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Stop using TokenStream::from_str to implement syn::parse_str #444

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dtolnay opened this issue Jun 18, 2018 · 1 comment
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Stop using TokenStream::from_str to implement syn::parse_str #444

dtolnay opened this issue Jun 18, 2018 · 1 comment
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dtolnay commented Jun 18, 2018

The FromStr impl has bizarre hygiene behavior because it was stabilized back in Rust 1.15.0. Instead we should have syn::parse_str do something more like LitStr::parse by respanning the input to a reasonable span, probably Span::call_site().

I believe the bizarreness is tracked in rust-lang/rust#50050 -- the spans produced by FromStr are intended to be "copy and paste hygiene" but are somehow not actually.

@alexcrichton
@dtolnay dtolnay added this to the 0.15 milestone Jun 18, 2018
@dtolnay dtolnay mentioned this issue Jun 18, 2018
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konstin added a commit to konstin/capybara that referenced this issue Jun 19, 2018
@konstin
Work around macro hygiene bug
1340d43 
See dtolnay/syn#444
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dtolnay commented Jul 22, 2018

This has been obviated upstream by rust-lang/rust#51762.

@dtolnay dtolnay closed this as completed Jul 22, 2018
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