Stabilize #![feature(slice_patterns)] in 1.42.0

src/libcore/lib.rs

@@ -133,7 +133,7 @@
 #![feature(associated_type_bounds)]
 #![feature(const_type_id)]
 #![feature(const_caller_location)]
-#![feature(slice_patterns)]
+#![cfg_attr(bootstrap, feature(slice_patterns))]
 
 #[prelude_import]
 #[allow(unused)]

src/libcore/tests/lib.rs

@@ -19,7 +19,7 @@
 #![feature(range_is_empty)]
 #![feature(raw)]
 #![feature(saturating_neg)]
-#![feature(slice_patterns)]
+#![cfg_attr(bootstrap, feature(slice_patterns))]
 #![feature(sort_internals)]
 #![feature(slice_partition_at_index)]
 #![feature(specialization)]

src/librustc/benches/lib.rs

@@ -1,4 +1,4 @@
-#![feature(slice_patterns)]
+#![cfg_attr(bootstrap, feature(slice_patterns))]
 #![feature(test)]
 
 extern crate test;

src/librustc/lib.rs

@@ -42,7 +42,7 @@
 #![feature(optin_builtin_traits)]
 #![feature(option_expect_none)]
 #![feature(range_is_empty)]
-#![feature(slice_patterns)]
+#![cfg_attr(bootstrap, feature(slice_patterns))]
 #![feature(specialization)]
 #![feature(unboxed_closures)]
 #![feature(thread_local)]

src/librustc_ast_passes/feature_gate.rs

@@ -470,29 +470,8 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
         visit::walk_expr(self, e)
     }
 
-    fn visit_arm(&mut self, arm: &'a ast::Arm) {
-        visit::walk_arm(self, arm)
-    }
-
     fn visit_pat(&mut self, pattern: &'a ast::Pat) {
         match &pattern.kind {
-            PatKind::Slice(pats) => {
-                for pat in &*pats {
-                    let span = pat.span;
-                    let inner_pat = match &pat.kind {
-                        PatKind::Ident(.., Some(pat)) => pat,
-                        _ => pat,
-                    };
-                    if inner_pat.is_rest() {
-                        gate_feature_post!(
-                            &self,
-                            slice_patterns,
-                            span,
-                            "subslice patterns are unstable"
-                        );
-                    }
-                }
-            }
             PatKind::Box(..) => {
                 gate_feature_post!(
                     &self,

src/librustc_ast_passes/lib.rs

@@ -2,7 +2,7 @@
 //! parsed by `rustc_parse` and then lowered, after the passes in this crate,
 //! by `rustc_ast_lowering`.
 
-#![feature(slice_patterns)]
+#![cfg_attr(bootstrap, feature(slice_patterns))]
 
 pub mod ast_validation;
 pub mod feature_gate;

src/librustc_codegen_ssa/lib.rs

@@ -4,7 +4,7 @@
 #![feature(box_syntax)]
 #![feature(core_intrinsics)]
 #![feature(libc)]
-#![feature(slice_patterns)]
+#![cfg_attr(bootstrap, feature(slice_patterns))]
 #![feature(stmt_expr_attributes)]
 #![feature(try_blocks)]
 #![feature(in_band_lifetimes)]

src/librustc_error_codes/error_codes/E0527.md

@@ -17,8 +17,6 @@ Ensure that the pattern is consistent with the size of the matched
 array. Additional elements can be matched with `..`:
 
 ```
-#![feature(slice_patterns)]
-
 let r = &[1, 2, 3, 4];
 match r {
     &[a, b, ..] => { // ok!

src/librustc_error_codes/error_codes/E0528.md

@@ -4,8 +4,6 @@ matched array.
 Example of erroneous code:
 
 ```compile_fail,E0528
-#![feature(slice_patterns)]
-
 let r = &[1, 2];
 match r {
     &[a, b, c, rest @ ..] => { // error: pattern requires at least 3
@@ -19,8 +17,6 @@ Ensure that the matched array has at least as many elements as the pattern
 requires. You can match an arbitrary number of remaining elements with `..`:
 
 ```
-#![feature(slice_patterns)]
-
 let r = &[1, 2, 3, 4, 5];
 match r {
     &[a, b, c, rest @ ..] => { // ok!

src/librustc_error_codes/error_codes/E0730.md

@@ -18,8 +18,6 @@ Ensure that the pattern is consistent with the size of the matched
 array. Additional elements can be matched with `..`:
 
 ```
-#![feature(slice_patterns)]
-
 let r = &[1, 2, 3, 4];
 match r {
     &[a, b, ..] => { // ok!

src/librustc_feature/accepted.rs

@@ -257,6 +257,8 @@ declare_features! (
     /// Allows relaxing the coherence rules such that
     /// `impl<T> ForeignTrait<LocalType> for ForeignType<T>` is permitted.
     (accepted, re_rebalance_coherence, "1.41.0", Some(55437), None),
+    /// Allows using subslice patterns, `[a, .., b]` and `[a, xs @ .., b]`.
+    (accepted, slice_patterns, "1.42.0", Some(62254), None),
 
     // -------------------------------------------------------------------------
     // feature-group-end: accepted features

src/librustc_feature/active.rs

@@ -262,9 +262,6 @@ declare_features! (
     /// Allows using non lexical lifetimes (RFC 2094).
     (active, nll, "1.0.0", Some(43234), None),
 
-    /// Allows using slice patterns.
-    (active, slice_patterns, "1.0.0", Some(62254), None),
-
     /// Allows the definition of `const` functions with some advanced features.
     (active, const_fn, "1.2.0", Some(57563), None),
 

src/librustc_metadata/lib.rs

@@ -10,7 +10,7 @@
 #![feature(proc_macro_internals)]
 #![feature(proc_macro_quote)]
 #![feature(rustc_private)]
-#![feature(slice_patterns)]
+#![cfg_attr(bootstrap, feature(slice_patterns))]
 #![feature(specialization)]
 #![feature(stmt_expr_attributes)]
 #![recursion_limit = "256"]

src/librustc_mir/lib.rs

@@ -7,7 +7,7 @@ Rust MIR: a lowered representation of Rust. Also: an experiment!
 #![feature(nll)]
 #![feature(in_band_lifetimes)]
 #![feature(inner_deref)]
-#![feature(slice_patterns)]
+#![cfg_attr(bootstrap, feature(slice_patterns))]
 #![feature(bool_to_option)]
 #![feature(box_patterns)]
 #![feature(box_syntax)]

src/librustc_mir_build/lib.rs

@@ -5,7 +5,7 @@
 #![feature(box_patterns)]
 #![feature(box_syntax)]
 #![feature(crate_visibility_modifier)]
-#![feature(slice_patterns)]
+#![cfg_attr(bootstrap, feature(slice_patterns))]
 #![feature(bool_to_option)]
 #![recursion_limit = "256"]
 

src/librustc_parse/lib.rs

@@ -2,7 +2,7 @@
 
 #![feature(bool_to_option)]
 #![feature(crate_visibility_modifier)]
-#![feature(slice_patterns)]
+#![cfg_attr(bootstrap, feature(slice_patterns))]
 
 use syntax::ast;
 use syntax::print::pprust;

src/librustc_passes/lib.rs

@@ -7,7 +7,7 @@
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
 #![feature(in_band_lifetimes)]
 #![feature(nll)]
-#![feature(slice_patterns)]
+#![cfg_attr(bootstrap, feature(slice_patterns))]
 #![recursion_limit = "256"]
 
 #[macro_use]

src/librustc_target/lib.rs

@@ -11,7 +11,7 @@
 #![feature(box_syntax)]
 #![feature(bool_to_option)]
 #![feature(nll)]
-#![feature(slice_patterns)]
+#![cfg_attr(bootstrap, feature(slice_patterns))]
 
 #[macro_use]
 extern crate log;

src/librustc_ty/lib.rs

@@ -8,7 +8,7 @@
 #![feature(bool_to_option)]
 #![feature(in_band_lifetimes)]
 #![feature(nll)]
-#![feature(slice_patterns)]
+#![cfg_attr(bootstrap, feature(slice_patterns))]
 #![recursion_limit = "256"]
 
 #[macro_use]

src/librustc_typeck/lib.rs

@@ -64,7 +64,7 @@ This API is completely unstable and subject to change.
 #![feature(exhaustive_patterns)]
 #![feature(in_band_lifetimes)]
 #![feature(nll)]
-#![feature(slice_patterns)]
+#![cfg_attr(bootstrap, feature(slice_patterns))]
 #![feature(try_blocks)]
 #![feature(never_type)]
 #![recursion_limit = "256"]

src/libstd/lib.rs

@@ -294,7 +294,7 @@
 #![feature(shrink_to)]
 #![feature(slice_concat_ext)]
 #![feature(slice_internals)]
-#![feature(slice_patterns)]
+#![cfg_attr(bootstrap, feature(slice_patterns))]
 #![feature(specialization)]
 #![feature(staged_api)]
 #![feature(std_internals)]

src/libsyntax/lib.rs

@@ -13,7 +13,7 @@
 #![feature(label_break_value)]
 #![feature(nll)]
 #![feature(try_trait)]
-#![feature(slice_patterns)]
+#![cfg_attr(bootstrap, feature(slice_patterns))]
 #![feature(unicode_internals)]
 #![recursion_limit = "256"]
 

src/test/mir-opt/uniform_array_move_out.rs

@@ -1,5 +1,4 @@
 #![feature(box_syntax)]
-#![feature(slice_patterns)]
 
 fn move_out_from_end() {
     let a = [box 1, box 2];

src/test/ui/match/match-vec-mismatch.rs → src/test/ui/array-slice-vec/slice-pat-type-mismatches.rs

@@ -1,5 +1,3 @@
-#![feature(slice_patterns)]
-
 fn main() {
     match "foo".to_string() {
         ['f', 'o', ..] => {}

src/test/ui/match/match-vec-mismatch.stderr → src/test/ui/array-slice-vec/slice-pat-type-mismatches.stderr

@@ -1,29 +1,29 @@
 error[E0425]: cannot find value `does_not_exist` in this scope
-  --> $DIR/match-vec-mismatch.rs:28:11
+  --> $DIR/slice-pat-type-mismatches.rs:26:11
    |
 LL |     match does_not_exist {
    |           ^^^^^^^^^^^^^^ not found in this scope
 
 error[E0529]: expected an array or slice, found `std::string::String`
-  --> $DIR/match-vec-mismatch.rs:5:9
+  --> $DIR/slice-pat-type-mismatches.rs:3:9
    |
 LL |         ['f', 'o', ..] => {}
    |         ^^^^^^^^^^^^^^ pattern cannot match with input type `std::string::String`
 
 error[E0527]: pattern requires 1 element but array has 3
-  --> $DIR/match-vec-mismatch.rs:20:9
+  --> $DIR/slice-pat-type-mismatches.rs:18:9
    |
 LL |         [0] => {},
    |         ^^^ expected 3 elements
 
 error[E0528]: pattern requires at least 4 elements but array has 3
-  --> $DIR/match-vec-mismatch.rs:25:9
+  --> $DIR/slice-pat-type-mismatches.rs:23:9
    |
 LL |         [0, 1, 2, 3, x @ ..] => {}
    |         ^^^^^^^^^^^^^^^^^^^^ pattern cannot match array of 3 elements
 
 error[E0282]: type annotations needed
-  --> $DIR/match-vec-mismatch.rs:36:9
+  --> $DIR/slice-pat-type-mismatches.rs:34:9
    |
 LL |         [] => {}
    |         ^^ cannot infer type

src/test/ui/parser/match-vec-invalid.rs → src/test/ui/array-slice-vec/subslice-only-once-semantic-restriction.rs

@@ -3,8 +3,6 @@ fn main() {
     match a {
         [1, tail @ .., tail @ ..] => {},
         //~^ ERROR identifier `tail` is bound more than once in the same pattern
-        //~| ERROR subslice patterns are unstable
-        //~| ERROR subslice patterns are unstable
         //~| ERROR `..` can only be used once per slice pattern
         _ => ()
     }

src/test/ui/array-slice-vec/subslice-only-once-semantic-restriction.stderr

@@ -0,0 +1,24 @@
+error[E0416]: identifier `tail` is bound more than once in the same pattern
+  --> $DIR/subslice-only-once-semantic-restriction.rs:4:24
+   |
+LL |         [1, tail @ .., tail @ ..] => {},
+   |                        ^^^^ used in a pattern more than once
+
+error: `..` can only be used once per slice pattern
+  --> $DIR/subslice-only-once-semantic-restriction.rs:4:31
+   |
+LL |         [1, tail @ .., tail @ ..] => {},
+   |                    --         ^^ can only be used once per slice pattern
+   |                    |
+   |                    previously used here
+
+error[E0308]: mismatched types
+  --> $DIR/subslice-only-once-semantic-restriction.rs:11:30
+   |
+LL | const RECOVERY_WITNESS: () = 0;
+   |                              ^ expected `()`, found integer
+
+error: aborting due to 3 previous errors
+
+Some errors have detailed explanations: E0308, E0416.
+For more information about an error, try `rustc --explain E0308`.

src/test/ui/array-slice-vec/subslice-patterns-const-eval-match.rs

@@ -2,7 +2,7 @@
 
 // run-pass
 
-#![feature(slice_patterns, const_fn, const_if_match)]
+#![feature(const_fn, const_if_match)]
 #[derive(PartialEq, Debug, Clone)]
 struct N(u8);
 

src/test/ui/array-slice-vec/subslice-patterns-const-eval.rs

@@ -2,8 +2,6 @@
 
 // run-pass
 
-#![feature(slice_patterns)]
-
 #[derive(PartialEq, Debug, Clone)]
 struct N(u8);
 

src/test/ui/array-slice-vec/subslice-patterns-pass.rs

@@ -4,8 +4,6 @@
 
 // run-pass
 
-#![feature(slice_patterns)]
-
 #![allow(unreachable_patterns)]
 
 use std::convert::identity;

src/test/ui/array-slice-vec/vec-matching-fixed.rs

@@ -1,7 +1,5 @@
 // run-pass
 
-#![feature(slice_patterns)]
-
 fn a() {
     let x = [1, 2, 3];
     match x {

src/test/ui/array-slice-vec/vec-matching-fold.rs

@@ -1,7 +1,5 @@
 // run-pass
 
-#![feature(slice_patterns)]
-
 use std::fmt::Debug;
 
 fn foldl<T, U, F>(values: &[T],

src/test/ui/array-slice-vec/vec-matching-legal-tail-element-borrow.rs

@@ -1,7 +1,6 @@
 // run-pass
-#![allow(unused_variables)]
 
-#![feature(slice_patterns)]
+#![allow(unused_variables)]
 
 pub fn main() {
     let x = &[1, 2, 3, 4, 5];

src/test/ui/array-slice-vec/vec-matching.rs

@@ -1,7 +1,5 @@
 // run-pass
 
-#![feature(slice_patterns)]
-
 fn a() {
     let x = [1];
     match x {