New upstream version 1.69.0+dfsg1

[rustc.git] / compiler / rustc_infer / src / infer / freshen.rs

diff --git a/compiler/rustc_infer/src/infer/freshen.rs b/compiler/rustc_infer/src/infer/freshen.rs
index 8f53b1ccdf45829c758721072cf55d1063f730ff..f09f93abf45d6f7488ef241cb923a51ebbbbd5c7 100644 (file)
--- a/compiler/rustc_infer/src/infer/freshen.rs
+++ b/compiler/rustc_infer/src/infer/freshen.rs
@@ -34,7 +34,7 @@ use super::InferCtxt;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_middle::infer::unify_key::ToType;
 use rustc_middle::ty::fold::TypeFolder;
-use rustc_middle::ty::{self, Ty, TyCtxt, TypeFoldable, TypeSuperFoldable, TypeVisitable};
+use rustc_middle::ty::{self, Ty, TyCtxt, TypeFoldable, TypeSuperFoldable, TypeVisitableExt};
 use std::collections::hash_map::Entry;
 
 pub struct TypeFreshener<'a, 'tcx> {
@@ -58,14 +58,9 @@ impl<'a, 'tcx> TypeFreshener<'a, 'tcx> {
         }
     }
 
-    fn freshen_ty<F>(
-        &mut self,
-        opt_ty: Option<Ty<'tcx>>,
-        key: ty::InferTy,
-        freshener: F,
-    ) -> Ty<'tcx>
+    fn freshen_ty<F>(&mut self, opt_ty: Option<Ty<'tcx>>, key: ty::InferTy, mk_fresh: F) -> Ty<'tcx>
     where
-        F: FnOnce(u32) -> ty::InferTy,
+        F: FnOnce(u32) -> Ty<'tcx>,
     {
         if let Some(ty) = opt_ty {
             return ty.fold_with(self);
@@ -76,7 +71,7 @@ impl<'a, 'tcx> TypeFreshener<'a, 'tcx> {
             Entry::Vacant(entry) => {
                 let index = self.ty_freshen_count;
                 self.ty_freshen_count += 1;
-                let t = self.infcx.tcx.mk_ty_infer(freshener(index));
+                let t = mk_fresh(index);
                 entry.insert(t);
                 t
             }
@@ -110,8 +105,8 @@ impl<'a, 'tcx> TypeFreshener<'a, 'tcx> {
     }
 }
 
-impl<'a, 'tcx> TypeFolder<'tcx> for TypeFreshener<'a, 'tcx> {
-    fn tcx<'b>(&'b self) -> TyCtxt<'tcx> {
+impl<'a, 'tcx> TypeFolder<TyCtxt<'tcx>> for TypeFreshener<'a, 'tcx> {
+    fn interner(&self) -> TyCtxt<'tcx> {
         self.infcx.tcx
     }
 
@@ -126,92 +121,36 @@ impl<'a, 'tcx> TypeFolder<'tcx> for TypeFreshener<'a, 'tcx> {
             | ty::ReFree(_)
             | ty::ReVar(_)
             | ty::RePlaceholder(..)
+            | ty::ReError(_)
             | ty::ReErased => {
                 // replace all free regions with 'erased
-                self.tcx().lifetimes.re_erased
+                self.interner().lifetimes.re_erased
             }
             ty::ReStatic => {
                 if self.keep_static {
                     r
                 } else {
-                    self.tcx().lifetimes.re_erased
+                    self.interner().lifetimes.re_erased
                 }
             }
         }
     }
 
+    #[inline]
     fn fold_ty(&mut self, t: Ty<'tcx>) -> Ty<'tcx> {
         if !t.needs_infer() && !t.has_erasable_regions() {
-            return t;
-        }
+            t
+        } else {
+            match *t.kind() {
+                ty::Infer(v) => self.fold_infer_ty(v).unwrap_or(t),
 
-        let tcx = self.infcx.tcx;
+                // This code is hot enough that a non-debug assertion here makes a noticeable
+                // difference on benchmarks like `wg-grammar`.
+                #[cfg(debug_assertions)]
+                ty::Placeholder(..) | ty::Bound(..) => bug!("unexpected type {:?}", t),
 
-        match *t.kind() {
-            ty::Infer(ty::TyVar(v)) => {
-                let opt_ty = self.infcx.inner.borrow_mut().type_variables().probe(v).known();
-                self.freshen_ty(opt_ty, ty::TyVar(v), ty::FreshTy)
+                _ => t.super_fold_with(self),
             }
-
-            ty::Infer(ty::IntVar(v)) => self.freshen_ty(
-                self.infcx
-                    .inner
-                    .borrow_mut()
-                    .int_unification_table()
-                    .probe_value(v)
-                    .map(|v| v.to_type(tcx)),
-                ty::IntVar(v),
-                ty::FreshIntTy,
-            ),
-
-            ty::Infer(ty::FloatVar(v)) => self.freshen_ty(
-                self.infcx
-                    .inner
-                    .borrow_mut()
-                    .float_unification_table()
-                    .probe_value(v)
-                    .map(|v| v.to_type(tcx)),
-                ty::FloatVar(v),
-                ty::FreshFloatTy,
-            ),
-
-            ty::Infer(ty::FreshTy(ct) | ty::FreshIntTy(ct) | ty::FreshFloatTy(ct)) => {
-                if ct >= self.ty_freshen_count {
-                    bug!(
-                        "Encountered a freshend type with id {} \
-                          but our counter is only at {}",
-                        ct,
-                        self.ty_freshen_count
-                    );
-                }
-                t
-            }
-
-            ty::Generator(..)
-            | ty::Bool
-            | ty::Char
-            | ty::Int(..)
-            | ty::Uint(..)
-            | ty::Float(..)
-            | ty::Adt(..)
-            | ty::Str
-            | ty::Error(_)
-            | ty::Array(..)
-            | ty::Slice(..)
-            | ty::RawPtr(..)
-            | ty::Ref(..)
-            | ty::FnDef(..)
-            | ty::FnPtr(_)
-            | ty::Dynamic(..)
-            | ty::Never
-            | ty::Tuple(..)
-            | ty::Alias(..)
-            | ty::Foreign(..)
-            | ty::Param(..)
-            | ty::Closure(..)
-            | ty::GeneratorWitness(..) => t.super_fold_with(self),
-
-            ty::Placeholder(..) | ty::Bound(..) => bug!("unexpected type {:?}", t),
         }
     }
 
@@ -252,3 +191,54 @@ impl<'a, 'tcx> TypeFolder<'tcx> for TypeFreshener<'a, 'tcx> {
         }
     }
 }
+
+impl<'a, 'tcx> TypeFreshener<'a, 'tcx> {
+    // This is separate from `fold_ty` to keep that method small and inlinable.
+    #[inline(never)]
+    fn fold_infer_ty(&mut self, v: ty::InferTy) -> Option<Ty<'tcx>> {
+        match v {
+            ty::TyVar(v) => {
+                let opt_ty = self.infcx.inner.borrow_mut().type_variables().probe(v).known();
+                Some(self.freshen_ty(opt_ty, ty::TyVar(v), |n| self.infcx.tcx.mk_fresh_ty(n)))
+            }
+
+            ty::IntVar(v) => Some(
+                self.freshen_ty(
+                    self.infcx
+                        .inner
+                        .borrow_mut()
+                        .int_unification_table()
+                        .probe_value(v)
+                        .map(|v| v.to_type(self.infcx.tcx)),
+                    ty::IntVar(v),
+                    |n| self.infcx.tcx.mk_fresh_int_ty(n),
+                ),
+            ),
+
+            ty::FloatVar(v) => Some(
+                self.freshen_ty(
+                    self.infcx
+                        .inner
+                        .borrow_mut()
+                        .float_unification_table()
+                        .probe_value(v)
+                        .map(|v| v.to_type(self.infcx.tcx)),
+                    ty::FloatVar(v),
+                    |n| self.infcx.tcx.mk_fresh_float_ty(n),
+                ),
+            ),
+
+            ty::FreshTy(ct) | ty::FreshIntTy(ct) | ty::FreshFloatTy(ct) => {
+                if ct >= self.ty_freshen_count {
+                    bug!(
+                        "Encountered a freshend type with id {} \
+                          but our counter is only at {}",
+                        ct,
+                        self.ty_freshen_count
+                    );
+                }
+                None
+            }
+        }
+    }
+}