syntax/ext: Remove the trait-object indirection of the ext_ctxt object.

src/libsyntax/ext/base.rs

@@ -202,35 +202,7 @@ pub fn syntax_expander_table() -> SyntaxEnv {
 // One of these is made during expansion and incrementally updated as we go;
 // when a macro expansion occurs, the resulting nodes have the backtrace()
 // -> expn_info of their expansion context stored into their span.
-pub trait ext_ctxt {
+pub struct ext_ctxt {
-    fn codemap(&self) -> @CodeMap;
-    fn parse_sess(&self) -> @mut parse::ParseSess;
-    fn cfg(&self) -> ast::crate_cfg;
-    fn call_site(&self) -> span;
-    fn print_backtrace(&self);
-    fn backtrace(&self) -> Option<@ExpnInfo>;
-    fn mod_push(&self, mod_name: ast::ident);
-    fn mod_pop(&self);
-    fn mod_path(&self) -> ~[ast::ident];
-    fn bt_push(&self, ei: codemap::ExpnInfo);
-    fn bt_pop(&self);
-    fn span_fatal(&self, sp: span, msg: &str) -> !;
-    fn span_err(&self, sp: span, msg: &str);
-    fn span_warn(&self, sp: span, msg: &str);
-    fn span_unimpl(&self, sp: span, msg: &str) -> !;
-    fn span_bug(&self, sp: span, msg: &str) -> !;
-    fn bug(&self, msg: &str) -> !;
-    fn next_id(&self) -> ast::node_id;
-    fn trace_macros(&self) -> bool;
-    fn set_trace_macros(&self, x: bool);
-    /* for unhygienic identifier transformation */
-    fn str_of(&self, id: ast::ident) -> ~str;
-    fn ident_of(&self, st: &str) -> ast::ident;
-}
-
-pub fn mk_ctxt(parse_sess: @mut parse::ParseSess, cfg: ast::crate_cfg)
-            -> @ext_ctxt {
-    struct CtxtRepr {
     parse_sess: @mut parse::ParseSess,
     cfg: ast::crate_cfg,
     backtrace: @mut Option<@ExpnInfo>,
@@ -242,8 +214,9 @@ pub fn mk_ctxt(parse_sess: @mut parse::ParseSess, cfg: ast::crate_cfg)
     // moment. - nmatsakis
     mod_path: @mut ~[ast::ident],
     trace_mac: @mut bool
-    }
+}
-    impl ext_ctxt for CtxtRepr {
+
+pub impl ext_ctxt {
     fn codemap(&self) -> @CodeMap { self.parse_sess.cm }
     fn parse_sess(&self) -> @mut parse::ParseSess { self.parse_sess }
     fn cfg(&self) -> ast::crate_cfg { copy self.cfg }
@@ -271,7 +244,8 @@ pub fn mk_ctxt(parse_sess: @mut parse::ParseSess, cfg: ast::crate_cfg)
     }
     fn bt_pop(&self) {
         match *self.backtrace {
-              Some(@ExpandedFrom(CallInfo {
+            Some(@ExpandedFrom(
+                CallInfo {
                     call_site: span {expn_info: prev, _}, _
                 })) => {
                 *self.backtrace = prev
@@ -304,7 +278,7 @@ pub fn mk_ctxt(parse_sess: @mut parse::ParseSess, cfg: ast::crate_cfg)
         self.parse_sess.span_diagnostic.handler().bug(msg);
     }
     fn next_id(&self) -> ast::node_id {
-            return parse::next_node_id(self.parse_sess);
+        parse::next_node_id(self.parse_sess)
     }
     fn trace_macros(&self) -> bool {
         *self.trace_mac
@@ -318,15 +292,17 @@ pub fn mk_ctxt(parse_sess: @mut parse::ParseSess, cfg: ast::crate_cfg)
     fn ident_of(&self, st: &str) -> ast::ident {
         self.parse_sess.interner.intern(st)
     }
-    }
+}
-    let imp: @CtxtRepr = @CtxtRepr {
+
+pub fn mk_ctxt(parse_sess: @mut parse::ParseSess, cfg: ast::crate_cfg)
+    -> @ext_ctxt {
+    @ext_ctxt {
         parse_sess: parse_sess,
         cfg: cfg,
         backtrace: @mut None,
         mod_path: @mut ~[],
         trace_mac: @mut false
-    };
+    }
-    ((imp) as @ext_ctxt)
 }
 
 pub fn expr_to_str(cx: @ext_ctxt, expr: @ast::expr, err_msg: ~str) -> ~str {