Change the hashcounts in raw Lit variants from usize to u16.

This reduces the size of `Token` from 32 bytes to 24 bytes on 64-bit
platforms.

src/libsyntax/parse/lexer/mod.rs

@@ -133,12 +133,12 @@ pub fn try_next_token(&mut self) -> Result<TokenAndSpan, ()> {
         Ok(ret_val)
     }
 
-    fn fail_unterminated_raw_string(&self, pos: BytePos, hash_count: usize) {
+    fn fail_unterminated_raw_string(&self, pos: BytePos, hash_count: u16) {
         let mut err = self.struct_span_fatal(pos, pos, "unterminated raw string");
         err.span_label(self.mk_sp(pos, pos), "unterminated raw string");
         if hash_count > 0 {
             err.note(&format!("this raw string should be terminated with `\"{}`",
-                              "#".repeat(hash_count)));
+                              "#".repeat(hash_count as usize)));
         }
         err.emit();
         FatalError.raise();
@@ -1439,7 +1439,7 @@ fn next_token_inner(&mut self) -> Result<token::Token, ()> {
             'r' => {
                 let start_bpos = self.pos;
                 self.bump();
-                let mut hash_count = 0;
+                let mut hash_count: u16 = 0;
                 while self.ch_is('#') {
                     self.bump();
                     hash_count += 1;

src/libsyntax/parse/token.rs

@@ -72,9 +72,9 @@ pub enum Lit {
     Integer(ast::Name),
     Float(ast::Name),
     Str_(ast::Name),
-    StrRaw(ast::Name, usize), /* raw str delimited by n hash symbols */
+    StrRaw(ast::Name, u16), /* raw str delimited by n hash symbols */
     ByteStr(ast::Name),
-    ByteStrRaw(ast::Name, usize), /* raw byte str delimited by n hash symbols */
+    ByteStrRaw(ast::Name, u16), /* raw byte str delimited by n hash symbols */
 }
 
 impl Lit {