Auto merge of #70742 - Mark-Simulacrum:beta-next, r=Mark-Simulacrum

[beta] backport 4 PRs

This backports the following PRs:

* parse_and_disallow_postfix_after_cast: account for `ExprKind::Err`. #70556
* Account for bad placeholder types in where clauses #70294
* Fix "since" field for `Once::is_complete`'s `#[stable]` attribute #70018
* Ensure HAS_FREE_LOCAL_NAMES is set for ReFree #69956

All commits cherry picked cleanly.

src/librustc/ty/mod.rs

@@ -554,24 +554,26 @@ bitflags! {
         /// Does this have [ConstKind::Placeholder]?
         const HAS_CT_PLACEHOLDER        = 1 << 8;
 
+        /// `true` if there are "names" of regions and so forth
+        /// that are local to a particular fn/inferctxt
+        const HAS_FREE_LOCAL_REGIONS    = 1 << 9;
+
         /// `true` if there are "names" of types and regions and so forth
         /// that are local to a particular fn
         const HAS_FREE_LOCAL_NAMES      = TypeFlags::HAS_TY_PARAM.bits
-                                        | TypeFlags::HAS_RE_PARAM.bits
                                         | TypeFlags::HAS_CT_PARAM.bits
                                         | TypeFlags::HAS_TY_INFER.bits
-                                        | TypeFlags::HAS_RE_INFER.bits
                                         | TypeFlags::HAS_CT_INFER.bits
                                         | TypeFlags::HAS_TY_PLACEHOLDER.bits
-                                        | TypeFlags::HAS_RE_PLACEHOLDER.bits
-                                        | TypeFlags::HAS_CT_PLACEHOLDER.bits;
+                                        | TypeFlags::HAS_CT_PLACEHOLDER.bits
+                                        | TypeFlags::HAS_FREE_LOCAL_REGIONS.bits;
 
         /// Does this have [Projection] or [UnnormalizedProjection]?
-        const HAS_TY_PROJECTION         = 1 << 9;
+        const HAS_TY_PROJECTION         = 1 << 10;
         /// Does this have [Opaque]?
-        const HAS_TY_OPAQUE             = 1 << 10;
+        const HAS_TY_OPAQUE             = 1 << 11;
         /// Does this have [ConstKind::Unevaluated]?
-        const HAS_CT_PROJECTION         = 1 << 11;
+        const HAS_CT_PROJECTION         = 1 << 12;
 
         /// Could this type be normalized further?
         const HAS_PROJECTION            = TypeFlags::HAS_TY_PROJECTION.bits
@@ -580,21 +582,21 @@ bitflags! {
 
         /// Present if the type belongs in a local type context.
         /// Set for placeholders and inference variables that are not "Fresh".
-        const KEEP_IN_LOCAL_TCX         = 1 << 12;
+        const KEEP_IN_LOCAL_TCX         = 1 << 13;
 
         /// Is an error type reachable?
-        const HAS_TY_ERR                = 1 << 13;
+        const HAS_TY_ERR                = 1 << 14;
 
         /// Does this have any region that "appears free" in the type?
         /// Basically anything but [ReLateBound] and [ReErased].
-        const HAS_FREE_REGIONS          = 1 << 14;
+        const HAS_FREE_REGIONS          = 1 << 15;
 
         /// Does this have any [ReLateBound] regions? Used to check
         /// if a global bound is safe to evaluate.
-        const HAS_RE_LATE_BOUND         = 1 << 15;
+        const HAS_RE_LATE_BOUND         = 1 << 16;
 
         /// Does this have any [ReErased] regions?
-        const HAS_RE_ERASED             = 1 << 16;
+        const HAS_RE_ERASED             = 1 << 17;
 
         /// Flags representing the nominal content of a type,
         /// computed by FlagsComputation. If you add a new nominal
@@ -608,6 +610,7 @@ bitflags! {
                                         | TypeFlags::HAS_TY_PLACEHOLDER.bits
                                         | TypeFlags::HAS_RE_PLACEHOLDER.bits
                                         | TypeFlags::HAS_CT_PLACEHOLDER.bits
+                                        | TypeFlags::HAS_FREE_LOCAL_REGIONS.bits
                                         | TypeFlags::HAS_TY_PROJECTION.bits
                                         | TypeFlags::HAS_TY_OPAQUE.bits
                                         | TypeFlags::HAS_CT_PROJECTION.bits

src/librustc/ty/sty.rs

@@ -1743,42 +1743,42 @@ impl RegionKind {
         }
     }
 
-    pub fn keep_in_local_tcx(&self) -> bool {
-        if let ty::ReVar(..) = self { true } else { false }
-    }
-
     pub fn type_flags(&self) -> TypeFlags {
         let mut flags = TypeFlags::empty();
 
-        if self.keep_in_local_tcx() {
-            flags = flags | TypeFlags::KEEP_IN_LOCAL_TCX;
-        }
-
         match *self {
             ty::ReVar(..) => {
                 flags = flags | TypeFlags::HAS_FREE_REGIONS;
+                flags = flags | TypeFlags::HAS_FREE_LOCAL_REGIONS;
                 flags = flags | TypeFlags::HAS_RE_INFER;
+                flags = flags | TypeFlags::KEEP_IN_LOCAL_TCX;
             }
             ty::RePlaceholder(..) => {
                 flags = flags | TypeFlags::HAS_FREE_REGIONS;
+                flags = flags | TypeFlags::HAS_FREE_LOCAL_REGIONS;
                 flags = flags | TypeFlags::HAS_RE_PLACEHOLDER;
             }
-            ty::ReLateBound(..) => {
-                flags = flags | TypeFlags::HAS_RE_LATE_BOUND;
-            }
             ty::ReEarlyBound(..) => {
                 flags = flags | TypeFlags::HAS_FREE_REGIONS;
+                flags = flags | TypeFlags::HAS_FREE_LOCAL_REGIONS;
                 flags = flags | TypeFlags::HAS_RE_PARAM;
             }
-            ty::ReEmpty(_) | ty::ReStatic | ty::ReFree { .. } | ty::ReScope { .. } => {
+            ty::ReFree { .. } | ty::ReScope { .. } => {
                 flags = flags | TypeFlags::HAS_FREE_REGIONS;
+                flags = flags | TypeFlags::HAS_FREE_LOCAL_REGIONS;
             }
-            ty::ReErased => {
-                flags = flags | TypeFlags::HAS_RE_ERASED;
+            ty::ReEmpty(_) | ty::ReStatic => {
+                flags = flags | TypeFlags::HAS_FREE_REGIONS;
             }
             ty::ReClosureBound(..) => {
                 flags = flags | TypeFlags::HAS_FREE_REGIONS;
             }
+            ty::ReLateBound(..) => {
+                flags = flags | TypeFlags::HAS_RE_LATE_BOUND;
+            }
+            ty::ReErased => {
+                flags = flags | TypeFlags::HAS_RE_ERASED;
+            }
         }
 
         debug!("type_flags({:?}) = {:?}", self, flags);

src/librustc_parse/parser/expr.rs

@@ -638,6 +638,7 @@ impl<'a> Parser<'a> {
                     ExprKind::MethodCall(_, _) => "a method call",
                     ExprKind::Call(_, _) => "a function call",
                     ExprKind::Await(_) => "`.await`",
+                    ExprKind::Err => return Ok(with_postfix),
                     _ => unreachable!("parse_dot_or_call_expr_with_ shouldn't produce this"),
                 }
             );

src/librustc_typeck/astconv.rs

@@ -23,7 +23,7 @@ use rustc_errors::{pluralize, struct_span_err, Applicability, DiagnosticId};
 use rustc_hir as hir;
 use rustc_hir::def::{CtorOf, DefKind, Namespace, Res};
 use rustc_hir::def_id::DefId;
-use rustc_hir::intravisit::Visitor;
+use rustc_hir::intravisit::{walk_generics, Visitor};
 use rustc_hir::print;
 use rustc_hir::{Constness, ExprKind, GenericArg, GenericArgs};
 use rustc_infer::traits;
@@ -838,18 +838,6 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 }
             },
         );
-        if !inferred_params.is_empty() {
-            // We always collect the spans for placeholder types when evaluating `fn`s, but we
-            // only want to emit an error complaining about them if infer types (`_`) are not
-            // allowed. `allow_ty_infer` gates this behavior.
-            crate::collect::placeholder_type_error(
-                tcx,
-                inferred_params[0],
-                &[],
-                inferred_params,
-                false,
-            );
-        }
 
         self.complain_about_missing_type_params(
             missing_type_params,
@@ -2734,7 +2722,13 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
             }
             hir::TyKind::BareFn(ref bf) => {
                 require_c_abi_if_c_variadic(tcx, &bf.decl, bf.abi, ast_ty.span);
-                tcx.mk_fn_ptr(self.ty_of_fn(bf.unsafety, bf.abi, &bf.decl, &[], None))
+                tcx.mk_fn_ptr(self.ty_of_fn(
+                    bf.unsafety,
+                    bf.abi,
+                    &bf.decl,
+                    &hir::Generics::empty(),
+                    None,
+                ))
             }
             hir::TyKind::TraitObject(ref bounds, ref lifetime) => {
                 self.conv_object_ty_poly_trait_ref(ast_ty.span, bounds, lifetime)
@@ -2917,7 +2911,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         unsafety: hir::Unsafety,
         abi: abi::Abi,
         decl: &hir::FnDecl<'_>,
-        generic_params: &[hir::GenericParam<'_>],
+        generics: &hir::Generics<'_>,
         ident_span: Option<Span>,
     ) -> ty::PolyFnSig<'tcx> {
         debug!("ty_of_fn");
@@ -2929,6 +2923,8 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         for ty in decl.inputs {
             visitor.visit_ty(ty);
         }
+        walk_generics(&mut visitor, generics);
+
         let input_tys = decl.inputs.iter().map(|a| self.ty_of_arg(a, None));
         let output_ty = match decl.output {
             hir::FnRetTy::Return(ref output) => {
@@ -2950,7 +2946,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
             crate::collect::placeholder_type_error(
                 tcx,
                 ident_span.map(|sp| sp.shrink_to_hi()).unwrap_or(DUMMY_SP),
-                generic_params,
+                &generics.params[..],
                 visitor.0,
                 ident_span.is_some(),
             );
@@ -2976,8 +2972,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 tcx.sess,
                 decl.output.span(),
                 E0581,
-                "return type references {} \
-                                            which is not constrained by the fn input types",
+                "return type references {} which is not constrained by the fn input types",
                 lifetime_name
             );
             if let ty::BrAnon(_) = *br {
@@ -2988,8 +2983,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 // though we can easily give a hint that ought to be
                 // relevant.
                 err.note(
-                    "lifetimes appearing in an associated type \
-                          are not considered constrained",
+                    "lifetimes appearing in an associated type are not considered constrained",
                 );
             }
             err.emit();

src/librustc_typeck/check/mod.rs

@@ -1004,7 +1004,14 @@ fn typeck_tables_of_with_fallback<'tcx>(
         let fcx = if let (Some(header), Some(decl)) = (fn_header, fn_decl) {
             let fn_sig = if crate::collect::get_infer_ret_ty(&decl.output).is_some() {
                 let fcx = FnCtxt::new(&inh, param_env, body.value.hir_id);
-                AstConv::ty_of_fn(&fcx, header.unsafety, header.abi, decl, &[], None)
+                AstConv::ty_of_fn(
+                    &fcx,
+                    header.unsafety,
+                    header.abi,
+                    decl,
+                    &hir::Generics::empty(),
+                    None,
+                )
             } else {
                 tcx.fn_sig(def_id)
             };

src/librustc_typeck/collect.rs

@@ -1467,7 +1467,7 @@ fn fn_sig(tcx: TyCtxt<'_>, def_id: DefId) -> ty::PolyFnSig<'_> {
                     sig.header.unsafety,
                     sig.header.abi,
                     &sig.decl,
-                    &generics.params[..],
+                    &generics,
                     Some(ident.span),
                 ),
             }
@@ -1478,14 +1478,9 @@ fn fn_sig(tcx: TyCtxt<'_>, def_id: DefId) -> ty::PolyFnSig<'_> {
             ident,
             generics,
             ..
-        }) => AstConv::ty_of_fn(
-            &icx,
-            header.unsafety,
-            header.abi,
-            decl,
-            &generics.params[..],
-            Some(ident.span),
-        ),
+        }) => {
+            AstConv::ty_of_fn(&icx, header.unsafety, header.abi, decl, &generics, Some(ident.span))
+        }
 
         ForeignItem(&hir::ForeignItem { kind: ForeignItemKind::Fn(ref fn_decl, _, _), .. }) => {
             let abi = tcx.hir().get_foreign_abi(hir_id);
@@ -2110,7 +2105,14 @@ fn compute_sig_of_foreign_fn_decl<'tcx>(
     } else {
         hir::Unsafety::Unsafe
     };
-    let fty = AstConv::ty_of_fn(&ItemCtxt::new(tcx, def_id), unsafety, abi, decl, &[], None);
+    let fty = AstConv::ty_of_fn(
+        &ItemCtxt::new(tcx, def_id),
+        unsafety,
+        abi,
+        decl,
+        &hir::Generics::empty(),
+        None,
+    );
 
     // Feature gate SIMD types in FFI, since I am not sure that the
     // ABIs are handled at all correctly. -huonw

src/libstd/sync/once.rs

@@ -363,7 +363,7 @@ impl Once {
     /// assert!(handle.join().is_err());
     /// assert_eq!(INIT.is_completed(), false);
     /// ```
-    #[stable(feature = "once_is_completed", since = "1.44.0")]
+    #[stable(feature = "once_is_completed", since = "1.43.0")]
     #[inline]
     pub fn is_completed(&self) -> bool {
         // An `Acquire` load is enough because that makes all the initialization

src/test/ui/did_you_mean/bad-assoc-ty.rs

@@ -49,4 +49,36 @@ trait K<A, B> {}
 fn foo<X: K<_, _>>(x: X) {}
 //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
 
+fn bar<F>(_: F) where F: Fn() -> _ {}
+//~^ ERROR the type placeholder `_` is not allowed within types on item signatures
+
+fn baz<F: Fn() -> _>(_: F) {}
+//~^ ERROR the type placeholder `_` is not allowed within types on item signatures
+
+struct L<F>(F) where F: Fn() -> _;
+//~^ ERROR the type placeholder `_` is not allowed within types on item signatures
+struct M<F> where F: Fn() -> _ {
+//~^ ERROR the type placeholder `_` is not allowed within types on item signatures
+    a: F,
+}
+enum N<F> where F: Fn() -> _ {
+//~^ ERROR the type placeholder `_` is not allowed within types on item signatures
+    Foo(F),
+}
+
+union O<F> where F: Fn() -> _ {
+//~^ ERROR the type placeholder `_` is not allowed within types on item signatures
+//~| ERROR unions with non-`Copy` fields are unstable
+    foo: F,
+}
+
+trait P<F> where F: Fn() -> _ {
+//~^ ERROR the type placeholder `_` is not allowed within types on item signatures
+}
+
+trait Q {
+    fn foo<F>(_: F) where F: Fn() -> _ {}
+    //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
+}
+
 fn main() {}