Fix `num-macros` `FromPrimitive` implementation
Current solution follow syntax proposed in rust-lang/rfcs#1681. Tracking issue rust-lang/rust#35900 Close #227
This commit is contained in:
Łukasz Jan Niemier
parent
a11be641ed
commit
11f8289ed4
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@ -1,17 +1,26 @@
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[package]
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name = "num-macros"
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version = "0.1.33"
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authors = ["The Rust Project Developers"]
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license = "MIT/Apache-2.0"
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homepage = "https://github.com/rust-num/num"
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repository = "https://github.com/rust-num/num"
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documentation = "http://rust-num.github.io/num"
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keywords = ["mathematics", "numerics"]
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description = "Numeric syntax extensions"
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documentation = "http://rust-num.github.io/num"
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homepage = "https://github.com/rust-num/num"
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keywords = ["mathematics", "numerics"]
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license = "MIT/Apache-2.0"
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name = "num-macros"
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repository = "https://github.com/rust-num/num"
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version = "0.1.33"
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[lib]
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name = "num_macros"
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plugin = true
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[dependencies]
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quote = "0.1.3"
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syn = "0.5.2"
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[dev-dependencies]
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num = { path = "..", version = "0.1" }
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[dev-dependencies.num]
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path = ".."
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version = "0.1"
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[lib]
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crate-type = ["rustc-macro"]
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name = "num_macros"
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rustc-macro = true
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test = false
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@ -8,43 +8,24 @@
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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#![feature(plugin_registrar, rustc_private)]
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#![crate_type = "rustc-macro"]
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#![feature(rustc_macro, rustc_macro_lib)]
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extern crate syntax;
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extern crate syntax_ext;
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extern crate rustc_plugin;
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extern crate syn;
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#[macro_use]
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extern crate quote;
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extern crate rustc_macro;
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use syntax::ast::{MetaItem, Expr, BinOpKind};
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use syntax::ast;
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use syntax::codemap::Span;
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use syntax::ext::base::{ExtCtxt, Annotatable};
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use syntax::ext::build::AstBuilder;
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use syntax_ext::deriving::generic::*;
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use syntax_ext::deriving::generic::ty::*;
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use syntax::parse::token::InternedString;
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use syntax::ptr::P;
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use syntax::ext::base::MultiDecorator;
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use syntax::parse::token;
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use rustc_macro::TokenStream;
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use rustc_plugin::Registry;
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use syn::Body::Enum;
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macro_rules! pathvec {
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($($x:ident)::+) => (
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vec![ $( stringify!($x) ),+ ]
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)
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}
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#[rustc_macro_derive(FromPrimitive)]
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pub fn from_primitive(input: TokenStream) -> TokenStream {
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let source = input.to_string();
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macro_rules! path {
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($($x:tt)*) => (
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::syntax_ext::deriving::generic::ty::Path::new( pathvec!( $($x)* ) )
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)
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}
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macro_rules! path_local {
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($x:ident) => (
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::syntax_ext::deriving::generic::ty::Path::new_local(stringify!($x))
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)
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}
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let ast = syn::parse_item(&source).unwrap();
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// panic!("{:?}", ast);
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macro_rules! pathvec_std {
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($cx:expr, $first:ident :: $($rest:ident)::+) => ({
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@ -111,91 +92,32 @@ pub fn expand_deriving_from_primitive(cx: &mut ExtCtxt,
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supports_unions: false,
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};
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trait_def.expand(cx, mitem, &item, push)
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let mut idx = 0;
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let variants: Vec<_> = variants.iter()
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.map(|variant| {
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let ident = &variant.ident;
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let tt = quote!(#idx => Some(#name::#ident));
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idx += 1;
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tt
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})
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.collect();
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let res = quote! {
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#ast
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impl ::num::traits::FromPrimitive for #name {
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fn from_i64(n: i64) -> Option<Self> {
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Self::from_u64(n as u64)
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}
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fn cs_from(name: &str, cx: &mut ExtCtxt, trait_span: Span, substr: &Substructure) -> P<Expr> {
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if substr.nonself_args.len() != 1 {
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cx.span_bug(trait_span, "incorrect number of arguments in `derive(FromPrimitive)`")
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fn from_u64(n: u64) -> Option<Self> {
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match n {
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#(variants,)*
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_ => None,
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}
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let n = &substr.nonself_args[0];
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match *substr.fields {
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StaticStruct(..) => {
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cx.span_err(trait_span, "`FromPrimitive` cannot be derived for structs");
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return cx.expr_fail(trait_span, InternedString::new(""));
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}
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StaticEnum(enum_def, _) => {
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if enum_def.variants.is_empty() {
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cx.span_err(trait_span,
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"`FromPrimitive` cannot be derived for enums with no variants");
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return cx.expr_fail(trait_span, InternedString::new(""));
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}
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let mut arms = Vec::new();
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for variant in &enum_def.variants {
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match variant.node.data {
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ast::VariantData::Unit(..) => {
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let span = variant.span;
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// expr for `$n == $variant as $name`
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let path = cx.path(span, vec![substr.type_ident, variant.node.name]);
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let variant = cx.expr_path(path);
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let ty = cx.ty_ident(span, cx.ident_of(name));
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let cast = cx.expr_cast(span, variant.clone(), ty);
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let guard = cx.expr_binary(span, BinOpKind::Eq, n.clone(), cast);
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// expr for `Some($variant)`
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let body = cx.expr_some(span, variant);
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// arm for `_ if $guard => $body`
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let arm = ast::Arm {
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attrs: vec!(),
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pats: vec!(cx.pat_wild(span)),
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guard: Some(guard),
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body: body,
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};
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arms.push(arm);
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}
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ast::VariantData::Tuple(..) => {
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cx.span_err(trait_span,
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"`FromPrimitive` cannot be derived for \
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enum variants with arguments");
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return cx.expr_fail(trait_span,
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InternedString::new(""));
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}
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ast::VariantData::Struct(..) => {
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cx.span_err(trait_span,
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"`FromPrimitive` cannot be derived for enums \
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with struct variants");
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return cx.expr_fail(trait_span,
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InternedString::new(""));
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}
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}
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}
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// arm for `_ => None`
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let arm = ast::Arm {
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attrs: vec!(),
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pats: vec!(cx.pat_wild(trait_span)),
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guard: None,
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body: cx.expr_none(trait_span),
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};
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arms.push(arm);
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cx.expr_match(trait_span, n.clone(), arms)
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}
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_ => cx.span_bug(trait_span, "expected StaticEnum in derive(FromPrimitive)")
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}
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}
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#[plugin_registrar]
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#[doc(hidden)]
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pub fn plugin_registrar(reg: &mut Registry) {
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reg.register_syntax_extension(
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token::intern("derive_NumFromPrimitive"),
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MultiDecorator(Box::new(expand_deriving_from_primitive)));
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res.to_string().parse().unwrap()
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}
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@ -8,12 +8,13 @@
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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#![feature(custom_derive, plugin)]
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#![plugin(num_macros)]
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#![feature(rustc_macro)]
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extern crate num;
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#[macro_use]
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extern crate num_macros;
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#[derive(Debug, PartialEq, NumFromPrimitive)]
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#[derive(Debug, PartialEq, FromPrimitive)]
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enum Color {
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Red,
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Blue,
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@ -22,15 +23,11 @@ enum Color {
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#[test]
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fn test_from_primitive() {
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let v: Vec<Option<Color>> = vec![
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num::FromPrimitive::from_u64(0),
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let v: [Option<Color>; 4] = [num::FromPrimitive::from_u64(0),
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num::FromPrimitive::from_u64(1),
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num::FromPrimitive::from_u64(2),
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num::FromPrimitive::from_u64(3),
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];
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num::FromPrimitive::from_u64(3)];
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assert_eq!(
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v,
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vec![Some(Color::Red), Some(Color::Blue), Some(Color::Green), None]
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);
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assert_eq!(v,
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[Some(Color::Red), Some(Color::Blue), Some(Color::Green), None]);
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}
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