auto merge of #20104 : alexcrichton/rust/rollup, r=alexcrichton

7 files changed, 60 insertions, 34 deletions

diff --git a/src/libsyntax/ext/base.rs b/src/libsyntax/ext/base.rs
index 3947a602809..aefbb2a1fea 100644
--- a/src/libsyntax/ext/base.rs
+++ b/src/libsyntax/ext/base.rs
@@ -490,7 +490,7 @@ impl<'a> ExtCtxt<'a> {
 
     /// Returns a `Folder` for deeply expanding all macros in a AST node.
     pub fn expander<'b>(&'b mut self) -> expand::MacroExpander<'b, 'a> {
-        expand::MacroExpander { cx: self }
+        expand::MacroExpander::new(self)
     }
 
     pub fn new_parser_from_tts(&self, tts: &[ast::TokenTree])
diff --git a/src/libsyntax/ext/build.rs b/src/libsyntax/ext/build.rs
index d35091f8ab0..9d4992f7453 100644
--- a/src/libsyntax/ext/build.rs
+++ b/src/libsyntax/ext/build.rs
@@ -868,7 +868,7 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
     }
 
     fn expr_match(&self, span: Span, arg: P<ast::Expr>, arms: Vec<ast::Arm>) -> P<Expr> {
-        self.expr(span, ast::ExprMatch(arg, arms, ast::MatchNormal))
+        self.expr(span, ast::ExprMatch(arg, arms, ast::MatchSource::Normal))
     }
 
     fn expr_if(&self, span: Span, cond: P<ast::Expr>,
diff --git a/src/libsyntax/ext/expand.rs b/src/libsyntax/ext/expand.rs
index 20c8ff20b71..b10ae7a09db 100644
--- a/src/libsyntax/ext/expand.rs
+++ b/src/libsyntax/ext/expand.rs
@@ -15,6 +15,7 @@ use ast::{ItemMac, MacStmtWithSemicolon, Mrk, Stmt, StmtDecl, StmtMac};
 use ast::{StmtExpr, StmtSemi};
 use ast::TokenTree;
 use ast;
+use ast_util::path_to_ident;
 use ext::mtwt;
 use ext::build::AstBuilder;
 use attr;
@@ -37,6 +38,30 @@ enum Either<L,R> {
     Right(R)
 }
 
+pub fn expand_type(t: P<ast::Ty>,
+                   fld: &mut MacroExpander,
+                   impl_ty: Option<P<ast::Ty>>)
+                   -> P<ast::Ty> {
+    debug!("expanding type {} with impl_ty {}", t, impl_ty);
+    let t = match (t.node.clone(), impl_ty) {
+        // Expand uses of `Self` in impls to the concrete type.
+        (ast::Ty_::TyPath(ref path, _), Some(ref impl_ty)) => {
+            let path_as_ident = path_to_ident(path);
+            // Note unhygenic comparison here. I think this is correct, since
+            // even though `Self` is almost just a type parameter, the treatment
+            // for this expansion is as if it were a keyword.
+            if path_as_ident.is_some() &&
+               path_as_ident.unwrap().name == token::special_idents::type_self.name {
+                impl_ty.clone()
+            } else {
+                t
+            }
+        }
+        _ => t
+    };
+    fold::noop_fold_ty(t, fld)
+}
+
 pub fn expand_expr(e: P<ast::Expr>, fld: &mut MacroExpander) -> P<ast::Expr> {
     e.and_then(|ast::Expr {id, node, span}| match node {
         // expr_mac should really be expr_ext or something; it's the
@@ -97,7 +122,7 @@ pub fn expand_expr(e: P<ast::Expr>, fld: &mut MacroExpander) -> P<ast::Expr> {
             // `match <expr> { ... }`
             let arms = vec![pat_arm, break_arm];
             let match_expr = fld.cx.expr(span,
-                                         ast::ExprMatch(expr, arms, ast::MatchWhileLetDesugar));
+                                    ast::ExprMatch(expr, arms, ast::MatchSource::WhileLetDesugar));
 
             // `[opt_ident]: loop { ... }`
             let loop_block = fld.cx.block_expr(match_expr);
@@ -158,6 +183,8 @@ pub fn expand_expr(e: P<ast::Expr>, fld: &mut MacroExpander) -> P<ast::Expr> {
                 arms
             };
 
+            let contains_else_clause = elseopt.is_some();
+
             // `_ => [<elseopt> | ()]`
             let else_arm = {
                 let pat_under = fld.cx.pat_wild(span);
@@ -170,7 +197,11 @@ pub fn expand_expr(e: P<ast::Expr>, fld: &mut MacroExpander) -> P<ast::Expr> {
             arms.extend(else_if_arms.into_iter());
             arms.push(else_arm);
 
-            let match_expr = fld.cx.expr(span, ast::ExprMatch(expr, arms, ast::MatchIfLetDesugar));
+            let match_expr = fld.cx.expr(span,
+                                         ast::ExprMatch(expr, arms,
+                                                ast::MatchSource::IfLetDesugar {
+                                                    contains_else_clause: contains_else_clause,
+                                                }));
             fld.fold_expr(match_expr)
         }
 
@@ -1059,6 +1090,14 @@ fn expand_and_rename_fn_decl_and_block(fn_decl: P<ast::FnDecl>, block: P<ast::Bl
 /// A tree-folder that performs macro expansion
 pub struct MacroExpander<'a, 'b:'a> {
     pub cx: &'a mut ExtCtxt<'b>,
+    // The type of the impl currently being expanded.
+    current_impl_type: Option<P<ast::Ty>>,
+}
+
+impl<'a, 'b> MacroExpander<'a, 'b> {
+    pub fn new(cx: &'a mut ExtCtxt<'b>) -> MacroExpander<'a, 'b> {
+        MacroExpander { cx: cx, current_impl_type: None }
+    }
 }
 
 impl<'a, 'b> Folder for MacroExpander<'a, 'b> {
@@ -1071,7 +1110,14 @@ impl<'a, 'b> Folder for MacroExpander<'a, 'b> {
     }
 
     fn fold_item(&mut self, item: P<ast::Item>) -> SmallVector<P<ast::Item>> {
-        expand_item(item, self)
+        let prev_type = self.current_impl_type.clone();
+        if let ast::Item_::ItemImpl(_, _, _, ref ty, _) = item.node {
+            self.current_impl_type = Some(ty.clone());
+        }
+
+        let result = expand_item(item, self);
+        self.current_impl_type = prev_type;
+        result
     }
 
     fn fold_item_underscore(&mut self, item: ast::Item_) -> ast::Item_ {
@@ -1094,6 +1140,11 @@ impl<'a, 'b> Folder for MacroExpander<'a, 'b> {
         expand_method(method, self)
     }
 
+    fn fold_ty(&mut self, t: P<ast::Ty>) -> P<ast::Ty> {
+        let impl_type = self.current_impl_type.clone();
+        expand_type(t, self, impl_type)
+    }
+
     fn new_span(&mut self, span: Span) -> Span {
         new_span(self.cx, span)
     }
@@ -1138,9 +1189,7 @@ pub fn expand_crate(parse_sess: &parse::ParseSess,
                     user_exts: Vec<NamedSyntaxExtension>,
                     c: Crate) -> Crate {
     let mut cx = ExtCtxt::new(parse_sess, c.config.clone(), cfg);
-    let mut expander = MacroExpander {
-        cx: &mut cx,
-    };
+    let mut expander = MacroExpander::new(&mut cx);
 
     for ExportedMacros { crate_name, macros } in imported_macros.into_iter() {
         let name = format!("<{} macros>", token::get_ident(crate_name))
diff --git a/src/libsyntax/ext/format.rs b/src/libsyntax/ext/format.rs
index 5d595474e9c..95c7fcc564a 100644
--- a/src/libsyntax/ext/format.rs
+++ b/src/libsyntax/ext/format.rs
@@ -654,6 +654,7 @@ impl<'a, 'b> Context<'a, 'b> {
             Known(ref tyname) => {
                 match tyname.as_slice() {
                     ""  => "Show",
+                    "?" => "Show",
                     "e" => "LowerExp",
                     "E" => "UpperExp",
                     "o" => "Octal",
diff --git a/src/libsyntax/ext/mtwt.rs b/src/libsyntax/ext/mtwt.rs
index ae979020bc7..f0392912878 100644
--- a/src/libsyntax/ext/mtwt.rs
+++ b/src/libsyntax/ext/mtwt.rs
@@ -21,7 +21,7 @@ use ast::{Ident, Mrk, Name, SyntaxContext};
 
 use std::cell::RefCell;
 use std::collections::HashMap;
-use std::collections::hash_map::{Occupied, Vacant};
+use std::collections::hash_map::Entry::{Occupied, Vacant};
 
 /// The SCTable contains a table of SyntaxContext_'s. It
 /// represents a flattened tree structure, to avoid having
diff --git a/src/libsyntax/ext/tt/macro_parser.rs b/src/libsyntax/ext/tt/macro_parser.rs
index 4785fe37293..bc639c32380 100644
--- a/src/libsyntax/ext/tt/macro_parser.rs
+++ b/src/libsyntax/ext/tt/macro_parser.rs
@@ -98,7 +98,7 @@ use ptr::P;
 use std::mem;
 use std::rc::Rc;
 use std::collections::HashMap;
-use std::collections::hash_map::{Vacant, Occupied};
+use std::collections::hash_map::Entry::{Vacant, Occupied};
 
 // To avoid costly uniqueness checks, we require that `MatchSeq` always has
 // a nonempty body.
diff --git a/src/libsyntax/ext/tt/transcribe.rs b/src/libsyntax/ext/tt/transcribe.rs
index e2439bad178..378dbba07fa 100644
--- a/src/libsyntax/ext/tt/transcribe.rs
+++ b/src/libsyntax/ext/tt/transcribe.rs
@@ -106,30 +106,6 @@ enum LockstepIterSize {
     LisContradiction(String),
 }
 
-// NOTE(stage0): Remove impl after a snapshot
-#[cfg(stage0)]
-impl Add<LockstepIterSize, LockstepIterSize> for LockstepIterSize {
-    fn add(&self, other: &LockstepIterSize) -> LockstepIterSize {
-        match *self {
-            LisUnconstrained => other.clone(),
-            LisContradiction(_) => self.clone(),
-            LisConstraint(l_len, l_id) => match *other {
-                LisUnconstrained => self.clone(),
-                LisContradiction(_) => other.clone(),
-                LisConstraint(r_len, _) if l_len == r_len => self.clone(),
-                LisConstraint(r_len, r_id) => {
-                    let l_n = token::get_ident(l_id);
-                    let r_n = token::get_ident(r_id);
-                    LisContradiction(format!("inconsistent lockstep iteration: \
-                                              '{}' has {} items, but '{}' has {}",
-                                              l_n, l_len, r_n, r_len).to_string())
-                }
-            },
-        }
-    }
-}
-
-#[cfg(not(stage0))]  // NOTE(stage0): Remove cfg after a snapshot
 impl Add<LockstepIterSize, LockstepIterSize> for LockstepIterSize {
     fn add(self, other: LockstepIterSize) -> LockstepIterSize {
         match self {