Handle negative literals a bit better #65
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ngg
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Mar 9, 2018
src/to_tokens.rs
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| macro_rules! signed_primitive { | ||
| ($(($t:ident => $signed:ident))*) => ($( |
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The $signed part is actually the unsigned version, and it's not used, could be removed.
Looks like upstream in rust-lang/rust negative integers are represented as two tokens instead of one token (and it looks like proc_macro may erroneously (?) accept negative integers as literals, see rust-lang/rust#48889). As a result tweak the `ToTokens` impls for signed integers to maybe put a `-` token out in front. Similar treatment is applied to f32/f64 as well. Special treatment is required, however, for the `iNN::min_value()` constants. The actual integral portion isn't actually representable as a positive integer literal (as it'd overflow back to negative) so to handle this case everything is just represented as a u64 literal cast to the right type.
alexcrichton
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dtolnay
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Mar 28, 2018
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I would prefer not to work around this so that we are motivated to fix rust-lang/rust#48889 sooner rather than later.
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Looks like upstream in rust-lang/rust negative integers are represented as two
tokens instead of one token (and it looks like proc_macro may erroneously (?)
accept negative integers as literals, see rust-lang/rust#48889). As a result
tweak the
ToTokensimpls for signed integers to maybe put a-token out infront. Similar treatment is applied to f32/f64 as well.
Special treatment is required, however, for the
iNN::min_value()constants.The actual integral portion isn't actually representable as a positive integer
literal (as it'd overflow back to negative) so to handle this case everything is
just represented as a u64 literal cast to the right type.