Auto merge of #34552 - Manishearth:rollup, r=Manishearth

Rollup of 11 pull requests

- Successful merges: #34355, #34446, #34459, #34460, #34467, #34495, #34497, #34499, #34513, #34536, #34542
- Failed merges:

7 files changed, 66 insertions, 123 deletions

diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index a352715b20b..cc033cec8b8 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -19,7 +19,6 @@ pub use util::ThinVec;
 use syntax_pos::{mk_sp, Span, DUMMY_SP, ExpnId};
 use codemap::{respan, Spanned};
 use abi::Abi;
-use errors;
 use parse::token::{self, keywords, InternedString};
 use print::pprust;
 use ptr::P;
@@ -362,15 +361,6 @@ pub const CRATE_NODE_ID: NodeId = 0;
 /// small, positive ids.
 pub const DUMMY_NODE_ID: NodeId = !0;
 
-pub trait NodeIdAssigner {
-    fn next_node_id(&self) -> NodeId;
-    fn peek_node_id(&self) -> NodeId;
-
-    fn diagnostic(&self) -> &errors::Handler {
-        panic!("this ID assigner cannot emit diagnostics")
-    }
-}
-
 /// The AST represents all type param bounds as types.
 /// typeck::collect::compute_bounds matches these against
 /// the "special" built-in traits (see middle::lang_items) and
diff --git a/src/libsyntax/attr.rs b/src/libsyntax/attr.rs
index da2967e306f..3c88fb8f670 100644
--- a/src/libsyntax/attr.rs
+++ b/src/libsyntax/attr.rs
@@ -839,7 +839,7 @@ impl HasAttrs for StmtKind {
     fn attrs(&self) -> &[Attribute] {
         match *self {
             StmtKind::Local(ref local) => local.attrs(),
-            StmtKind::Item(ref item) => item.attrs(),
+            StmtKind::Item(..) => &[],
             StmtKind::Expr(ref expr) | StmtKind::Semi(ref expr) => expr.attrs(),
             StmtKind::Mac(ref mac) => {
                 let (_, _, ref attrs) = **mac;
@@ -851,7 +851,7 @@ impl HasAttrs for StmtKind {
     fn map_attrs<F: FnOnce(Vec<Attribute>) -> Vec<Attribute>>(self, f: F) -> Self {
         match self {
             StmtKind::Local(local) => StmtKind::Local(local.map_attrs(f)),
-            StmtKind::Item(item) => StmtKind::Item(item.map_attrs(f)),
+            StmtKind::Item(..) => self,
             StmtKind::Expr(expr) => StmtKind::Expr(expr.map_attrs(f)),
             StmtKind::Semi(expr) => StmtKind::Semi(expr.map_attrs(f)),
             StmtKind::Mac(mac) => StmtKind::Mac(mac.map(|(mac, style, attrs)| {
diff --git a/src/libsyntax/config.rs b/src/libsyntax/config.rs
index 961763c6025..eaf82f5f43d 100644
--- a/src/libsyntax/config.rs
+++ b/src/libsyntax/config.rs
@@ -213,12 +213,7 @@ impl<'a> fold::Folder for StripUnconfigured<'a> {
     }
 
     fn fold_stmt(&mut self, stmt: ast::Stmt) -> SmallVector<ast::Stmt> {
-        // avoid calling `visit_stmt_or_expr_attrs` on items
-        match stmt.node {
-            ast::StmtKind::Item(_) => {}
-            _ => self.visit_stmt_or_expr_attrs(stmt.attrs()),
-        }
-
+        self.visit_stmt_or_expr_attrs(stmt.attrs());
         self.configure(stmt).map(|stmt| fold::noop_fold_stmt(stmt, self))
                             .unwrap_or(SmallVector::zero())
     }
diff --git a/src/libsyntax/ext/base.rs b/src/libsyntax/ext/base.rs
index 757b039fcac..ca38ef068d0 100644
--- a/src/libsyntax/ext/base.rs
+++ b/src/libsyntax/ext/base.rs
@@ -443,6 +443,10 @@ impl MacResult for DummyResult {
             span: self.span,
         }))
     }
+
+    fn make_ty(self: Box<DummyResult>) -> Option<P<ast::Ty>> {
+        Some(DummyResult::raw_ty(self.span))
+    }
 }
 
 /// An enum representing the different kinds of syntax extensions.
diff --git a/src/libsyntax/ext/expand.rs b/src/libsyntax/ext/expand.rs
index 3036a88430a..c670283e559 100644
--- a/src/libsyntax/ext/expand.rs
+++ b/src/libsyntax/ext/expand.rs
@@ -43,18 +43,19 @@ trait MacroGenerable: Sized {
     fn fold_with<F: Folder>(self, folder: &mut F) -> Self;
     fn visit_with<V: Visitor>(&self, visitor: &mut V);
 
-    // Return a placeholder expansion to allow compilation to continue after an erroring expansion.
-    fn dummy(span: Span) -> Self;
-
     // The user-friendly name of the node type (e.g. "expression", "item", etc.) for diagnostics.
     fn kind_name() -> &'static str;
+
+    // Return a placeholder expansion to allow compilation to continue after an erroring expansion.
+    fn dummy(span: Span) -> Self {
+        Self::make_with(DummyResult::any(span)).unwrap()
+    }
 }
 
 macro_rules! impl_macro_generable {
     ($($ty:ty: $kind_name:expr, .$make:ident,
                $(.$fold:ident)*  $(lift .$fold_elt:ident)*,
-               $(.$visit:ident)* $(lift .$visit_elt:ident)*,
-               |$span:ident| $dummy:expr;)*) => { $(
+               $(.$visit:ident)* $(lift .$visit_elt:ident)*;)*) => { $(
         impl MacroGenerable for $ty {
             fn kind_name() -> &'static str { $kind_name }
             fn make_with<'a>(result: Box<MacResult + 'a>) -> Option<Self> { result.$make() }
@@ -66,31 +67,24 @@ macro_rules! impl_macro_generable {
                 $( visitor.$visit(self) )*
                 $( for item in self.as_slice() { visitor. $visit_elt (item) } )*
             }
-            fn dummy($span: Span) -> Self { $dummy }
         }
     )* }
 }
 
 impl_macro_generable! {
-    P<ast::Pat>: "pattern", .make_pat, .fold_pat, .visit_pat, |span| P(DummyResult::raw_pat(span));
-    P<ast::Ty>:  "type",    .make_ty,  .fold_ty,  .visit_ty,  |span| DummyResult::raw_ty(span);
-    P<ast::Expr>:
-        "expression", .make_expr, .fold_expr, .visit_expr, |span| DummyResult::raw_expr(span);
-    SmallVector<ast::Stmt>:
-        "statement",  .make_stmts, lift .fold_stmt, lift .visit_stmt, |_span| SmallVector::zero();
-    SmallVector<P<ast::Item>>:
-        "item",       .make_items, lift .fold_item, lift .visit_item, |_span| SmallVector::zero();
+    P<ast::Expr>: "expression", .make_expr, .fold_expr, .visit_expr;
+    P<ast::Pat>:  "pattern",    .make_pat,  .fold_pat,  .visit_pat;
+    P<ast::Ty>:   "type",       .make_ty,   .fold_ty,   .visit_ty;
+    SmallVector<ast::Stmt>: "statement", .make_stmts, lift .fold_stmt, lift .visit_stmt;
+    SmallVector<P<ast::Item>>: "item",   .make_items, lift .fold_item, lift .visit_item;
     SmallVector<ast::TraitItem>:
-        "trait item", .make_trait_items, lift .fold_trait_item, lift .visit_trait_item,
-        |_span| SmallVector::zero();
+        "trait item", .make_trait_items, lift .fold_trait_item, lift .visit_trait_item;
     SmallVector<ast::ImplItem>:
-        "impl item",  .make_impl_items,  lift .fold_impl_item,  lift .visit_impl_item,
-        |_span| SmallVector::zero();
+        "impl item",  .make_impl_items,  lift .fold_impl_item,  lift .visit_impl_item;
 }
 
 impl MacroGenerable for Option<P<ast::Expr>> {
     fn kind_name() -> &'static str { "expression" }
-    fn dummy(_span: Span) -> Self { None }
     fn make_with<'a>(result: Box<MacResult + 'a>) -> Option<Self> {
         result.make_expr().map(Some)
     }
@@ -208,7 +202,7 @@ fn expand_mac_invoc<T>(mac: ast::Mac, ident: Option<Ident>, attrs: Vec<ast::Attr
                                           &fld.cx.ecfg.features.unwrap());
         }
 
-        if path.segments.len() > 1 {
+        if path.segments.len() > 1 || path.global || !path.segments[0].parameters.is_empty() {
             fld.cx.span_err(path.span, "expected macro name without module separators");
             return None;
         }
@@ -691,7 +685,7 @@ impl<'a> Folder for PatIdentRenamer<'a> {
 }
 
 fn expand_multi_modified(a: Annotatable, fld: &mut MacroExpander) -> SmallVector<Annotatable> {
-    let new_items: SmallVector<Annotatable> = match a {
+    match a {
         Annotatable::Item(it) => match it.node {
             ast::ItemKind::Mac(..) => {
                 it.and_then(|it| match it.node {
@@ -728,63 +722,6 @@ fn expand_multi_modified(a: Annotatable, fld: &mut MacroExpander) -> SmallVector
             expand_impl_item(ii.unwrap(), fld).into_iter().
                 map(|ii| Annotatable::ImplItem(P(ii))).collect()
         }
-    };
-
-    new_items.into_iter().flat_map(|a| decorate(a, fld)).collect()
-}
-
-fn decorate(a: Annotatable, fld: &mut MacroExpander) -> SmallVector<Annotatable> {
-    let mut decorator_items = SmallVector::zero();
-    let mut new_attrs = Vec::new();
-    expand_decorators(a.clone(), fld, &mut decorator_items, &mut new_attrs);
-
-    let mut new_items = SmallVector::one(a.fold_attrs(new_attrs));
-    new_items.push_all(decorator_items);
-    new_items
-}
-
-fn expand_decorators(a: Annotatable,
-                     fld: &mut MacroExpander,
-                     decorator_items: &mut SmallVector<Annotatable>,
-                     new_attrs: &mut Vec<ast::Attribute>)
-{
-    for attr in a.attrs() {
-        let mname = intern(&attr.name());
-        match fld.cx.syntax_env.find(mname) {
-            Some(rc) => match *rc {
-                MultiDecorator(ref dec) => {
-                    attr::mark_used(&attr);
-
-                    fld.cx.bt_push(ExpnInfo {
-                        call_site: attr.span,
-                        callee: NameAndSpan {
-                            format: MacroAttribute(mname),
-                            span: Some(attr.span),
-                            // attributes can do whatever they like,
-                            // for now.
-                            allow_internal_unstable: true,
-                        }
-                    });
-
-                    let mut items: SmallVector<Annotatable> = SmallVector::zero();
-                    dec.expand(fld.cx,
-                               attr.span,
-                               &attr.node.value,
-                               &a,
-                               &mut |ann| items.push(ann));
-
-                    for item in items {
-                        for configured_item in item.fold_with(&mut fld.strip_unconfigured()) {
-                            decorator_items.extend(expand_annotatable(configured_item, fld));
-                        }
-                    }
-
-                    fld.cx.bt_pop();
-                }
-                _ => new_attrs.push((*attr).clone()),
-            },
-            _ => new_attrs.push((*attr).clone()),
-        }
     }
 }
 
@@ -793,9 +730,12 @@ fn expand_annotatable(mut item: Annotatable, fld: &mut MacroExpander) -> SmallVe
     item = item.map_attrs(|mut attrs| {
         for i in 0..attrs.len() {
             if let Some(extension) = fld.cx.syntax_env.find(intern(&attrs[i].name())) {
-                if let MultiModifier(..) = *extension {
-                    multi_modifier = Some((attrs.remove(i), extension));
-                    break;
+                match *extension {
+                    MultiModifier(..) | MultiDecorator(..) => {
+                        multi_modifier = Some((attrs.remove(i), extension));
+                        break;
+                    }
+                    _ => {}
                 }
             }
         }
@@ -804,23 +744,32 @@ fn expand_annotatable(mut item: Annotatable, fld: &mut MacroExpander) -> SmallVe
 
     match multi_modifier {
         None => expand_multi_modified(item, fld),
-        Some((attr, extension)) => match *extension {
-            MultiModifier(ref mac) => {
-                attr::mark_used(&attr);
-                fld.cx.bt_push(ExpnInfo {
-                    call_site: attr.span,
-                    callee: NameAndSpan {
-                        format: MacroAttribute(intern(&attr.name())),
-                        span: Some(attr.span),
-                        // attributes can do whatever they like, for now
-                        allow_internal_unstable: true,
-                    }
-                });
-                let modified = mac.expand(fld.cx, attr.span, &attr.node.value, item);
-                fld.cx.bt_pop();
-                modified.into_iter().flat_map(|it| expand_annotatable(it, fld)).collect()
-            }
-            _ => unreachable!(),
+        Some((attr, extension)) => {
+            attr::mark_used(&attr);
+            fld.cx.bt_push(ExpnInfo {
+                call_site: attr.span,
+                callee: NameAndSpan {
+                    format: MacroAttribute(intern(&attr.name())),
+                    span: Some(attr.span),
+                    // attributes can do whatever they like, for now
+                    allow_internal_unstable: true,
+                }
+            });
+
+            let modified = match *extension {
+                MultiModifier(ref mac) => mac.expand(fld.cx, attr.span, &attr.node.value, item),
+                MultiDecorator(ref mac) => {
+                    let mut items = Vec::new();
+                    mac.expand(fld.cx, attr.span, &attr.node.value, &item,
+                               &mut |item| items.push(item));
+                    items.push(item);
+                    items
+                }
+                _ => unreachable!(),
+            };
+
+            fld.cx.bt_pop();
+            modified.into_iter().flat_map(|it| expand_annotatable(it, fld)).collect()
         }
     }
 }
diff --git a/src/libsyntax/fold.rs b/src/libsyntax/fold.rs
index 6789e7be058..ed6f09eed64 100644
--- a/src/libsyntax/fold.rs
+++ b/src/libsyntax/fold.rs
@@ -1102,7 +1102,6 @@ pub fn noop_fold_pat<T: Folder>(p: P<Pat>, folder: &mut T) -> P<Pat> {
 
 pub fn noop_fold_expr<T: Folder>(Expr {id, node, span, attrs}: Expr, folder: &mut T) -> Expr {
     Expr {
-        id: folder.new_id(id),
         node: match node {
             ExprKind::Box(e) => {
                 ExprKind::Box(folder.fold_expr(e))
@@ -1270,9 +1269,19 @@ pub fn noop_fold_expr<T: Folder>(Expr {id, node, span, attrs}: Expr, folder: &mu
                         fields.move_map(|x| folder.fold_field(x)),
                         maybe_expr.map(|x| folder.fold_expr(x)))
             },
-            ExprKind::Paren(ex) => ExprKind::Paren(folder.fold_expr(ex)),
+            ExprKind::Paren(ex) => {
+                let sub_expr = folder.fold_expr(ex);
+                return Expr {
+                    // Nodes that are equal modulo `Paren` sugar no-ops should have the same ids.
+                    id: sub_expr.id,
+                    node: ExprKind::Paren(sub_expr),
+                    span: folder.new_span(span),
+                    attrs: fold_attrs(attrs.into(), folder).into(),
+                };
+            }
             ExprKind::Try(ex) => ExprKind::Try(folder.fold_expr(ex)),
         },
+        id: folder.new_id(id),
         span: folder.new_span(span),
         attrs: fold_attrs(attrs.into(), folder).into(),
     }
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index 813d90103b8..20a54228d01 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -553,10 +553,6 @@ impl<'a> Parser<'a> {
         self.expect_one_of(edible, inedible)
     }
 
-    pub fn commit_stmt_expecting(&mut self, edible: token::Token) -> PResult<'a, ()> {
-        self.commit_stmt(&[edible], &[])
-    }
-
     /// returns the span of expr, if it was not interpolated or the span of the interpolated token
     fn interpolated_or_expr_span(&self,
                                  expr: PResult<'a, P<Expr>>)
@@ -4122,7 +4118,7 @@ impl<'a> Parser<'a> {
                 _ => { // all other kinds of statements:
                     let mut hi = span.hi;
                     if classify::stmt_ends_with_semi(&node) {
-                        self.commit_stmt_expecting(token::Semi)?;
+                        self.commit_stmt(&[token::Semi], &[])?;
                         hi = self.last_span.hi;
                     }