Auto merge of #116605 - GuillaumeGomez:rollup-12ba2o6, r=GuillaumeGomez

Rollup of 7 pull requests

Successful merges:

 - #109422 (rustdoc-search: add impl disambiguator to duplicate assoc items)
 - #116250 (On type error of closure call argument, point at earlier calls that affected inference)
 - #116444 (add test for const-eval error in dead code during monomorphization)
 - #116503 (Update docs for mips target tier demotion.)
 - #116559 (Mark `new_in` as `const` for BTree collections)
 - #116560 (In smir use `FxIndexMap` to store indexed ids)
 - #116574 (Update books)

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

6 files changed, 156 insertions, 38 deletions

diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
index c0332a48be3..9b7f8f80310 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
@@ -16,6 +16,7 @@ use rustc_errors::{
 use rustc_hir as hir;
 use rustc_hir::def::{CtorOf, DefKind, Res};
 use rustc_hir::def_id::DefId;
+use rustc_hir::intravisit::Visitor;
 use rustc_hir::{ExprKind, Node, QPath};
 use rustc_hir_analysis::astconv::AstConv;
 use rustc_hir_analysis::check::intrinsicck::InlineAsmCtxt;
@@ -28,7 +29,7 @@ use rustc_infer::infer::TypeTrace;
 use rustc_infer::infer::{DefineOpaqueTypes, InferOk};
 use rustc_middle::ty::adjustment::AllowTwoPhase;
 use rustc_middle::ty::visit::TypeVisitableExt;
-use rustc_middle::ty::{self, IsSuggestable, Ty};
+use rustc_middle::ty::{self, IsSuggestable, Ty, TyCtxt};
 use rustc_session::Session;
 use rustc_span::symbol::{kw, Ident};
 use rustc_span::{self, sym, BytePos, Span};
@@ -722,6 +723,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         &mut err,
                         fn_def_id,
                         callee_ty,
+                        call_expr,
+                        None,
                         Some(mismatch_idx),
                         is_method,
                     );
@@ -826,6 +829,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 &mut err,
                 fn_def_id,
                 callee_ty,
+                call_expr,
+                Some(expected_ty),
                 Some(expected_idx.as_usize()),
                 is_method,
             );
@@ -1208,7 +1213,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
 
         // Call out where the function is defined
-        self.label_fn_like(&mut err, fn_def_id, callee_ty, None, is_method);
+        self.label_fn_like(&mut err, fn_def_id, callee_ty, call_expr, None, None, is_method);
 
         // And add a suggestion block for all of the parameters
         let suggestion_text = match suggestion_text {
@@ -1899,6 +1904,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         err: &mut Diagnostic,
         callable_def_id: Option<DefId>,
         callee_ty: Option<Ty<'tcx>>,
+        call_expr: &'tcx hir::Expr<'tcx>,
+        expected_ty: Option<Ty<'tcx>>,
         // A specific argument should be labeled, instead of all of them
         expected_idx: Option<usize>,
         is_method: bool,
@@ -2015,6 +2022,46 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             let param = expected_idx
                 .and_then(|expected_idx| self.tcx.hir().body(*body).params.get(expected_idx));
             let (kind, span) = if let Some(param) = param {
+                // Try to find earlier invocations of this closure to find if the type mismatch
+                // is because of inference. If we find one, point at them.
+                let mut call_finder = FindClosureArg { tcx: self.tcx, calls: vec![] };
+                let node = self.tcx
+                    .opt_local_def_id_to_hir_id(self.tcx.hir().get_parent_item(call_expr.hir_id))
+                    .and_then(|hir_id| self.tcx.hir().find(hir_id));
+                match node {
+                    Some(hir::Node::Item(item)) => call_finder.visit_item(item),
+                    Some(hir::Node::TraitItem(item)) => call_finder.visit_trait_item(item),
+                    Some(hir::Node::ImplItem(item)) => call_finder.visit_impl_item(item),
+                    _ => {}
+                }
+                let typeck = self.typeck_results.borrow();
+                for (rcvr, args) in call_finder.calls {
+                    if let Some(rcvr_ty) = typeck.node_type_opt(rcvr.hir_id)
+                        && let ty::Closure(call_def_id, _) = rcvr_ty.kind()
+                        && def_id == *call_def_id
+                        && let Some(idx) = expected_idx
+                        && let Some(arg) = args.get(idx)
+                        && let Some(arg_ty) = typeck.node_type_opt(arg.hir_id)
+                        && let Some(expected_ty) = expected_ty
+                        && self.can_eq(self.param_env, arg_ty, expected_ty)
+                    {
+                        let mut sp: MultiSpan = vec![arg.span].into();
+                        sp.push_span_label(
+                            arg.span,
+                            format!("expected because this argument is of type `{arg_ty}`"),
+                        );
+                        sp.push_span_label(rcvr.span, "in this closure call");
+                        err.span_note(
+                            sp,
+                            format!(
+                                "expected because the closure was earlier called with an \
+                                argument of type `{arg_ty}`",
+                            ),
+                        );
+                        break;
+                    }
+                }
+
                 ("closure parameter", param.span)
             } else {
                 ("closure", self.tcx.def_span(def_id))
@@ -2028,3 +2075,23 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
     }
 }
+
+struct FindClosureArg<'tcx> {
+    tcx: TyCtxt<'tcx>,
+    calls: Vec<(&'tcx hir::Expr<'tcx>, &'tcx [hir::Expr<'tcx>])>,
+}
+
+impl<'tcx> Visitor<'tcx> for FindClosureArg<'tcx> {
+    type NestedFilter = rustc_middle::hir::nested_filter::All;
+
+    fn nested_visit_map(&mut self) -> Self::Map {
+        self.tcx.hir()
+    }
+
+    fn visit_expr(&mut self, ex: &'tcx hir::Expr<'tcx>) {
+        if let hir::ExprKind::Call(rcvr, args) = ex.kind {
+            self.calls.push((rcvr, args));
+        }
+        hir::intravisit::walk_expr(self, ex);
+    }
+}
diff --git a/compiler/rustc_smir/Cargo.toml b/compiler/rustc_smir/Cargo.toml
index 3e0d6baab6a..2b77044d6bf 100644
--- a/compiler/rustc_smir/Cargo.toml
+++ b/compiler/rustc_smir/Cargo.toml
@@ -4,6 +4,7 @@ version = "0.0.0"
 edition = "2021"
 
 [dependencies]
+rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_driver = { path = "../rustc_driver" }
 rustc_hir = { path = "../rustc_hir" }
 rustc_interface = { path = "../rustc_interface" }
diff --git a/compiler/rustc_smir/src/rustc_internal/mod.rs b/compiler/rustc_smir/src/rustc_internal/mod.rs
index 36eb2247253..e3c84f06543 100644
--- a/compiler/rustc_smir/src/rustc_internal/mod.rs
+++ b/compiler/rustc_smir/src/rustc_internal/mod.rs
@@ -3,24 +3,27 @@
 //! For that, we define APIs that will temporarily be public to 3P that exposes rustc internal APIs
 //! until stable MIR is complete.
 
-use std::ops::{ControlFlow, Index};
-
 use crate::rustc_internal;
 use crate::rustc_smir::Tables;
+use rustc_data_structures::fx;
 use rustc_driver::{Callbacks, Compilation, RunCompiler};
 use rustc_interface::{interface, Queries};
 use rustc_middle::mir::interpret::AllocId;
 use rustc_middle::ty::TyCtxt;
 use rustc_span::def_id::{CrateNum, DefId};
 use rustc_span::Span;
+use stable_mir::ty::IndexedVal;
 use stable_mir::CompilerError;
+use std::fmt::Debug;
+use std::hash::Hash;
+use std::ops::{ControlFlow, Index};
 
 impl<'tcx> Index<stable_mir::DefId> for Tables<'tcx> {
     type Output = DefId;
 
     #[inline(always)]
     fn index(&self, index: stable_mir::DefId) -> &Self::Output {
-        &self.def_ids[index.0]
+        &self.def_ids[index]
     }
 }
 
@@ -29,7 +32,7 @@ impl<'tcx> Index<stable_mir::ty::Span> for Tables<'tcx> {
 
     #[inline(always)]
     fn index(&self, index: stable_mir::ty::Span) -> &Self::Output {
-        &self.spans[index.0]
+        &self.spans[index]
     }
 }
 
@@ -95,36 +98,15 @@ impl<'tcx> Tables<'tcx> {
     }
 
     fn create_def_id(&mut self, did: DefId) -> stable_mir::DefId {
-        // FIXME: this becomes inefficient when we have too many ids
-        for (i, &d) in self.def_ids.iter().enumerate() {
-            if d == did {
-                return stable_mir::DefId(i);
-            }
-        }
-        let id = self.def_ids.len();
-        self.def_ids.push(did);
-        stable_mir::DefId(id)
+        self.def_ids.create_or_fetch(did)
     }
 
     fn create_alloc_id(&mut self, aid: AllocId) -> stable_mir::AllocId {
-        // FIXME: this becomes inefficient when we have too many ids
-        if let Some(i) = self.alloc_ids.iter().position(|a| *a == aid) {
-            return stable_mir::AllocId(i);
-        };
-        let id = self.def_ids.len();
-        self.alloc_ids.push(aid);
-        stable_mir::AllocId(id)
+        self.alloc_ids.create_or_fetch(aid)
     }
 
     pub(crate) fn create_span(&mut self, span: Span) -> stable_mir::ty::Span {
-        for (i, &sp) in self.spans.iter().enumerate() {
-            if sp == span {
-                return stable_mir::ty::Span(i);
-            }
-        }
-        let id = self.spans.len();
-        self.spans.push(span);
-        stable_mir::ty::Span(id)
+        self.spans.create_or_fetch(span)
     }
 }
 
@@ -134,7 +116,13 @@ pub fn crate_num(item: &stable_mir::Crate) -> CrateNum {
 
 pub fn run(tcx: TyCtxt<'_>, f: impl FnOnce()) {
     stable_mir::run(
-        Tables { tcx, def_ids: vec![], alloc_ids: vec![], spans: vec![], types: vec![] },
+        Tables {
+            tcx,
+            def_ids: rustc_internal::IndexMap { index_map: fx::FxIndexMap::default() },
+            alloc_ids: rustc_internal::IndexMap { index_map: fx::FxIndexMap::default() },
+            spans: rustc_internal::IndexMap { index_map: fx::FxIndexMap::default() },
+            types: vec![],
+        },
         f,
     );
 }
@@ -197,3 +185,29 @@ where
         })
     }
 }
+
+/// Simmilar to rustc's `FxIndexMap`, `IndexMap` with extra
+/// safety features added.
+pub struct IndexMap<K, V> {
+    index_map: fx::FxIndexMap<K, V>,
+}
+
+impl<K: PartialEq + Hash + Eq, V: Copy + Debug + PartialEq + IndexedVal> IndexMap<K, V> {
+    pub fn create_or_fetch(&mut self, key: K) -> V {
+        let len = self.index_map.len();
+        let v = self.index_map.entry(key).or_insert(V::to_val(len));
+        *v
+    }
+}
+
+impl<K: PartialEq + Hash + Eq, V: Copy + Debug + PartialEq + IndexedVal> Index<V>
+    for IndexMap<K, V>
+{
+    type Output = K;
+
+    fn index(&self, index: V) -> &Self::Output {
+        let (k, v) = self.index_map.get_index(index.to_index()).unwrap();
+        assert_eq!(*v, index, "Provided value doesn't match with indexed value");
+        k
+    }
+}
diff --git a/compiler/rustc_smir/src/rustc_smir/mod.rs b/compiler/rustc_smir/src/rustc_smir/mod.rs
index 0c474192240..2a265fc1f5b 100644
--- a/compiler/rustc_smir/src/rustc_smir/mod.rs
+++ b/compiler/rustc_smir/src/rustc_smir/mod.rs
@@ -7,6 +7,7 @@
 //!
 //! For now, we are developing everything inside `rustc`, thus, we keep this module private.
 
+use crate::rustc_internal::IndexMap;
 use crate::rustc_smir::hir::def::DefKind;
 use crate::rustc_smir::stable_mir::ty::{BoundRegion, EarlyBoundRegion, Region};
 use rustc_hir as hir;
@@ -201,9 +202,9 @@ impl<S, R: PartialEq> PartialEq<R> for MaybeStable<S, R> {
 
 pub struct Tables<'tcx> {
     pub tcx: TyCtxt<'tcx>,
-    pub def_ids: Vec<DefId>,
-    pub alloc_ids: Vec<AllocId>,
-    pub spans: Vec<rustc_span::Span>,
+    pub def_ids: IndexMap<DefId, stable_mir::DefId>,
+    pub alloc_ids: IndexMap<AllocId, stable_mir::AllocId>,
+    pub spans: IndexMap<rustc_span::Span, Span>,
     pub types: Vec<MaybeStable<stable_mir::ty::TyKind, Ty<'tcx>>>,
 }
 
diff --git a/compiler/stable_mir/src/lib.rs b/compiler/stable_mir/src/lib.rs
index 79f598b6faa..f371f46204f 100644
--- a/compiler/stable_mir/src/lib.rs
+++ b/compiler/stable_mir/src/lib.rs
@@ -22,7 +22,8 @@ use std::fmt;
 use std::fmt::Debug;
 
 use self::ty::{
-    GenericPredicates, Generics, ImplDef, ImplTrait, Span, TraitDecl, TraitDef, Ty, TyKind,
+    GenericPredicates, Generics, ImplDef, ImplTrait, IndexedVal, Span, TraitDecl, TraitDef, Ty,
+    TyKind,
 };
 
 #[macro_use]
@@ -41,7 +42,7 @@ pub type CrateNum = usize;
 
 /// A unique identification number for each item accessible for the current compilation unit.
 #[derive(Clone, Copy, PartialEq, Eq)]
-pub struct DefId(pub usize);
+pub struct DefId(usize);
 
 impl Debug for DefId {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
@@ -52,9 +53,28 @@ impl Debug for DefId {
     }
 }
 
+impl IndexedVal for DefId {
+    fn to_val(index: usize) -> Self {
+        DefId(index)
+    }
+
+    fn to_index(&self) -> usize {
+        self.0
+    }
+}
+
 /// A unique identification number for each provenance
 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
-pub struct AllocId(pub usize);
+pub struct AllocId(usize);
+
+impl IndexedVal for AllocId {
+    fn to_val(index: usize) -> Self {
+        AllocId(index)
+    }
+    fn to_index(&self) -> usize {
+        self.0
+    }
+}
 
 /// A list of crate items.
 pub type CrateItems = Vec<CrateItem>;
diff --git a/compiler/stable_mir/src/ty.rs b/compiler/stable_mir/src/ty.rs
index 6029e3c11ad..691af15da8c 100644
--- a/compiler/stable_mir/src/ty.rs
+++ b/compiler/stable_mir/src/ty.rs
@@ -75,7 +75,7 @@ pub struct Placeholder<T> {
 }
 
 #[derive(Clone, Copy, PartialEq, Eq)]
-pub struct Span(pub usize);
+pub struct Span(usize);
 
 impl Debug for Span {
     fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
@@ -86,6 +86,15 @@ impl Debug for Span {
     }
 }
 
+impl IndexedVal for Span {
+    fn to_val(index: usize) -> Self {
+        Span(index)
+    }
+    fn to_index(&self) -> usize {
+        self.0
+    }
+}
+
 #[derive(Clone, Debug)]
 pub enum TyKind {
     RigidTy(RigidTy),
@@ -565,3 +574,9 @@ pub enum ImplPolarity {
     Negative,
     Reservation,
 }
+
+pub trait IndexedVal {
+    fn to_val(index: usize) -> Self;
+
+    fn to_index(&self) -> usize;
+}