Auto merge of #89882 - matthiaskrgr:rollup-1dh7pz8, r=matthiaskrgr

Rollup of 6 pull requests

Successful merges:

 - #89390 (Fix incorrect Box::pin suggestion)
 - #89433 (Fix ctrl-c causing reads of stdin to return empty on Windows.)
 - #89823 (Switch order of terms to prevent overflow)
 - #89865 (Allow static linking LLVM with ThinLTO)
 - #89873 (Add missing word to `FromStr` trait documentation)
 - #89878 (Fix missing remaining compiler specific cfg information)

Failed merges:

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

compiler/rustc_trait_selection/src/traits/project.rs

@@ -558,7 +558,7 @@ impl<'me, 'tcx> BoundVarReplacer<'me, 'tcx> {
     fn universe_for(&mut self, debruijn: ty::DebruijnIndex) -> ty::UniverseIndex {
         let infcx = self.infcx;
         let index =
-            self.universe_indices.len() - debruijn.as_usize() + self.current_index.as_usize() - 1;
+            self.universe_indices.len() + self.current_index.as_usize() - debruijn.as_usize() - 1;
         let universe = self.universe_indices[index].unwrap_or_else(|| {
             for i in self.universe_indices.iter_mut().take(index + 1) {
                 *i = i.or_else(|| Some(infcx.create_next_universe()))

compiler/rustc_typeck/src/check/coercion.rs

@@ -42,7 +42,7 @@ use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
 use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
 use rustc_infer::infer::{Coercion, InferOk, InferResult};
-use rustc_infer::traits::Obligation;
+use rustc_infer::traits::{Obligation, TraitEngine, TraitEngineExt};
 use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::adjustment::{
     Adjust, Adjustment, AllowTwoPhase, AutoBorrow, AutoBorrowMutability, PointerCast,
@@ -146,6 +146,7 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
             .and_then(|InferOk { value: ty, obligations }| success(f(ty), ty, obligations))
     }
 
+    #[instrument(skip(self))]
     fn coerce(&self, a: Ty<'tcx>, b: Ty<'tcx>) -> CoerceResult<'tcx> {
         // First, remove any resolved type variables (at the top level, at least):
         let a = self.shallow_resolve(a);
@@ -933,14 +934,25 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     }
 
     /// Same as `try_coerce()`, but without side-effects.
+    ///
+    /// Returns false if the coercion creates any obligations that result in
+    /// errors.
     pub fn can_coerce(&self, expr_ty: Ty<'tcx>, target: Ty<'tcx>) -> bool {
         let source = self.resolve_vars_with_obligations(expr_ty);
-        debug!("coercion::can({:?} -> {:?})", source, target);
+        debug!("coercion::can_with_predicates({:?} -> {:?})", source, target);
 
         let cause = self.cause(rustc_span::DUMMY_SP, ObligationCauseCode::ExprAssignable);
         // We don't ever need two-phase here since we throw out the result of the coercion
         let coerce = Coerce::new(self, cause, AllowTwoPhase::No);
-        self.probe(|_| coerce.coerce(source, target)).is_ok()
+        self.probe(|_| {
+            let ok = match coerce.coerce(source, target) {
+                Ok(ok) => ok,
+                _ => return false,
+            };
+            let mut fcx = traits::FulfillmentContext::new_in_snapshot();
+            fcx.register_predicate_obligations(self, ok.obligations);
+            fcx.select_where_possible(&self).is_ok()
+        })
     }
 
     /// Given a type and a target type, this function will calculate and return

compiler/rustc_typeck/src/check/fn_ctxt/suggestions.rs

@@ -341,7 +341,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 for (sp, label) in spans_and_labels {
                     multi_span.push_span_label(sp, label);
                 }
-                err.span_note(multi_span, "closures can only be coerced to `fn` types if they do not capture any variables");
+                err.span_note(
+                    multi_span,
+                    "closures can only be coerced to `fn` types if they do not capture any variables"
+                );
             }
         }
     }
@@ -361,15 +364,19 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             return false;
         }
         let pin_did = self.tcx.lang_items().pin_type();
-        match expected.kind() {
-            ty::Adt(def, _) if Some(def.did) != pin_did => return false,
-            // This guards the `unwrap` and `mk_box` below.
-            _ if pin_did.is_none() || self.tcx.lang_items().owned_box().is_none() => return false,
-            _ => {}
+        // This guards the `unwrap` and `mk_box` below.
+        if pin_did.is_none() || self.tcx.lang_items().owned_box().is_none() {
+            return false;
         }
-        let boxed_found = self.tcx.mk_box(found);
-        let new_found = self.tcx.mk_lang_item(boxed_found, LangItem::Pin).unwrap();
-        if self.can_coerce(new_found, expected) {
+        match expected.kind() {
+            ty::Adt(def, _) if Some(def.did) == pin_did => (),
+            _ => return false,
+        }
+        let box_found = self.tcx.mk_box(found);
+        let pin_box_found = self.tcx.mk_lang_item(box_found, LangItem::Pin).unwrap();
+        let pin_found = self.tcx.mk_lang_item(found, LangItem::Pin).unwrap();
+        if self.can_coerce(pin_box_found, expected) {
+            debug!("can coerce {:?} to {:?}, suggesting Box::pin", pin_box_found, expected);
             match found.kind() {
                 ty::Adt(def, _) if def.is_box() => {
                     err.help("use `Box::pin`");
@@ -381,11 +388,19 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                             (expr.span.shrink_to_lo(), "Box::pin(".to_string()),
                             (expr.span.shrink_to_hi(), ")".to_string()),
                         ],
-                        Applicability::MachineApplicable,
+                        Applicability::MaybeIncorrect,
                     );
                 }
             }
             true
+        } else if self.can_coerce(pin_found, expected) {
+            match found.kind() {
+                ty::Adt(def, _) if def.is_box() => {
+                    err.help("use `Box::pin`");
+                    true
+                }
+                _ => false,
+            }
         } else {
             false
         }