From 569ca2bad04dec9c6b7bc4864bd0216e3bea9c5e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Le=C3=B3n=20Orell=20Valerian=20Liehr?= <me@fmease.dev>
Date: Sun, 19 Feb 2023 17:21:29 +0100
Subject: [PATCH] Deduplicate fresh_item_substs

---
 .../rustc_hir_analysis/src/astconv/mod.rs     | 65 ++++++++++---------
 compiler/rustc_hir_typeck/src/method/probe.rs | 30 +--------
 2 files changed, 35 insertions(+), 60 deletions(-)

diff --git a/compiler/rustc_hir_analysis/src/astconv/mod.rs b/compiler/rustc_hir_analysis/src/astconv/mod.rs
index f43b92254eb..4098de59f9e 100644
--- a/compiler/rustc_hir_analysis/src/astconv/mod.rs
+++ b/compiler/rustc_hir_analysis/src/astconv/mod.rs
@@ -2239,7 +2239,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                     let ocx = ObligationCtxt::new_in_snapshot(&infcx);
 
                     let impl_ty = tcx.type_of(impl_);
-                    let impl_substs = self.fresh_item_substs(impl_, &infcx);
+                    let impl_substs = infcx.fresh_item_substs(impl_);
                     let impl_ty = impl_ty.subst(tcx, impl_substs);
                     let impl_ty = ocx.normalize(&cause, param_env, impl_ty);
 
@@ -2306,36 +2306,6 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         ))
     }
 
-    // FIXME(fmease): Copied from `rustc_hir_typeck::method::probe`. Deduplicate.
-    fn fresh_item_substs(&self, def_id: DefId, infcx: &InferCtxt<'tcx>) -> SubstsRef<'tcx> {
-        let tcx = self.tcx();
-
-        InternalSubsts::for_item(tcx, def_id, |param, _| match param.kind {
-            GenericParamDefKind::Lifetime => tcx.lifetimes.re_erased.into(),
-            GenericParamDefKind::Type { .. } => infcx
-                .next_ty_var(TypeVariableOrigin {
-                    kind: TypeVariableOriginKind::SubstitutionPlaceholder,
-                    span: tcx.def_span(def_id),
-                })
-                .into(),
-            GenericParamDefKind::Const { .. } => {
-                let span = tcx.def_span(def_id);
-                let origin = ConstVariableOrigin {
-                    kind: ConstVariableOriginKind::SubstitutionPlaceholder,
-                    span,
-                };
-                infcx
-                    .next_const_var(
-                        tcx.type_of(param.def_id)
-                            .no_bound_vars()
-                            .expect("const parameter types cannot be generic"),
-                        origin,
-                    )
-                    .into()
-            }
-        })
-    }
-
     fn lookup_assoc_ty(
         &self,
         name: Ident,
@@ -3531,3 +3501,36 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         }
     }
 }
+
+pub trait InferCtxtExt<'tcx> {
+    fn fresh_item_substs(&self, def_id: DefId) -> SubstsRef<'tcx>;
+}
+
+impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> {
+    fn fresh_item_substs(&self, def_id: DefId) -> SubstsRef<'tcx> {
+        InternalSubsts::for_item(self.tcx, def_id, |param, _| match param.kind {
+            GenericParamDefKind::Lifetime => self.tcx.lifetimes.re_erased.into(),
+            GenericParamDefKind::Type { .. } => self
+                .next_ty_var(TypeVariableOrigin {
+                    kind: TypeVariableOriginKind::SubstitutionPlaceholder,
+                    span: self.tcx.def_span(def_id),
+                })
+                .into(),
+            GenericParamDefKind::Const { .. } => {
+                let span = self.tcx.def_span(def_id);
+                let origin = ConstVariableOrigin {
+                    kind: ConstVariableOriginKind::SubstitutionPlaceholder,
+                    span,
+                };
+                self.next_const_var(
+                    self.tcx
+                        .type_of(param.def_id)
+                        .no_bound_vars()
+                        .expect("const parameter types cannot be generic"),
+                    origin,
+                )
+                .into()
+            }
+        })
+    }
+}
diff --git a/compiler/rustc_hir_typeck/src/method/probe.rs b/compiler/rustc_hir_typeck/src/method/probe.rs
index 0b9226802cf..eb6c0b7686b 100644
--- a/compiler/rustc_hir_typeck/src/method/probe.rs
+++ b/compiler/rustc_hir_typeck/src/method/probe.rs
@@ -9,12 +9,11 @@ use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::Applicability;
 use rustc_hir as hir;
 use rustc_hir::def::DefKind;
+use rustc_hir_analysis::astconv::InferCtxtExt as _;
 use rustc_hir_analysis::autoderef::{self, Autoderef};
 use rustc_infer::infer::canonical::OriginalQueryValues;
 use rustc_infer::infer::canonical::{Canonical, QueryResponse};
-use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
 use rustc_infer::infer::{self, InferOk, TyCtxtInferExt};
-use rustc_middle::infer::unify_key::{ConstVariableOrigin, ConstVariableOriginKind};
 use rustc_middle::middle::stability;
 use rustc_middle::ty::fast_reject::{simplify_type, TreatParams};
 use rustc_middle::ty::AssocItem;
@@ -1941,33 +1940,6 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
         (self.tcx.type_of(impl_def_id), self.fresh_item_substs(impl_def_id))
     }
 
-    fn fresh_item_substs(&self, def_id: DefId) -> SubstsRef<'tcx> {
-        InternalSubsts::for_item(self.tcx, def_id, |param, _| match param.kind {
-            GenericParamDefKind::Lifetime => self.tcx.lifetimes.re_erased.into(),
-            GenericParamDefKind::Type { .. } => self
-                .next_ty_var(TypeVariableOrigin {
-                    kind: TypeVariableOriginKind::SubstitutionPlaceholder,
-                    span: self.tcx.def_span(def_id),
-                })
-                .into(),
-            GenericParamDefKind::Const { .. } => {
-                let span = self.tcx.def_span(def_id);
-                let origin = ConstVariableOrigin {
-                    kind: ConstVariableOriginKind::SubstitutionPlaceholder,
-                    span,
-                };
-                self.next_const_var(
-                    self.tcx
-                        .type_of(param.def_id)
-                        .no_bound_vars()
-                        .expect("const parameter types cannot be generic"),
-                    origin,
-                )
-                .into()
-            }
-        })
-    }
-
     /// Replaces late-bound-regions bound by `value` with `'static` using
     /// `ty::erase_late_bound_regions`.
     ///