From e06d50cf327aed841de4394b7183aa815bb3ed9e Mon Sep 17 00:00:00 2001 From: Michael Goulet Date: Mon, 24 Mar 2025 16:21:31 +0000 Subject: [PATCH] Revert "Rollup merge of #136127 - WaffleLapkin:dyn_ptr_unwrap_cast, r=compiler-errors" This reverts commit 84c2050bf63f734246572345aedca9edb2abe96e, reversing changes made to a96fa317d78c78a9de996afd317603c6970efc0d. --- compiler/rustc_hir_typeck/src/coercion.rs | 68 +-------- .../ui/cast/ptr-to-trait-obj-wrap-add-auto.rs | 36 ----- .../ptr-to-trait-obj-wrap-add-auto.stderr | 48 ------ .../ptr-to-trait-obj-wrap-different-args.rs | 36 ----- ...tr-to-trait-obj-wrap-different-args.stderr | 43 ------ ...ptr-to-trait-obj-wrap-different-regions.rs | 41 ----- ...to-trait-obj-wrap-different-regions.stderr | 140 ------------------ tests/ui/cast/ptr-to-trait-obj-wrap.rs | 32 ---- 8 files changed, 8 insertions(+), 436 deletions(-) delete mode 100644 tests/ui/cast/ptr-to-trait-obj-wrap-add-auto.rs delete mode 100644 tests/ui/cast/ptr-to-trait-obj-wrap-add-auto.stderr delete mode 100644 tests/ui/cast/ptr-to-trait-obj-wrap-different-args.rs delete mode 100644 tests/ui/cast/ptr-to-trait-obj-wrap-different-args.stderr delete mode 100644 tests/ui/cast/ptr-to-trait-obj-wrap-different-regions.rs delete mode 100644 tests/ui/cast/ptr-to-trait-obj-wrap-different-regions.stderr delete mode 100644 tests/ui/cast/ptr-to-trait-obj-wrap.rs diff --git a/compiler/rustc_hir_typeck/src/coercion.rs b/compiler/rustc_hir_typeck/src/coercion.rs index 4cbc42b99ea35..f42ca3af2b35c 100644 --- a/compiler/rustc_hir_typeck/src/coercion.rs +++ b/compiler/rustc_hir_typeck/src/coercion.rs @@ -41,8 +41,8 @@ use rustc_abi::ExternAbi; use rustc_attr_parsing::InlineAttr; use rustc_errors::codes::*; use rustc_errors::{Applicability, Diag, struct_span_code_err}; +use rustc_hir as hir; use rustc_hir::def_id::{DefId, LocalDefId}; -use rustc_hir::{self as hir, LangItem}; use rustc_hir_analysis::hir_ty_lowering::HirTyLowerer; use rustc_infer::infer::relate::RelateResult; use rustc_infer::infer::{Coercion, DefineOpaqueTypes, InferOk, InferResult}; @@ -55,7 +55,7 @@ use rustc_middle::ty::adjustment::{ Adjust, Adjustment, AllowTwoPhase, AutoBorrow, AutoBorrowMutability, PointerCoercion, }; use rustc_middle::ty::error::TypeError; -use rustc_middle::ty::{self, AliasTy, GenericArgsRef, Ty, TyCtxt, TypeVisitableExt}; +use rustc_middle::ty::{self, GenericArgsRef, Ty, TyCtxt, TypeVisitableExt}; use rustc_span::{BytePos, DUMMY_SP, DesugaringKind, Span}; use rustc_trait_selection::infer::InferCtxtExt as _; use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt; @@ -592,63 +592,6 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> { // Create an obligation for `Source: CoerceUnsized`. let cause = self.cause(self.cause.span, ObligationCauseCode::Coercion { source, target }); - let root_obligation = Obligation::new( - self.tcx, - cause.clone(), - self.fcx.param_env, - ty::TraitRef::new(self.tcx, coerce_unsized_did, [coerce_source, coerce_target]), - ); - - // If the root `Source: CoerceUnsized` obligation can't possibly hold, - // we don't have to assume that this is unsizing coercion (it will always lead to an error) - // - // However, we don't want to bail early all the time, since the unholdable obligations - // may be interesting for diagnostics (such as trying to coerce `&T` to `&dyn Id`), - // so we only bail if there (likely) is another way to convert the types. - if !self.infcx.predicate_may_hold(&root_obligation) { - if let Some(dyn_metadata_adt_def_id) = self.tcx.lang_items().get(LangItem::DynMetadata) - && let Some(metadata_type_def_id) = self.tcx.lang_items().get(LangItem::Metadata) - { - self.probe(|_| { - let ocx = ObligationCtxt::new(&self.infcx); - - // returns `true` if `::Metadata` is `DynMetadata<_>` - let has_dyn_trait_metadata = |ty| { - let metadata_ty: Result<_, _> = ocx.structurally_normalize_ty( - &ObligationCause::dummy(), - self.fcx.param_env, - Ty::new_alias( - self.tcx, - ty::AliasTyKind::Projection, - AliasTy::new(self.tcx, metadata_type_def_id, [ty]), - ), - ); - - metadata_ty.is_ok_and(|metadata_ty| { - metadata_ty - .ty_adt_def() - .is_some_and(|d| d.did() == dyn_metadata_adt_def_id) - }) - }; - - // If both types are raw pointers to a (wrapper over a) trait object, - // this might be a cast like `*const W -> *const dyn Trait`. - // So it's better to bail and try that. (even if the cast is not possible, for - // example due to vtables not matching, cast diagnostic will likely still be better) - // - // N.B. use `target`, not `coerce_target` (the latter is a var) - if let &ty::RawPtr(source_pointee, _) = coerce_source.kind() - && let &ty::RawPtr(target_pointee, _) = target.kind() - && has_dyn_trait_metadata(source_pointee) - && has_dyn_trait_metadata(target_pointee) - { - return Err(TypeError::Mismatch); - } - - Ok(()) - })?; - } - } // Use a FIFO queue for this custom fulfillment procedure. // @@ -657,7 +600,12 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> { // and almost never more than 3. By using a SmallVec we avoid an // allocation, at the (very small) cost of (occasionally) having to // shift subsequent elements down when removing the front element. - let mut queue: SmallVec<[PredicateObligation<'tcx>; 4]> = smallvec![root_obligation]; + let mut queue: SmallVec<[PredicateObligation<'tcx>; 4]> = smallvec![Obligation::new( + self.tcx, + cause, + self.fcx.param_env, + ty::TraitRef::new(self.tcx, coerce_unsized_did, [coerce_source, coerce_target]) + )]; // Keep resolving `CoerceUnsized` and `Unsize` predicates to avoid // emitting a coercion in cases like `Foo<$1>` -> `Foo<$2>`, where diff --git a/tests/ui/cast/ptr-to-trait-obj-wrap-add-auto.rs b/tests/ui/cast/ptr-to-trait-obj-wrap-add-auto.rs deleted file mode 100644 index cfc0a97989dc1..0000000000000 --- a/tests/ui/cast/ptr-to-trait-obj-wrap-add-auto.rs +++ /dev/null @@ -1,36 +0,0 @@ -// Combination of `ptr-to-trait-obj-wrap.rs` and `ptr-to-trait-obj-add-auto.rs`. -// -// Checks that you *can't* add auto traits to trait object in pointer casts involving wrapping said -// traits structures. - -trait A {} - -struct W(T); -struct X(T); - -fn unwrap(a: *const W) -> *const (dyn A + Send) { - a as _ - //~^ error: cannot add auto trait `Send` to dyn bound via pointer cast -} - -fn unwrap_nested(a: *const W>) -> *const W { - a as _ - //~^ error: cannot add auto trait `Send` to dyn bound via pointer cast -} - -fn rewrap(a: *const W) -> *const X { - a as _ - //~^ error: cannot add auto trait `Send` to dyn bound via pointer cast -} - -fn rewrap_nested(a: *const W>) -> *const W> { - a as _ - //~^ error: cannot add auto trait `Send` to dyn bound via pointer cast -} - -fn wrap(a: *const dyn A) -> *const W { - a as _ - //~^ error: cannot add auto trait `Send` to dyn bound via pointer cast -} - -fn main() {} diff --git a/tests/ui/cast/ptr-to-trait-obj-wrap-add-auto.stderr b/tests/ui/cast/ptr-to-trait-obj-wrap-add-auto.stderr deleted file mode 100644 index 42cdbc34ee827..0000000000000 --- a/tests/ui/cast/ptr-to-trait-obj-wrap-add-auto.stderr +++ /dev/null @@ -1,48 +0,0 @@ -error[E0804]: cannot add auto trait `Send` to dyn bound via pointer cast - --> $DIR/ptr-to-trait-obj-wrap-add-auto.rs:12:5 - | -LL | a as _ - | ^^^^^^ unsupported cast - | - = note: this could allow UB elsewhere - = help: use `transmute` if you're sure this is sound - -error[E0804]: cannot add auto trait `Send` to dyn bound via pointer cast - --> $DIR/ptr-to-trait-obj-wrap-add-auto.rs:17:5 - | -LL | a as _ - | ^^^^^^ unsupported cast - | - = note: this could allow UB elsewhere - = help: use `transmute` if you're sure this is sound - -error[E0804]: cannot add auto trait `Send` to dyn bound via pointer cast - --> $DIR/ptr-to-trait-obj-wrap-add-auto.rs:22:5 - | -LL | a as _ - | ^^^^^^ unsupported cast - | - = note: this could allow UB elsewhere - = help: use `transmute` if you're sure this is sound - -error[E0804]: cannot add auto trait `Send` to dyn bound via pointer cast - --> $DIR/ptr-to-trait-obj-wrap-add-auto.rs:27:5 - | -LL | a as _ - | ^^^^^^ unsupported cast - | - = note: this could allow UB elsewhere - = help: use `transmute` if you're sure this is sound - -error[E0804]: cannot add auto trait `Send` to dyn bound via pointer cast - --> $DIR/ptr-to-trait-obj-wrap-add-auto.rs:32:5 - | -LL | a as _ - | ^^^^^^ unsupported cast - | - = note: this could allow UB elsewhere - = help: use `transmute` if you're sure this is sound - -error: aborting due to 5 previous errors - -For more information about this error, try `rustc --explain E0804`. diff --git a/tests/ui/cast/ptr-to-trait-obj-wrap-different-args.rs b/tests/ui/cast/ptr-to-trait-obj-wrap-different-args.rs deleted file mode 100644 index ebe7a06a7a158..0000000000000 --- a/tests/ui/cast/ptr-to-trait-obj-wrap-different-args.rs +++ /dev/null @@ -1,36 +0,0 @@ -// Combination of `ptr-to-trait-obj-different-args.rs` and `ptr-to-trait-obj-wrap.rs`. -// -// Checks that you *can't* change type arguments of trait objects in pointer casts involving -// wrapping said traits structures. - -trait A {} - -struct W(T); -struct X(T); - -fn unwrap(a: *const W>) -> *const dyn A { - a as _ - //~^ error casting `*const W<(dyn A + 'static)>` as `*const dyn A` is invalid -} - -fn unwrap_nested(a: *const W>>) -> *const W> { - a as _ - //~^ error casting `*const W + 'static)>>` as `*const W>` is invalid -} - -fn rewrap(a: *const W>) -> *const X> { - a as _ - //~^ error: casting `*const W<(dyn A + 'static)>` as `*const X>` is invalid -} - -fn rewrap_nested(a: *const W>>) -> *const W>> { - a as _ - //~^ error: casting `*const W + 'static)>>` as `*const W>>` is invalid -} - -fn wrap(a: *const dyn A) -> *const W> { - a as _ - //~^ error: casting `*const (dyn A + 'static)` as `*const W>` is invalid -} - -fn main() {} diff --git a/tests/ui/cast/ptr-to-trait-obj-wrap-different-args.stderr b/tests/ui/cast/ptr-to-trait-obj-wrap-different-args.stderr deleted file mode 100644 index 4f85b208d05ac..0000000000000 --- a/tests/ui/cast/ptr-to-trait-obj-wrap-different-args.stderr +++ /dev/null @@ -1,43 +0,0 @@ -error[E0606]: casting `*const W<(dyn A + 'static)>` as `*const dyn A` is invalid - --> $DIR/ptr-to-trait-obj-wrap-different-args.rs:12:5 - | -LL | a as _ - | ^^^^^^ - | - = note: the trait objects may have different vtables - -error[E0606]: casting `*const W + 'static)>>` as `*const W>` is invalid - --> $DIR/ptr-to-trait-obj-wrap-different-args.rs:17:5 - | -LL | a as _ - | ^^^^^^ - | - = note: the trait objects may have different vtables - -error[E0606]: casting `*const W<(dyn A + 'static)>` as `*const X>` is invalid - --> $DIR/ptr-to-trait-obj-wrap-different-args.rs:22:5 - | -LL | a as _ - | ^^^^^^ - | - = note: the trait objects may have different vtables - -error[E0606]: casting `*const W + 'static)>>` as `*const W>>` is invalid - --> $DIR/ptr-to-trait-obj-wrap-different-args.rs:27:5 - | -LL | a as _ - | ^^^^^^ - | - = note: the trait objects may have different vtables - -error[E0606]: casting `*const (dyn A + 'static)` as `*const W>` is invalid - --> $DIR/ptr-to-trait-obj-wrap-different-args.rs:32:5 - | -LL | a as _ - | ^^^^^^ - | - = note: the trait objects may have different vtables - -error: aborting due to 5 previous errors - -For more information about this error, try `rustc --explain E0606`. diff --git a/tests/ui/cast/ptr-to-trait-obj-wrap-different-regions.rs b/tests/ui/cast/ptr-to-trait-obj-wrap-different-regions.rs deleted file mode 100644 index b0941277d01d3..0000000000000 --- a/tests/ui/cast/ptr-to-trait-obj-wrap-different-regions.rs +++ /dev/null @@ -1,41 +0,0 @@ -// Combination of `ptr-to-trait-obj-different-regions-misc.rs` and `ptr-to-trait-obj-wrap.rs`. -// -// Checks that you *can't* change lifetime arguments of trait objects in pointer casts involving -// wrapping said traits structures. - -trait A<'a> {} - -struct W(T); -struct X(T); - -fn unwrap<'a, 'b>(a: *const W>) -> *const dyn A<'b> { - a as _ - //~^ error - //~| error -} - -fn unwrap_nested<'a, 'b>(a: *const W>>) -> *const W> { - a as _ - //~^ error - //~| error -} - -fn rewrap<'a, 'b>(a: *const W>) -> *const X> { - a as _ - //~^ error: lifetime may not live long enough - //~| error: lifetime may not live long enough -} - -fn rewrap_nested<'a, 'b>(a: *const W>>) -> *const W>> { - a as _ - //~^ error: lifetime may not live long enough - //~| error: lifetime may not live long enough -} - -fn wrap<'a, 'b>(a: *const dyn A<'a>) -> *const W> { - a as _ - //~^ error: lifetime may not live long enough - //~| error: lifetime may not live long enough -} - -fn main() {} diff --git a/tests/ui/cast/ptr-to-trait-obj-wrap-different-regions.stderr b/tests/ui/cast/ptr-to-trait-obj-wrap-different-regions.stderr deleted file mode 100644 index 17a0ca3c34fc8..0000000000000 --- a/tests/ui/cast/ptr-to-trait-obj-wrap-different-regions.stderr +++ /dev/null @@ -1,140 +0,0 @@ -error: lifetime may not live long enough - --> $DIR/ptr-to-trait-obj-wrap-different-regions.rs:12:5 - | -LL | fn unwrap<'a, 'b>(a: *const W>) -> *const dyn A<'b> { - | -- -- lifetime `'b` defined here - | | - | lifetime `'a` defined here -LL | a as _ - | ^^^^^^ function was supposed to return data with lifetime `'a` but it is returning data with lifetime `'b` - | - = help: consider adding the following bound: `'b: 'a` - -error: lifetime may not live long enough - --> $DIR/ptr-to-trait-obj-wrap-different-regions.rs:12:5 - | -LL | fn unwrap<'a, 'b>(a: *const W>) -> *const dyn A<'b> { - | -- -- lifetime `'b` defined here - | | - | lifetime `'a` defined here -LL | a as _ - | ^^^^^^ function was supposed to return data with lifetime `'b` but it is returning data with lifetime `'a` - | - = help: consider adding the following bound: `'a: 'b` - -help: `'b` and `'a` must be the same: replace one with the other - -error: lifetime may not live long enough - --> $DIR/ptr-to-trait-obj-wrap-different-regions.rs:18:5 - | -LL | fn unwrap_nested<'a, 'b>(a: *const W>>) -> *const W> { - | -- -- lifetime `'b` defined here - | | - | lifetime `'a` defined here -LL | a as _ - | ^^^^^^ function was supposed to return data with lifetime `'a` but it is returning data with lifetime `'b` - | - = help: consider adding the following bound: `'b: 'a` - -error: lifetime may not live long enough - --> $DIR/ptr-to-trait-obj-wrap-different-regions.rs:18:5 - | -LL | fn unwrap_nested<'a, 'b>(a: *const W>>) -> *const W> { - | -- -- lifetime `'b` defined here - | | - | lifetime `'a` defined here -LL | a as _ - | ^^^^^^ function was supposed to return data with lifetime `'b` but it is returning data with lifetime `'a` - | - = help: consider adding the following bound: `'a: 'b` - -help: `'b` and `'a` must be the same: replace one with the other - | - = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no` - -error: lifetime may not live long enough - --> $DIR/ptr-to-trait-obj-wrap-different-regions.rs:24:5 - | -LL | fn rewrap<'a, 'b>(a: *const W>) -> *const X> { - | -- -- lifetime `'b` defined here - | | - | lifetime `'a` defined here -LL | a as _ - | ^^^^^^ function was supposed to return data with lifetime `'a` but it is returning data with lifetime `'b` - | - = help: consider adding the following bound: `'b: 'a` - -error: lifetime may not live long enough - --> $DIR/ptr-to-trait-obj-wrap-different-regions.rs:24:5 - | -LL | fn rewrap<'a, 'b>(a: *const W>) -> *const X> { - | -- -- lifetime `'b` defined here - | | - | lifetime `'a` defined here -LL | a as _ - | ^^^^^^ function was supposed to return data with lifetime `'b` but it is returning data with lifetime `'a` - | - = help: consider adding the following bound: `'a: 'b` - -help: `'b` and `'a` must be the same: replace one with the other - | - = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no` - -error: lifetime may not live long enough - --> $DIR/ptr-to-trait-obj-wrap-different-regions.rs:30:5 - | -LL | fn rewrap_nested<'a, 'b>(a: *const W>>) -> *const W>> { - | -- -- lifetime `'b` defined here - | | - | lifetime `'a` defined here -LL | a as _ - | ^^^^^^ function was supposed to return data with lifetime `'a` but it is returning data with lifetime `'b` - | - = help: consider adding the following bound: `'b: 'a` - -error: lifetime may not live long enough - --> $DIR/ptr-to-trait-obj-wrap-different-regions.rs:30:5 - | -LL | fn rewrap_nested<'a, 'b>(a: *const W>>) -> *const W>> { - | -- -- lifetime `'b` defined here - | | - | lifetime `'a` defined here -LL | a as _ - | ^^^^^^ function was supposed to return data with lifetime `'b` but it is returning data with lifetime `'a` - | - = help: consider adding the following bound: `'a: 'b` - -help: `'b` and `'a` must be the same: replace one with the other - | - = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no` - -error: lifetime may not live long enough - --> $DIR/ptr-to-trait-obj-wrap-different-regions.rs:36:5 - | -LL | fn wrap<'a, 'b>(a: *const dyn A<'a>) -> *const W> { - | -- -- lifetime `'b` defined here - | | - | lifetime `'a` defined here -LL | a as _ - | ^^^^^^ function was supposed to return data with lifetime `'a` but it is returning data with lifetime `'b` - | - = help: consider adding the following bound: `'b: 'a` - -error: lifetime may not live long enough - --> $DIR/ptr-to-trait-obj-wrap-different-regions.rs:36:5 - | -LL | fn wrap<'a, 'b>(a: *const dyn A<'a>) -> *const W> { - | -- -- lifetime `'b` defined here - | | - | lifetime `'a` defined here -LL | a as _ - | ^^^^^^ function was supposed to return data with lifetime `'b` but it is returning data with lifetime `'a` - | - = help: consider adding the following bound: `'a: 'b` - -help: `'b` and `'a` must be the same: replace one with the other - | - = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no` - -error: aborting due to 10 previous errors - diff --git a/tests/ui/cast/ptr-to-trait-obj-wrap.rs b/tests/ui/cast/ptr-to-trait-obj-wrap.rs deleted file mode 100644 index 9809ea80f95cf..0000000000000 --- a/tests/ui/cast/ptr-to-trait-obj-wrap.rs +++ /dev/null @@ -1,32 +0,0 @@ -// Checks that various casts of pointers to trait objects wrapped in structures -// work. Note that the metadata doesn't change when a DST is wrapped in a -// structure, so these casts *are* fine. -// -//@ check-pass - -trait A {} - -struct W(T); -struct X(T); - -fn unwrap(a: *const W) -> *const dyn A { - a as _ -} - -fn unwrap_nested(a: *const W>) -> *const W { - a as _ -} - -fn rewrap(a: *const W) -> *const X { - a as _ -} - -fn rewrap_nested(a: *const W>) -> *const W> { - a as _ -} - -fn wrap(a: *const dyn A) -> *const W { - a as _ -} - -fn main() {}