diff --git a/src/libextra/arc.rs b/src/libextra/arc.rs
index 40ddea53895..1cb30eaa040 100644
--- a/src/libextra/arc.rs
+++ b/src/libextra/arc.rs
@@ -505,7 +505,7 @@ impl<T:Freeze + Send> RWArc<T> {
         let inner = x.unwrap();
         let RWArcInner { failed: failed, data: data, _ } = inner;
         if failed {
-            fail2!(~"Can't unwrap poisoned RWArc - another task failed inside!")
+            fail2!("Can't unwrap poisoned RWArc - another task failed inside!")
         }
         data
     }
diff --git a/src/libextra/test.rs b/src/libextra/test.rs
index 1370a0690ca..16937e38695 100644
--- a/src/libextra/test.rs
+++ b/src/libextra/test.rs
@@ -125,7 +125,7 @@ pub fn test_main(args: &[~str], tests: ~[TestDescAndFn]) {
     let opts =
         match parse_opts(args) {
             Some(Ok(o)) => o,
-            Some(Err(msg)) => fail2!(msg),
+            Some(Err(msg)) => fail2!("{}", msg),
             None => return
         };
     if !run_tests_console(&opts, tests) { fail2!("Some tests failed"); }
diff --git a/src/libsyntax/abi.rs b/src/libsyntax/abi.rs
index 883020e637a..4875ef6d3ca 100644
--- a/src/libsyntax/abi.rs
+++ b/src/libsyntax/abi.rs
@@ -221,7 +221,7 @@ impl AbiSet {
             let data = abi.data();
             for other_abi in abis.slice(0, i).iter() {
                 let other_data = other_abi.data();
-                debug!("abis=(%?,%?) datas=(%?,%?)",
+                debug2!("abis=({:?},{:?}) datas=({:?},{:?})",
                        abi, data.abi_arch,
                        other_abi, other_data.abi_arch);
                 match (&data.abi_arch, &other_data.abi_arch) {
@@ -273,7 +273,7 @@ impl ToStr for AbiSet {
             strs.push(abi.data().name);
             true
         };
-        fmt!("\"%s\"", strs.connect(" "))
+        format!("\"{}\"", strs.connect(" "))
     }
 }
 
@@ -306,7 +306,7 @@ fn cannot_combine(n: Abi, m: Abi) {
                          (m == a && n == b));
         }
         None => {
-            fail!("Invalid match not detected");
+            fail2!("Invalid match not detected");
         }
     }
 }
@@ -318,7 +318,7 @@ fn can_combine(n: Abi, m: Abi) {
     set.add(m);
     match set.check_valid() {
         Some((_, _)) => {
-            fail!("Valid match declared invalid");
+            fail2!("Valid match declared invalid");
         }
         None => {}
     }
@@ -367,7 +367,7 @@ fn abi_to_str_c_aaps() {
     let mut set = AbiSet::empty();
     set.add(Aapcs);
     set.add(C);
-    debug!("set = %s", set.to_str());
+    debug2!("set = {}", set.to_str());
     assert!(set.to_str() == ~"\"aapcs C\"");
 }
 
@@ -375,7 +375,7 @@ fn abi_to_str_c_aaps() {
 fn abi_to_str_rust() {
     let mut set = AbiSet::empty();
     set.add(Rust);
-    debug!("set = %s", set.to_str());
+    debug2!("set = {}", set.to_str());
     assert!(set.to_str() == ~"\"Rust\"");
 }
 
diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index 7e4cbf8e975..f2d7ebdd599 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -47,8 +47,8 @@ impl Eq for Ident {
             // if it should be non-hygienic (most things are), just compare the
             // 'name' fields of the idents. Or, even better, replace the idents
             // with Name's.
-            fail!(fmt!("not allowed to compare these idents: %?, %?. Probably \
-                       related to issue #6993", self, other));
+            fail2!("not allowed to compare these idents: {:?}, {:?}.
+                    Probably related to issue \\#6993", self, other);
         }
     }
     fn ne(&self, other: &Ident) -> bool {
diff --git a/src/libsyntax/ast_map.rs b/src/libsyntax/ast_map.rs
index 1323db7acba..105d222926e 100644
--- a/src/libsyntax/ast_map.rs
+++ b/src/libsyntax/ast_map.rs
@@ -66,7 +66,7 @@ pub fn path_ident_to_str(p: &path, i: Ident, itr: @ident_interner) -> ~str {
     if p.is_empty() {
         itr.get(i.name).to_owned()
     } else {
-        fmt!("%s::%s", path_to_str(*p, itr), itr.get(i.name))
+        format!("{}::{}", path_to_str(*p, itr), itr.get(i.name))
     }
 }
 
@@ -96,7 +96,7 @@ pub fn impl_pretty_name(trait_ref: &Option<trait_ref>,
             // XXX: this dollar sign is actually a relic of being one of the
             //      very few valid symbol names on unix. These kinds of
             //      details shouldn't be exposed way up here in the ast.
-            let s = fmt!("%s$%s",
+            let s = format!("{}${}",
                          itr.get(trait_ref.path.segments.last().identifier.name),
                          itr.get(ty_ident.name));
             path_pretty_name(Ident::new(itr.gensym(s)), hash)
@@ -185,7 +185,7 @@ impl Ctx {
                                                          item,
                                                          p));
                     }
-                    _ => fail!("struct def parent wasn't an item")
+                    _ => fail2!("struct def parent wasn't an item")
                 }
             }
         }
@@ -426,7 +426,7 @@ pub fn map_decoded_item(diag: @mut span_handler,
 pub fn node_id_to_str(map: map, id: NodeId, itr: @ident_interner) -> ~str {
     match map.find(&id) {
       None => {
-        fmt!("unknown node (id=%d)", id)
+        format!("unknown node (id={})", id)
       }
       Some(&node_item(item, path)) => {
         let path_str = path_ident_to_str(path, item.ident, itr);
@@ -442,46 +442,46 @@ pub fn node_id_to_str(map: map, id: NodeId, itr: @ident_interner) -> ~str {
           item_impl(*) => ~"impl",
           item_mac(*) => ~"macro"
         };
-        fmt!("%s %s (id=%?)", item_str, path_str, id)
+        format!("{} {} (id={})", item_str, path_str, id)
       }
       Some(&node_foreign_item(item, abi, _, path)) => {
-        fmt!("foreign item %s with abi %? (id=%?)",
+        format!("foreign item {} with abi {:?} (id={})",
              path_ident_to_str(path, item.ident, itr), abi, id)
       }
       Some(&node_method(m, _, path)) => {
-        fmt!("method %s in %s (id=%?)",
+        format!("method {} in {} (id={})",
              itr.get(m.ident.name), path_to_str(*path, itr), id)
       }
       Some(&node_trait_method(ref tm, _, path)) => {
         let m = ast_util::trait_method_to_ty_method(&**tm);
-        fmt!("method %s in %s (id=%?)",
+        format!("method {} in {} (id={})",
              itr.get(m.ident.name), path_to_str(*path, itr), id)
       }
       Some(&node_variant(ref variant, _, path)) => {
-        fmt!("variant %s in %s (id=%?)",
+        format!("variant {} in {} (id={})",
              itr.get(variant.node.name.name), path_to_str(*path, itr), id)
       }
       Some(&node_expr(expr)) => {
-        fmt!("expr %s (id=%?)", pprust::expr_to_str(expr, itr), id)
+        format!("expr {} (id={})", pprust::expr_to_str(expr, itr), id)
       }
       Some(&node_callee_scope(expr)) => {
-        fmt!("callee_scope %s (id=%?)", pprust::expr_to_str(expr, itr), id)
+        format!("callee_scope {} (id={})", pprust::expr_to_str(expr, itr), id)
       }
       Some(&node_stmt(stmt)) => {
-        fmt!("stmt %s (id=%?)",
+        format!("stmt {} (id={})",
              pprust::stmt_to_str(stmt, itr), id)
       }
       Some(&node_arg(pat)) => {
-        fmt!("arg %s (id=%?)", pprust::pat_to_str(pat, itr), id)
+        format!("arg {} (id={})", pprust::pat_to_str(pat, itr), id)
       }
       Some(&node_local(ident)) => {
-        fmt!("local (id=%?, name=%s)", id, itr.get(ident.name))
+        format!("local (id={}, name={})", id, itr.get(ident.name))
       }
       Some(&node_block(ref block)) => {
-        fmt!("block %s (id=%?)", pprust::block_to_str(block, itr), id)
+        format!("block {} (id={})", pprust::block_to_str(block, itr), id)
       }
       Some(&node_struct_ctor(_, _, path)) => {
-        fmt!("struct_ctor %s (id=%?)", path_to_str(*path, itr), id)
+        format!("struct_ctor {} (id={})", path_to_str(*path, itr), id)
       }
     }
 }
@@ -491,6 +491,6 @@ pub fn node_item_query<Result>(items: map, id: NodeId,
                                error_msg: ~str) -> Result {
     match items.find(&id) {
         Some(&node_item(it, _)) => query(it),
-        _ => fail!(error_msg)
+        _ => fail2!("{}", error_msg)
     }
 }
diff --git a/src/libsyntax/ast_util.rs b/src/libsyntax/ast_util.rs
index 9e23501a13b..f93fc1e81da 100644
--- a/src/libsyntax/ast_util.rs
+++ b/src/libsyntax/ast_util.rs
@@ -45,7 +45,7 @@ pub fn stmt_id(s: &Stmt) -> NodeId {
       StmtDecl(_, id) => id,
       StmtExpr(_, id) => id,
       StmtSemi(_, id) => id,
-      StmtMac(*) => fail!("attempted to analyze unexpanded stmt")
+      StmtMac(*) => fail2!("attempted to analyze unexpanded stmt")
     }
 }
 
@@ -72,7 +72,7 @@ pub fn def_id_of_def(d: Def) -> DefId {
         local_def(id)
       }
 
-      DefPrimTy(_) => fail!()
+      DefPrimTy(_) => fail2!()
     }
 }
 
@@ -756,7 +756,7 @@ pub fn new_mark_internal(m:Mrk, tail:SyntaxContext,table:&mut SCTable)
         }
         true => {
             match table.mark_memo.find(&key) {
-                None => fail!(~"internal error: key disappeared 2013042901"),
+                None => fail2!("internal error: key disappeared 2013042901"),
                 Some(idxptr) => {*idxptr}
             }
         }
@@ -783,7 +783,7 @@ pub fn new_rename_internal(id:Ident, to:Name, tail:SyntaxContext, table: &mut SC
         }
         true => {
             match table.rename_memo.find(&key) {
-                None => fail!(~"internal error: key disappeared 2013042902"),
+                None => fail2!("internal error: key disappeared 2013042902"),
                 Some(idxptr) => {*idxptr}
             }
         }
@@ -816,9 +816,9 @@ pub fn get_sctable() -> @mut SCTable {
 
 /// print out an SCTable for debugging
 pub fn display_sctable(table : &SCTable) {
-    error!("SC table:");
+    error2!("SC table:");
     for (idx,val) in table.table.iter().enumerate() {
-        error!("%4u : %?",idx,val);
+        error2!("{:4u} : {:?}",idx,val);
     }
 }
 
@@ -880,7 +880,7 @@ pub fn resolve_internal(id : Ident,
                             resolvedthis
                         }
                     }
-                    IllegalCtxt() => fail!(~"expected resolvable context, got IllegalCtxt")
+                    IllegalCtxt() => fail2!("expected resolvable context, got IllegalCtxt")
                 }
             };
             resolve_table.insert(key,resolved);
@@ -921,7 +921,7 @@ pub fn marksof(ctxt: SyntaxContext, stopname: Name, table: &SCTable) -> ~[Mrk] {
                     loopvar = tl;
                 }
             }
-            IllegalCtxt => fail!(~"expected resolvable context, got IllegalCtxt")
+            IllegalCtxt => fail2!("expected resolvable context, got IllegalCtxt")
         }
     }
 }
@@ -932,7 +932,7 @@ pub fn mtwt_outer_mark(ctxt: SyntaxContext) -> Mrk {
     let sctable = get_sctable();
     match sctable.table[ctxt] {
         ast::Mark(mrk,_) => mrk,
-        _ => fail!("can't retrieve outer mark when outside is not a mark")
+        _ => fail2!("can't retrieve outer mark when outside is not a mark")
     }
 }
 
@@ -1064,7 +1064,7 @@ mod test {
                     sc = tail;
                     loop;
                 }
-                IllegalCtxt => fail!("expected resolvable context, got IllegalCtxt")
+                IllegalCtxt => fail2!("expected resolvable context, got IllegalCtxt")
             }
         }
     }
diff --git a/src/libsyntax/attr.rs b/src/libsyntax/attr.rs
index 47a7d0fbf9e..31905f6ccc7 100644
--- a/src/libsyntax/attr.rs
+++ b/src/libsyntax/attr.rs
@@ -168,17 +168,17 @@ pub fn mk_sugared_doc_attr(text: @str, lo: BytePos, hi: BytePos) -> Attribute {
 /// span included in the `==` comparison a plain MetaItem.
 pub fn contains(haystack: &[@ast::MetaItem],
                 needle: @ast::MetaItem) -> bool {
-    debug!("attr::contains (name=%s)", needle.name());
+    debug2!("attr::contains (name={})", needle.name());
     do haystack.iter().any |item| {
-        debug!("  testing: %s", item.name());
+        debug2!("  testing: {}", item.name());
         item.node == needle.node
     }
 }
 
 pub fn contains_name<AM: AttrMetaMethods>(metas: &[AM], name: &str) -> bool {
-    debug!("attr::contains_name (name=%s)", name);
+    debug2!("attr::contains_name (name={})", name);
     do metas.iter().any |item| {
-        debug!("  testing: %s", item.name());
+        debug2!("  testing: {}", item.name());
         name == item.name()
     }
 }
@@ -279,23 +279,23 @@ pub fn test_cfg<AM: AttrMetaMethods, It: Iterator<AM>>
     // this would be much nicer as a chain of iterator adaptors, but
     // this doesn't work.
     let some_cfg_matches = do metas.any |mi| {
-        debug!("testing name: %s", mi.name());
+        debug2!("testing name: {}", mi.name());
         if "cfg" == mi.name() { // it is a #[cfg()] attribute
-            debug!("is cfg");
+            debug2!("is cfg");
             no_cfgs = false;
              // only #[cfg(...)] ones are understood.
             match mi.meta_item_list() {
                 Some(cfg_meta) => {
-                    debug!("is cfg(...)");
+                    debug2!("is cfg(...)");
                     do cfg_meta.iter().all |cfg_mi| {
-                        debug!("cfg(%s[...])", cfg_mi.name());
+                        debug2!("cfg({}[...])", cfg_mi.name());
                         match cfg_mi.node {
                             ast::MetaList(s, ref not_cfgs) if "not" == s => {
-                                debug!("not!");
+                                debug2!("not!");
                                 // inside #[cfg(not(...))], so these need to all
                                 // not match.
                                 not_cfgs.iter().all(|mi| {
-                                    debug!("cfg(not(%s[...]))", mi.name());
+                                    debug2!("cfg(not({}[...]))", mi.name());
                                     !contains(cfg, *mi)
                                 })
                             }
@@ -309,7 +309,7 @@ pub fn test_cfg<AM: AttrMetaMethods, It: Iterator<AM>>
             false
         }
     };
-    debug!("test_cfg (no_cfgs=%?, some_cfg_matches=%?)", no_cfgs, some_cfg_matches);
+    debug2!("test_cfg (no_cfgs={}, some_cfg_matches={})", no_cfgs, some_cfg_matches);
     no_cfgs || some_cfg_matches
 }
 
@@ -359,7 +359,7 @@ pub fn require_unique_names(diagnostic: @mut span_handler,
 
         if !set.insert(name) {
             diagnostic.span_fatal(meta.span,
-                                  fmt!("duplicate meta item `%s`", name));
+                                  format!("duplicate meta item `{}`", name));
         }
     }
 }
diff --git a/src/libsyntax/codemap.rs b/src/libsyntax/codemap.rs
index c8e40b82e0c..de8f45c880d 100644
--- a/src/libsyntax/codemap.rs
+++ b/src/libsyntax/codemap.rs
@@ -290,7 +290,7 @@ impl CodeMap {
 
     pub fn mk_substr_filename(&self, sp: Span) -> ~str {
         let pos = self.lookup_char_pos(sp.lo);
-        return fmt!("<%s:%u:%u>", pos.file.name,
+        return format!("<{}:{}:{}>", pos.file.name,
                     pos.line, pos.col.to_uint());
     }
 
@@ -336,7 +336,7 @@ impl CodeMap {
 
         let lo = self.lookup_char_pos_adj(sp.lo);
         let hi = self.lookup_char_pos_adj(sp.hi);
-        return fmt!("%s:%u:%u: %u:%u", lo.filename,
+        return format!("{}:{}:{}: {}:{}", lo.filename,
                     lo.line, lo.col.to_uint(), hi.line, hi.col.to_uint())
     }
 
@@ -374,7 +374,7 @@ impl CodeMap {
         for fm in self.files.iter() { if filename == fm.name { return *fm; } }
         //XXjdm the following triggers a mismatched type bug
         //      (or expected function, found _|_)
-        fail!(); // ("asking for " + filename + " which we don't know about");
+        fail2!(); // ("asking for " + filename + " which we don't know about");
     }
 }
 
@@ -393,7 +393,7 @@ impl CodeMap {
             }
         }
         if (a >= len) {
-            fail!("position %u does not resolve to a source location", pos.to_uint())
+            fail2!("position {} does not resolve to a source location", pos.to_uint())
         }
 
         return a;
@@ -419,11 +419,11 @@ impl CodeMap {
         let chpos = self.bytepos_to_local_charpos(pos);
         let linebpos = f.lines[a];
         let linechpos = self.bytepos_to_local_charpos(linebpos);
-        debug!("codemap: byte pos %? is on the line at byte pos %?",
+        debug2!("codemap: byte pos {:?} is on the line at byte pos {:?}",
                pos, linebpos);
-        debug!("codemap: char pos %? is on the line at char pos %?",
+        debug2!("codemap: char pos {:?} is on the line at char pos {:?}",
                chpos, linechpos);
-        debug!("codemap: byte is on line: %?", line);
+        debug2!("codemap: byte is on line: {:?}", line);
         assert!(chpos >= linechpos);
         return Loc {
             file: f,
@@ -435,7 +435,7 @@ impl CodeMap {
     fn span_to_str_no_adj(&self, sp: Span) -> ~str {
         let lo = self.lookup_char_pos(sp.lo);
         let hi = self.lookup_char_pos(sp.hi);
-        return fmt!("%s:%u:%u: %u:%u", lo.file.name,
+        return format!("{}:{}:{}: {}:{}", lo.file.name,
                     lo.line, lo.col.to_uint(), hi.line, hi.col.to_uint())
     }
 
@@ -450,7 +450,7 @@ impl CodeMap {
     // Converts an absolute BytePos to a CharPos relative to the file it is
     // located in
     fn bytepos_to_local_charpos(&self, bpos: BytePos) -> CharPos {
-        debug!("codemap: converting %? to char pos", bpos);
+        debug2!("codemap: converting {:?} to char pos", bpos);
         let idx = self.lookup_filemap_idx(bpos);
         let map = self.files[idx];
 
@@ -458,7 +458,7 @@ impl CodeMap {
         let mut total_extra_bytes = 0;
 
         for mbc in map.multibyte_chars.iter() {
-            debug!("codemap: %?-byte char at %?", mbc.bytes, mbc.pos);
+            debug2!("codemap: {:?}-byte char at {:?}", mbc.bytes, mbc.pos);
             if mbc.pos < bpos {
                 total_extra_bytes += mbc.bytes;
                 // We should never see a byte position in the middle of a
diff --git a/src/libsyntax/diagnostic.rs b/src/libsyntax/diagnostic.rs
index aa06e1bee41..03b47f89ab6 100644
--- a/src/libsyntax/diagnostic.rs
+++ b/src/libsyntax/diagnostic.rs
@@ -69,7 +69,7 @@ struct CodemapT {
 impl span_handler for CodemapT {
     fn span_fatal(@mut self, sp: Span, msg: &str) -> ! {
         self.handler.emit(Some((self.cm, sp)), msg, fatal);
-        fail!();
+        fail2!();
     }
     fn span_err(@mut self, sp: Span, msg: &str) {
         self.handler.emit(Some((self.cm, sp)), msg, error);
@@ -95,7 +95,7 @@ impl span_handler for CodemapT {
 impl handler for HandlerT {
     fn fatal(@mut self, msg: &str) -> ! {
         self.emit.emit(None, msg, fatal);
-        fail!();
+        fail2!();
     }
     fn err(@mut self, msg: &str) {
         self.emit.emit(None, msg, error);
@@ -116,7 +116,7 @@ impl handler for HandlerT {
           0u => return,
           1u => s = ~"aborting due to previous error",
           _  => {
-            s = fmt!("aborting due to %u previous errors",
+            s = format!("aborting due to {} previous errors",
                      self.err_count);
           }
         }
@@ -143,7 +143,7 @@ impl handler for HandlerT {
 }
 
 pub fn ice_msg(msg: &str) -> ~str {
-    fmt!("internal compiler error: %s", msg)
+    format!("internal compiler error: {}", msg)
 }
 
 pub fn mk_span_handler(handler: @mut handler, cm: @codemap::CodeMap)
@@ -228,12 +228,12 @@ fn print_diagnostic(topic: &str, lvl: level, msg: &str) {
     let stderr = io::stderr();
 
     if !topic.is_empty() {
-        stderr.write_str(fmt!("%s ", topic));
+        stderr.write_str(format!("{} ", topic));
     }
 
-    print_maybe_styled(fmt!("%s: ", diagnosticstr(lvl)),
+    print_maybe_styled(format!("{}: ", diagnosticstr(lvl)),
                             term::attr::ForegroundColor(diagnosticcolor(lvl)));
-    print_maybe_styled(fmt!("%s\n", msg), term::attr::Bold);
+    print_maybe_styled(format!("{}\n", msg), term::attr::Bold);
 }
 
 pub struct DefaultEmitter;
@@ -273,13 +273,13 @@ fn highlight_lines(cm: @codemap::CodeMap,
     }
     // Print the offending lines
     for line in display_lines.iter() {
-        io::stderr().write_str(fmt!("%s:%u ", fm.name, *line + 1u));
+        io::stderr().write_str(format!("{}:{} ", fm.name, *line + 1u));
         let s = fm.get_line(*line as int) + "\n";
         io::stderr().write_str(s);
     }
     if elided {
         let last_line = display_lines[display_lines.len() - 1u];
-        let s = fmt!("%s:%u ", fm.name, last_line + 1u);
+        let s = format!("{}:{} ", fm.name, last_line + 1u);
         let mut indent = s.len();
         let mut out = ~"";
         while indent > 0u {
@@ -339,7 +339,7 @@ fn print_macro_backtrace(cm: @codemap::CodeMap, sp: Span) {
     for ei in sp.expn_info.iter() {
         let ss = ei.callee.span.map_default(~"", |span| cm.span_to_str(*span));
         print_diagnostic(ss, note,
-                         fmt!("in expansion of %s!", ei.callee.name));
+                         format!("in expansion of {}!", ei.callee.name));
         let ss = cm.span_to_str(ei.call_site);
         print_diagnostic(ss, note, "expansion site");
         print_macro_backtrace(cm, ei.call_site);
diff --git a/src/libsyntax/ext/asm.rs b/src/libsyntax/ext/asm.rs
index d47435dab56..9241e8c4fbc 100644
--- a/src/libsyntax/ext/asm.rs
+++ b/src/libsyntax/ext/asm.rs
@@ -111,7 +111,7 @@ pub fn expand_asm(cx: @ExtCtxt, sp: Span, tts: &[ast::token_tree])
                         p.eat(&token::COMMA);
                     }
 
-                    let clob = fmt!("~{%s}", p.parse_str());
+                    let clob = format!("~\\{{}\\}", p.parse_str());
                     clobs.push(clob);
                 }
 
diff --git a/src/libsyntax/ext/base.rs b/src/libsyntax/ext/base.rs
index 4824924bc0f..3b4be1de3e8 100644
--- a/src/libsyntax/ext/base.rs
+++ b/src/libsyntax/ext/base.rs
@@ -423,7 +423,7 @@ pub fn expr_to_str(cx: @ExtCtxt, expr: @ast::Expr, err_msg: &str) -> @str {
 pub fn check_zero_tts(cx: @ExtCtxt, sp: Span, tts: &[ast::token_tree],
                       name: &str) {
     if tts.len() != 0 {
-        cx.span_fatal(sp, fmt!("%s takes no arguments", name));
+        cx.span_fatal(sp, format!("{} takes no arguments", name));
     }
 }
 
@@ -433,12 +433,12 @@ pub fn get_single_str_from_tts(cx: @ExtCtxt,
                                name: &str)
                                -> @str {
     if tts.len() != 1 {
-        cx.span_fatal(sp, fmt!("%s takes 1 argument.", name));
+        cx.span_fatal(sp, format!("{} takes 1 argument.", name));
     }
 
     match tts[0] {
         ast::tt_tok(_, token::LIT_STR(ident)) => cx.str_of(ident),
-        _ => cx.span_fatal(sp, fmt!("%s requires a string.", name)),
+        _ => cx.span_fatal(sp, format!("{} requires a string.", name)),
     }
 }
 
@@ -539,11 +539,11 @@ impl <K: Eq + Hash + IterBytes + 'static, V: 'static> MapChain<K,V>{
     // names? I think not.
     // delaying implementing this....
     pub fn each_key (&self, _f: &fn (&K)->bool) {
-        fail!("unimplemented 2013-02-15T10:01");
+        fail2!("unimplemented 2013-02-15T10:01");
     }
 
     pub fn each_value (&self, _f: &fn (&V) -> bool) {
-        fail!("unimplemented 2013-02-15T10:02");
+        fail2!("unimplemented 2013-02-15T10:02");
     }
 
     // Returns a copy of the value that the name maps to.
@@ -586,7 +586,7 @@ impl <K: Eq + Hash + IterBytes + 'static, V: 'static> MapChain<K,V>{
                 if satisfies_pred(map,&n,pred) {
                     map.insert(key,ext);
                 } else {
-                    fail!(~"expected map chain containing satisfying frame")
+                    fail2!("expected map chain containing satisfying frame")
                 }
             },
             ConsMapChain (~ref mut map, rest) => {
diff --git a/src/libsyntax/ext/deriving/clone.rs b/src/libsyntax/ext/deriving/clone.rs
index 9ef995b0d57..5b107a49175 100644
--- a/src/libsyntax/ext/deriving/clone.rs
+++ b/src/libsyntax/ext/deriving/clone.rs
@@ -86,10 +86,10 @@ fn cs_clone(
             all_fields = af;
         },
         EnumNonMatching(*) => cx.span_bug(span,
-                                          fmt!("Non-matching enum variants in `deriving(%s)`",
+                                          format!("Non-matching enum variants in `deriving({})`",
                                                name)),
         StaticEnum(*) | StaticStruct(*) => cx.span_bug(span,
-                                                       fmt!("Static method in `deriving(%s)`",
+                                                       format!("Static method in `deriving({})`",
                                                             name))
     }
 
@@ -105,7 +105,7 @@ fn cs_clone(
                 let ident = match o_id {
                     Some(i) => i,
                     None => cx.span_bug(span,
-                                        fmt!("unnamed field in normal struct in `deriving(%s)`",
+                                        format!("unnamed field in normal struct in `deriving({})`",
                                              name))
                 };
                 cx.field_imm(span, ident, subcall(self_f))
diff --git a/src/libsyntax/ext/deriving/decodable.rs b/src/libsyntax/ext/deriving/decodable.rs
index 66cd2d511a8..91fe71c5414 100644
--- a/src/libsyntax/ext/deriving/decodable.rs
+++ b/src/libsyntax/ext/deriving/decodable.rs
@@ -84,7 +84,7 @@ fn decodable_substructure(cx: @ExtCtxt, span: Span,
                     } else {
                         let mut fields = vec::with_capacity(n);
                         for i in range(0, n) {
-                            fields.push(getarg(fmt!("_field%u", i).to_managed(), i));
+                            fields.push(getarg(format!("_field{}", i).to_managed(), i));
                         }
                         cx.expr_call_ident(span, substr.type_ident, fields)
                     }
diff --git a/src/libsyntax/ext/deriving/encodable.rs b/src/libsyntax/ext/deriving/encodable.rs
index 99b2359232c..d1c436c045d 100644
--- a/src/libsyntax/ext/deriving/encodable.rs
+++ b/src/libsyntax/ext/deriving/encodable.rs
@@ -125,7 +125,7 @@ fn encodable_substructure(cx: @ExtCtxt, span: Span,
             for (i, f) in fields.iter().enumerate() {
                 let (name, val) = match *f {
                     (Some(id), e, _) => (cx.str_of(id), e),
-                    (None, e, _) => (fmt!("_field%u", i).to_managed(), e)
+                    (None, e, _) => (format!("_field{}", i).to_managed(), e)
                 };
                 let enc = cx.expr_method_call(span, val, encode, ~[blkencoder]);
                 let lambda = cx.lambda_expr_1(span, enc, blkarg);
diff --git a/src/libsyntax/ext/deriving/generic.rs b/src/libsyntax/ext/deriving/generic.rs
index 646b65d080b..f5e45eec7e0 100644
--- a/src/libsyntax/ext/deriving/generic.rs
+++ b/src/libsyntax/ext/deriving/generic.rs
@@ -487,7 +487,7 @@ impl<'self> MethodDef<'self> {
 
         for (i, ty) in self.args.iter().enumerate() {
             let ast_ty = ty.to_ty(cx, span, type_ident, generics);
-            let ident = cx.ident_of(fmt!("__arg_%u", i));
+            let ident = cx.ident_of(format!("__arg_{}", i));
             arg_tys.push((ident, ast_ty));
 
             let arg_expr = cx.expr_ident(span, ident);
@@ -582,7 +582,8 @@ impl<'self> MethodDef<'self> {
         for i in range(0u, self_args.len()) {
             let (pat, ident_expr) = create_struct_pattern(cx, span,
                                                           type_ident, struct_def,
-                                                          fmt!("__self_%u", i), ast::MutImmutable);
+                                                          format!("__self_{}", i),
+                                                          ast::MutImmutable);
             patterns.push(pat);
             raw_fields.push(ident_expr);
         }
@@ -767,7 +768,7 @@ impl<'self> MethodDef<'self> {
             let current_match_str = if match_count == 0 {
                 ~"__self"
             } else {
-                fmt!("__arg_%u", match_count)
+                format!("__arg_{}", match_count)
             };
 
             let mut arms = ~[];
@@ -948,7 +949,7 @@ fn create_struct_pattern(cx: @ExtCtxt,
             }
         };
         let path = cx.path_ident(span,
-                                 cx.ident_of(fmt!("%s_%u", prefix, i)));
+                                 cx.ident_of(format!("{}_{}", prefix, i)));
         paths.push(path.clone());
         ident_expr.push((opt_id, cx.expr_path(path)));
     }
@@ -993,7 +994,7 @@ fn create_enum_variant_pattern(cx: @ExtCtxt,
             let mut ident_expr = ~[];
             for i in range(0u, variant_args.len()) {
                 let path = cx.path_ident(span,
-                                         cx.ident_of(fmt!("%s_%u", prefix, i)));
+                                         cx.ident_of(format!("{}_{}", prefix, i)));
 
                 paths.push(path.clone());
                 ident_expr.push((None, cx.expr_path(path)));
diff --git a/src/libsyntax/ext/deriving/mod.rs b/src/libsyntax/ext/deriving/mod.rs
index dfd4f79cd9e..a428c6704f9 100644
--- a/src/libsyntax/ext/deriving/mod.rs
+++ b/src/libsyntax/ext/deriving/mod.rs
@@ -101,8 +101,8 @@ pub fn expand_meta_deriving(cx: @ExtCtxt,
                             "Default" => expand!(default::expand_deriving_default),
 
                             ref tname => {
-                                cx.span_err(titem.span, fmt!("unknown \
-                                    `deriving` trait: `%s`", *tname));
+                                cx.span_err(titem.span, format!("unknown \
+                                    `deriving` trait: `{}`", *tname));
                                 in_items
                             }
                         }
diff --git a/src/libsyntax/ext/env.rs b/src/libsyntax/ext/env.rs
index e97af9cbfb1..63a45b06e16 100644
--- a/src/libsyntax/ext/env.rs
+++ b/src/libsyntax/ext/env.rs
@@ -43,7 +43,7 @@ pub fn expand_env(cx: @ExtCtxt, sp: Span, tts: &[ast::token_tree])
 
     let var = expr_to_str(cx, exprs[0], "expected string literal");
     let msg = match exprs.len() {
-        1 => fmt!("Environment variable %s not defined", var).to_managed(),
+        1 => format!("Environment variable {} not defined", var).to_managed(),
         2 => expr_to_str(cx, exprs[1], "expected string literal"),
         _ => cx.span_fatal(sp, "env! takes 1 or 2 arguments")
     };
diff --git a/src/libsyntax/ext/expand.rs b/src/libsyntax/ext/expand.rs
index 697df52513d..e8307bf5786 100644
--- a/src/libsyntax/ext/expand.rs
+++ b/src/libsyntax/ext/expand.rs
@@ -51,7 +51,7 @@ pub fn expand_expr(extsbox: @mut SyntaxEnv,
                     if (pth.segments.len() > 1u) {
                         cx.span_fatal(
                             pth.span,
-                            fmt!("expected macro name without module \
+                            format!("expected macro name without module \
                                   separators"));
                     }
                     let extname = &pth.segments[0].identifier;
@@ -61,7 +61,7 @@ pub fn expand_expr(extsbox: @mut SyntaxEnv,
                         None => {
                             cx.span_fatal(
                                 pth.span,
-                                fmt!("macro undefined: '%s'", extnamestr))
+                                format!("macro undefined: '{}'", extnamestr))
                         }
                         Some(@SE(NormalTT(expandfun, exp_span))) => {
                             cx.bt_push(ExpnInfo {
@@ -92,8 +92,8 @@ pub fn expand_expr(extsbox: @mut SyntaxEnv,
                                     _ => {
                                         cx.span_fatal(
                                             pth.span,
-                                            fmt!(
-                                                "non-expr macro in expr pos: %s",
+                                            format!(
+                                                "non-expr macro in expr pos: {}",
                                                 extnamestr
                                             )
                                         )
@@ -119,7 +119,7 @@ pub fn expand_expr(extsbox: @mut SyntaxEnv,
                         _ => {
                             cx.span_fatal(
                                 pth.span,
-                                fmt!("'%s' is not a tt-style macro", extnamestr)
+                                format!("'{}' is not a tt-style macro", extnamestr)
                             )
                         }
                     }
@@ -353,13 +353,13 @@ pub fn expand_item_mac(extsbox: @mut SyntaxEnv,
     let fm = fresh_mark();
     let expanded = match (*extsbox).find(&extname.name) {
         None => cx.span_fatal(pth.span,
-                              fmt!("macro undefined: '%s!'", extnamestr)),
+                              format!("macro undefined: '{}!'", extnamestr)),
 
         Some(@SE(NormalTT(expander, span))) => {
             if it.ident.name != parse::token::special_idents::invalid.name {
                 cx.span_fatal(pth.span,
-                              fmt!("macro %s! expects no ident argument, \
-                                    given '%s'", extnamestr,
+                              format!("macro {}! expects no ident argument, \
+                                    given '{}'", extnamestr,
                                    ident_to_str(&it.ident)));
             }
             cx.bt_push(ExpnInfo {
@@ -377,7 +377,7 @@ pub fn expand_item_mac(extsbox: @mut SyntaxEnv,
         Some(@SE(IdentTT(expander, span))) => {
             if it.ident.name == parse::token::special_idents::invalid.name {
                 cx.span_fatal(pth.span,
-                              fmt!("macro %s! expects an ident argument",
+                              format!("macro {}! expects an ident argument",
                                    extnamestr));
             }
             cx.bt_push(ExpnInfo {
@@ -393,7 +393,7 @@ pub fn expand_item_mac(extsbox: @mut SyntaxEnv,
             expander.expand(cx, it.span, it.ident, marked_tts, marked_ctxt)
         }
         _ => cx.span_fatal(
-            it.span, fmt!("%s! is not legal in item position", extnamestr))
+            it.span, format!("{}! is not legal in item position", extnamestr))
     };
 
     let maybe_it = match expanded {
@@ -402,7 +402,7 @@ pub fn expand_item_mac(extsbox: @mut SyntaxEnv,
                 .and_then(|i| fld.fold_item(i))
         }
         MRExpr(_) => {
-            cx.span_fatal(pth.span, fmt!("expr macro in item position: %s", extnamestr))
+            cx.span_fatal(pth.span, format!("expr macro in item position: {}", extnamestr))
         }
         MRAny(any_macro) => {
             any_macro.make_item()
@@ -429,8 +429,8 @@ fn insert_macro(exts: SyntaxEnv, name: ast::Name, transformer: @Transformer) {
         match t {
             &@BlockInfo(BlockInfo {macros_escape:false,_}) => true,
             &@BlockInfo(BlockInfo {_}) => false,
-            _ => fail!(fmt!("special identifier %? was bound to a non-BlockInfo",
-                            special_block_name))
+            _ => fail2!("special identifier {:?} was bound to a non-BlockInfo",
+                        special_block_name)
         }
     };
     exts.insert_into_frame(name,transformer,intern(special_block_name),
@@ -463,7 +463,7 @@ pub fn expand_stmt(extsbox: @mut SyntaxEnv,
     let extnamestr = ident_to_str(extname);
     let fully_expanded: @ast::Stmt = match (*extsbox).find(&extname.name) {
         None => {
-            cx.span_fatal(pth.span, fmt!("macro undefined: '%s'", extnamestr))
+            cx.span_fatal(pth.span, format!("macro undefined: '{}'", extnamestr))
         }
 
         Some(@SE(NormalTT(expandfun, exp_span))) => {
@@ -496,7 +496,7 @@ pub fn expand_stmt(extsbox: @mut SyntaxEnv,
                 MRAny(any_macro) => any_macro.make_stmt(),
                 _ => cx.span_fatal(
                     pth.span,
-                    fmt!("non-stmt macro in stmt pos: %s", extnamestr))
+                    format!("non-stmt macro in stmt pos: {}", extnamestr))
             };
             let marked_after = mark_stmt(expanded,fm);
 
@@ -521,7 +521,7 @@ pub fn expand_stmt(extsbox: @mut SyntaxEnv,
 
         _ => {
             cx.span_fatal(pth.span,
-                          fmt!("'%s' is not a tt-style macro", extnamestr))
+                          format!("'{}' is not a tt-style macro", extnamestr))
         }
     };
 
@@ -741,7 +741,7 @@ pub fn expand_block_elts(exts: SyntaxEnv, b: &Block, fld: &MacroExpander)
 fn mustbesome<T>(val : Option<T>) -> T {
     match val {
         Some(v) => v,
-        None => fail!("rename_fold returned None")
+        None => fail2!("rename_fold returned None")
     }
 }
 
@@ -749,8 +749,8 @@ fn mustbesome<T>(val : Option<T>) -> T {
 fn get_block_info(exts : SyntaxEnv) -> BlockInfo {
     match exts.find_in_topmost_frame(&intern(special_block_name)) {
         Some(@BlockInfo(bi)) => bi,
-        _ => fail!(fmt!("special identifier %? was bound to a non-BlockInfo",
-                       @" block"))
+        _ => fail2!("special identifier {:?} was bound to a non-BlockInfo",
+                    @" block")
     }
 }
 
@@ -782,7 +782,7 @@ pub fn renames_to_fold(renames: @mut ~[(ast::Ident,ast::Name)]) -> @ast_fold {
 fn apply_pending_renames(folder : @ast_fold, stmt : ast::Stmt) -> @ast::Stmt {
     match folder.fold_stmt(&stmt) {
         Some(s) => s,
-        None => fail!(fmt!("renaming of stmt produced None"))
+        None => fail2!("renaming of stmt produced None")
     }
 }
 
@@ -813,7 +813,7 @@ pub fn std_macros() -> @str {
     mod fmt_extension {
         #[macro_escape];
 
-        macro_rules! fmt(($($arg:tt)*) => (oldfmt!($($arg)*)))
+        macro_rules! fmt(($($arg:tt)*) => (oldformat!($($arg)*)))
 
         macro_rules! log(
             ($lvl:expr, $arg:expr) => ({
@@ -821,7 +821,7 @@ pub fn std_macros() -> @str {
                 if lvl <= __log_level() {
                     format_args!(|args| {
                         ::std::logging::log(lvl, args)
-                    }, \"{}\", fmt!(\"%?\", $arg))
+                    }, \"{}\", format!(\"{:?}\", $arg))
                 }
             });
             ($lvl:expr, $($arg:expr),+) => ({
@@ -829,7 +829,7 @@ pub fn std_macros() -> @str {
                 if lvl <= __log_level() {
                     format_args!(|args| {
                         ::std::logging::log(lvl, args)
-                    }, \"{}\", fmt!($($arg),+))
+                    }, \"{}\", format!($($arg),+))
                 }
             })
         )
@@ -842,13 +842,13 @@ pub fn std_macros() -> @str {
 
         macro_rules! fail(
             () => (
-                fail!(\"explicit failure\")
+                fail2!(\"explicit failure\")
             );
             ($msg:expr) => (
                 ::std::sys::FailWithCause::fail_with($msg, file!(), line!())
             );
             ($( $arg:expr ),+) => (
-                ::std::sys::FailWithCause::fail_with(fmt!( $($arg),+ ), file!(), line!())
+                ::std::sys::FailWithCause::fail_with(format!( $($arg),+ ), file!(), line!())
             )
         )
     }
@@ -896,7 +896,7 @@ pub fn std_macros() -> @str {
         };
         ($cond:expr, $( $arg:expr ),+) => {
             if !$cond {
-                ::std::sys::FailWithCause::fail_with(fmt!( $($arg),+ ), file!(), line!())
+                ::std::sys::FailWithCause::fail_with(format!( $($arg),+ ), file!(), line!())
             }
         }
     )
@@ -1164,7 +1164,7 @@ pub fn inject_std_macros(parse_sess: @mut parse::ParseSess,
                                               ~[],
                                               parse_sess) {
         Some(item) => item,
-        None => fail!("expected core macros to parse correctly")
+        None => fail2!("expected core macros to parse correctly")
     };
 
     let injector = @Injector {
@@ -1422,16 +1422,16 @@ mod test {
     use util::parser_testing::{string_to_pat, string_to_tts, strs_to_idents};
     use visit;
 
-    // make sure that fail! is present
+    // make sure that fail2! is present
     #[test] fn fail_exists_test () {
-        let src = @"fn main() { fail!(\"something appropriately gloomy\");}";
+        let src = @"fn main() { fail2!(\"something appropriately gloomy\");}";
         let sess = parse::new_parse_sess(None);
         let crate_ast = parse::parse_crate_from_source_str(
             @"<test>",
             src,
             ~[],sess);
         let crate_ast = inject_std_macros(sess, ~[], crate_ast);
-        // don't bother with striping, doesn't affect fail!.
+        // don't bother with striping, doesn't affect fail2!.
         expand_crate(sess,~[],crate_ast);
     }
 
@@ -1489,7 +1489,7 @@ mod test {
             cfg,~[],sess);
         match item_ast {
             Some(_) => (), // success
-            None => fail!("expected this to parse")
+            None => fail2!("expected this to parse")
         }
     }
 
@@ -1528,7 +1528,7 @@ mod test {
         let marked_once_ctxt =
             match marked_once[0] {
                 ast::tt_tok(_,token::IDENT(id,_)) => id.ctxt,
-                _ => fail!(fmt!("unexpected shape for marked tts: %?",marked_once[0]))
+                _ => fail2!(format!("unexpected shape for marked tts: {:?}",marked_once[0]))
             };
         assert_eq!(mtwt_marksof(marked_once_ctxt,invalid_name),~[fm]);
         let remarked = mtwt_cancel_outer_mark(marked_once,marked_once_ctxt);
@@ -1536,7 +1536,7 @@ mod test {
         match remarked[0] {
             ast::tt_tok(_,token::IDENT(id,_)) =>
             assert_eq!(mtwt_marksof(id.ctxt,invalid_name),~[]),
-            _ => fail!(fmt!("unexpected shape for marked tts: %?",remarked[0]))
+            _ => fail2!(format!("unexpected shape for marked tts: {:?}",remarked[0]))
         }
     }
 
@@ -1583,7 +1583,7 @@ mod test {
 
     //fn expand_and_resolve(crate_str: @str) -> ast::crate {
         //let expanded_ast = expand_crate_str(crate_str);
-        // std::io::println(fmt!("expanded: %?\n",expanded_ast));
+        // std::io::println(format!("expanded: {:?}\n",expanded_ast));
         //mtwt_resolve_crate(expanded_ast)
     //}
     //fn expand_and_resolve_and_pretty_print (crate_str : @str) -> ~str {
@@ -1693,8 +1693,8 @@ mod test {
                                                     invalid_name);
                     if (!(varref_name==binding_name)){
                         std::io::println("uh oh, should match but doesn't:");
-                        std::io::println(fmt!("varref: %?",varref));
-                        std::io::println(fmt!("binding: %?", bindings[binding_idx]));
+                        std::io::println(format!("varref: {:?}",varref));
+                        std::io::println(format!("binding: {:?}", bindings[binding_idx]));
                         ast_util::display_sctable(get_sctable());
                     }
                     assert_eq!(varref_name,binding_name);
@@ -1712,12 +1712,12 @@ mod test {
                         println!("text of test case: \"{}\"", teststr);
                         println!("");
                         println!("uh oh, matches but shouldn't:");
-                        std::io::println(fmt!("varref: %?",varref));
+                        std::io::println(format!("varref: {:?}",varref));
                         // good lord, you can't make a path with 0 segments, can you?
                         println!("varref's first segment's uint: {}, and string: \"{}\"",
                                  varref.segments[0].identifier.name,
                                  ident_to_str(&varref.segments[0].identifier));
-                        std::io::println(fmt!("binding: %?", bindings[binding_idx]));
+                        std::io::println(format!("binding: {:?}", bindings[binding_idx]));
                         ast_util::display_sctable(get_sctable());
                     }
                     assert!(!fail);
@@ -1727,7 +1727,7 @@ mod test {
     }
 
     #[test] fn fmt_in_macro_used_inside_module_macro() {
-        let crate_str = @"macro_rules! fmt_wrap(($b:expr)=>(fmt!(\"left: %?\", $b)))
+        let crate_str = @"macro_rules! fmt_wrap(($b:expr)=>($b.to_str()))
 macro_rules! foo_module (() => (mod generated { fn a() { let xx = 147; fmt_wrap!(xx);}}))
 foo_module!()
 ";
@@ -1739,7 +1739,7 @@ foo_module!()
             bindings.iter().filter(|b|{@"xx" == (ident_to_str(*b))}).collect();
         let cxbind = match cxbinds {
             [b] => b,
-            _ => fail!("expected just one binding for ext_cx")
+            _ => fail2!("expected just one binding for ext_cx")
         };
         let resolved_binding = mtwt_resolve(*cxbind);
         // find all the xx varrefs:
@@ -1751,15 +1751,16 @@ foo_module!()
                                      }).enumerate() {
             if (mtwt_resolve(v.segments[0].identifier) != resolved_binding) {
                 std::io::println("uh oh, xx binding didn't match xx varref:");
-                std::io::println(fmt!("this is xx varref # %?",idx));
-                std::io::println(fmt!("binding: %?",cxbind));
-                std::io::println(fmt!("resolves to: %?",resolved_binding));
-                std::io::println(fmt!("varref: %?",v.segments[0].identifier));
-                std::io::println(fmt!("resolves to: %?",mtwt_resolve(v.segments[0].identifier)));
+                std::io::println(format!("this is xx varref \\# {:?}",idx));
+                std::io::println(format!("binding: {:?}",cxbind));
+                std::io::println(format!("resolves to: {:?}",resolved_binding));
+                std::io::println(format!("varref: {:?}",v.segments[0].identifier));
+                std::io::println(format!("resolves to: {:?}",
+                                         mtwt_resolve(v.segments[0].identifier)));
                 let table = get_sctable();
                 std::io::println("SC table:");
                 for (idx,val) in table.table.iter().enumerate() {
-                    std::io::println(fmt!("%4u : %?",idx,val));
+                    std::io::println(format!("{:4u} : {:?}",idx,val));
                 }
             }
             assert_eq!(mtwt_resolve(v.segments[0].identifier),resolved_binding);
diff --git a/src/libsyntax/ext/fmt.rs b/src/libsyntax/ext/fmt.rs
index d48fa03c0ef..cd364e7ad64 100644
--- a/src/libsyntax/ext/fmt.rs
+++ b/src/libsyntax/ext/fmt.rs
@@ -34,7 +34,7 @@ pub fn expand_syntax_ext(cx: @ExtCtxt, sp: Span, tts: &[ast::token_tree])
         expr_to_str(cx, args[0],
                     "first argument to fmt! must be a string literal.");
     let fmtspan = args[0].span;
-    debug!("Format string: %s", fmt);
+    debug2!("Format string: {}", fmt);
     fn parse_fmt_err_(cx: @ExtCtxt, sp: Span, msg: &str) -> ! {
         cx.span_fatal(sp, msg);
     }
@@ -198,53 +198,53 @@ fn pieces_to_expr(cx: @ExtCtxt, sp: Span,
                               cx.expr_mut_addr_of(arg.span, buf));
     }
     fn log_conv(c: &Conv) {
-        debug!("Building conversion:");
+        debug2!("Building conversion:");
         match c.param {
-          Some(p) => { debug!("param: %s", p.to_str()); }
-          _ => debug!("param: none")
+          Some(p) => { debug2!("param: {}", p.to_str()); }
+          _ => debug2!("param: none")
         }
         for f in c.flags.iter() {
             match *f {
-              FlagLeftJustify => debug!("flag: left justify"),
-              FlagLeftZeroPad => debug!("flag: left zero pad"),
-              FlagSpaceForSign => debug!("flag: left space pad"),
-              FlagSignAlways => debug!("flag: sign always"),
-              FlagAlternate => debug!("flag: alternate")
+              FlagLeftJustify => debug2!("flag: left justify"),
+              FlagLeftZeroPad => debug2!("flag: left zero pad"),
+              FlagSpaceForSign => debug2!("flag: left space pad"),
+              FlagSignAlways => debug2!("flag: sign always"),
+              FlagAlternate => debug2!("flag: alternate")
             }
         }
         match c.width {
           CountIs(i) =>
-              debug!("width: count is %s", i.to_str()),
+              debug2!("width: count is {}", i.to_str()),
           CountIsParam(i) =>
-              debug!("width: count is param %s", i.to_str()),
-          CountIsNextParam => debug!("width: count is next param"),
-          CountImplied => debug!("width: count is implied")
+              debug2!("width: count is param {}", i.to_str()),
+          CountIsNextParam => debug2!("width: count is next param"),
+          CountImplied => debug2!("width: count is implied")
         }
         match c.precision {
           CountIs(i) =>
-              debug!("prec: count is %s", i.to_str()),
+              debug2!("prec: count is {}", i.to_str()),
           CountIsParam(i) =>
-              debug!("prec: count is param %s", i.to_str()),
-          CountIsNextParam => debug!("prec: count is next param"),
-          CountImplied => debug!("prec: count is implied")
+              debug2!("prec: count is param {}", i.to_str()),
+          CountIsNextParam => debug2!("prec: count is next param"),
+          CountImplied => debug2!("prec: count is implied")
         }
         match c.ty {
-          TyBool => debug!("type: bool"),
-          TyStr => debug!("type: str"),
-          TyChar => debug!("type: char"),
+          TyBool => debug2!("type: bool"),
+          TyStr => debug2!("type: str"),
+          TyChar => debug2!("type: char"),
           TyInt(s) => match s {
-            Signed => debug!("type: signed"),
-            Unsigned => debug!("type: unsigned")
+            Signed => debug2!("type: signed"),
+            Unsigned => debug2!("type: unsigned")
           },
-          TyBits => debug!("type: bits"),
+          TyBits => debug2!("type: bits"),
           TyHex(cs) => match cs {
-            CaseUpper => debug!("type: uhex"),
-            CaseLower => debug!("type: lhex"),
+            CaseUpper => debug2!("type: uhex"),
+            CaseLower => debug2!("type: lhex"),
           },
-          TyOctal => debug!("type: octal"),
-          TyFloat => debug!("type: float"),
-          TyPointer => debug!("type: pointer"),
-          TyPoly => debug!("type: poly")
+          TyOctal => debug2!("type: octal"),
+          TyFloat => debug2!("type: float"),
+          TyPointer => debug2!("type: pointer"),
+          TyPoly => debug2!("type: poly")
         }
     }
 
@@ -319,7 +319,7 @@ fn pieces_to_expr(cx: @ExtCtxt, sp: Span,
     let expected_nargs = n + 1u; // n conversions + the fmt string
     if expected_nargs < nargs {
         cx.span_fatal
-            (sp, fmt!("too many arguments to fmt!. found %u, expected %u",
+            (sp, format!("too many arguments to fmt!. found {}, expected {}",
                            nargs, expected_nargs));
     }
 
diff --git a/src/libsyntax/ext/format.rs b/src/libsyntax/ext/format.rs
index ef3879f56ae..a9e5318db40 100644
--- a/src/libsyntax/ext/format.rs
+++ b/src/libsyntax/ext/format.rs
@@ -51,7 +51,7 @@ struct Context {
 
 impl Context {
     /// Parses the arguments from the given list of tokens, returning None if
-    /// there's a parse error so we can continue parsing other fmt! expressions.
+    /// there's a parse error so we can continue parsing other format! expressions.
     fn parse_args(&mut self, sp: Span,
                   tts: &[ast::token_tree]) -> (@ast::Expr, Option<@ast::Expr>) {
         let p = rsparse::new_parser_from_tts(self.ecx.parse_sess(),
@@ -92,8 +92,8 @@ impl Context {
                     }
                     _ => {
                         self.ecx.span_err(*p.span,
-                                          fmt!("expected ident for named \
-                                                argument, but found `%s`",
+                                          format!("expected ident for named \
+                                                argument, but found `{}`",
                                                p.this_token_to_str()));
                         return (extra, None);
                     }
@@ -104,8 +104,8 @@ impl Context {
                 match self.names.find(&name) {
                     None => {}
                     Some(prev) => {
-                        self.ecx.span_err(e.span, fmt!("duplicate argument \
-                                                        named `%s`", name));
+                        self.ecx.span_err(e.span, format!("duplicate argument \
+                                                        named `{}`", name));
                         self.ecx.parse_sess.span_diagnostic.span_note(
                             prev.span, "previously here");
                         loop
@@ -207,13 +207,13 @@ impl Context {
                         match arm.selector {
                             Left(name) => {
                                 self.ecx.span_err(self.fmtsp,
-                                                  fmt!("duplicate selector \
-                                                       `%?`", name));
+                                                  format!("duplicate selector \
+                                                           `{:?}`", name));
                             }
                             Right(idx) => {
                                 self.ecx.span_err(self.fmtsp,
-                                                  fmt!("duplicate selector \
-                                                       `=%u`", idx));
+                                                  format!("duplicate selector \
+                                                           `={}`", idx));
                             }
                         }
                     }
@@ -227,7 +227,7 @@ impl Context {
                 for arm in arms.iter() {
                     if !seen_cases.insert(arm.selector) {
                         self.ecx.span_err(self.fmtsp,
-                                          fmt!("duplicate selector `%s`",
+                                          format!("duplicate selector `{}`",
                                                arm.selector));
                     } else if arm.selector == "" {
                         self.ecx.span_err(self.fmtsp,
@@ -245,8 +245,8 @@ impl Context {
         match arg {
             Left(arg) => {
                 if arg < 0 || self.args.len() <= arg {
-                    let msg = fmt!("invalid reference to argument `%u` (there \
-                                    are %u arguments)", arg, self.args.len());
+                    let msg = format!("invalid reference to argument `{}` (there \
+                                    are {} arguments)", arg, self.args.len());
                     self.ecx.span_err(self.fmtsp, msg);
                     return;
                 }
@@ -260,7 +260,7 @@ impl Context {
                 let span = match self.names.find(&name) {
                     Some(e) => e.span,
                     None => {
-                        let msg = fmt!("there is no argument named `%s`", name);
+                        let msg = format!("there is no argument named `{}`", name);
                         self.ecx.span_err(self.fmtsp, msg);
                         return;
                     }
@@ -298,20 +298,20 @@ impl Context {
         match (cur, ty) {
             (Known(cur), Known(ty)) => {
                 self.ecx.span_err(sp,
-                                  fmt!("argument redeclared with type `%s` when \
-                                        it was previously `%s`", ty, cur));
+                                  format!("argument redeclared with type `{}` when \
+                                           it was previously `{}`", ty, cur));
             }
             (Known(cur), _) => {
                 self.ecx.span_err(sp,
-                                  fmt!("argument used to format with `%s` was \
-                                        attempted to not be used for formatting",
-                                        cur));
+                                  format!("argument used to format with `{}` was \
+                                           attempted to not be used for formatting",
+                                           cur));
             }
             (_, Known(ty)) => {
                 self.ecx.span_err(sp,
-                                  fmt!("argument previously used as a format \
-                                        argument attempted to be used as `%s`",
-                                        ty));
+                                  format!("argument previously used as a format \
+                                           argument attempted to be used as `{}`",
+                                           ty));
             }
             (_, _) => {
                 self.ecx.span_err(sp, "argument declared with multiple formats");
@@ -405,7 +405,7 @@ impl Context {
                         }).collect();
                         let (lr, selarg) = match arm.selector {
                             Left(t) => {
-                                let p = ctpath(fmt!("%?", t));
+                                let p = ctpath(format!("{:?}", t));
                                 let p = self.ecx.path_global(sp, p);
                                 (self.ecx.ident_of("Left"),
                                  self.ecx.expr_path(p))
@@ -444,7 +444,7 @@ impl Context {
                 ~[]
             ), None);
             let st = ast::item_static(ty, ast::MutImmutable, method);
-            let static_name = self.ecx.ident_of(fmt!("__static_method_%u",
+            let static_name = self.ecx.ident_of(format!("__static_method_{}",
                                                      self.method_statics.len()));
             // Flag these statics as `address_insignificant` so LLVM can
             // merge duplicate globals as much as possible (which we're
@@ -538,7 +538,7 @@ impl Context {
         }
     }
 
-    /// Actually builds the expression which the ifmt! block will be expanded
+    /// Actually builds the expression which the iformat! block will be expanded
     /// to
     fn to_expr(&self, extra: @ast::Expr) -> @ast::Expr {
         let mut lets = ~[];
@@ -584,13 +584,13 @@ impl Context {
         //      foo(bar(&1))
         // the lifetime of `1` doesn't outlast the call to `bar`, so it's not
         // vald for the call to `foo`. To work around this all arguments to the
-        // fmt! string are shoved into locals. Furthermore, we shove the address
+        // format! string are shoved into locals. Furthermore, we shove the address
         // of each variable because we don't want to move out of the arguments
         // passed to this function.
         for (i, &e) in self.args.iter().enumerate() {
             if self.arg_types[i].is_none() { loop } // error already generated
 
-            let name = self.ecx.ident_of(fmt!("__arg%u", i));
+            let name = self.ecx.ident_of(format!("__arg{}", i));
             let e = self.ecx.expr_addr_of(e.span, e);
             lets.push(self.ecx.stmt_let(e.span, false, name, e));
             locals.push(self.format_arg(e.span, Left(i),
@@ -599,7 +599,7 @@ impl Context {
         for (&name, &e) in self.names.iter() {
             if !self.name_types.contains_key(&name) { loop }
 
-            let lname = self.ecx.ident_of(fmt!("__arg%s", name));
+            let lname = self.ecx.ident_of(format!("__arg{}", name));
             let e = self.ecx.expr_addr_of(e.span, e);
             lets.push(self.ecx.stmt_let(e.span, false, lname, e));
             names[*self.name_positions.get(&name)] =
@@ -662,8 +662,8 @@ impl Context {
                     "x" => "LowerHex",
                     "X" => "UpperHex",
                     _ => {
-                        self.ecx.span_err(sp, fmt!("unknown format trait \
-                                                    `%s`", tyname));
+                        self.ecx.span_err(sp, format!("unknown format trait \
+                                                       `{}`", tyname));
                         "Dummy"
                     }
                 }
diff --git a/src/libsyntax/ext/quote.rs b/src/libsyntax/ext/quote.rs
index 6527b083cc1..24a5f9d5e3c 100644
--- a/src/libsyntax/ext/quote.rs
+++ b/src/libsyntax/ext/quote.rs
@@ -255,8 +255,8 @@ pub mod rt {
             match res {
                 Some(ast) => ast,
                 None => {
-                    error!("Parse error with ```\n%s\n```", s);
-                    fail!()
+                    error2!("Parse error with ```\n{}\n```", s);
+                    fail2!()
                 }
             }
         }
@@ -484,7 +484,7 @@ fn mk_token(cx: @ExtCtxt, sp: Span, tok: &token::Token) -> @ast::Expr {
                                       ~[mk_ident(cx, sp, ident)]);
         }
 
-        INTERPOLATED(_) => fail!("quote! with interpolated token"),
+        INTERPOLATED(_) => fail2!("quote! with interpolated token"),
 
         _ => ()
     }
@@ -522,7 +522,7 @@ fn mk_token(cx: @ExtCtxt, sp: Span, tok: &token::Token) -> @ast::Expr {
         DOLLAR => "DOLLAR",
         UNDERSCORE => "UNDERSCORE",
         EOF => "EOF",
-        _ => fail!()
+        _ => fail2!()
     };
     cx.expr_ident(sp, id_ext(name))
 }
@@ -547,7 +547,7 @@ fn mk_tt(cx: @ExtCtxt, sp: Span, tt: &ast::token_tree)
         }
 
         ast::tt_delim(ref tts) => mk_tts(cx, sp, **tts),
-        ast::tt_seq(*) => fail!("tt_seq in quote!"),
+        ast::tt_seq(*) => fail2!("tt_seq in quote!"),
 
         ast::tt_nonterminal(sp, ident) => {
 
diff --git a/src/libsyntax/ext/tt/macro_parser.rs b/src/libsyntax/ext/tt/macro_parser.rs
index aa4183837e3..7db64feb809 100644
--- a/src/libsyntax/ext/tt/macro_parser.rs
+++ b/src/libsyntax/ext/tt/macro_parser.rs
@@ -122,7 +122,7 @@ pub struct MatcherPos {
 pub fn copy_up(mpu: &matcher_pos_up) -> ~MatcherPos {
     match *mpu {
       matcher_pos_up(Some(ref mp)) => (*mp).clone(),
-      _ => fail!()
+      _ => fail2!()
     }
 }
 
@@ -384,14 +384,14 @@ pub fn parse(
                 let nts = bb_eis.map(|ei| {
                     match ei.elts[ei.idx].node {
                       match_nonterminal(ref bind,ref name,_) => {
-                        fmt!("%s ('%s')", ident_to_str(name),
+                        format!("{} ('{}')", ident_to_str(name),
                              ident_to_str(bind))
                       }
-                      _ => fail!()
+                      _ => fail2!()
                     } }).connect(" or ");
-                return error(sp, fmt!(
+                return error(sp, format!(
                     "Local ambiguity: multiple parsing options: \
-                     built-in NTs %s or %u other options.",
+                     built-in NTs {} or {} other options.",
                     nts, next_eis.len()));
             } else if (bb_eis.len() == 0u && next_eis.len() == 0u) {
                 return failure(sp, ~"No rules expected the token: "
@@ -412,7 +412,7 @@ pub fn parse(
                         parse_nt(&rust_parser, ident_to_str(name))));
                     ei.idx += 1u;
                   }
-                  _ => fail!()
+                  _ => fail2!()
                 }
                 cur_eis.push(ei);
 
diff --git a/src/libsyntax/ext/tt/transcribe.rs b/src/libsyntax/ext/tt/transcribe.rs
index 8a858f3d985..f8d48d00db9 100644
--- a/src/libsyntax/ext/tt/transcribe.rs
+++ b/src/libsyntax/ext/tt/transcribe.rs
@@ -117,7 +117,7 @@ fn lookup_cur_matched(r: &mut TtReader, name: Ident) -> @named_match {
     match r.interpolations.find_copy(&name) {
         Some(s) => lookup_cur_matched_by_matched(r, s),
         None => {
-            r.sp_diag.span_fatal(r.cur_span, fmt!("unknown macro variable `%s`",
+            r.sp_diag.span_fatal(r.cur_span, format!("unknown macro variable `{}`",
                                                   ident_to_str(&name)));
         }
     }
@@ -142,9 +142,9 @@ fn lockstep_iter_size(t: &token_tree, r: &mut TtReader) -> lis {
             lis_constraint(r_len, ref r_id) => {
                 let l_n = ident_to_str(l_id);
                 let r_n = ident_to_str(r_id);
-                lis_contradiction(fmt!("Inconsistent lockstep iteration: \
-                                       '%s' has %u items, but '%s' has %u",
-                                        l_n, l_len, r_n, r_len))
+                lis_contradiction(format!("Inconsistent lockstep iteration: \
+                                           '{}' has {} items, but '{}' has {}",
+                                           l_n, l_len, r_n, r_len))
             }
           }
         }
@@ -294,7 +294,7 @@ pub fn tt_next_token(r: &mut TtReader) -> TokenAndSpan {
               matched_seq(*) => {
                 r.sp_diag.span_fatal(
                     r.cur_span, /* blame the macro writer */
-                    fmt!("variable '%s' is still repeating at this depth",
+                    format!("variable '{}' is still repeating at this depth",
                          ident_to_str(&ident)));
               }
             }
diff --git a/src/libsyntax/fold.rs b/src/libsyntax/fold.rs
index b823ff726ac..909f5e5c443 100644
--- a/src/libsyntax/fold.rs
+++ b/src/libsyntax/fold.rs
@@ -892,7 +892,7 @@ mod test {
                 let a_val = $a;
                 let b_val = $b;
                 if !(pred_val(a_val,b_val)) {
-                    fail!("expected args satisfying %s, got %? and %?",
+                    fail2!("expected args satisfying {}, got {:?} and {:?}",
                           $predname, a_val, b_val);
                 }
             }
diff --git a/src/libsyntax/opt_vec.rs b/src/libsyntax/opt_vec.rs
index 46940d2d4da..ca93cbaea39 100644
--- a/src/libsyntax/opt_vec.rs
+++ b/src/libsyntax/opt_vec.rs
@@ -66,7 +66,7 @@ impl<T> OptVec<T> {
 
     pub fn get<'a>(&'a self, i: uint) -> &'a T {
         match *self {
-            Empty => fail!("Invalid index %u", i),
+            Empty => fail2!("Invalid index {}", i),
             Vec(ref v) => &v[i]
         }
     }
diff --git a/src/libsyntax/parse/attr.rs b/src/libsyntax/parse/attr.rs
index 1bc334f1140..dba2f0b9417 100644
--- a/src/libsyntax/parse/attr.rs
+++ b/src/libsyntax/parse/attr.rs
@@ -32,7 +32,7 @@ impl parser_attr for Parser {
     fn parse_outer_attributes(&self) -> ~[ast::Attribute] {
         let mut attrs: ~[ast::Attribute] = ~[];
         loop {
-            debug!("parse_outer_attributes: self.token=%?",
+            debug2!("parse_outer_attributes: self.token={:?}",
                    self.token);
             match *self.token {
               token::INTERPOLATED(token::nt_attr(*)) => {
@@ -67,7 +67,7 @@ impl parser_attr for Parser {
     // if permit_inner is true, then a trailing `;` indicates an inner
     // attribute
     fn parse_attribute(&self, permit_inner: bool) -> ast::Attribute {
-        debug!("parse_attributes: permit_inner=%? self.token=%?",
+        debug2!("parse_attributes: permit_inner={:?} self.token={:?}",
                permit_inner, self.token);
         let (span, value) = match *self.token {
             INTERPOLATED(token::nt_attr(attr)) => {
@@ -85,8 +85,8 @@ impl parser_attr for Parser {
                 (mk_sp(lo, hi), meta_item)
             }
             _ => {
-                self.fatal(fmt!("expected `#` but found `%s`",
-                                self.this_token_to_str()));
+                self.fatal(format!("expected `\\#` but found `{}`",
+                                   self.this_token_to_str()));
             }
         };
         let style = if permit_inner && *self.token == token::SEMI {
diff --git a/src/libsyntax/parse/comments.rs b/src/libsyntax/parse/comments.rs
index 88c9fc3e0f7..f163bec7d4e 100644
--- a/src/libsyntax/parse/comments.rs
+++ b/src/libsyntax/parse/comments.rs
@@ -134,7 +134,7 @@ pub fn strip_doc_comment_decoration(comment: &str) -> ~str {
         return lines.connect("\n");
     }
 
-    fail!("not a doc-comment: %s", comment);
+    fail2!("not a doc-comment: {}", comment);
 }
 
 fn read_to_eol(rdr: @mut StringReader) -> ~str {
@@ -161,7 +161,7 @@ fn consume_non_eol_whitespace(rdr: @mut StringReader) {
 }
 
 fn push_blank_line_comment(rdr: @mut StringReader, comments: &mut ~[cmnt]) {
-    debug!(">>> blank-line comment");
+    debug2!(">>> blank-line comment");
     let v: ~[~str] = ~[];
     comments.push(cmnt {style: blank_line, lines: v, pos: rdr.last_pos});
 }
@@ -179,9 +179,9 @@ fn consume_whitespace_counting_blank_lines(rdr: @mut StringReader,
 
 fn read_shebang_comment(rdr: @mut StringReader, code_to_the_left: bool,
                                             comments: &mut ~[cmnt]) {
-    debug!(">>> shebang comment");
+    debug2!(">>> shebang comment");
     let p = rdr.last_pos;
-    debug!("<<< shebang comment");
+    debug2!("<<< shebang comment");
     comments.push(cmnt {
         style: if code_to_the_left { trailing } else { isolated },
         lines: ~[read_one_line_comment(rdr)],
@@ -191,19 +191,19 @@ fn read_shebang_comment(rdr: @mut StringReader, code_to_the_left: bool,
 
 fn read_line_comments(rdr: @mut StringReader, code_to_the_left: bool,
                                           comments: &mut ~[cmnt]) {
-    debug!(">>> line comments");
+    debug2!(">>> line comments");
     let p = rdr.last_pos;
     let mut lines: ~[~str] = ~[];
     while rdr.curr == '/' && nextch(rdr) == '/' {
         let line = read_one_line_comment(rdr);
-        debug!("%s", line);
+        debug2!("{}", line);
         if is_doc_comment(line) { // doc-comments are not put in comments
             break;
         }
         lines.push(line);
         consume_non_eol_whitespace(rdr);
     }
-    debug!("<<< line comments");
+    debug2!("<<< line comments");
     if !lines.is_empty() {
         comments.push(cmnt {
             style: if code_to_the_left { trailing } else { isolated },
@@ -242,14 +242,14 @@ fn trim_whitespace_prefix_and_push_line(lines: &mut ~[~str],
         }
         None => s,
     };
-    debug!("pushing line: %s", s1);
+    debug2!("pushing line: {}", s1);
     lines.push(s1);
 }
 
 fn read_block_comment(rdr: @mut StringReader,
                       code_to_the_left: bool,
                       comments: &mut ~[cmnt]) {
-    debug!(">>> block comment");
+    debug2!(">>> block comment");
     let p = rdr.last_pos;
     let mut lines: ~[~str] = ~[];
     let col: CharPos = rdr.col;
@@ -275,7 +275,7 @@ fn read_block_comment(rdr: @mut StringReader,
     } else {
         let mut level: int = 1;
         while level > 0 {
-            debug!("=== block comment level %d", level);
+            debug2!("=== block comment level {}", level);
             if is_eof(rdr) {
                 (rdr as @mut reader).fatal(~"unterminated block comment");
             }
@@ -311,7 +311,7 @@ fn read_block_comment(rdr: @mut StringReader,
     if !is_eof(rdr) && rdr.curr != '\n' && lines.len() == 1u {
         style = mixed;
     }
-    debug!("<<< block comment");
+    debug2!("<<< block comment");
     comments.push(cmnt {style: style, lines: lines, pos: p});
 }
 
@@ -324,15 +324,15 @@ fn peeking_at_comment(rdr: @mut StringReader) -> bool {
 fn consume_comment(rdr: @mut StringReader,
                    code_to_the_left: bool,
                    comments: &mut ~[cmnt]) {
-    debug!(">>> consume comment");
+    debug2!(">>> consume comment");
     if rdr.curr == '/' && nextch(rdr) == '/' {
         read_line_comments(rdr, code_to_the_left, comments);
     } else if rdr.curr == '/' && nextch(rdr) == '*' {
         read_block_comment(rdr, code_to_the_left, comments);
     } else if rdr.curr == '#' && nextch(rdr) == '!' {
         read_shebang_comment(rdr, code_to_the_left, comments);
-    } else { fail!(); }
-    debug!("<<< consume comment");
+    } else { fail2!(); }
+    debug2!("<<< consume comment");
 }
 
 #[deriving(Clone)]
@@ -378,11 +378,11 @@ pub fn gather_comments_and_literals(span_diagnostic:
         let TokenAndSpan {tok: tok, sp: sp} = rdr.peek();
         if token::is_lit(&tok) {
             do with_str_from(rdr, bstart) |s| {
-                debug!("tok lit: %s", s);
+                debug2!("tok lit: {}", s);
                 literals.push(lit {lit: s.to_owned(), pos: sp.lo});
             }
         } else {
-            debug!("tok: %s", token::to_str(get_ident_interner(), &tok));
+            debug2!("tok: {}", token::to_str(get_ident_interner(), &tok));
         }
         first_read = false;
     }
diff --git a/src/libsyntax/parse/lexer.rs b/src/libsyntax/parse/lexer.rs
index 09adcc66ea5..640c7c220e5 100644
--- a/src/libsyntax/parse/lexer.rs
+++ b/src/libsyntax/parse/lexer.rs
@@ -133,7 +133,7 @@ impl reader for TtReader {
     fn is_eof(@mut self) -> bool { self.cur_tok == token::EOF }
     fn next_token(@mut self) -> TokenAndSpan {
         let r = tt_next_token(self);
-        debug!("TtReader: r=%?", r);
+        debug2!("TtReader: r={:?}", r);
         return r;
     }
     fn fatal(@mut self, m: ~str) -> ! {
@@ -261,7 +261,7 @@ fn hex_digit_val(c: char) -> int {
     if in_range(c, '0', '9') { return (c as int) - ('0' as int); }
     if in_range(c, 'a', 'f') { return (c as int) - ('a' as int) + 10; }
     if in_range(c, 'A', 'F') { return (c as int) - ('A' as int) + 10; }
-    fail!();
+    fail2!();
 }
 
 fn bin_digit_value(c: char) -> int { if c == '0' { return 0; } return 1; }
@@ -569,8 +569,7 @@ fn scan_number(c: char, rdr: @mut StringReader) -> token::Token {
                                ~"int literal is too large")
         };
 
-        debug!("lexing %s as an unsuffixed integer literal",
-               num_str);
+        debug2!("lexing {} as an unsuffixed integer literal", num_str);
         return token::LIT_INT_UNSUFFIXED(parsed as i64);
     }
 }
diff --git a/src/libsyntax/parse/mod.rs b/src/libsyntax/parse/mod.rs
index a492a2283e3..67bcab31956 100644
--- a/src/libsyntax/parse/mod.rs
+++ b/src/libsyntax/parse/mod.rs
@@ -416,18 +416,18 @@ mod test {
                         _ => assert_eq!("wrong 4","correct")
                     },
                     _ => {
-                        error!("failing value 3: %?",first_set);
+                        error2!("failing value 3: {:?}",first_set);
                         assert_eq!("wrong 3","correct")
                     }
                 },
                 _ => {
-                    error!("failing value 2: %?",delim_elts);
+                    error2!("failing value 2: {:?}",delim_elts);
                     assert_eq!("wrong","correct");
                 }
 
             },
             _ => {
-                error!("failing value: %?",tts);
+                error2!("failing value: {:?}",tts);
                 assert_eq!("wrong 1","correct");
             }
         }
diff --git a/src/libsyntax/parse/obsolete.rs b/src/libsyntax/parse/obsolete.rs
index 66774cb275b..adf0c208da4 100644
--- a/src/libsyntax/parse/obsolete.rs
+++ b/src/libsyntax/parse/obsolete.rs
@@ -261,10 +261,10 @@ impl ParserObsoleteMethods for Parser {
               kind: ObsoleteSyntax,
               kind_str: &str,
               desc: &str) {
-        self.span_err(sp, fmt!("obsolete syntax: %s", kind_str));
+        self.span_err(sp, format!("obsolete syntax: {}", kind_str));
 
         if !self.obsolete_set.contains(&kind) {
-            self.sess.span_diagnostic.handler().note(fmt!("%s", desc));
+            self.sess.span_diagnostic.handler().note(format!("{}", desc));
             self.obsolete_set.insert(kind);
         }
     }
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index 5a68e32a533..4dd09cbcbd2 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -362,8 +362,8 @@ impl Parser {
     pub fn unexpected_last(&self, t: &token::Token) -> ! {
         self.span_fatal(
             *self.last_span,
-            fmt!(
-                "unexpected token: `%s`",
+            format!(
+                "unexpected token: `{}`",
                 self.token_to_str(t)
             )
         );
@@ -371,8 +371,8 @@ impl Parser {
 
     pub fn unexpected(&self) -> ! {
         self.fatal(
-            fmt!(
-                "unexpected token: `%s`",
+            format!(
+                "unexpected token: `{}`",
                 self.this_token_to_str()
             )
         );
@@ -385,8 +385,8 @@ impl Parser {
             self.bump();
         } else {
             self.fatal(
-                fmt!(
-                    "expected `%s` but found `%s`",
+                format!(
+                    "expected `{}` but found `{}`",
                     self.token_to_str(t),
                     self.this_token_to_str()
                 )
@@ -414,9 +414,9 @@ impl Parser {
             let actual = self.this_token_to_str();
             self.fatal(
                 if expected.len() != 1 {
-                    fmt!("expected one of `%s` but found `%s`", expect, actual)
+                    format!("expected one of `{}` but found `{}`", expect, actual)
                 } else {
-                    fmt!("expected `%s` but found `%s`", expect, actual)
+                    format!("expected `{}` but found `{}`", expect, actual)
                 }
             )
         }
@@ -444,7 +444,7 @@ impl Parser {
     // followed by some token from the set edible + inedible.  Recover
     // from anticipated input errors, discarding erroneous characters.
     pub fn commit_expr(&self, e: @Expr, edible: &[token::Token], inedible: &[token::Token]) {
-        debug!("commit_expr %?", e);
+        debug2!("commit_expr {:?}", e);
         match e.node {
             ExprPath(*) => {
                 // might be unit-struct construction; check for recoverableinput error.
@@ -464,7 +464,7 @@ impl Parser {
     // followed by some token from the set edible + inedible.  Check
     // for recoverable input errors, discarding erroneous characters.
     pub fn commit_stmt(&self, s: @Stmt, edible: &[token::Token], inedible: &[token::Token]) {
-        debug!("commit_stmt %?", s);
+        debug2!("commit_stmt {:?}", s);
         let _s = s; // unused, but future checks might want to inspect `s`.
         if self.last_token.map_default(false, |t|is_ident_or_path(*t)) {
             let expected = vec::append(edible.to_owned(), inedible);
@@ -490,8 +490,8 @@ impl Parser {
             }
             _ => {
                 self.fatal(
-                    fmt!(
-                        "expected ident, found `%s`",
+                    format!(
+                        "expected ident, found `{}`",
                         self.this_token_to_str()
                     )
                 );
@@ -536,8 +536,8 @@ impl Parser {
     pub fn expect_keyword(&self, kw: keywords::Keyword) {
         if !self.eat_keyword(kw) {
             self.fatal(
-                fmt!(
-                    "expected `%s`, found `%s`",
+                format!(
+                    "expected `{}`, found `{}`",
                     self.id_to_str(kw.to_ident()).to_str(),
                     self.this_token_to_str()
                 )
@@ -549,14 +549,14 @@ impl Parser {
     pub fn check_strict_keywords(&self) {
         if token::is_strict_keyword(self.token) {
             self.span_err(*self.last_span,
-                          fmt!("found `%s` in ident position", self.this_token_to_str()));
+                          format!("found `{}` in ident position", self.this_token_to_str()));
         }
     }
 
     // signal an error if the current token is a reserved keyword
     pub fn check_reserved_keywords(&self) {
         if token::is_reserved_keyword(self.token) {
-            self.fatal(fmt!("`%s` is a reserved keyword", self.this_token_to_str()));
+            self.fatal(format!("`{}` is a reserved keyword", self.this_token_to_str()));
         }
     }
 
@@ -571,7 +571,7 @@ impl Parser {
                 self.span.lo + BytePos(1u),
                 self.span.hi
             ),
-            _ => self.fatal(fmt!("expected `%s`, found `%s`",
+            _ => self.fatal(format!("expected `{}`, found `{}`",
                                  self.token_to_str(&token::GT),
                                  self.this_token_to_str()))
         }
@@ -938,13 +938,13 @@ impl Parser {
             };
 
             let hi = p.last_span.hi;
-            debug!("parse_trait_methods(): trait method signature ends in \
-                    `%s`",
+            debug2!("parse_trait_methods(): trait method signature ends in \
+                    `{}`",
                    self.this_token_to_str());
             match *p.token {
               token::SEMI => {
                 p.bump();
-                debug!("parse_trait_methods(): parsing required method");
+                debug2!("parse_trait_methods(): parsing required method");
                 // NB: at the moment, visibility annotations on required
                 // methods are ignored; this could change.
                 if vis != ast::inherited {
@@ -963,7 +963,7 @@ impl Parser {
                 })
               }
               token::LBRACE => {
-                debug!("parse_trait_methods(): parsing provided method");
+                debug2!("parse_trait_methods(): parsing provided method");
                 let (inner_attrs, body) =
                     p.parse_inner_attrs_and_block();
                 let attrs = vec::append(attrs, inner_attrs);
@@ -984,8 +984,8 @@ impl Parser {
 
               _ => {
                     p.fatal(
-                        fmt!(
-                            "expected `;` or `{` but found `%s`",
+                        format!(
+                            "expected `;` or `\\{` but found `{}`",
                             self.this_token_to_str()
                         )
                     );
@@ -1153,8 +1153,7 @@ impl Parser {
             } = self.parse_path(LifetimeAndTypesAndBounds);
             ty_path(path, bounds, ast::DUMMY_NODE_ID)
         } else {
-            self.fatal(fmt!("expected type, found token %?",
-                            *self.token));
+            self.fatal(format!("expected type, found token {:?}", *self.token));
         };
 
         let sp = mk_sp(lo, self.last_span.hi);
@@ -1245,7 +1244,7 @@ impl Parser {
             _ => 0
         };
 
-        debug!("parser is_named_argument offset:%u", offset);
+        debug2!("parser is_named_argument offset:{}", offset);
 
         if offset == 0 {
             is_plain_ident_or_underscore(&*self.token)
@@ -1261,7 +1260,7 @@ impl Parser {
     pub fn parse_arg_general(&self, require_name: bool) -> arg {
         let is_mutbl = self.eat_keyword(keywords::Mut);
         let pat = if require_name || self.is_named_argument() {
-            debug!("parse_arg_general parse_pat (require_name:%?)",
+            debug2!("parse_arg_general parse_pat (require_name:{:?})",
                    require_name);
             self.parse_arg_mode();
             let pat = self.parse_pat();
@@ -1273,7 +1272,7 @@ impl Parser {
             self.expect(&token::COLON);
             pat
         } else {
-            debug!("parse_arg_general ident_to_pat");
+            debug2!("parse_arg_general ident_to_pat");
             ast_util::ident_to_pat(ast::DUMMY_NODE_ID,
                                    *self.last_span,
                                    special_idents::invalid)
@@ -1581,7 +1580,7 @@ impl Parser {
             }
 
             _ => {
-                self.fatal(fmt!("Expected a lifetime name"));
+                self.fatal(format!("Expected a lifetime name"));
             }
         }
     }
@@ -1614,7 +1613,7 @@ impl Parser {
                 token::GT => { return res; }
                 token::BINOP(token::SHR) => { return res; }
                 _ => {
-                    self.fatal(fmt!("expected `,` or `>` after lifetime name, got: %?",
+                    self.fatal(format!("expected `,` or `>` after lifetime name, got: {:?}",
                                     *self.token));
                 }
             }
@@ -2067,8 +2066,8 @@ impl Parser {
               token::RPAREN | token::RBRACE | token::RBRACKET
               => {
                 p.fatal(
-                    fmt!(
-                        "incorrect close delimiter: `%s`",
+                    format!(
+                        "incorrect close delimiter: `{}`",
                         p.this_token_to_str()
                     )
                 );
@@ -2561,10 +2560,10 @@ impl Parser {
                 // There may be other types of expressions that can
                 // represent the callee in `for` and `do` expressions
                 // but they aren't represented by tests
-                debug!("sugary call on %?", e.node);
+                debug2!("sugary call on {:?}", e.node);
                 self.span_fatal(
                     e.span,
-                    fmt!("`%s` must be followed by a block call", keyword));
+                    format!("`{}` must be followed by a block call", keyword));
             }
         }
     }
@@ -2759,8 +2758,8 @@ impl Parser {
                 self.bump();
                 if *self.token != token::RBRACE {
                     self.fatal(
-                        fmt!(
-                            "expected `}`, found `%s`",
+                        format!(
+                            "expected `\\}`, found `{}`",
                             self.this_token_to_str()
                         )
                     );
@@ -3543,8 +3542,8 @@ impl Parser {
     fn expect_self_ident(&self) {
         if !self.is_self_ident() {
             self.fatal(
-                fmt!(
-                    "expected `self` but found `%s`",
+                format!(
+                    "expected `self` but found `{}`",
                     self.this_token_to_str()
                 )
             );
@@ -3682,8 +3681,8 @@ impl Parser {
                 }
                 _ => {
                     self.fatal(
-                        fmt!(
-                            "expected `,` or `)`, found `%s`",
+                        format!(
+                            "expected `,` or `)`, found `{}`",
                             self.this_token_to_str()
                         )
                     );
@@ -3920,7 +3919,7 @@ impl Parser {
                 }
             }
             if fields.len() == 0 {
-                self.fatal(fmt!("Unit-like struct definition should be written as `struct %s;`",
+                self.fatal(format!("Unit-like struct definition should be written as `struct {};`",
                                 get_ident_interner().get(class_name.name)));
             }
             self.bump();
@@ -3949,9 +3948,9 @@ impl Parser {
             fields = ~[];
         } else {
             self.fatal(
-                fmt!(
-                    "expected `{`, `(`, or `;` after struct name \
-                    but found `%s`",
+                format!(
+                    "expected `\\{`, `(`, or `;` after struct name \
+                    but found `{}`",
                     self.this_token_to_str()
                 )
             );
@@ -3995,7 +3994,7 @@ impl Parser {
             token::RBRACE => {}
             _ => {
                 self.span_fatal(*self.span,
-                                fmt!("expected `,`, or '}' but found `%s`",
+                                format!("expected `,`, or '\\}' but found `{}`",
                                      self.this_token_to_str()));
             }
         }
@@ -4064,7 +4063,7 @@ impl Parser {
                 attrs = attrs_remaining + attrs;
                 first = false;
             }
-            debug!("parse_mod_items: parse_item_or_view_item(attrs=%?)",
+            debug2!("parse_mod_items: parse_item_or_view_item(attrs={:?})",
                    attrs);
             match self.parse_item_or_view_item(attrs,
                                                true /* macros allowed */) {
@@ -4075,7 +4074,7 @@ impl Parser {
                                  the module");
               }
               _ => {
-                self.fatal(fmt!("expected item but found `%s`",
+                self.fatal(format!("expected item but found `{}`",
                                 self.this_token_to_str()));
               }
             }
@@ -4167,11 +4166,11 @@ impl Parser {
                     (true, false) => default_path,
                     (false, true) => secondary_path,
                     (false, false) => {
-                        self.span_fatal(id_sp, fmt!("file not found for module `%s`", mod_name));
+                        self.span_fatal(id_sp, format!("file not found for module `{}`", mod_name));
                     }
                     (true, true) => {
                         self.span_fatal(id_sp,
-                                        fmt!("file for module `%s` found at both %s and %s",
+                                        format!("file for module `{}` found at both {} and {}",
                                              mod_name, default_path_str, secondary_path_str));
                     }
                 }
@@ -4323,7 +4322,7 @@ impl Parser {
             self.expect_keyword(keywords::Mod);
         } else if *self.token != token::LBRACE {
             self.span_fatal(*self.span,
-                            fmt!("expected `{` or `mod` but found `%s`",
+                            format!("expected `\\{` or `mod` but found `{}`",
                                  self.this_token_to_str()));
         }
 
@@ -4340,8 +4339,8 @@ impl Parser {
             _ => {
                 if must_be_named_mod {
                     self.span_fatal(*self.span,
-                                    fmt!("expected foreign module name but \
-                                          found `%s`",
+                                    format!("expected foreign module name but \
+                                          found `{}`",
                                          self.this_token_to_str()));
                 }
 
@@ -4566,7 +4565,7 @@ impl Parser {
                             if abis.contains(abi) {
                                 self.span_err(
                                     *self.span,
-                                    fmt!("ABI `%s` appears twice",
+                                    format!("ABI `{}` appears twice",
                                          word));
                             } else {
                                 abis.add(abi);
@@ -4576,9 +4575,9 @@ impl Parser {
                         None => {
                             self.span_err(
                                 *self.span,
-                                fmt!("illegal ABI: \
-                                      expected one of [%s], \
-                                      found `%s`",
+                                format!("illegal ABI: \
+                                      expected one of [{}], \
+                                      found `{}`",
                                      abi::all_names().connect(", "),
                                      word));
                         }
@@ -4853,7 +4852,7 @@ impl Parser {
 
         let first_ident = self.parse_ident();
         let mut path = ~[first_ident];
-        debug!("parsed view_path: %s", self.id_to_str(first_ident));
+        debug2!("parsed view_path: {}", self.id_to_str(first_ident));
         match *self.token {
           token::EQ => {
             // x = foo::bar
@@ -5061,7 +5060,7 @@ impl Parser {
                     break;
                 }
                 iovi_foreign_item(_) => {
-                    fail!();
+                    fail2!();
                 }
             }
             attrs = self.parse_outer_attributes();
@@ -5084,7 +5083,7 @@ impl Parser {
                     items.push(item)
                 }
                 iovi_foreign_item(_) => {
-                    fail!();
+                    fail2!();
                 }
             }
         }
diff --git a/src/libsyntax/parse/token.rs b/src/libsyntax/parse/token.rs
index eec4a81b2cf..d0faf917688 100644
--- a/src/libsyntax/parse/token.rs
+++ b/src/libsyntax/parse/token.rs
@@ -193,11 +193,11 @@ pub fn to_str(input: @ident_interner, t: &Token) -> ~str {
         }
         body
       }
-      LIT_STR(ref s) => { fmt!("\"%s\"", ident_to_str(s).escape_default()) }
+      LIT_STR(ref s) => { format!("\"{}\"", ident_to_str(s).escape_default()) }
 
       /* Name components */
       IDENT(s, _) => input.get(s.name).to_owned(),
-      LIFETIME(s) => fmt!("'%s", input.get(s.name)),
+      LIFETIME(s) => format!("'{}", input.get(s.name)),
       UNDERSCORE => ~"_",
 
       /* Other */
@@ -214,8 +214,8 @@ pub fn to_str(input: @ident_interner, t: &Token) -> ~str {
                       nt_block(*) => ~"block",
                       nt_stmt(*) => ~"statement",
                       nt_pat(*) => ~"pattern",
-                      nt_attr(*) => fail!("should have been handled"),
-                      nt_expr(*) => fail!("should have been handled above"),
+                      nt_attr(*) => fail2!("should have been handled"),
+                      nt_expr(*) => fail2!("should have been handled above"),
                       nt_ty(*) => ~"type",
                       nt_ident(*) => ~"identifier",
                       nt_path(*) => ~"path",
@@ -269,7 +269,7 @@ pub fn flip_delimiter(t: &token::Token) -> token::Token {
       RPAREN => LPAREN,
       RBRACE => LBRACE,
       RBRACKET => LBRACKET,
-      _ => fail!()
+      _ => fail2!()
     }
 }
 
@@ -553,7 +553,7 @@ pub fn fresh_name(src : &ast::Ident) -> Name {
     // good error messages and uses of struct names in ambiguous could-be-binding
     // locations. Also definitely destroys the guarantee given above about ptr_eq.
     /*let num = rand::rng().gen_uint_range(0,0xffff);
-    gensym(fmt!("%s_%u",ident_to_str(src),num))*/
+    gensym(format!("{}_{}",ident_to_str(src),num))*/
 }
 
 // it looks like there oughta be a str_ptr_eq fn, but no one bothered to implement it?
diff --git a/src/libsyntax/print/pp.rs b/src/libsyntax/print/pp.rs
index 615f3301373..58d73ad687c 100644
--- a/src/libsyntax/print/pp.rs
+++ b/src/libsyntax/print/pp.rs
@@ -111,7 +111,7 @@ impl token {
 
 pub fn tok_str(t: token) -> ~str {
     match t {
-        STRING(s, len) => return fmt!("STR(%s,%d)", s, len),
+        STRING(s, len) => return format!("STR({},{})", s, len),
         BREAK(_) => return ~"BREAK",
         BEGIN(_) => return ~"BEGIN",
         END => return ~"END",
@@ -131,7 +131,7 @@ pub fn buf_str(toks: ~[token], szs: ~[int], left: uint, right: uint,
         if i != left {
             s.push_str(", ");
         }
-        s.push_str(fmt!("%d=%s", szs[i], tok_str(toks[i])));
+        s.push_str(format!("{}={}", szs[i], tok_str(toks[i])));
         i += 1u;
         i %= n;
     }
@@ -152,7 +152,7 @@ pub fn mk_printer(out: @io::Writer, linewidth: uint) -> @mut Printer {
     // Yes 3, it makes the ring buffers big enough to never
     // fall behind.
     let n: uint = 3 * linewidth;
-    debug!("mk_printer %u", linewidth);
+    debug2!("mk_printer {}", linewidth);
     let token: ~[token] = vec::from_elem(n, EOF);
     let size: ~[int] = vec::from_elem(n, 0);
     let scan_stack: ~[uint] = vec::from_elem(n, 0u);
@@ -288,7 +288,7 @@ impl Printer {
         self.token[self.right] = t;
     }
     pub fn pretty_print(&mut self, t: token) {
-        debug!("pp ~[%u,%u]", self.left, self.right);
+        debug2!("pp ~[{},{}]", self.left, self.right);
         match t {
           EOF => {
             if !self.scan_stack_empty {
@@ -305,7 +305,7 @@ impl Printer {
                 self.left = 0u;
                 self.right = 0u;
             } else { self.advance_right(); }
-            debug!("pp BEGIN(%d)/buffer ~[%u,%u]",
+            debug2!("pp BEGIN({})/buffer ~[{},{}]",
                    b.offset, self.left, self.right);
             self.token[self.right] = t;
             self.size[self.right] = -self.right_total;
@@ -313,10 +313,10 @@ impl Printer {
           }
           END => {
             if self.scan_stack_empty {
-                debug!("pp END/print ~[%u,%u]", self.left, self.right);
+                debug2!("pp END/print ~[{},{}]", self.left, self.right);
                 self.print(t, 0);
             } else {
-                debug!("pp END/buffer ~[%u,%u]", self.left, self.right);
+                debug2!("pp END/buffer ~[{},{}]", self.left, self.right);
                 self.advance_right();
                 self.token[self.right] = t;
                 self.size[self.right] = -1;
@@ -330,7 +330,7 @@ impl Printer {
                 self.left = 0u;
                 self.right = 0u;
             } else { self.advance_right(); }
-            debug!("pp BREAK(%d)/buffer ~[%u,%u]",
+            debug2!("pp BREAK({})/buffer ~[{},{}]",
                    b.offset, self.left, self.right);
             self.check_stack(0);
             self.scan_push(self.right);
@@ -340,11 +340,11 @@ impl Printer {
           }
           STRING(s, len) => {
             if self.scan_stack_empty {
-                debug!("pp STRING('%s')/print ~[%u,%u]",
+                debug2!("pp STRING('{}')/print ~[{},{}]",
                        s, self.left, self.right);
                 self.print(t, len);
             } else {
-                debug!("pp STRING('%s')/buffer ~[%u,%u]",
+                debug2!("pp STRING('{}')/buffer ~[{},{}]",
                        s, self.left, self.right);
                 self.advance_right();
                 self.token[self.right] = t;
@@ -356,14 +356,14 @@ impl Printer {
         }
     }
     pub fn check_stream(&mut self) {
-        debug!("check_stream ~[%u, %u] with left_total=%d, right_total=%d",
+        debug2!("check_stream ~[{}, {}] with left_total={}, right_total={}",
                self.left, self.right, self.left_total, self.right_total);
         if self.right_total - self.left_total > self.space {
-            debug!("scan window is %d, longer than space on line (%d)",
+            debug2!("scan window is {}, longer than space on line ({})",
                    self.right_total - self.left_total, self.space);
             if !self.scan_stack_empty {
                 if self.left == self.scan_stack[self.bottom] {
-                    debug!("setting %u to infinity and popping", self.left);
+                    debug2!("setting {} to infinity and popping", self.left);
                     self.size[self.scan_pop_bottom()] = size_infinity;
                 }
             }
@@ -372,7 +372,7 @@ impl Printer {
         }
     }
     pub fn scan_push(&mut self, x: uint) {
-        debug!("scan_push %u", x);
+        debug2!("scan_push {}", x);
         if self.scan_stack_empty {
             self.scan_stack_empty = false;
         } else {
@@ -408,7 +408,7 @@ impl Printer {
         assert!((self.right != self.left));
     }
     pub fn advance_left(&mut self, x: token, L: int) {
-        debug!("advnce_left ~[%u,%u], sizeof(%u)=%d", self.left, self.right,
+        debug2!("advnce_left ~[{},{}], sizeof({})={}", self.left, self.right,
                self.left, L);
         if L >= 0 {
             self.print(x, L);
@@ -451,13 +451,13 @@ impl Printer {
         }
     }
     pub fn print_newline(&mut self, amount: int) {
-        debug!("NEWLINE %d", amount);
+        debug2!("NEWLINE {}", amount);
         (*self.out).write_str("\n");
         self.pending_indentation = 0;
         self.indent(amount);
     }
     pub fn indent(&mut self, amount: int) {
-        debug!("INDENT %d", amount);
+        debug2!("INDENT {}", amount);
         self.pending_indentation += amount;
     }
     pub fn get_top(&mut self) -> print_stack_elt {
@@ -480,9 +480,9 @@ impl Printer {
         (*self.out).write_str(s);
     }
     pub fn print(&mut self, x: token, L: int) {
-        debug!("print %s %d (remaining line space=%d)", tok_str(x), L,
+        debug2!("print {} {} (remaining line space={})", tok_str(x), L,
                self.space);
-        debug!("%s", buf_str(self.token.clone(),
+        debug2!("{}", buf_str(self.token.clone(),
                              self.size.clone(),
                              self.left,
                              self.right,
@@ -491,13 +491,13 @@ impl Printer {
           BEGIN(b) => {
             if L > self.space {
                 let col = self.margin - self.space + b.offset;
-                debug!("print BEGIN -> push broken block at col %d", col);
+                debug2!("print BEGIN -> push broken block at col {}", col);
                 self.print_stack.push(print_stack_elt {
                     offset: col,
                     pbreak: broken(b.breaks)
                 });
             } else {
-                debug!("print BEGIN -> push fitting block");
+                debug2!("print BEGIN -> push fitting block");
                 self.print_stack.push(print_stack_elt {
                     offset: 0,
                     pbreak: fits
@@ -505,7 +505,7 @@ impl Printer {
             }
           }
           END => {
-            debug!("print END -> pop END");
+            debug2!("print END -> pop END");
             let print_stack = &mut *self.print_stack;
             assert!((print_stack.len() != 0u));
             print_stack.pop();
@@ -514,24 +514,24 @@ impl Printer {
             let top = self.get_top();
             match top.pbreak {
               fits => {
-                debug!("print BREAK(%d) in fitting block", b.blank_space);
+                debug2!("print BREAK({}) in fitting block", b.blank_space);
                 self.space -= b.blank_space;
                 self.indent(b.blank_space);
               }
               broken(consistent) => {
-                debug!("print BREAK(%d+%d) in consistent block",
+                debug2!("print BREAK({}+{}) in consistent block",
                        top.offset, b.offset);
                 self.print_newline(top.offset + b.offset);
                 self.space = self.margin - (top.offset + b.offset);
               }
               broken(inconsistent) => {
                 if L > self.space {
-                    debug!("print BREAK(%d+%d) w/ newline in inconsistent",
+                    debug2!("print BREAK({}+{}) w/ newline in inconsistent",
                            top.offset, b.offset);
                     self.print_newline(top.offset + b.offset);
                     self.space = self.margin - (top.offset + b.offset);
                 } else {
-                    debug!("print BREAK(%d) w/o newline in inconsistent",
+                    debug2!("print BREAK({}) w/o newline in inconsistent",
                            b.blank_space);
                     self.indent(b.blank_space);
                     self.space -= b.blank_space;
@@ -540,7 +540,7 @@ impl Printer {
             }
           }
           STRING(s, len) => {
-            debug!("print STRING(%s)", s);
+            debug2!("print STRING({})", s);
             assert_eq!(L, len);
             // assert!(L <= space);
             self.space -= len;
@@ -548,7 +548,7 @@ impl Printer {
           }
           EOF => {
             // EOF should never get here.
-            fail!();
+            fail2!();
           }
         }
     }
diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index dee8d710a73..bc1a4721207 100644
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -453,10 +453,10 @@ pub fn print_type(s: @ps, ty: &ast::Ty) {
           word(s.s, ")");
       }
       ast::ty_mac(_) => {
-          fail!("print_type doesn't know how to print a ty_mac");
+          fail2!("print_type doesn't know how to print a ty_mac");
       }
       ast::ty_infer => {
-          fail!("print_type shouldn't see a ty_infer");
+          fail2!("print_type shouldn't see a ty_infer");
       }
 
     }
@@ -709,7 +709,7 @@ pub fn print_struct(s: @ps,
             popen(s);
             do commasep(s, inconsistent, struct_def.fields) |s, field| {
                 match field.node.kind {
-                    ast::named_field(*) => fail!("unexpected named field"),
+                    ast::named_field(*) => fail2!("unexpected named field"),
                     ast::unnamed_field => {
                         maybe_print_comment(s, field.span.lo);
                         print_type(s, &field.node.ty);
@@ -728,7 +728,7 @@ pub fn print_struct(s: @ps,
 
         for field in struct_def.fields.iter() {
             match field.node.kind {
-                ast::unnamed_field => fail!("unexpected unnamed field"),
+                ast::unnamed_field => fail2!("unexpected unnamed field"),
                 ast::named_field(ident, visibility) => {
                     hardbreak_if_not_bol(s);
                     maybe_print_comment(s, field.span.lo);
@@ -1017,7 +1017,7 @@ pub fn print_if(s: @ps, test: &ast::Expr, blk: &ast::Block,
               }
               // BLEAH, constraints would be great here
               _ => {
-                  fail!("print_if saw if with weird alternative");
+                  fail2!("print_if saw if with weird alternative");
               }
             }
           }
@@ -1042,7 +1042,7 @@ pub fn print_mac(s: @ps, m: &ast::mac) {
 
 pub fn print_vstore(s: @ps, t: ast::Vstore) {
     match t {
-        ast::VstoreFixed(Some(i)) => word(s.s, fmt!("%u", i)),
+        ast::VstoreFixed(Some(i)) => word(s.s, format!("{}", i)),
         ast::VstoreFixed(None) => word(s.s, "_"),
         ast::VstoreUniq => word(s.s, "~"),
         ast::VstoreBox => word(s.s, "@"),
@@ -1319,7 +1319,7 @@ pub fn print_expr(s: @ps, expr: &ast::Expr) {
                         }
                         end(s); // close enclosing cbox
                     }
-                    None => fail!()
+                    None => fail2!()
                 }
             } else {
                 // the block will close the pattern's ibox
@@ -2299,7 +2299,7 @@ mod test {
 
     fn string_check<T:Eq> (given : &T, expected: &T) {
         if !(given == expected) {
-            fail!("given %?, expected %?", given, expected);
+            fail2!("given {:?}, expected {:?}", given, expected);
         }
     }