auto merge of #12533 : alexcrichton/rust/svh, r=brson

These hashes are used to detect changes to upstream crates and generate errors which mention that crates possibly need recompilation.

More details can be found in the respective commit messages below. This change is also accompanied with a much needed refactoring of some of the crate loading code to focus more on crate ids instead of name/version pairs.

Closes #12601

2 files changed, 26 insertions, 13 deletions

diff --git a/src/libsyntax/ext/deriving/show.rs b/src/libsyntax/ext/deriving/show.rs
index 5286720b9fc..4b9925c8d9f 100644
--- a/src/libsyntax/ext/deriving/show.rs
+++ b/src/libsyntax/ext/deriving/show.rs
@@ -135,5 +135,6 @@ fn show_substructure(cx: &mut ExtCtxt, span: Span,
     // phew, not our responsibility any more!
     format::expand_preparsed_format_args(cx, span,
                                          format_closure,
-                                         format_string, exprs, HashMap::new())
+                                         format_string, exprs, ~[],
+                                         HashMap::new())
 }
diff --git a/src/libsyntax/ext/format.rs b/src/libsyntax/ext/format.rs
index 1b73d42c79a..2642ee00458 100644
--- a/src/libsyntax/ext/format.rs
+++ b/src/libsyntax/ext/format.rs
@@ -43,9 +43,13 @@ struct Context<'a> {
     // them.
     args: ~[@ast::Expr],
     arg_types: ~[Option<ArgumentType>],
-    // Parsed named expressions and the types that we've found for them so far
+    // Parsed named expressions and the types that we've found for them so far.
+    // Note that we keep a side-array of the ordering of the named arguments
+    // found to be sure that we can translate them in the same order that they
+    // were declared in.
     names: HashMap<~str, @ast::Expr>,
     name_types: HashMap<~str, ArgumentType>,
+    name_ordering: ~[~str],
 
     // Collection of the compiled `rt::Piece` structures
     pieces: ~[@ast::Expr],
@@ -63,12 +67,15 @@ struct Context<'a> {
 ///
 /// If parsing succeeds, the second return value is:
 ///
-///     Some((fmtstr, unnamed arguments, named arguments))
-fn parse_args(ecx: &mut ExtCtxt, sp: Span,
-              tts: &[ast::TokenTree]) -> (@ast::Expr, Option<(@ast::Expr, ~[@ast::Expr],
-                                                              HashMap<~str, @ast::Expr>)>) {
+///     Some((fmtstr, unnamed arguments, ordering of named arguments,
+///           named arguments))
+fn parse_args(ecx: &mut ExtCtxt, sp: Span, tts: &[ast::TokenTree])
+    -> (@ast::Expr, Option<(@ast::Expr, ~[@ast::Expr], ~[~str],
+                            HashMap<~str, @ast::Expr>)>)
+{
     let mut args = ~[];
     let mut names = HashMap::<~str, @ast::Expr>::new();
+    let mut order = ~[];
 
     let mut p = rsparse::new_parser_from_tts(ecx.parse_sess(),
                                              ecx.cfg(),
@@ -125,12 +132,13 @@ fn parse_args(ecx: &mut ExtCtxt, sp: Span,
                     continue
                 }
             }
+            order.push(name.to_str());
             names.insert(name.to_str(), e);
         } else {
             args.push(p.parse_expr());
         }
     }
-    return (extra, Some((fmtstr, args, names)));
+    return (extra, Some((fmtstr, args, order, names)));
 }
 
 impl<'a> Context<'a> {
@@ -661,10 +669,11 @@ impl<'a> Context<'a> {
             locals.push(self.format_arg(e.span, Exact(i),
                                         self.ecx.expr_ident(e.span, name)));
         }
-        for (name, &e) in self.names.iter() {
-            if !self.name_types.contains_key(name) {
-                continue
-            }
+        for name in self.name_ordering.iter() {
+            let e = match self.names.find(name) {
+                Some(&e) if self.name_types.contains_key(name) => e,
+                Some(..) | None => continue
+            };
 
             let lname = self.ecx.ident_of(format!("__arg{}", *name));
             pats.push(self.ecx.pat_ident(e.span, lname));
@@ -810,8 +819,9 @@ pub fn expand_args(ecx: &mut ExtCtxt, sp: Span,
                    tts: &[ast::TokenTree]) -> base::MacResult {
 
     match parse_args(ecx, sp, tts) {
-        (extra, Some((efmt, args, names))) => {
-            MRExpr(expand_preparsed_format_args(ecx, sp, extra, efmt, args, names))
+        (extra, Some((efmt, args, order, names))) => {
+            MRExpr(expand_preparsed_format_args(ecx, sp, extra, efmt, args,
+                                                order, names))
         }
         (_, None) => MRExpr(ecx.expr_uint(sp, 2))
     }
@@ -823,6 +833,7 @@ pub fn expand_args(ecx: &mut ExtCtxt, sp: Span,
 pub fn expand_preparsed_format_args(ecx: &mut ExtCtxt, sp: Span,
                                     extra: @ast::Expr,
                                     efmt: @ast::Expr, args: ~[@ast::Expr],
+                                    name_ordering: ~[~str],
                                     names: HashMap<~str, @ast::Expr>) -> @ast::Expr {
     let arg_types = vec::from_fn(args.len(), |_| None);
     let mut cx = Context {
@@ -832,6 +843,7 @@ pub fn expand_preparsed_format_args(ecx: &mut ExtCtxt, sp: Span,
         names: names,
         name_positions: HashMap::new(),
         name_types: HashMap::new(),
+        name_ordering: name_ordering,
         nest_level: 0,
         next_arg: 0,
         pieces: ~[],