Auto merge of #152982 - JonathanBrouwer:rollup-7T28A8b, r=JonathanBrouwer

Rollup of 8 pull requests

Successful merges:

 - #149366 (GVN: consider constants of primitive types as deterministic)
 - #152779 (Clarify aspects of query macros)
 - #152958 (`rustc_queries` simplifications)
 - #152385 (Feature gate for defaulted associated type_consts with associated_type_defaults )
 - #152708 (Build: Add `stdenv.cc.cc.lib` to Nix dependencies)
 - #152921 (Add build.rustdoc option to bootstrap config)
 - #152926 (Fix ICE when an associated type is wrongly marked as `final`)
 - #152927 (Index expressions rendered the index: subexpression as the id, instea…)

Author: bors

bootstrap.example.toml

@@ -302,6 +302,11 @@
 # If you set this, you likely want to set `cargo` as well.
 #build.rustc = "/path/to/rustc"
 
+# Use this rustdoc binary as the stage0 snapshot rustdoc.
+# If unspecified, then the binary "rustdoc" (with platform-specific extension, e.g. ".exe")
+# in the same directory as "rustc" will be used.
+#build.rustdoc = "/path/to/rustdoc"
+
 # Instead of downloading the src/stage0 version of rustfmt specified,
 # use this rustfmt binary instead as the stage0 snapshot rustfmt.
 #build.rustfmt = "/path/to/rustfmt"

compiler/rustc_ast_lowering/src/item.rs

@@ -1085,9 +1085,18 @@ impl<'hir> LoweringContext<'_, 'hir> {
             }
         };
 
-        let (defaultness, _) = self.lower_defaultness(i.kind.defaultness(), has_value, || {
-            hir::Defaultness::Default { has_value }
-        });
+        let defaultness = match i.kind.defaultness() {
+            // We do not yet support `final` on trait associated items other than functions.
+            // Even though we reject `final` on non-functions during AST validation, we still
+            // need to stop propagating it here because later compiler passes do not expect
+            // and cannot handle such items.
+            Defaultness::Final(..) if !matches!(i.kind, AssocItemKind::Fn(..)) => {
+                Defaultness::Implicit
+            }
+            defaultness => defaultness,
+        };
+        let (defaultness, _) = self
+            .lower_defaultness(defaultness, has_value, || hir::Defaultness::Default { has_value });
 
         let item = hir::TraitItem {
             owner_id: trait_item_def_id,

compiler/rustc_ast_passes/src/feature_gate.rs

@@ -427,7 +427,7 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
                 false
             }
             ast::AssocItemKind::Const(box ast::ConstItem {
-                rhs_kind: ast::ConstItemRhsKind::TypeConst { .. },
+                rhs_kind: ast::ConstItemRhsKind::TypeConst { rhs },
                 ..
             }) => {
                 // Make sure this is only allowed if the feature gate is enabled.
@@ -438,6 +438,17 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
                     i.span,
                     "associated `type const` are unstable"
                 );
+                // Make sure associated `type const` defaults in traits are only allowed
+                // if the feature gate is enabled.
+                // #![feature(associated_type_defaults)]
+                if ctxt == AssocCtxt::Trait && rhs.is_some() {
+                    gate!(
+                        &self,
+                        associated_type_defaults,
+                        i.span,
+                        "associated type defaults are unstable"
+                    );
+                }
                 false
             }
             _ => false,

compiler/rustc_macros/src/query.rs

@@ -103,13 +103,11 @@ impl<T: Parse> Parse for List<T> {
 
 struct Desc {
     modifier: Ident,
-    tcx_binding: Option<Ident>,
     expr_list: Punctuated<Expr, Token![,]>,
 }
 
 struct CacheOnDiskIf {
     modifier: Ident,
-    tcx_binding: Option<Pat>,
     block: Block,
 }
 
@@ -192,35 +190,16 @@ fn parse_query_modifiers(input: ParseStream<'_>) -> Result<QueryModifiers> {
 
         if modifier == "desc" {
             // Parse a description modifier like:
-            // `desc { |tcx| "foo {}", tcx.item_path(key) }`
+            // `desc { "foo {}", tcx.item_path(key) }`
             let attr_content;
             braced!(attr_content in input);
-            let tcx_binding = if attr_content.peek(Token![|]) {
-                attr_content.parse::<Token![|]>()?;
-                let tcx = attr_content.parse()?;
-                attr_content.parse::<Token![|]>()?;
-                Some(tcx)
-            } else {
-                None
-            };
             let expr_list = attr_content.parse_terminated(Expr::parse, Token![,])?;
-            try_insert!(desc = Desc { modifier, tcx_binding, expr_list });
+            try_insert!(desc = Desc { modifier, expr_list });
         } else if modifier == "cache_on_disk_if" {
             // Parse a cache-on-disk modifier like:
-            //
-            // `cache_on_disk_if { true }`
-            // `cache_on_disk_if { key.is_local() }`
-            // `cache_on_disk_if(tcx) { tcx.is_typeck_child(key.to_def_id()) }`
-            let tcx_binding = if input.peek(token::Paren) {
-                let args;
-                parenthesized!(args in input);
-                let tcx = Pat::parse_single(&args)?;
-                Some(tcx)
-            } else {
-                None
-            };
+            // `cache_on_disk_if { tcx.is_typeck_child(key.to_def_id()) }`
             let block = input.parse()?;
-            try_insert!(cache_on_disk_if = CacheOnDiskIf { modifier, tcx_binding, block });
+            try_insert!(cache_on_disk_if = CacheOnDiskIf { modifier, block });
         } else if modifier == "arena_cache" {
             try_insert!(arena_cache = modifier);
         } else if modifier == "cycle_fatal" {
@@ -313,24 +292,24 @@ fn make_helpers_for_query(query: &Query, streams: &mut HelperTokenStreams) {
     erased_name.set_span(Span::call_site());
 
     // Generate a function to check whether we should cache the query to disk, for some key.
-    if let Some(CacheOnDiskIf { tcx_binding, block, .. }) = modifiers.cache_on_disk_if.as_ref() {
-        let tcx = tcx_binding.as_ref().map(|t| quote! { #t }).unwrap_or_else(|| quote! { _ });
-        // we're taking `key` by reference, but some rustc types usually prefer being passed by value
+    if let Some(CacheOnDiskIf { block, .. }) = modifiers.cache_on_disk_if.as_ref() {
+        // `pass_by_value`: some keys are marked with `rustc_pass_by_value`, but we take keys by
+        // reference here.
+        // FIXME: `pass_by_value` is badly named; `allow(rustc::pass_by_value)` actually means
+        // "allow pass by reference of `rustc_pass_by_value` types".
         streams.cache_on_disk_if_fns_stream.extend(quote! {
             #[allow(unused_variables, rustc::pass_by_value)]
             #[inline]
-            pub fn #erased_name<'tcx>(#tcx: TyCtxt<'tcx>, #key_pat: &crate::queries::#name::Key<'tcx>) -> bool
+            pub fn #erased_name<'tcx>(tcx: TyCtxt<'tcx>, #key_pat: &#key_ty) -> bool
             #block
         });
     }
 
-    let Desc { tcx_binding, expr_list, .. } = &modifiers.desc;
-    let tcx = tcx_binding.as_ref().map_or_else(|| quote! { _ }, |t| quote! { #t });
+    let Desc { expr_list, .. } = &modifiers.desc;
 
     let desc = quote! {
         #[allow(unused_variables)]
-        pub fn #erased_name<'tcx>(tcx: TyCtxt<'tcx>, key: #key_ty) -> String {
-            let (#tcx, #key_pat) = (tcx, key);
+        pub fn #erased_name<'tcx>(tcx: TyCtxt<'tcx>, #key_pat: #key_ty) -> String {
             format!(#expr_list)
         }
     };

compiler/rustc_middle/src/dep_graph/dep_node.rs

@@ -324,11 +324,12 @@ impl StableOrd for WorkProductId {
     const THIS_IMPLEMENTATION_HAS_BEEN_TRIPLE_CHECKED: () = ();
 }
 
+// Note: `$K` and `$V` are unused but present so this can be called by `rustc_with_all_queries`.
 macro_rules! define_dep_nodes {
     (
         $(
             $(#[$attr:meta])*
-            [$($modifiers:tt)*] fn $variant:ident($($K:tt)*) -> $V:ty,
+            [$($modifiers:tt)*] fn $variant:ident($K:ty) -> $V:ty,
         )*
     ) => {
 
@@ -382,20 +383,20 @@ macro_rules! define_dep_nodes {
 }
 
 // Create various data structures for each query, and also for a few things
-// that aren't queries.
+// that aren't queries. The key and return types aren't used, hence the use of `()`.
 rustc_with_all_queries!(define_dep_nodes![
     /// We use this for most things when incr. comp. is turned off.
-    [] fn Null() -> (),
+    [] fn Null(()) -> (),
     /// We use this to create a forever-red node.
-    [] fn Red() -> (),
+    [] fn Red(()) -> (),
     /// We use this to create a side effect node.
-    [] fn SideEffect() -> (),
+    [] fn SideEffect(()) -> (),
     /// We use this to create the anon node with zero dependencies.
-    [] fn AnonZeroDeps() -> (),
-    [] fn TraitSelect() -> (),
-    [] fn CompileCodegenUnit() -> (),
-    [] fn CompileMonoItem() -> (),
-    [] fn Metadata() -> (),
+    [] fn AnonZeroDeps(()) -> (),
+    [] fn TraitSelect(()) -> (),
+    [] fn CompileCodegenUnit(()) -> (),
+    [] fn CompileMonoItem(()) -> (),
+    [] fn Metadata(()) -> (),
 ]);
 
 // WARNING: `construct` is generic and does not know that `CompileCodegenUnit` takes `Symbol`s as keys.

compiler/rustc_middle/src/mir/consts.rs

@@ -181,26 +181,6 @@ impl ConstValue {
         Some(data.inner().inspect_with_uninit_and_ptr_outside_interpreter(start..end))
     }
 
-    /// Check if a constant may contain provenance information. This is used by MIR opts.
-    /// Can return `true` even if there is no provenance.
-    pub fn may_have_provenance(&self, tcx: TyCtxt<'_>, size: Size) -> bool {
-        match *self {
-            ConstValue::ZeroSized | ConstValue::Scalar(Scalar::Int(_)) => return false,
-            ConstValue::Scalar(Scalar::Ptr(..)) => return true,
-            // It's hard to find out the part of the allocation we point to;
-            // just conservatively check everything.
-            ConstValue::Slice { alloc_id, meta: _ } => {
-                !tcx.global_alloc(alloc_id).unwrap_memory().inner().provenance().ptrs().is_empty()
-            }
-            ConstValue::Indirect { alloc_id, offset } => !tcx
-                .global_alloc(alloc_id)
-                .unwrap_memory()
-                .inner()
-                .provenance()
-                .range_empty(AllocRange::from(offset..offset + size), &tcx),
-        }
-    }
-
     /// Check if a constant only contains uninitialized bytes.
     pub fn all_bytes_uninit(&self, tcx: TyCtxt<'_>) -> bool {
         let ConstValue::Indirect { alloc_id, .. } = self else {
@@ -474,39 +454,6 @@ impl<'tcx> Const<'tcx> {
         let val = ConstValue::Scalar(s);
         Self::Val(val, ty)
     }
-
-    /// Return true if any evaluation of this constant always returns the same value,
-    /// taking into account even pointer identity tests.
-    pub fn is_deterministic(&self) -> bool {
-        // Some constants may generate fresh allocations for pointers they contain,
-        // so using the same constant twice can yield two different results.
-        // Notably, valtrees purposefully generate new allocations.
-        match self {
-            Const::Ty(_, c) => match c.kind() {
-                ty::ConstKind::Param(..) => true,
-                // A valtree may be a reference. Valtree references correspond to a
-                // different allocation each time they are evaluated. Valtrees for primitive
-                // types are fine though.
-                ty::ConstKind::Value(cv) => cv.ty.is_primitive(),
-                ty::ConstKind::Unevaluated(..) | ty::ConstKind::Expr(..) => false,
-                // This can happen if evaluation of a constant failed. The result does not matter
-                // much since compilation is doomed.
-                ty::ConstKind::Error(..) => false,
-                // Should not appear in runtime MIR.
-                ty::ConstKind::Infer(..)
-                | ty::ConstKind::Bound(..)
-                | ty::ConstKind::Placeholder(..) => bug!(),
-            },
-            Const::Unevaluated(..) => false,
-            Const::Val(
-                ConstValue::Slice { .. }
-                | ConstValue::ZeroSized
-                | ConstValue::Scalar(_)
-                | ConstValue::Indirect { .. },
-                _,
-            ) => true,
-        }
-    }
 }
 
 /// An unevaluated (potentially generic) constant used in MIR.