Cleanup interfaces of Name, SyntaxContext and Ident

Make sure Name, SyntaxContext and Ident are passed by value
Make sure Idents don't serve as keys (or parts of keys) in maps, Ident comparison is not well defined

src/libsyntax/parse/token.rs

@@ -453,7 +453,7 @@ macro_rules! declare_special_idents_and_keywords {(
             #[allow(non_upper_case_globals)]
             pub const $si_static: ast::Ident = ast::Ident {
                 name: ast::Name($si_name),
-                ctxt: 0,
+                ctxt: ast::EMPTY_CTXT,
             };
          )*
     }
@@ -462,7 +462,7 @@ macro_rules! declare_special_idents_and_keywords {(
         use ast;
         $(
             #[allow(non_upper_case_globals)]
-            pub const $si_static: ast::Name =  ast::Name($si_name);
+            pub const $si_static: ast::Name = ast::Name($si_name);
         )*
     }
 
@@ -729,19 +729,19 @@ pub fn gensym(s: &str) -> ast::Name {
 /// Maps a string to an identifier with an empty syntax context.
 #[inline]
 pub fn str_to_ident(s: &str) -> ast::Ident {
-    ast::Ident::new(intern(s))
+    ast::Ident::with_empty_ctxt(intern(s))
 }
 
 /// Maps a string to a gensym'ed identifier.
 #[inline]
 pub fn gensym_ident(s: &str) -> ast::Ident {
-    ast::Ident::new(gensym(s))
+    ast::Ident::with_empty_ctxt(gensym(s))
 }
 
 // create a fresh name that maps to the same string as the old one.
 // note that this guarantees that str_ptr_eq(ident_to_string(src),interner_get(fresh_name(src)));
 // that is, that the new name and the old one are connected to ptr_eq strings.
-pub fn fresh_name(src: &ast::Ident) -> ast::Name {
+pub fn fresh_name(src: ast::Ident) -> ast::Name {
     let interner = get_ident_interner();
     interner.gensym_copy(src.name)
     // following: debug version. Could work in final except that it's incompatible with
@@ -753,7 +753,7 @@ pub fn fresh_name(src: &ast::Ident) -> ast::Name {
 
 // create a fresh mark.
 pub fn fresh_mark() -> ast::Mrk {
-    gensym("mark").usize() as u32
+    gensym("mark").0
 }
 
 #[cfg(test)]
@@ -763,7 +763,7 @@ mod tests {
     use ext::mtwt;
 
     fn mark_ident(id : ast::Ident, m : ast::Mrk) -> ast::Ident {
-        ast::Ident { name: id.name, ctxt:mtwt::apply_mark(m, id.ctxt) }
+        ast::Ident::new(id.name, mtwt::apply_mark(m, id.ctxt))
     }
 
     #[test] fn mtwt_token_eq_test() {