Move some utils out of `rustc_const_eval`

This allows us to get rid of the `rustc_const_eval->rustc_borrowck`
dependency edge which was delaying the compilation of borrowck.

The added utils in `rustc_middle` are small and should not affect
compile times there.

5 files changed, 1 insertions, 215 deletions

diff --git a/compiler/rustc_const_eval/src/transform/check_consts/ops.rs b/compiler/rustc_const_eval/src/transform/check_consts/ops.rs
index c0f5b3725b3..4fe842856aa 100644
--- a/compiler/rustc_const_eval/src/transform/check_consts/ops.rs
+++ b/compiler/rustc_const_eval/src/transform/check_consts/ops.rs
@@ -14,6 +14,7 @@ use rustc_middle::ty::print::with_no_trimmed_paths;
 use rustc_middle::ty::subst::{GenericArgKind, SubstsRef};
 use rustc_middle::ty::{suggest_constraining_type_param, Adt, Closure, FnDef, FnPtr, Param, Ty};
 use rustc_middle::ty::{Binder, TraitRef};
+use rustc_middle::util::{call_kind, CallDesugaringKind, CallKind};
 use rustc_session::parse::feature_err;
 use rustc_span::symbol::sym;
 use rustc_span::{BytePos, Pos, Span, Symbol};
@@ -21,7 +22,6 @@ use rustc_trait_selection::traits::SelectionContext;
 
 use super::ConstCx;
 use crate::errors;
-use crate::util::{call_kind, CallDesugaringKind, CallKind};
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum Status {
diff --git a/compiler/rustc_const_eval/src/util/call_kind.rs b/compiler/rustc_const_eval/src/util/call_kind.rs
deleted file mode 100644
index 995363c0edd..00000000000
--- a/compiler/rustc_const_eval/src/util/call_kind.rs
+++ /dev/null
@@ -1,137 +0,0 @@
-//! Common logic for borrowck use-after-move errors when moved into a `fn(self)`,
-//! as well as errors when attempting to call a non-const function in a const
-//! context.
-
-use rustc_hir::def_id::DefId;
-use rustc_hir::{lang_items, LangItem};
-use rustc_middle::ty::subst::SubstsRef;
-use rustc_middle::ty::{AssocItemContainer, Instance, ParamEnv, Ty, TyCtxt};
-use rustc_span::symbol::Ident;
-use rustc_span::{sym, DesugaringKind, Span};
-
-#[derive(Clone, Copy, PartialEq, Eq, Debug)]
-pub enum CallDesugaringKind {
-    /// for _ in x {} calls x.into_iter()
-    ForLoopIntoIter,
-    /// x? calls x.branch()
-    QuestionBranch,
-    /// x? calls type_of(x)::from_residual()
-    QuestionFromResidual,
-    /// try { ..; x } calls type_of(x)::from_output(x)
-    TryBlockFromOutput,
-}
-
-impl CallDesugaringKind {
-    pub fn trait_def_id(self, tcx: TyCtxt<'_>) -> DefId {
-        match self {
-            Self::ForLoopIntoIter => tcx.get_diagnostic_item(sym::IntoIterator).unwrap(),
-            Self::QuestionBranch | Self::TryBlockFromOutput => {
-                tcx.require_lang_item(LangItem::Try, None)
-            }
-            Self::QuestionFromResidual => tcx.get_diagnostic_item(sym::FromResidual).unwrap(),
-        }
-    }
-}
-
-#[derive(Clone, Copy, PartialEq, Eq, Debug)]
-pub enum CallKind<'tcx> {
-    /// A normal method call of the form `receiver.foo(a, b, c)`
-    Normal {
-        self_arg: Option<Ident>,
-        desugaring: Option<(CallDesugaringKind, Ty<'tcx>)>,
-        method_did: DefId,
-        method_substs: SubstsRef<'tcx>,
-    },
-    /// A call to `Fn(..)::call(..)`, desugared from `my_closure(a, b, c)`
-    FnCall { fn_trait_id: DefId, self_ty: Ty<'tcx> },
-    /// A call to an operator trait, desugared from operator syntax (e.g. `a << b`)
-    Operator { self_arg: Option<Ident>, trait_id: DefId, self_ty: Ty<'tcx> },
-    DerefCoercion {
-        /// The `Span` of the `Target` associated type
-        /// in the `Deref` impl we are using.
-        deref_target: Span,
-        /// The type `T::Deref` we are dereferencing to
-        deref_target_ty: Ty<'tcx>,
-        self_ty: Ty<'tcx>,
-    },
-}
-
-pub fn call_kind<'tcx>(
-    tcx: TyCtxt<'tcx>,
-    param_env: ParamEnv<'tcx>,
-    method_did: DefId,
-    method_substs: SubstsRef<'tcx>,
-    fn_call_span: Span,
-    from_hir_call: bool,
-    self_arg: Option<Ident>,
-) -> CallKind<'tcx> {
-    let parent = tcx.opt_associated_item(method_did).and_then(|assoc| {
-        let container_id = assoc.container_id(tcx);
-        match assoc.container {
-            AssocItemContainer::ImplContainer => tcx.trait_id_of_impl(container_id),
-            AssocItemContainer::TraitContainer => Some(container_id),
-        }
-    });
-
-    let fn_call = parent.and_then(|p| {
-        lang_items::FN_TRAITS.iter().filter_map(|&l| tcx.lang_items().get(l)).find(|&id| id == p)
-    });
-
-    let operator = if !from_hir_call && let Some(p) = parent {
-        lang_items::OPERATORS.iter().filter_map(|&l| tcx.lang_items().get(l)).find(|&id| id == p)
-    } else {
-        None
-    };
-
-    let is_deref = !from_hir_call && tcx.is_diagnostic_item(sym::deref_method, method_did);
-
-    // Check for a 'special' use of 'self' -
-    // an FnOnce call, an operator (e.g. `<<`), or a
-    // deref coercion.
-    let kind = if let Some(trait_id) = fn_call {
-        Some(CallKind::FnCall { fn_trait_id: trait_id, self_ty: method_substs.type_at(0) })
-    } else if let Some(trait_id) = operator {
-        Some(CallKind::Operator { self_arg, trait_id, self_ty: method_substs.type_at(0) })
-    } else if is_deref {
-        let deref_target = tcx.get_diagnostic_item(sym::deref_target).and_then(|deref_target| {
-            Instance::resolve(tcx, param_env, deref_target, method_substs).transpose()
-        });
-        if let Some(Ok(instance)) = deref_target {
-            let deref_target_ty = instance.ty(tcx, param_env);
-            Some(CallKind::DerefCoercion {
-                deref_target: tcx.def_span(instance.def_id()),
-                deref_target_ty,
-                self_ty: method_substs.type_at(0),
-            })
-        } else {
-            None
-        }
-    } else {
-        None
-    };
-
-    kind.unwrap_or_else(|| {
-        // This isn't a 'special' use of `self`
-        debug!(?method_did, ?fn_call_span);
-        let desugaring = if Some(method_did) == tcx.lang_items().into_iter_fn()
-            && fn_call_span.desugaring_kind() == Some(DesugaringKind::ForLoop)
-        {
-            Some((CallDesugaringKind::ForLoopIntoIter, method_substs.type_at(0)))
-        } else if fn_call_span.desugaring_kind() == Some(DesugaringKind::QuestionMark) {
-            if Some(method_did) == tcx.lang_items().branch_fn() {
-                Some((CallDesugaringKind::QuestionBranch, method_substs.type_at(0)))
-            } else if Some(method_did) == tcx.lang_items().from_residual_fn() {
-                Some((CallDesugaringKind::QuestionFromResidual, method_substs.type_at(0)))
-            } else {
-                None
-            }
-        } else if Some(method_did) == tcx.lang_items().from_output_fn()
-            && fn_call_span.desugaring_kind() == Some(DesugaringKind::TryBlock)
-        {
-            Some((CallDesugaringKind::TryBlockFromOutput, method_substs.type_at(0)))
-        } else {
-            None
-        };
-        CallKind::Normal { self_arg, desugaring, method_did, method_substs }
-    })
-}
diff --git a/compiler/rustc_const_eval/src/util/collect_writes.rs b/compiler/rustc_const_eval/src/util/collect_writes.rs
deleted file mode 100644
index 8d92bb35938..00000000000
--- a/compiler/rustc_const_eval/src/util/collect_writes.rs
+++ /dev/null
@@ -1,36 +0,0 @@
-use rustc_middle::mir::visit::PlaceContext;
-use rustc_middle::mir::visit::Visitor;
-use rustc_middle::mir::{Body, Local, Location};
-
-pub trait FindAssignments {
-    // Finds all statements that assign directly to local (i.e., X = ...)
-    // and returns their locations.
-    fn find_assignments(&self, local: Local) -> Vec<Location>;
-}
-
-impl<'tcx> FindAssignments for Body<'tcx> {
-    fn find_assignments(&self, local: Local) -> Vec<Location> {
-        let mut visitor = FindLocalAssignmentVisitor { needle: local, locations: vec![] };
-        visitor.visit_body(self);
-        visitor.locations
-    }
-}
-
-// The Visitor walks the MIR to return the assignment statements corresponding
-// to a Local.
-struct FindLocalAssignmentVisitor {
-    needle: Local,
-    locations: Vec<Location>,
-}
-
-impl<'tcx> Visitor<'tcx> for FindLocalAssignmentVisitor {
-    fn visit_local(&mut self, local: Local, place_context: PlaceContext, location: Location) {
-        if self.needle != local {
-            return;
-        }
-
-        if place_context.is_place_assignment() {
-            self.locations.push(location);
-        }
-    }
-}
diff --git a/compiler/rustc_const_eval/src/util/find_self_call.rs b/compiler/rustc_const_eval/src/util/find_self_call.rs
deleted file mode 100644
index 33ad128eeeb..00000000000
--- a/compiler/rustc_const_eval/src/util/find_self_call.rs
+++ /dev/null
@@ -1,36 +0,0 @@
-use rustc_middle::mir::*;
-use rustc_middle::ty::subst::SubstsRef;
-use rustc_middle::ty::{self, TyCtxt};
-use rustc_span::def_id::DefId;
-
-/// Checks if the specified `local` is used as the `self` parameter of a method call
-/// in the provided `BasicBlock`. If it is, then the `DefId` of the called method is
-/// returned.
-pub fn find_self_call<'tcx>(
-    tcx: TyCtxt<'tcx>,
-    body: &Body<'tcx>,
-    local: Local,
-    block: BasicBlock,
-) -> Option<(DefId, SubstsRef<'tcx>)> {
-    debug!("find_self_call(local={:?}): terminator={:?}", local, &body[block].terminator);
-    if let Some(Terminator { kind: TerminatorKind::Call { func, args, .. }, .. }) =
-        &body[block].terminator
-    {
-        debug!("find_self_call: func={:?}", func);
-        if let Operand::Constant(box Constant { literal, .. }) = func {
-            if let ty::FnDef(def_id, substs) = *literal.ty().kind() {
-                if let Some(ty::AssocItem { fn_has_self_parameter: true, .. }) =
-                    tcx.opt_associated_item(def_id)
-                {
-                    debug!("find_self_call: args={:?}", args);
-                    if let [Operand::Move(self_place) | Operand::Copy(self_place), ..] = **args {
-                        if self_place.as_local() == Some(local) {
-                            return Some((def_id, substs));
-                        }
-                    }
-                }
-            }
-        }
-    }
-    None
-}
diff --git a/compiler/rustc_const_eval/src/util/mod.rs b/compiler/rustc_const_eval/src/util/mod.rs
index c0aabd77cee..7641f560714 100644
--- a/compiler/rustc_const_eval/src/util/mod.rs
+++ b/compiler/rustc_const_eval/src/util/mod.rs
@@ -1,14 +1,9 @@
 mod alignment;
-mod call_kind;
 mod check_validity_requirement;
-pub mod collect_writes;
 mod compare_types;
-mod find_self_call;
 mod type_name;
 
 pub use self::alignment::is_disaligned;
-pub use self::call_kind::{call_kind, CallDesugaringKind, CallKind};
 pub use self::check_validity_requirement::check_validity_requirement;
 pub use self::compare_types::{is_equal_up_to_subtyping, is_subtype};
-pub use self::find_self_call::find_self_call;
 pub use self::type_name::type_name;