de, E>
               CowStrDeserializer<'a, E>
               StringDeserializer<E>
               U32Deserializer<E>
               serde::de::value::StrDeserializer<'a, E>
note: required by a bound in `visit_enum`
    --> /home/user/.cargo/registry/src/github.com-1ecc6299db9ec823/serde-1.0.27/src/de/mod.rs:1504:12
     |
1504 |         A: EnumAccess<'de>,
     |            ^^^^^^^^^^^^^^^ required by this bound in `visit_enum`

For more information about this error, try `rustc --explain E0277`.
error: could not compile `plist` due to 2 previous errors