Auto merge of #79278 - mark-i-m:stabilize-or-pattern, r=nikomatsakis

Stabilize or_patterns (RFC 2535, 2530, 2175)

closes #54883

This PR stabilizes the or_patterns feature in Rust 1.53.

This is blocked on the following (in order):
- [x] The crater run in #78935 (comment)
- [x] The resolution of the unresolved questions and a second crater run (#78935 (comment))
    - It looks like we will need to pursue some sort of edition-based transition for `:pat`.
- [x] Nomination and discussion by T-lang
- [x] Implement new behavior for `:pat` based on consensus (#80100).
- [ ] An FCP on stabilization

EDIT: Stabilization report is in #79278 (comment)

compiler/rustc_apfloat/src/lib.rs

@@ -34,7 +34,7 @@
 #![no_std]
 #![forbid(unsafe_code)]
 #![feature(nll)]
-#![feature(or_patterns)]
+#![cfg_attr(bootstrap, feature(or_patterns))]
 
 #[macro_use]
 extern crate alloc;

compiler/rustc_ast/src/lib.rs

@@ -16,7 +16,7 @@
 #![feature(crate_visibility_modifier)]
 #![feature(label_break_value)]
 #![feature(nll)]
-#![feature(or_patterns)]
+#![cfg_attr(bootstrap, feature(or_patterns))]
 #![recursion_limit = "256"]
 
 #[macro_use]

compiler/rustc_ast_lowering/src/lib.rs

@@ -31,7 +31,7 @@
 //! in the HIR, especially for multiple identifiers.
 
 #![feature(crate_visibility_modifier)]
-#![feature(or_patterns)]
+#![cfg_attr(bootstrap, feature(or_patterns))]
 #![feature(box_patterns)]
 #![recursion_limit = "256"]
 

compiler/rustc_ast_passes/src/feature_gate.rs

@@ -686,7 +686,6 @@ pub fn check_crate(krate: &ast::Crate, sess: &Session) {
         "to use an async block, remove the `||`: `async {`"
     );
     gate_all!(generators, "yield syntax is experimental");
-    gate_all!(or_patterns, "or-patterns syntax is experimental");
     gate_all!(raw_ref_op, "raw address of syntax is experimental");
     gate_all!(const_trait_bound_opt_out, "`?const` on trait bounds is experimental");
     gate_all!(const_trait_impl, "const trait impls are experimental");

compiler/rustc_ast_pretty/src/lib.rs

@@ -1,6 +1,6 @@
 #![feature(bool_to_option)]
 #![feature(crate_visibility_modifier)]
-#![feature(or_patterns)]
+#![cfg_attr(bootstrap, feature(or_patterns))]
 #![feature(box_patterns)]
 #![recursion_limit = "256"]
 

compiler/rustc_attr/src/lib.rs

@@ -4,7 +4,7 @@
 //! The goal is to move the definition of `MetaItem` and things that don't need to be in `syntax`
 //! to this crate.
 
-#![feature(or_patterns)]
+#![cfg_attr(bootstrap, feature(or_patterns))]
 
 #[macro_use]
 extern crate rustc_macros;

compiler/rustc_builtin_macros/src/lib.rs

@@ -8,7 +8,7 @@
 #![feature(crate_visibility_modifier)]
 #![feature(decl_macro)]
 #![feature(nll)]
-#![feature(or_patterns)]
+#![cfg_attr(bootstrap, feature(or_patterns))]
 #![feature(proc_macro_internals)]
 #![feature(proc_macro_quote)]
 #![recursion_limit = "256"]

compiler/rustc_codegen_llvm/src/lib.rs

@@ -12,7 +12,7 @@
 #![feature(extern_types)]
 #![feature(in_band_lifetimes)]
 #![feature(nll)]
-#![feature(or_patterns)]
+#![cfg_attr(bootstrap, feature(or_patterns))]
 #![recursion_limit = "256"]
 
 use back::write::{create_informational_target_machine, create_target_machine};

compiler/rustc_codegen_ssa/src/lib.rs

@@ -6,7 +6,7 @@
 #![feature(try_blocks)]
 #![feature(in_band_lifetimes)]
 #![feature(nll)]
-#![feature(or_patterns)]
+#![cfg_attr(bootstrap, feature(or_patterns))]
 #![feature(associated_type_bounds)]
 #![recursion_limit = "256"]
 #![feature(box_syntax)]

compiler/rustc_expand/src/expand.rs

@@ -22,7 +22,7 @@ use rustc_data_structures::stack::ensure_sufficient_stack;
 use rustc_data_structures::sync::Lrc;
 use rustc_errors::{Applicability, PResult};
 use rustc_feature::Features;
-use rustc_parse::parser::{AttemptLocalParseRecovery, ForceCollect, GateOr, Parser, RecoverComma};
+use rustc_parse::parser::{AttemptLocalParseRecovery, ForceCollect, Parser, RecoverComma};
 use rustc_parse::validate_attr;
 use rustc_session::lint::builtin::UNUSED_DOC_COMMENTS;
 use rustc_session::lint::BuiltinLintDiagnostics;
@@ -917,7 +917,7 @@ pub fn parse_ast_fragment<'a>(
         }
         AstFragmentKind::Ty => AstFragment::Ty(this.parse_ty()?),
         AstFragmentKind::Pat => {
-            AstFragment::Pat(this.parse_pat_allow_top_alt(None, GateOr::Yes, RecoverComma::No)?)
+            AstFragment::Pat(this.parse_pat_allow_top_alt(None, RecoverComma::No)?)
         }
         AstFragmentKind::Arms
         | AstFragmentKind::Fields

compiler/rustc_expand/src/lib.rs

@@ -2,7 +2,7 @@
 #![feature(crate_visibility_modifier)]
 #![feature(decl_macro)]
 #![feature(destructuring_assignment)]
-#![feature(or_patterns)]
+#![cfg_attr(bootstrap, feature(or_patterns))]
 #![feature(proc_macro_diagnostic)]
 #![feature(proc_macro_internals)]
 #![feature(proc_macro_span)]

compiler/rustc_feature/src/accepted.rs

@@ -277,6 +277,8 @@ declare_features! (
     (accepted, min_const_generics, "1.51.0", Some(74878), None),
     /// The `unsafe_op_in_unsafe_fn` lint (allowed by default): no longer treat an unsafe function as an unsafe block.
     (accepted, unsafe_block_in_unsafe_fn, "1.51.0", Some(71668), None),
+    /// Allows the use of or-patterns (e.g., `0 | 1`).
+    (accepted, or_patterns, "1.53.0", Some(54883), None),
 
     // -------------------------------------------------------------------------
     // feature-group-end: accepted features

compiler/rustc_feature/src/active.rs

@@ -488,9 +488,6 @@ declare_features! (
     /// Allows `impl Trait` to be used inside type aliases (RFC 2515).
     (active, type_alias_impl_trait, "1.38.0", Some(63063), None),
 
-    /// Allows the use of or-patterns (e.g., `0 | 1`).
-    (active, or_patterns, "1.38.0", Some(54883), None),
-
     /// Allows the definition of `const extern fn` and `const unsafe extern fn`.
     (active, const_extern_fn, "1.40.0", Some(64926), None),
 

compiler/rustc_hir/src/lib.rs

@@ -8,7 +8,7 @@
 #![feature(extended_key_value_attributes)]
 #![feature(in_band_lifetimes)]
 #![feature(once_cell)]
-#![feature(or_patterns)]
+#![cfg_attr(bootstrap, feature(or_patterns))]
 #![recursion_limit = "256"]
 
 #[macro_use]

compiler/rustc_hir_pretty/src/lib.rs

@@ -1,4 +1,4 @@
-#![feature(or_patterns)]
+#![cfg_attr(bootstrap, feature(or_patterns))]
 #![recursion_limit = "256"]
 
 use rustc_ast as ast;

compiler/rustc_infer/src/lib.rs

@@ -20,7 +20,7 @@
 #![feature(const_panic)]
 #![feature(extend_one)]
 #![feature(never_type)]
-#![feature(or_patterns)]
+#![cfg_attr(bootstrap, feature(or_patterns))]
 #![feature(in_band_lifetimes)]
 #![feature(control_flow_enum)]
 #![recursion_limit = "512"] // For rustdoc

compiler/rustc_lint/src/lib.rs

@@ -35,7 +35,7 @@
 #![feature(iter_order_by)]
 #![feature(never_type)]
 #![feature(nll)]
-#![feature(or_patterns)]
+#![cfg_attr(bootstrap, feature(or_patterns))]
 #![feature(half_open_range_patterns)]
 #![feature(exclusive_range_pattern)]
 #![feature(control_flow_enum)]

compiler/rustc_metadata/src/lib.rs

@@ -5,7 +5,7 @@
 #![feature(in_band_lifetimes)]
 #![feature(nll)]
 #![feature(once_cell)]
-#![feature(or_patterns)]
+#![cfg_attr(bootstrap, feature(or_patterns))]
 #![feature(proc_macro_internals)]
 #![feature(min_specialization)]
 #![feature(stmt_expr_attributes)]

compiler/rustc_middle/src/lib.rs

@@ -38,7 +38,7 @@
 #![feature(extern_types)]
 #![feature(nll)]
 #![feature(once_cell)]
-#![feature(or_patterns)]
+#![cfg_attr(bootstrap, feature(or_patterns))]
 #![feature(min_specialization)]
 #![feature(trusted_len)]
 #![feature(test)]

compiler/rustc_mir/src/lib.rs

@@ -27,7 +27,7 @@ Rust MIR: a lowered representation of Rust.
 #![feature(stmt_expr_attributes)]
 #![feature(trait_alias)]
 #![feature(option_get_or_insert_default)]
-#![feature(or_patterns)]
+#![cfg_attr(bootstrap, feature(or_patterns))]
 #![feature(once_cell)]
 #![feature(control_flow_enum)]
 #![recursion_limit = "256"]

compiler/rustc_mir_build/src/lib.rs

@@ -10,7 +10,7 @@
 #![feature(crate_visibility_modifier)]
 #![feature(bool_to_option)]
 #![feature(once_cell)]
-#![feature(or_patterns)]
+#![cfg_attr(bootstrap, feature(or_patterns))]
 #![recursion_limit = "256"]
 
 #[macro_use]

compiler/rustc_parse/src/lib.rs

@@ -3,7 +3,7 @@
 #![feature(crate_visibility_modifier)]
 #![feature(bindings_after_at)]
 #![feature(iter_order_by)]
-#![feature(or_patterns)]
+#![cfg_attr(bootstrap, feature(or_patterns))]
 #![feature(box_syntax)]
 #![feature(box_patterns)]
 #![recursion_limit = "256"]

compiler/rustc_parse/src/parser/expr.rs

@@ -1,4 +1,4 @@
-use super::pat::{GateOr, RecoverComma, PARAM_EXPECTED};
+use super::pat::{RecoverComma, PARAM_EXPECTED};
 use super::ty::{AllowPlus, RecoverQPath, RecoverReturnSign};
 use super::{AttrWrapper, BlockMode, ForceCollect, Parser, PathStyle, Restrictions, TokenType};
 use super::{SemiColonMode, SeqSep, TokenExpectType, TrailingToken};
@@ -1803,7 +1803,7 @@ impl<'a> Parser<'a> {
     /// The `let` token has already been eaten.
     fn parse_let_expr(&mut self, attrs: AttrVec) -> PResult<'a, P<Expr>> {
         let lo = self.prev_token.span;
-        let pat = self.parse_pat_allow_top_alt(None, GateOr::No, RecoverComma::Yes)?;
+        let pat = self.parse_pat_allow_top_alt(None, RecoverComma::Yes)?;
         self.expect(&token::Eq)?;
         let expr = self.with_res(self.restrictions | Restrictions::NO_STRUCT_LITERAL, |this| {
             this.parse_assoc_expr_with(1 + prec_let_scrutinee_needs_par(), None.into())
@@ -1866,7 +1866,7 @@ impl<'a> Parser<'a> {
             _ => None,
         };
 
-        let pat = self.parse_pat_allow_top_alt(None, GateOr::Yes, RecoverComma::Yes)?;
+        let pat = self.parse_pat_allow_top_alt(None, RecoverComma::Yes)?;
         if !self.eat_keyword(kw::In) {
             self.error_missing_in_for_loop();
         }
@@ -2073,7 +2073,7 @@ impl<'a> Parser<'a> {
         let attrs = self.parse_outer_attributes()?;
         self.collect_tokens_trailing_token(attrs, ForceCollect::No, |this, attrs| {
             let lo = this.token.span;
-            let pat = this.parse_pat_allow_top_alt(None, GateOr::No, RecoverComma::Yes)?;
+            let pat = this.parse_pat_allow_top_alt(None, RecoverComma::Yes)?;
             let guard = if this.eat_keyword(kw::If) {
                 let if_span = this.prev_token.span;
                 let cond = this.parse_expr()?;

compiler/rustc_parse/src/parser/mod.rs

@@ -14,7 +14,7 @@ use crate::lexer::UnmatchedBrace;
 pub use attr_wrapper::AttrWrapper;
 pub use diagnostics::AttemptLocalParseRecovery;
 use diagnostics::Error;
-pub use pat::{GateOr, RecoverComma};
+pub use pat::RecoverComma;
 pub use path::PathStyle;
 
 use rustc_ast::ptr::P;

compiler/rustc_parse/src/parser/nonterminal.rs

@@ -4,7 +4,7 @@ use rustc_ast_pretty::pprust;
 use rustc_errors::PResult;
 use rustc_span::symbol::{kw, Ident};
 
-use crate::parser::pat::{GateOr, RecoverComma};
+use crate::parser::pat::RecoverComma;
 use crate::parser::{FollowedByType, ForceCollect, Parser, PathStyle};
 
 impl<'a> Parser<'a> {
@@ -122,7 +122,7 @@ impl<'a> Parser<'a> {
                 token::NtPat(self.collect_tokens_no_attrs(|this| match kind {
                     NonterminalKind::Pat2018 { .. } => this.parse_pat_no_top_alt(None),
                     NonterminalKind::Pat2021 { .. } => {
-                        this.parse_pat_allow_top_alt(None, GateOr::Yes, RecoverComma::No)
+                        this.parse_pat_allow_top_alt(None, RecoverComma::No)
                     }
                     _ => unreachable!(),
                 })?)