Auto merge of rust-lang#123746 - fmease:rollup-pqkaizg, r=fmease

Rollup of 6 pull requests

Successful merges:

 - rust-lang#122470 (`f16` and `f128` step 4: basic library support)
 - rust-lang#122954 (Be more specific when flagging imports as redundant due to the extern prelude)
 - rust-lang#123314 (Skip `unused_parens` report for `Paren(Path(..))` in macro.)
 - rust-lang#123360 (Document restricted_std)
 - rust-lang#123703 (Use `fn` ptr signature instead of `{closure@..}` in infer error)
 - rust-lang#123732 (Factor some common `io::Error` constants)

r? `@ghost`
`@rustbot` modify labels: rollup

compiler/rustc_infer/messages.ftl

@@ -144,6 +144,9 @@ infer_fps_items_are_distinct = fn items are distinct from fn pointers
 infer_fps_remove_ref = consider removing the reference
 infer_fps_use_ref = consider using a reference
 infer_fulfill_req_lifetime = the type `{$ty}` does not fulfill the required lifetime
+
+infer_full_type_written = the full type name has been written to '{$path}'
+
 infer_implicit_static_lifetime_note = this has an implicit `'static` lifetime requirement
 infer_implicit_static_lifetime_suggestion = consider relaxing the implicit `'static` requirement
 infer_label_bad = {$bad_kind ->

compiler/rustc_infer/src/errors/mod.rs

@@ -18,6 +18,8 @@ use crate::infer::error_reporting::{
     ObligationCauseAsDiagArg,
 };
 
+use std::path::PathBuf;
+
 pub mod note_and_explain;
 
 #[derive(Diagnostic)]
@@ -47,6 +49,9 @@ pub struct AnnotationRequired<'a> {
     pub infer_subdiags: Vec<SourceKindSubdiag<'a>>,
     #[subdiagnostic]
     pub multi_suggestions: Vec<SourceKindMultiSuggestion<'a>>,
+    #[note(infer_full_type_written)]
+    pub was_written: Option<()>,
+    pub path: PathBuf,
 }
 
 // Copy of `AnnotationRequired` for E0283
@@ -65,6 +70,9 @@ pub struct AmbiguousImpl<'a> {
     pub infer_subdiags: Vec<SourceKindSubdiag<'a>>,
     #[subdiagnostic]
     pub multi_suggestions: Vec<SourceKindMultiSuggestion<'a>>,
+    #[note(infer_full_type_written)]
+    pub was_written: Option<()>,
+    pub path: PathBuf,
 }
 
 // Copy of `AnnotationRequired` for E0284
@@ -83,6 +91,9 @@ pub struct AmbiguousReturn<'a> {
     pub infer_subdiags: Vec<SourceKindSubdiag<'a>>,
     #[subdiagnostic]
     pub multi_suggestions: Vec<SourceKindMultiSuggestion<'a>>,
+    #[note(infer_full_type_written)]
+    pub was_written: Option<()>,
+    pub path: PathBuf,
 }
 
 // Used when a better one isn't available

compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs

@@ -18,13 +18,15 @@ use rustc_middle::infer::unify_key::{
 };
 use rustc_middle::ty::adjustment::{Adjust, Adjustment, AutoBorrow};
 use rustc_middle::ty::print::{FmtPrinter, PrettyPrinter, Print, Printer};
-use rustc_middle::ty::{self, InferConst};
-use rustc_middle::ty::{GenericArg, GenericArgKind, GenericArgsRef};
-use rustc_middle::ty::{IsSuggestable, Ty, TyCtxt, TypeckResults};
+use rustc_middle::ty::{
+    self, GenericArg, GenericArgKind, GenericArgsRef, InferConst, IsSuggestable, Ty, TyCtxt,
+    TypeFoldable, TypeFolder, TypeSuperFoldable, TypeckResults,
+};
 use rustc_span::symbol::{kw, sym, Ident};
-use rustc_span::{BytePos, Span};
+use rustc_span::{BytePos, Span, DUMMY_SP};
 use std::borrow::Cow;
 use std::iter;
+use std::path::PathBuf;
 
 pub enum TypeAnnotationNeeded {
     /// ```compile_fail,E0282
@@ -153,6 +155,29 @@ impl UnderspecifiedArgKind {
     }
 }
 
+struct ClosureEraser<'tcx> {
+    tcx: TyCtxt<'tcx>,
+}
+
+impl<'tcx> TypeFolder<TyCtxt<'tcx>> for ClosureEraser<'tcx> {
+    fn interner(&self) -> TyCtxt<'tcx> {
+        self.tcx
+    }
+
+    fn fold_ty(&mut self, ty: Ty<'tcx>) -> Ty<'tcx> {
+        match ty.kind() {
+            ty::Closure(_, args) => {
+                let closure_sig = args.as_closure().sig();
+                Ty::new_fn_ptr(
+                    self.tcx,
+                    self.tcx.signature_unclosure(closure_sig, hir::Unsafety::Normal),
+                )
+            }
+            _ => ty.super_fold_with(self),
+        }
+    }
+}
+
 fn fmt_printer<'a, 'tcx>(infcx: &'a InferCtxt<'tcx>, ns: Namespace) -> FmtPrinter<'a, 'tcx> {
     let mut printer = FmtPrinter::new(infcx.tcx, ns);
     let ty_getter = move |ty_vid| {
@@ -209,6 +234,10 @@ fn ty_to_string<'tcx>(
 ) -> String {
     let mut printer = fmt_printer(infcx, Namespace::TypeNS);
     let ty = infcx.resolve_vars_if_possible(ty);
+    // We use `fn` ptr syntax for closures, but this only works when the closure
+    // does not capture anything.
+    let ty = ty.fold_with(&mut ClosureEraser { tcx: infcx.tcx });
+
     match (ty.kind(), called_method_def_id) {
         // We don't want the regular output for `fn`s because it includes its path in
         // invalid pseudo-syntax, we want the `fn`-pointer output instead.
@@ -223,11 +252,6 @@ fn ty_to_string<'tcx>(
             "Vec<_>".to_string()
         }
         _ if ty.is_ty_or_numeric_infer() => "/* Type */".to_string(),
-        // FIXME: The same thing for closures, but this only works when the closure
-        // does not capture anything.
-        //
-        // We do have to hide the `extern "rust-call"` ABI in that case though,
-        // which is too much of a bother for now.
         _ => {
             ty.print(&mut printer).unwrap();
             printer.into_buffer()
@@ -387,6 +411,8 @@ impl<'tcx> InferCtxt<'tcx> {
                 infer_subdiags,
                 multi_suggestions,
                 bad_label,
+                was_written: None,
+                path: Default::default(),
             }),
             TypeAnnotationNeeded::E0283 => self.dcx().create_err(AmbiguousImpl {
                 span,
@@ -396,6 +422,8 @@ impl<'tcx> InferCtxt<'tcx> {
                 infer_subdiags,
                 multi_suggestions,
                 bad_label,
+                was_written: None,
+                path: Default::default(),
             }),
             TypeAnnotationNeeded::E0284 => self.dcx().create_err(AmbiguousReturn {
                 span,
@@ -405,6 +433,8 @@ impl<'tcx> InferCtxt<'tcx> {
                 infer_subdiags,
                 multi_suggestions,
                 bad_label,
+                was_written: None,
+                path: Default::default(),
             }),
         }
     }
@@ -442,7 +472,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
             return self.bad_inference_failure_err(failure_span, arg_data, error_code);
         };
 
-        let (source_kind, name) = kind.ty_localized_msg(self);
+        let (source_kind, name, path) = kind.ty_localized_msg(self);
         let failure_span = if should_label_span && !failure_span.overlaps(span) {
             Some(failure_span)
         } else {
@@ -518,15 +548,15 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                                 GenericArgKind::Lifetime(_) => bug!("unexpected lifetime"),
                                 GenericArgKind::Type(_) => self
                                     .next_ty_var(TypeVariableOrigin {
-                                        span: rustc_span::DUMMY_SP,
+                                        span: DUMMY_SP,
                                         kind: TypeVariableOriginKind::MiscVariable,
                                     })
                                     .into(),
                                 GenericArgKind::Const(arg) => self
                                     .next_const_var(
                                         arg.ty(),
                                         ConstVariableOrigin {
-                                            span: rustc_span::DUMMY_SP,
+                                            span: DUMMY_SP,
                                             kind: ConstVariableOriginKind::MiscVariable,
                                         },
                                     )
@@ -547,7 +577,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
             }
             InferSourceKind::FullyQualifiedMethodCall { receiver, successor, args, def_id } => {
                 let placeholder = Some(self.next_ty_var(TypeVariableOrigin {
-                    span: rustc_span::DUMMY_SP,
+                    span: DUMMY_SP,
                     kind: TypeVariableOriginKind::MiscVariable,
                 }));
                 if let Some(args) = args.make_suggestable(self.infcx.tcx, true, placeholder) {
@@ -584,7 +614,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
             }
             InferSourceKind::ClosureReturn { ty, data, should_wrap_expr } => {
                 let placeholder = Some(self.next_ty_var(TypeVariableOrigin {
-                    span: rustc_span::DUMMY_SP,
+                    span: DUMMY_SP,
                     kind: TypeVariableOriginKind::MiscVariable,
                 }));
                 if let Some(ty) = ty.make_suggestable(self.infcx.tcx, true, placeholder) {
@@ -606,6 +636,8 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                 infer_subdiags,
                 multi_suggestions,
                 bad_label: None,
+                was_written: path.as_ref().map(|_| ()),
+                path: path.unwrap_or_default(),
             }),
             TypeAnnotationNeeded::E0283 => self.dcx().create_err(AmbiguousImpl {
                 span,
@@ -615,6 +647,8 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                 infer_subdiags,
                 multi_suggestions,
                 bad_label: None,
+                was_written: path.as_ref().map(|_| ()),
+                path: path.unwrap_or_default(),
             }),
             TypeAnnotationNeeded::E0284 => self.dcx().create_err(AmbiguousReturn {
                 span,
@@ -624,6 +658,8 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                 infer_subdiags,
                 multi_suggestions,
                 bad_label: None,
+                was_written: path.as_ref().map(|_| ()),
+                path: path.unwrap_or_default(),
             }),
         }
     }
@@ -688,22 +724,23 @@ impl<'tcx> InferSource<'tcx> {
 }
 
 impl<'tcx> InferSourceKind<'tcx> {
-    fn ty_localized_msg(&self, infcx: &InferCtxt<'tcx>) -> (&'static str, String) {
+    fn ty_localized_msg(&self, infcx: &InferCtxt<'tcx>) -> (&'static str, String, Option<PathBuf>) {
+        let mut path = None;
         match *self {
             InferSourceKind::LetBinding { ty, .. }
             | InferSourceKind::ClosureArg { ty, .. }
             | InferSourceKind::ClosureReturn { ty, .. } => {
                 if ty.is_closure() {
-                    ("closure", closure_as_fn_str(infcx, ty))
+                    ("closure", closure_as_fn_str(infcx, ty), path)
                 } else if !ty.is_ty_or_numeric_infer() {
-                    ("normal", ty_to_string(infcx, ty, None))
+                    ("normal", infcx.tcx.short_ty_string(ty, &mut path), path)
                 } else {
-                    ("other", String::new())
+                    ("other", String::new(), path)
                 }
             }
             // FIXME: We should be able to add some additional info here.
             InferSourceKind::GenericArg { .. }
-            | InferSourceKind::FullyQualifiedMethodCall { .. } => ("other", String::new()),
+            | InferSourceKind::FullyQualifiedMethodCall { .. } => ("other", String::new(), path),
         }
     }
 }

compiler/rustc_lint/src/context/diagnostics.rs

@@ -105,7 +105,7 @@ pub(super) fn builtin(sess: &Session, diagnostic: BuiltinLintDiag, diag: &mut Di
         BuiltinLintDiag::RedundantImport(spans, ident) => {
             for (span, is_imported) in spans {
                 let introduced = if is_imported { "imported" } else { "defined" };
-                let span_msg = if span.is_dummy() { "by prelude" } else { "here" };
+                let span_msg = if span.is_dummy() { "by the extern prelude" } else { "here" };
                 diag.span_label(
                     span,
                     format!("the item `{ident}` is already {introduced} {span_msg}"),

compiler/rustc_lint/src/unused.rs

@@ -1074,10 +1074,14 @@ impl UnusedParens {
                 // Otherwise proceed with linting.
                 _ => {}
             }
-            let spans = inner
-                .span
-                .find_ancestor_inside(value.span)
-                .map(|inner| (value.span.with_hi(inner.lo()), value.span.with_lo(inner.hi())));
+            let spans = if !value.span.from_expansion() {
+                inner
+                    .span
+                    .find_ancestor_inside(value.span)
+                    .map(|inner| (value.span.with_hi(inner.lo()), value.span.with_lo(inner.hi())))
+            } else {
+                None
+            };
             self.emit_unused_delims(cx, value.span, spans, "pattern", keep_space, false);
         }
     }
@@ -1233,11 +1237,13 @@ impl EarlyLintPass for UnusedParens {
                         if self.with_self_ty_parens && b.generic_params.len() > 0 => {}
                     ast::TyKind::ImplTrait(_, bounds) if bounds.len() > 1 => {}
                     _ => {
-                        let spans = r
-                            .span
-                            .find_ancestor_inside(ty.span)
-                            .map(|r| (ty.span.with_hi(r.lo()), ty.span.with_lo(r.hi())));
-
+                        let spans = if !ty.span.from_expansion() {
+                            r.span
+                                .find_ancestor_inside(ty.span)
+                                .map(|r| (ty.span.with_hi(r.lo()), ty.span.with_lo(r.hi())))
+                        } else {
+                            None
+                        };
                         self.emit_unused_delims(cx, ty.span, spans, "type", (false, false), false);
                     }
                 }

library/core/src/clone.rs

@@ -227,13 +227,10 @@ mod impls {
     impl_clone! {
         usize u8 u16 u32 u64 u128
         isize i8 i16 i32 i64 i128
-        f32 f64
+        f16 f32 f64 f128
         bool char
     }
 
-    #[cfg(not(bootstrap))]
-    impl_clone! { f16 f128 }
-
     #[unstable(feature = "never_type", issue = "35121")]
     impl Clone for ! {
         #[inline]

library/core/src/cmp.rs

@@ -1497,12 +1497,9 @@ mod impls {
     }
 
     partial_eq_impl! {
-        bool char usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64
+        bool char usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f16 f32 f64 f128
     }
 
-    #[cfg(not(bootstrap))]
-    partial_eq_impl! { f16 f128 }
-
     macro_rules! eq_impl {
         ($($t:ty)*) => ($(
             #[stable(feature = "rust1", since = "1.0.0")]
@@ -1553,10 +1550,7 @@ mod impls {
         }
     }
 
-    partial_ord_impl! { f32 f64 }
-
-    #[cfg(not(bootstrap))]
-    partial_ord_impl! { f16 f128 }
+    partial_ord_impl! { f16 f32 f64 f128 }
 
     macro_rules! ord_impl {
         ($($t:ty)*) => ($(

library/core/src/convert/num.rs

@@ -34,8 +34,10 @@ macro_rules! impl_float_to_int {
     }
 }
 
+impl_float_to_int!(f16 => u8, u16, u32, u64, u128, usize, i8, i16, i32, i64, i128, isize);
 impl_float_to_int!(f32 => u8, u16, u32, u64, u128, usize, i8, i16, i32, i64, i128, isize);
 impl_float_to_int!(f64 => u8, u16, u32, u64, u128, usize, i8, i16, i32, i64, i128, isize);
+impl_float_to_int!(f128 => u8, u16, u32, u64, u128, usize, i8, i16, i32, i64, i128, isize);
 
 // Conversion traits for primitive integer and float types
 // Conversions T -> T are covered by a blanket impl and therefore excluded
@@ -163,7 +165,12 @@ impl_from!(u16 => f64, #[stable(feature = "lossless_float_conv", since = "1.6.0"
 impl_from!(u32 => f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
 
 // float -> float
+impl_from!(f16 => f32, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
+impl_from!(f16 => f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
+impl_from!(f16 => f128, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
 impl_from!(f32 => f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
+impl_from!(f32 => f128, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
+impl_from!(f64 => f128, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
 
 macro_rules! impl_float_from_bool {
     ($float:ty) => {

library/core/src/fmt/nofloat.rs

@@ -11,5 +11,7 @@ macro_rules! floating {
     };
 }
 
+floating! { f16 }
 floating! { f32 }
 floating! { f64 }
+floating! { f128 }

library/core/src/lib.rs

@@ -200,8 +200,6 @@
 //
 // Language features:
 // tidy-alphabetical-start
-#![cfg_attr(not(bootstrap), feature(f128))]
-#![cfg_attr(not(bootstrap), feature(f16))]
 #![feature(abi_unadjusted)]
 #![feature(adt_const_params)]
 #![feature(allow_internal_unsafe)]
@@ -226,6 +224,8 @@
 #![feature(doc_notable_trait)]
 #![feature(effects)]
 #![feature(extern_types)]
+#![feature(f128)]
+#![feature(f16)]
 #![feature(freeze_impls)]
 #![feature(fundamental)]
 #![feature(generic_arg_infer)]
@@ -347,6 +347,10 @@ pub mod u8;
 #[path = "num/shells/usize.rs"]
 pub mod usize;
 
+#[path = "num/f128.rs"]
+pub mod f128;
+#[path = "num/f16.rs"]
+pub mod f16;
 #[path = "num/f32.rs"]
 pub mod f32;
 #[path = "num/f64.rs"]