From 6fd0e50ecf25e3d1ef6185a3b85dfec24e9e8cb2 Mon Sep 17 00:00:00 2001
From: lcnr <rust@lcnr.de>
Date: Fri, 29 Aug 2025 10:42:44 +0200
Subject: [PATCH] autoderef final ty is already resolved

---
 compiler/rustc_hir_analysis/src/autoderef.rs  | 12 ++++--------
 compiler/rustc_hir_typeck/src/autoderef.rs    |  2 +-
 compiler/rustc_hir_typeck/src/callee.rs       |  5 ++---
 compiler/rustc_hir_typeck/src/expr.rs         |  2 +-
 compiler/rustc_hir_typeck/src/method/probe.rs |  2 +-
 compiler/rustc_hir_typeck/src/place_op.rs     |  3 +--
 6 files changed, 10 insertions(+), 16 deletions(-)

diff --git a/compiler/rustc_hir_analysis/src/autoderef.rs b/compiler/rustc_hir_analysis/src/autoderef.rs
index c88c534e13548..e27e68d36624e 100644
--- a/compiler/rustc_hir_analysis/src/autoderef.rs
+++ b/compiler/rustc_hir_analysis/src/autoderef.rs
@@ -202,14 +202,10 @@ impl<'a, 'tcx> Autoderef<'a, 'tcx> {
         Some((normalized_ty, ocx.into_pending_obligations()))
     }
 
-    /// Returns the final type we ended up with, which may be an inference
-    /// variable (we will resolve it first, if we want).
-    pub fn final_ty(&self, resolve: bool) -> Ty<'tcx> {
-        if resolve {
-            self.infcx.resolve_vars_if_possible(self.state.cur_ty)
-        } else {
-            self.state.cur_ty
-        }
+    /// Returns the final type we ended up with, which may be an unresolved
+    /// inference variable.
+    pub fn final_ty(&self) -> Ty<'tcx> {
+        self.state.cur_ty
     }
 
     pub fn step_count(&self) -> usize {
diff --git a/compiler/rustc_hir_typeck/src/autoderef.rs b/compiler/rustc_hir_typeck/src/autoderef.rs
index 7af26623ce764..4fe77278706ec 100644
--- a/compiler/rustc_hir_typeck/src/autoderef.rs
+++ b/compiler/rustc_hir_typeck/src/autoderef.rs
@@ -42,7 +42,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         let mut obligations = PredicateObligations::new();
         let targets =
-            steps.iter().skip(1).map(|&(ty, _)| ty).chain(iter::once(autoderef.final_ty(false)));
+            steps.iter().skip(1).map(|&(ty, _)| ty).chain(iter::once(autoderef.final_ty()));
         let steps: Vec<_> = steps
             .iter()
             .map(|&(source, kind)| {
diff --git a/compiler/rustc_hir_typeck/src/callee.rs b/compiler/rustc_hir_typeck/src/callee.rs
index 4200afb74e634..c6a4d78dcc830 100644
--- a/compiler/rustc_hir_typeck/src/callee.rs
+++ b/compiler/rustc_hir_typeck/src/callee.rs
@@ -86,7 +86,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             result = self.try_overloaded_call_step(call_expr, callee_expr, arg_exprs, &autoderef);
         }
 
-        match autoderef.final_ty(false).kind() {
+        match autoderef.final_ty().kind() {
             ty::FnDef(def_id, _) => {
                 let abi = self.tcx.fn_sig(def_id).skip_binder().skip_binder().abi;
                 self.check_call_abi(abi, call_expr.span);
@@ -200,8 +200,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         arg_exprs: &'tcx [hir::Expr<'tcx>],
         autoderef: &Autoderef<'a, 'tcx>,
     ) -> Option<CallStep<'tcx>> {
-        let adjusted_ty =
-            self.structurally_resolve_type(autoderef.span(), autoderef.final_ty(false));
+        let adjusted_ty = self.structurally_resolve_type(autoderef.span(), autoderef.final_ty());
 
         // If the callee is a function pointer or a closure, then we're all set.
         match *adjusted_ty.kind() {
diff --git a/compiler/rustc_hir_typeck/src/expr.rs b/compiler/rustc_hir_typeck/src/expr.rs
index 940f0e3708d0a..a652e08905a55 100644
--- a/compiler/rustc_hir_typeck/src/expr.rs
+++ b/compiler/rustc_hir_typeck/src/expr.rs
@@ -2918,7 +2918,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // Emits an error if we deref an infer variable, like calling `.field` on a base type
         // of `&_`. We can also use this to suppress unnecessary "missing field" errors that
         // will follow ambiguity errors.
-        let final_ty = self.structurally_resolve_type(autoderef.span(), autoderef.final_ty(false));
+        let final_ty = self.structurally_resolve_type(autoderef.span(), autoderef.final_ty());
         if let ty::Error(_) = final_ty.kind() {
             return final_ty;
         }
diff --git a/compiler/rustc_hir_typeck/src/method/probe.rs b/compiler/rustc_hir_typeck/src/method/probe.rs
index bb4748b05651b..ab584eb7c909e 100644
--- a/compiler/rustc_hir_typeck/src/method/probe.rs
+++ b/compiler/rustc_hir_typeck/src/method/probe.rs
@@ -629,7 +629,7 @@ pub(crate) fn method_autoderef_steps<'tcx>(
             .collect();
         (steps, autoderef_via_deref.reached_recursion_limit())
     };
-    let final_ty = autoderef_via_deref.final_ty(true);
+    let final_ty = autoderef_via_deref.final_ty();
     let opt_bad_ty = match final_ty.kind() {
         ty::Infer(ty::TyVar(_)) | ty::Error(_) => Some(MethodAutoderefBadTy {
             reached_raw_pointer,
diff --git a/compiler/rustc_hir_typeck/src/place_op.rs b/compiler/rustc_hir_typeck/src/place_op.rs
index fedc75abe4927..1125e98408045 100644
--- a/compiler/rustc_hir_typeck/src/place_op.rs
+++ b/compiler/rustc_hir_typeck/src/place_op.rs
@@ -109,8 +109,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         index_ty: Ty<'tcx>,
         index_expr: &hir::Expr<'_>,
     ) -> Option<(/*index type*/ Ty<'tcx>, /*element type*/ Ty<'tcx>)> {
-        let adjusted_ty =
-            self.structurally_resolve_type(autoderef.span(), autoderef.final_ty(false));
+        let adjusted_ty = self.structurally_resolve_type(autoderef.span(), autoderef.final_ty());
         debug!(
             "try_index_step(expr={:?}, base_expr={:?}, adjusted_ty={:?}, \
              index_ty={:?})",