Support byte string keys in phf_macros (fixes rust-phf#76)

Because of rust-lang/rust#31260, a cast must be inserted
explicitly instead of letting rustc implicitly coercing the type.

phf_macros/src/lib.rs

@@ -42,13 +42,15 @@ extern crate phf_generator;
 
 use std::collections::HashMap;
 use std::collections::hash_map::Entry::{Occupied, Vacant};
-use syntax::ast::{self, TokenTree, Expr, ExprLit, ExprVec};
+use syntax::ast::{self, Expr, ExprLit, ExprVec, MutImmutable, TokenTree, TyVec};
 use syntax::codemap::{Span, Spanned};
 use syntax::ext::base::{DummyResult, ExtCtxt, MacResult};
+use syntax::ext::build::AstBuilder;
 use syntax::fold::Folder;
 use syntax::parse;
 use syntax::parse::token::{InternedString, Comma, Eof, FatArrow};
 use syntax::print::pprust;
+use syntax::ptr::P;
 use rustc_plugin::Registry;
 use phf_generator::HashState;
 use std::env;
@@ -166,6 +168,7 @@ fn parse_map(cx: &mut ExtCtxt, tts: &[TokenTree]) -> Option<Vec<Entry>> {
  bad = true;
  Key::Str(InternedString::new(""))
  });
+ let key = adjust_key(cx, key);
 
  if !parser.eat(&FatArrow) {
  cx.span_err(parser.span, "expected `=>`");
@@ -205,6 +208,7 @@ fn parse_set(cx: &mut ExtCtxt, tts: &[TokenTree]) -> Option<Vec<Entry>> {
  bad = true;
  Key::Str(InternedString::new(""))
  });
+ let key = adjust_key(cx, key);
 
  entries.push(Entry {
  key_contents: key_contents,
@@ -285,6 +289,26 @@ fn parse_key(cx: &mut ExtCtxt, e: &Expr) -> Option<Key> {
  }
 }
 
+fn adjust_key(cx: &mut ExtCtxt, e: P<Expr>) -> P<Expr> {
+ let coerce_as_slice = match e.node {
+ ExprLit(ref lit) => {
+ match lit.node {
+ ast::LitByteStr(_) => true,
+ _ => false,
+ }
+ },
+ _ => false,
+ };
+ if coerce_as_slice {
+ let u8_type = cx.ty_path(cx.path_ident(e.span, cx.ident_of("u8")));
+ let array_type = cx.ty(e.span, TyVec(u8_type));
+ let slice_type = cx.ty_rptr(e.span, array_type, None, MutImmutable);
+ cx.expr_cast(e.span, e, slice_type)
+ } else {
+ e
+ }
+}
+
 fn has_duplicates(cx: &mut ExtCtxt, sp: Span, entries: &[Entry]) -> bool {
  let mut dups = false;
  let mut strings = HashMap::new();

phf_macros/tests/test.rs

@@ -17,6 +17,11 @@ mod map {
  "foo" => 10
  );
 
+ #[allow(dead_code)]
+ static BYTE_STRING_KEY: phf::Map<&'static [u8], &'static str> = phf_map!(
+ b"camembert" => "delicious",
+ );
+
  #[test]
  fn test_two() {
  static MAP: phf::Map<&'static str, isize> = phf_map!(