Remove feature gates for if let, while let, and tuple indexing

Closes #19469

Author: nrc

src/libsyntax/feature_gate.rs

@@ -65,13 +65,13 @@ static KNOWN_FEATURES: &'static [(&'static str, Status)] = &[
     ("unboxed_closures", Active),
     ("import_shadowing", Active),
     ("advanced_slice_patterns", Active),
-    ("tuple_indexing", Active),
+    ("tuple_indexing", Accepted),
     ("associated_types", Active),
     ("visible_private_types", Active),
     ("slicing_syntax", Active),
 
-    ("if_let", Active),
-    ("while_let", Active),
+    ("if_let", Accepted),
+    ("while_let", Accepted),
 
     // if you change this list without updating src/doc/reference.md, cmr will be sad
 
@@ -309,24 +309,11 @@ impl<'a, 'v> Visitor<'v> for Context<'a> {
                                   "unboxed closures are a work-in-progress \
                                    feature with known bugs");
             }
-            ast::ExprTupField(..) => {
-                self.gate_feature("tuple_indexing",
-                                  e.span,
-                                  "tuple indexing is experimental");
-            }
-            ast::ExprIfLet(..) => {
-                self.gate_feature("if_let", e.span,
-                                  "`if let` syntax is experimental");
-            }
             ast::ExprSlice(..) => {
                 self.gate_feature("slicing_syntax",
                                   e.span,
                                   "slicing syntax is experimental");
             }
-            ast::ExprWhileLet(..) => {
-                self.gate_feature("while_let", e.span,
-                                  "`while let` syntax is experimental");
-            }
             _ => {}
         }
         visit::walk_expr(self, e);

src/test/compile-fail/borrow-tuple-fields.rs

@@ -8,8 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(tuple_indexing)]
-
 struct Foo(Box<int>, int);
 
 struct Bar(int, int);

src/test/compile-fail/if-let.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(macro_rules,if_let)]
+#![feature(macro_rules)]
 
 fn macros() {
     macro_rules! foo{

src/test/compile-fail/issue-18566.rs

@@ -8,8 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(tuple_indexing)]
-
 struct MyPtr<'a>(&'a mut uint);
 impl<'a> Deref<uint> for MyPtr<'a> {
     fn deref<'b>(&'b self) -> &'b uint { self.0 }

src/test/compile-fail/issue-19244-1.rs

@@ -8,8 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(tuple_indexing)]
-
 const TUP: (uint,) = (42,);
 
 fn main() {

src/test/compile-fail/lint-unnecessary-parens.rs

@@ -9,7 +9,6 @@
 // except according to those terms.
 
 #![deny(unused_parens)]
-#![feature(if_let,while_let)]
 
 #[deriving(Eq, PartialEq)]
 struct X { y: bool }

src/test/compile-fail/move-fragments-1.rs

@@ -8,8 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(tuple_indexing)]
-
 // Test that we correctly compute the move fragments for a fn.
 //
 // Note that the code below is not actually incorrect; the

src/test/compile-fail/move-out-of-tuple-field.rs

@@ -8,8 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(tuple_indexing)]
-
 struct Foo(Box<int>);
 
 fn main() {

src/test/compile-fail/tuple-index-not-tuple.rs

@@ -8,8 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(tuple_indexing)]
-
 struct Point { x: int, y: int }
 struct Empty;
 

src/test/compile-fail/tuple-index-out-of-bounds.rs

@@ -8,8 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(tuple_indexing)]
-
 struct Point(int, int);
 
 fn main() {

src/test/compile-fail/while-let.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(macro_rules,while_let)]
+#![feature(macro_rules)]
 
 fn macros() {
     macro_rules! foo{