prost-derive: compatible with "nightly" proc-macro2 #89
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proc-macro2 0.3 tries to be compatible with the non-nightly 0.2 versions, even if the nightly feature is enabled. This fixes compile errors when another dependency requires the "nightly" feature of proc-macro2.
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The new 0.3 proc-macro2 makes it easy to be compatible using different feature sets. ("nightly" versus "non-nightly"), I could revert most of the required changes by updating dependencies. |
ngg
changed the title
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It would be great to see this merged! @danburkert any blockers? I'm using the |
| @@ -696,7 +696,7 @@ impl DefaultValue { | |||
| DefaultValue::String(ref value) => quote!(#value.to_owned()), | |||
| DefaultValue::Bytes(ref value) if value.is_empty() => quote!(::std::vec::Vec::new()), | |||
| DefaultValue::Bytes(ref value) => { | |||
| let lit = LitByteStr::new(value, Span::def_site()); | |||
| let lit = LitByteStr::new(value, Span::call_site()); | |||
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Just curious, do you know of any resources that document what the actual difference is here? I was mostly guessing we I introduced this during the syn 0.11 to 0.12 transition.
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call_site() will mean what def_site() meant previously, everything is unhygienic (visible from outside the macro). The def_site() will be hygienic, invisible from outside. But that is not currently possible on stable, that's a nightly-only feature. Macros 2.0 will be finalized before Rust 2018 (so in the next few months) and after that it will be possible to write hygienic macros too.
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Looks good. I tried to think of a way this could be regression tested, but came up short. @ngg do you know any ways it could be tested? |
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Probably you could add a "nightly" feature to prost-derive which would depend on the "nightly" feature of proc-macro2 and you could run tests with this feature too on travis |
This fixes compatibility with proc-macro2 if it has its "nightly"
feature enabled (it can be if another crate requires it).
Closes #88.