Auto merge of rust-lang#105979 - matthiaskrgr:rollup-2luw3mx, r=matthiaskrgr

Rollup of 8 pull requests

Successful merges:

 - rust-lang#105791 (docs: add long error explanation for error E0472)
 - rust-lang#105897 (Fix an opaque type ICE)
 - rust-lang#105904 (Fix arch flag on i686-apple-darwin)
 - rust-lang#105949 (Bump `cfg-if` to `1.0` in rustc crates)
 - rust-lang#105964 (rustdoc: prevent CSS layout of line numbers shrinking into nothing)
 - rust-lang#105972 (rustdoc: simplify section anchor CSS)
 - rust-lang#105973 (Avoid going through the happy path in case of non-fn builtin calls)
 - rust-lang#105976 (Remove unused `check-stage2-T-arm-linux-androideabi-H-x86_64-unknown-linux-gnu` make rule)

Failed merges:

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

Author: bors

Cargo.lock

@@ -3590,7 +3590,7 @@ version = "0.0.0"
 dependencies = [
  "arrayvec",
  "bitflags",
- "cfg-if 0.1.10",
+ "cfg-if 1.0.0",
  "ena",
  "indexmap",
  "jobserver",
@@ -4374,7 +4374,7 @@ dependencies = [
 name = "rustc_span"
 version = "0.0.0"
 dependencies = [
- "cfg-if 0.1.10",
+ "cfg-if 1.0.0",
  "md-5",
  "rustc_arena",
  "rustc_data_structures",

compiler/rustc_borrowck/src/diagnostics/region_errors.rs

@@ -18,11 +18,11 @@ use rustc_infer::infer::{
 use rustc_middle::hir::place::PlaceBase;
 use rustc_middle::mir::{ConstraintCategory, ReturnConstraint};
 use rustc_middle::ty::subst::InternalSubsts;
-use rustc_middle::ty::Region;
 use rustc_middle::ty::TypeVisitor;
 use rustc_middle::ty::{self, RegionVid, Ty};
+use rustc_middle::ty::{Region, TyCtxt};
 use rustc_span::symbol::{kw, Ident};
-use rustc_span::Span;
+use rustc_span::{Span, DUMMY_SP};
 
 use crate::borrowck_errors;
 use crate::session_diagnostics::{
@@ -70,7 +70,25 @@ impl<'tcx> ConstraintDescription for ConstraintCategory<'tcx> {
 ///
 /// Usually we expect this to either be empty or contain a small number of items, so we can avoid
 /// allocation most of the time.
-pub(crate) type RegionErrors<'tcx> = Vec<RegionErrorKind<'tcx>>;
+pub(crate) struct RegionErrors<'tcx>(Vec<RegionErrorKind<'tcx>>, TyCtxt<'tcx>);
+
+impl<'tcx> RegionErrors<'tcx> {
+    pub fn new(tcx: TyCtxt<'tcx>) -> Self {
+        Self(vec![], tcx)
+    }
+    #[track_caller]
+    pub fn push(&mut self, val: impl Into<RegionErrorKind<'tcx>>) {
+        let val = val.into();
+        self.1.sess.delay_span_bug(DUMMY_SP, "{val:?}");
+        self.0.push(val);
+    }
+    pub fn is_empty(&self) -> bool {
+        self.0.is_empty()
+    }
+    pub fn into_iter(self) -> impl Iterator<Item = RegionErrorKind<'tcx>> {
+        self.0.into_iter()
+    }
+}
 
 #[derive(Clone, Debug)]
 pub(crate) enum RegionErrorKind<'tcx> {

compiler/rustc_borrowck/src/region_infer/mod.rs

@@ -562,7 +562,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         let mir_def_id = body.source.def_id();
         self.propagate_constraints(body);
 
-        let mut errors_buffer = RegionErrors::new();
+        let mut errors_buffer = RegionErrors::new(infcx.tcx);
 
         // If this is a closure, we can propagate unsatisfied
         // `outlives_requirements` to our creator, so create a vector
@@ -1647,26 +1647,29 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         let longer_fr_scc = self.constraint_sccs.scc(longer_fr);
         debug!("check_bound_universal_region: longer_fr_scc={:?}", longer_fr_scc,);
 
-        // If we have some bound universal region `'a`, then the only
-        // elements it can contain is itself -- we don't know anything
-        // else about it!
-        let Some(error_element) = ({
-            self.scc_values.elements_contained_in(longer_fr_scc).find(|element| match element {
-                RegionElement::Location(_) => true,
-                RegionElement::RootUniversalRegion(_) => true,
-                RegionElement::PlaceholderRegion(placeholder1) => placeholder != *placeholder1,
-            })
-        }) else {
-            return;
-        };
-        debug!("check_bound_universal_region: error_element = {:?}", error_element);
+        for error_element in self.scc_values.elements_contained_in(longer_fr_scc) {
+            match error_element {
+                RegionElement::Location(_) | RegionElement::RootUniversalRegion(_) => {}
+                // If we have some bound universal region `'a`, then the only
+                // elements it can contain is itself -- we don't know anything
+                // else about it!
+                RegionElement::PlaceholderRegion(placeholder1) => {
+                    if placeholder == placeholder1 {
+                        continue;
+                    }
+                }
+            }
 
-        // Find the region that introduced this `error_element`.
-        errors_buffer.push(RegionErrorKind::BoundUniversalRegionError {
-            longer_fr,
-            error_element,
-            placeholder,
-        });
+            errors_buffer.push(RegionErrorKind::BoundUniversalRegionError {
+                longer_fr,
+                error_element,
+                placeholder,
+            });
+
+            // Stop after the first error, it gets too noisy otherwise, and does not provide more information.
+            break;
+        }
+        debug!("check_bound_universal_region: all bounds satisfied");
     }
 
     #[instrument(level = "debug", skip(self, infcx, errors_buffer))]

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -1153,27 +1153,31 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
         category: ConstraintCategory<'tcx>,
     ) -> Fallible<()> {
         let annotated_type = self.user_type_annotations[user_ty.base].inferred_ty;
+        trace!(?annotated_type);
         let mut curr_projected_ty = PlaceTy::from_ty(annotated_type);
 
         let tcx = self.infcx.tcx;
 
         for proj in &user_ty.projs {
+            if let ty::Alias(ty::Opaque, ..) = curr_projected_ty.ty.kind() {
+                // There is nothing that we can compare here if we go through an opaque type.
+                // We're always in its defining scope as we can otherwise not project through
+                // it, so we're constraining it anyways.
+                return Ok(());
+            }
             let projected_ty = curr_projected_ty.projection_ty_core(
                 tcx,
                 self.param_env,
                 proj,
-                |this, field, _| {
+                |this, field, ()| {
                     let ty = this.field_ty(tcx, field);
                     self.normalize(ty, locations)
                 },
                 |_, _| unreachable!(),
             );
             curr_projected_ty = projected_ty;
         }
-        debug!(
-            "user_ty base: {:?} freshened: {:?} projs: {:?} yields: {:?}",
-            user_ty.base, annotated_type, user_ty.projs, curr_projected_ty
-        );
+        trace!(?curr_projected_ty);
 
         let ty = curr_projected_ty.ty;
         self.relate_types(ty, v.xform(ty::Variance::Contravariant), a, locations, category)?;

compiler/rustc_data_structures/Cargo.toml

@@ -8,7 +8,7 @@ edition = "2021"
 [dependencies]
 arrayvec = { version = "0.7", default-features = false }
 bitflags = "1.2.1"
-cfg-if = "0.1.2"
+cfg-if = "1.0"
 ena = "0.14"
 indexmap = { version = "1.9.1" }
 jobserver_crate = { version = "0.1.13", package = "jobserver" }
@@ -21,7 +21,11 @@ rustc-hash = "1.1.0"
 rustc_index = { path = "../rustc_index", package = "rustc_index" }
 rustc_macros = { path = "../rustc_macros" }
 rustc_serialize = { path = "../rustc_serialize" }
-smallvec = { version = "1.8.1", features = ["const_generics", "union", "may_dangle"] }
+smallvec = { version = "1.8.1", features = [
+    "const_generics",
+    "union",
+    "may_dangle",
+] }
 stable_deref_trait = "1.0.0"
 stacker = "0.1.15"
 tempfile = "3.2"

compiler/rustc_error_codes/src/error_codes.rs

@@ -249,6 +249,7 @@ E0464: include_str!("./error_codes/E0464.md"),
 E0466: include_str!("./error_codes/E0466.md"),
 E0468: include_str!("./error_codes/E0468.md"),
 E0469: include_str!("./error_codes/E0469.md"),
+E0472: include_str!("./error_codes/E0472.md"),
 E0477: include_str!("./error_codes/E0477.md"),
 E0478: include_str!("./error_codes/E0478.md"),
 E0482: include_str!("./error_codes/E0482.md"),
@@ -599,7 +600,6 @@ E0791: include_str!("./error_codes/E0791.md"),
 //  E0467, // removed
 //  E0470, // removed
 //  E0471, // constant evaluation error (in pattern)
-    E0472, // llvm_asm! is unsupported on this target
 //  E0473, // dereference of reference outside its lifetime
 //  E0474, // captured variable `..` does not outlive the enclosing closure
 //  E0475, // index of slice outside its lifetime

compiler/rustc_error_codes/src/error_codes/E0472.md

@@ -0,0 +1,31 @@
+Inline assembly (`asm!`) is not supported on this target.
+
+Example of erroneous code:
+
+```ignore (cannot-change-target)
+// compile-flags: --target sparc64-unknown-linux-gnu
+#![no_std]
+
+use core::arch::asm;
+
+fn main() {
+    unsafe {
+        asm!(""); // error: inline assembly is not supported on this target
+    }
+}
+```
+
+The Rust compiler does not support inline assembly, with the `asm!` macro
+(previously `llvm_asm!`), for all targets. All Tier 1 targets do support this
+macro but support among Tier 2 and 3 targets is not guaranteed (even when they
+have `std` support). Note that this error is related to
+`error[E0658]: inline assembly is not stable yet on this architecture`, but
+distinct in that with `E0472` support is not planned or in progress.
+
+There is no way to easily fix this issue, however:
+ * Consider if you really need inline assembly, is there some other way to
+   achieve your goal (intrinsics, etc)?
+ * Consider writing your assembly externally, linking with it and calling it
+   from Rust.
+ * Consider contributing to <https://github.com/rust-lang/rust> and help
+   integrate support for your target!

compiler/rustc_hir_typeck/src/callee.rs

@@ -4,7 +4,7 @@ use super::{Expectation, FnCtxt, TupleArgumentsFlag};
 
 use crate::type_error_struct;
 use rustc_ast::util::parser::PREC_POSTFIX;
-use rustc_errors::{struct_span_err, Applicability, Diagnostic, StashKey};
+use rustc_errors::{struct_span_err, Applicability, Diagnostic, ErrorGuaranteed, StashKey};
 use rustc_hir as hir;
 use rustc_hir::def::{self, CtorKind, Namespace, Res};
 use rustc_hir::def_id::DefId;
@@ -424,21 +424,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     }
                 }
 
-                self.report_invalid_callee(call_expr, callee_expr, callee_ty, arg_exprs);
-
-                // This is the "default" function signature, used in case of error.
-                // In that case, we check each argument against "error" in order to
-                // set up all the node type bindings.
-                (
-                    ty::Binder::dummy(self.tcx.mk_fn_sig(
-                        self.err_args(arg_exprs.len()).into_iter(),
-                        self.tcx.ty_error(),
-                        false,
-                        hir::Unsafety::Normal,
-                        abi::Abi::Rust,
-                    )),
-                    None,
-                )
+                let err = self.report_invalid_callee(call_expr, callee_expr, callee_ty, arg_exprs);
+
+                return self.tcx.ty_error_with_guaranteed(err);
             }
         };
 
@@ -591,7 +579,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         callee_expr: &'tcx hir::Expr<'tcx>,
         callee_ty: Ty<'tcx>,
         arg_exprs: &'tcx [hir::Expr<'tcx>],
-    ) {
+    ) -> ErrorGuaranteed {
         let mut unit_variant = None;
         if let hir::ExprKind::Path(qpath) = &callee_expr.kind
             && let Res::Def(def::DefKind::Ctor(kind, CtorKind::Const), _)
@@ -720,7 +708,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 err.span_label(span, label);
             }
         }
-        err.emit();
+        err.emit()
     }
 
     fn confirm_deferred_closure_call(

compiler/rustc_middle/src/mir/tcx.rs

@@ -32,8 +32,9 @@ impl<'tcx> PlaceTy<'tcx> {
     /// not carry a `Ty` for `T`.)
     ///
     /// Note that the resulting type has not been normalized.
+    #[instrument(level = "debug", skip(tcx), ret)]
     pub fn field_ty(self, tcx: TyCtxt<'tcx>, f: Field) -> Ty<'tcx> {
-        let answer = match self.ty.kind() {
+        match self.ty.kind() {
             ty::Adt(adt_def, substs) => {
                 let variant_def = match self.variant_index {
                     None => adt_def.non_enum_variant(),
@@ -47,9 +48,7 @@ impl<'tcx> PlaceTy<'tcx> {
             }
             ty::Tuple(tys) => tys[f.index()],
             _ => bug!("extracting field of non-tuple non-adt: {:?}", self),
-        };
-        debug!("field_ty self: {:?} f: {:?} yields: {:?}", self, f, answer);
-        answer
+        }
     }
 
     /// Convenience wrapper around `projection_ty_core` for

compiler/rustc_middle/src/ty/subst.rs

@@ -400,6 +400,7 @@ impl<'tcx> InternalSubsts<'tcx> {
     }
 
     #[inline]
+    #[track_caller]
     pub fn type_at(&self, i: usize) -> Ty<'tcx> {
         if let GenericArgKind::Type(ty) = self[i].unpack() {
             ty
@@ -409,6 +410,7 @@ impl<'tcx> InternalSubsts<'tcx> {
     }
 
     #[inline]
+    #[track_caller]
     pub fn region_at(&self, i: usize) -> ty::Region<'tcx> {
         if let GenericArgKind::Lifetime(lt) = self[i].unpack() {
             lt
@@ -418,6 +420,7 @@ impl<'tcx> InternalSubsts<'tcx> {
     }
 
     #[inline]
+    #[track_caller]
     pub fn const_at(&self, i: usize) -> ty::Const<'tcx> {
         if let GenericArgKind::Const(ct) = self[i].unpack() {
             ct
@@ -427,6 +430,7 @@ impl<'tcx> InternalSubsts<'tcx> {
     }
 
     #[inline]
+    #[track_caller]
     pub fn type_for_def(&self, def: &ty::GenericParamDef) -> GenericArg<'tcx> {
         self.type_at(def.index as usize).into()
     }