[DO NOT MERGE] Crate local distributed slice

Cargo.lock

@@ -3812,6 +3812,8 @@ name = "rustc_hir_analysis"
 version = "0.0.0"
 dependencies = [
  "itertools",
+ "rand 0.9.1",
+ "rand_xoshiro",
  "rustc_abi",
  "rustc_arena",
  "rustc_ast",

compiler/rustc_ast/src/ast.rs

@@ -3614,6 +3614,24 @@ pub struct DelegationMac {
     pub body: Option<P<Block>>,
 }
 
+#[derive(Clone, Encodable, Decodable, Debug, Default)]
+pub enum DistributedSlice {
+    /// This const or static has nothing to do with global registration whatsoever
+    #[default]
+    None,
+    /// This const or static declares a global registry that can be added to
+    Declaration(Span, NodeId),
+    /// This const (we never do this to statics) represents an addition to a global registry
+    /// declared somewhere else.
+    Addition { declaration: Path, id: NodeId },
+    /// This const (we never do this to statics) represents an addition of an array
+    /// to a global registry declared somewhere else. All elements are added, though not necessarily
+    /// in the same order as in the original slice.
+    AdditionMany { declaration: Path, id: NodeId },
+    /// Applied to an invalid item, error guaranteed to have be emitted
+    Err(ErrorGuaranteed),
+}
+
 #[derive(Clone, Encodable, Decodable, Debug)]
 pub struct StaticItem {
     pub ident: Ident,
@@ -3622,6 +3640,7 @@ pub struct StaticItem {
     pub mutability: Mutability,
     pub expr: Option<P<Expr>>,
     pub define_opaque: Option<ThinVec<(NodeId, Path)>>,
+    pub distributed_slice: DistributedSlice,
 }
 
 #[derive(Clone, Encodable, Decodable, Debug)]
@@ -3632,6 +3651,7 @@ pub struct ConstItem {
     pub ty: P<Ty>,
     pub expr: Option<P<Expr>>,
     pub define_opaque: Option<ThinVec<(NodeId, Path)>>,
+    pub distributed_slice: DistributedSlice,
 }
 
 // Adding a new variant? Please update `test_item` in `tests/ui/macros/stringify.rs`.

compiler/rustc_ast/src/visit.rs

@@ -451,10 +451,27 @@ macro_rules! common_visitor_and_walkers {
                         mutability: _,
                         expr,
                         define_opaque,
+                        distributed_slice,
                     }) => {
                         try_visit!(vis.visit_ident(ident));
                         try_visit!(vis.visit_ty(ty));
                         visit_opt!(vis, visit_expr, expr);
+                        match distributed_slice {
+                            DistributedSlice::None => {}
+                            DistributedSlice::Err(..) => {}
+                            DistributedSlice::Declaration(span, id) => {
+                                try_visit!(visit_span(vis, span));
+                                try_visit!(visit_id(vis, id));
+                            }
+                            DistributedSlice::Addition { declaration, id } => {
+                                try_visit!(vis.visit_path(declaration$(${ignore($lt)}, *id)?));
+                                try_visit!(visit_id(vis, id));
+                            }
+                            DistributedSlice::AdditionMany { declaration, id } => {
+                                try_visit!(vis.visit_path(declaration$(${ignore($lt)}, *id)?));
+                                try_visit!(visit_id(vis, id));
+                            }
+                        }
                         walk_define_opaques(vis, define_opaque)
                     }
                     ItemKind::Const(item) => {
@@ -614,12 +631,31 @@ macro_rules! common_visitor_and_walkers {
         }
 
         fn walk_const_item<$($lt,)? V: $Visitor$(<$lt>)?>(vis: &mut V, item: &$($lt)? $($mut)? ConstItem) $(-> <V as Visitor<$lt>>::Result)? {
-            let ConstItem { defaultness, ident, generics, ty, expr, define_opaque } = item;
+            let ConstItem { defaultness, ident, generics, ty, expr, define_opaque, distributed_slice } = item;
             try_visit!(visit_defaultness(vis, defaultness));
             try_visit!(vis.visit_ident(ident));
             try_visit!(vis.visit_generics(generics));
             try_visit!(vis.visit_ty(ty));
             visit_opt!(vis, visit_expr, expr);
+
+            match distributed_slice {
+                DistributedSlice::None => {}
+                DistributedSlice::Err(..) => {}
+                DistributedSlice::Declaration(span, id) => {
+                    try_visit!(visit_span(vis, span));
+                    try_visit!(visit_id(vis, id));
+                }
+                DistributedSlice::Addition { declaration, id } => {
+                    try_visit!(vis.visit_path(declaration$(${ignore($lt)}, *id)?));
+                    try_visit!(visit_id(vis, id));
+                }
+                DistributedSlice::AdditionMany { declaration, id } => {
+                    try_visit!(vis.visit_path(declaration$(${ignore($lt)}, *id)?));
+                    try_visit!(visit_id(vis, id));
+                }
+            }
+
+
             walk_define_opaques(vis, define_opaque)
         }
 
@@ -739,6 +775,7 @@ macro_rules! common_visitor_and_walkers {
                         expr,
                         safety: _,
                         define_opaque,
+                        distributed_slice: _,
                     }) => {
                         try_visit!(vis.visit_ident(ident));
                         try_visit!(vis.visit_ty(ty));

compiler/rustc_ast_lowering/messages.ftl

@@ -56,6 +56,11 @@ ast_lowering_coroutine_too_many_parameters =
 ast_lowering_default_field_in_tuple = default fields are not supported in tuple structs
     .label = default fields are only supported on structs
 
+ast_lowering_distributed_slice_elements_wrong_expr =
+    `distributed_slice_elements!()` only accepts a path or array literal
+    .note = arbitrary expressions are not supported
+ast_lowering_distributed_slice_with_initializer =
+    distributed slice elements are added with `distributed_slice_element!(...)`
 ast_lowering_does_not_support_modifiers =
     the `{$class_name}` register class does not support template modifiers
 

compiler/rustc_ast_lowering/src/block.rs

@@ -97,7 +97,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         // Let statements are allowed to have impl trait in bindings.
         let super_ = l.super_;
         let ty = l.ty.as_ref().map(|t| {
-            self.lower_ty(t, self.impl_trait_in_bindings_ctxt(ImplTraitPosition::Variable))
+            self.lower_ty(t, self.impl_trait_in_bindings_ctxt(ImplTraitPosition::Variable), false)
         });
         let init = l.kind.init().map(|init| self.lower_expr(init));
         let hir_id = self.lower_node_id(l.id);

compiler/rustc_ast_lowering/src/errors.rs

@@ -475,3 +475,18 @@ pub(crate) struct UseConstGenericArg {
     #[suggestion_part(code = "{other_args}")]
     pub call_args: Span,
 }
+
+#[derive(Diagnostic)]
+#[diag(ast_lowering_distributed_slice_with_initializer)]
+pub(crate) struct DistributedSliceWithInitializer {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(ast_lowering_distributed_slice_elements_wrong_expr)]
+#[note]
+pub(crate) struct DistributedSliceElementsWrongExpr {
+    #[primary_span]
+    pub span: Span,
+}

compiler/rustc_ast_lowering/src/expr.rs

@@ -106,7 +106,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 ExprKind::ConstBlock(c) => hir::ExprKind::ConstBlock(self.lower_const_block(c)),
                 ExprKind::Repeat(expr, count) => {
                     let expr = self.lower_expr(expr);
-                    let count = self.lower_array_length_to_const_arg(count);
+                    let count = self.lower_array_length_to_const_arg(count, false);
                     hir::ExprKind::Repeat(expr, count)
                 }
                 ExprKind::Tup(elts) => hir::ExprKind::Tup(self.lower_exprs(elts)),
@@ -154,14 +154,20 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 }
                 ExprKind::Cast(expr, ty) => {
                     let expr = self.lower_expr(expr);
-                    let ty =
-                        self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Cast));
+                    let ty = self.lower_ty(
+                        ty,
+                        ImplTraitContext::Disallowed(ImplTraitPosition::Cast),
+                        false,
+                    );
                     hir::ExprKind::Cast(expr, ty)
                 }
                 ExprKind::Type(expr, ty) => {
                     let expr = self.lower_expr(expr);
-                    let ty =
-                        self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Cast));
+                    let ty = self.lower_ty(
+                        ty,
+                        ImplTraitContext::Disallowed(ImplTraitPosition::Cast),
+                        false,
+                    );
                     hir::ExprKind::Type(expr, ty)
                 }
                 ExprKind::AddrOf(k, m, ohs) => {
@@ -329,6 +335,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     self.lower_ty(
                         container,
                         ImplTraitContext::Disallowed(ImplTraitPosition::OffsetOf),
+                        false,
                     ),
                     self.arena.alloc_from_iter(fields.iter().map(|&ident| self.lower_ident(ident))),
                 ),
@@ -360,7 +367,11 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     *kind,
                     self.lower_expr(expr),
                     ty.as_ref().map(|ty| {
-                        self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Cast))
+                        self.lower_ty(
+                            ty,
+                            ImplTraitContext::Disallowed(ImplTraitPosition::Cast),
+                            false,
+                        )
                     }),
                 ),
 
@@ -417,7 +428,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
             hir::ConstBlock {
                 def_id,
                 hir_id: this.lower_node_id(c.id),
-                body: this.lower_const_body(c.value.span, Some(&c.value)),
+                body: this.lower_const_body(c.value.span, Some(&c.value), None),
             }
         })
     }