stabilize min_const_generics

Author: lcnr

compiler/rustc_arena/src/lib.rs

@@ -16,7 +16,7 @@
 #![feature(new_uninit)]
 #![feature(maybe_uninit_slice)]
 #![feature(array_value_iter)]
-#![feature(min_const_generics)]
+#![cfg_attr(bootstrap, feature(min_const_generics))]
 #![feature(min_specialization)]
 #![cfg_attr(test, feature(test))]
 

compiler/rustc_ast/src/ast.rs

@@ -1128,7 +1128,7 @@ impl Expr {
     /// Is this expr either `N`, or `{ N }`.
     ///
     /// If this is not the case, name resolution does not resolve `N` when using
-    /// `feature(min_const_generics)` as more complex expressions are not supported.
+    /// `min_const_generics` as more complex expressions are not supported.
     pub fn is_potential_trivial_const_param(&self) -> bool {
         let this = if let ExprKind::Block(ref block, None) = self.kind {
             if block.stmts.len() == 1 {

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -773,14 +773,12 @@ fn validate_generic_param_order<'a>(
         err.span_suggestion(
             span,
             &format!(
-                "reorder the parameters: lifetimes{}",
+                "reorder the parameters: lifetimes, {}",
                 if sess.features_untracked().const_generics {
-                    ", then consts and types"
-                } else if sess.features_untracked().min_const_generics {
-                    ", then types, then consts"
+                    "then consts and types"
                 } else {
-                    ", then types"
-                },
+                    "then types, then consts"
+                }
             ),
             ordered_params.clone(),
             Applicability::MachineApplicable,

compiler/rustc_ast_passes/src/feature_gate.rs

@@ -1,7 +1,7 @@
 use rustc_ast as ast;
 use rustc_ast::visit::{self, AssocCtxt, FnCtxt, FnKind, Visitor};
 use rustc_ast::{AssocTyConstraint, AssocTyConstraintKind, NodeId};
-use rustc_ast::{GenericParam, GenericParamKind, PatKind, RangeEnd, VariantData};
+use rustc_ast::{PatKind, RangeEnd, VariantData};
 use rustc_errors::struct_span_err;
 use rustc_feature::{AttributeGate, BUILTIN_ATTRIBUTE_MAP};
 use rustc_feature::{Features, GateIssue};
@@ -529,19 +529,6 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
         visit::walk_fn(self, fn_kind, span)
     }
 
-    fn visit_generic_param(&mut self, param: &'a GenericParam) {
-        if let GenericParamKind::Const { .. } = param.kind {
-            gate_feature_fn!(
-                &self,
-                |x: &Features| x.const_generics || x.min_const_generics,
-                param.ident.span,
-                sym::min_const_generics,
-                "const generics are unstable"
-            );
-        }
-        visit::walk_generic_param(self, param)
-    }
-
     fn visit_assoc_ty_constraint(&mut self, constraint: &'a AssocTyConstraint) {
         if let AssocTyConstraintKind::Bound { .. } = constraint.kind {
             gate_feature_post!(

compiler/rustc_data_structures/src/lib.rs

@@ -27,7 +27,7 @@
 #![feature(thread_id_value)]
 #![feature(extend_one)]
 #![feature(const_panic)]
-#![feature(min_const_generics)]
+#![cfg_attr(bootstrap, feature(min_const_generics))]
 #![feature(new_uninit)]
 #![feature(once_cell)]
 #![feature(maybe_uninit_uninit_array)]

compiler/rustc_feature/src/accepted.rs

@@ -273,6 +273,8 @@ declare_features! (
     /// Allows patterns with concurrent by-move and by-ref bindings.
     /// For example, you can write `Foo(a, ref b)` where `a` is by-move and `b` is by-ref.
     (accepted, move_ref_pattern, "1.48.0", Some(68354), None),
+    /// The smallest useful subset of `const_generics`.
+    (accepted, min_const_generics, "1.51.0", Some(74878), None),
 
     // -------------------------------------------------------------------------
     // feature-group-end: accepted features

compiler/rustc_feature/src/active.rs

@@ -578,9 +578,6 @@ declare_features! (
     /// Allows calling `transmute` in const fn
     (active, const_fn_transmute, "1.46.0", Some(53605), None),
 
-    /// The smallest useful subset of `const_generics`.
-    (active, min_const_generics, "1.47.0", Some(74878), None),
-
     /// Allows `if let` guard in match arms.
     (active, if_let_guard, "1.47.0", Some(51114), None),
 
@@ -651,5 +648,7 @@ pub const INCOMPLETE_FEATURES: &[Symbol] = &[
 
 /// Some features are not allowed to be used together at the same time, if
 /// the two are present, produce an error.
-pub const INCOMPATIBLE_FEATURES: &[(Symbol, Symbol)] =
-    &[(sym::const_generics, sym::min_const_generics)];
+///
+/// Currently empty, but we will probably need this again in the future,
+/// so let's keep it in for now.
+pub const INCOMPATIBLE_FEATURES: &[(Symbol, Symbol)] = &[];

compiler/rustc_lint/src/builtin.rs

@@ -2299,7 +2299,7 @@ impl EarlyLintPass for IncompleteFeatures {
     }
 }
 
-const HAS_MIN_FEATURES: &[Symbol] = &[sym::const_generics, sym::specialization];
+const HAS_MIN_FEATURES: &[Symbol] = &[sym::specialization];
 
 declare_lint! {
     /// The `invalid_value` lint detects creating a value that is not valid,

compiler/rustc_middle/src/ty/context.rs

@@ -1386,7 +1386,7 @@ impl<'tcx> TyCtxt<'tcx> {
     #[inline]
     pub fn lazy_normalization(self) -> bool {
         let features = self.features();
-        // Note: We do not enable lazy normalization for `features.min_const_generics`.
+        // Note: We do not enable lazy normalization for `min_const_generics`.
         features.const_generics || features.lazy_normalization_consts
     }
 

compiler/rustc_middle/src/ty/mod.rs

@@ -1638,8 +1638,6 @@ pub type PlaceholderConst<'tcx> = Placeholder<BoundConst<'tcx>>;
 /// which cause cycle errors.
 ///
 /// ```rust
-/// #![feature(const_generics)]
-///
 /// struct A;
 /// impl A {
 ///     fn foo<const N: usize>(&self) -> [u8; N] { [0; N] }