Place parenthetical notation under the unboxed_closure feature-gate.

Consolidate the `unboxed_closure_sugar` and `unboxed_closure` feature gates.

Author: nikomatsakis

src/doc/reference.md

@@ -2560,10 +2560,6 @@ The currently implemented features of the reference compiler are:
 * `trace_macros` - Allows use of the `trace_macros` macro, which is a nasty
                    hack that will certainly be removed.
 
-* `unboxed_closure_sugar` - Allows using `|Foo| -> Bar` as a trait bound
-                            meaning one of the `Fn` traits. Still
-                            experimental.
-
 * `unboxed_closures` - A work in progress feature with many known bugs.
 
 * `unsafe_destructor` - Allows use of the `#[unsafe_destructor]` attribute,

src/libsyntax/feature_gate.rs

@@ -59,7 +59,6 @@ static KNOWN_FEATURES: &'static [(&'static str, Status)] = &[
     ("linkage", Active),
     ("struct_inherit", Removed),
     ("overloaded_calls", Active),
-    ("unboxed_closure_sugar", Active),
 
     ("quad_precision_float", Removed),
 
@@ -381,7 +380,7 @@ impl<'a, 'v> Visitor<'v> for Context<'a> {
                 fn_decl: &'v ast::FnDecl,
                 block: &'v ast::Block,
                 span: Span,
-                _: NodeId) {
+                _node_id: NodeId) {
         match fn_kind {
             visit::FkItemFn(_, _, _, abi) if abi == RustIntrinsic => {
                 self.gate_feature("intrinsics",
@@ -392,6 +391,19 @@ impl<'a, 'v> Visitor<'v> for Context<'a> {
         }
         visit::walk_fn(self, fn_kind, fn_decl, block, span);
     }
+
+    fn visit_path_parameters(&mut self, path_span: Span, parameters: &'v ast::PathParameters) {
+        match *parameters {
+            ast::ParenthesizedParameters(..) => {
+                self.gate_feature("unboxed_closures",
+                                  path_span,
+                                  "parenthetical parameter notation is subject to change");
+            }
+            ast::AngleBracketedParameters(..) => { }
+        }
+
+        visit::walk_path_parameters(self, path_span, parameters)
+    }
 }
 
 pub fn check_crate(span_handler: &SpanHandler, krate: &ast::Crate) -> (Features, Vec<Span>) {

src/test/compile-fail/borrowck-unboxed-closures.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(overloaded_calls)]
+#![feature(overloaded_calls, unboxed_closures)]
 
 fn a<F:Fn(int, int) -> int>(mut f: F) {
     let g = &mut f;

src/test/compile-fail/issue-16939.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(overloaded_calls)]
+#![feature(overloaded_calls, unboxed_closures)]
 
 // Make sure we don't ICE when making an overloaded call with the
 // wrong arity.

src/test/compile-fail/regionck-unboxed-closure-lifetimes.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(unboxed_closure_sugar, unboxed_closures, overloaded_calls)]
+#![feature(unboxed_closures, overloaded_calls)]
 
 use std::ops::FnMut;
 

src/test/compile-fail/unboxed-closure-sugar-default.rs

@@ -11,7 +11,7 @@
 // Test interaction between unboxed closure sugar and default type
 // parameters (should be exactly as if angle brackets were used).
 
-#![feature(default_type_params)]
+#![feature(default_type_params, unboxed_closures)]
 #![allow(dead_code)]
 
 struct Foo<T,U,V=T> {

src/test/compile-fail/unboxed-closure-sugar-equiv.rs

@@ -13,6 +13,7 @@
 // angle brackets. This test covers only simple types and in
 // particular doesn't test bound regions.
 
+#![feature(unboxed_closures)]
 #![allow(dead_code)]
 
 struct Foo<T,U> {

src/test/compile-fail/unboxed-closure-sugar-nonexistent-trait.rs

@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![feature(unboxed_closures)]
+
 fn f<F:Nonexist(int) -> int>(x: F) {} //~ ERROR nonexistent trait `Nonexist`
 
 type Typedef = int;

src/test/compile-fail/unboxed-closure-sugar-region.rs

@@ -12,7 +12,7 @@
 // parameters (should be exactly as if angle brackets were used
 // and regions omitted).
 
-#![feature(default_type_params)]
+#![feature(default_type_params, unboxed_closures)]
 #![allow(dead_code)]
 
 use std::kinds::marker;

src/test/compile-fail/unboxed-closure-sugar-wrong-number-number-type-parameters-1.rs

@@ -9,6 +9,7 @@
 // except according to those terms.
 
 struct One<A>;
+#![feature(unboxed_closures)]
 
 fn foo(_: One()) //~ ERROR wrong number of type arguments
 {}