diff --git a/compiler/rustc_middle/src/ty/sty.rs b/compiler/rustc_middle/src/ty/sty.rs index edab7fe58baea..a14d09bbb7006 100644 --- a/compiler/rustc_middle/src/ty/sty.rs +++ b/compiler/rustc_middle/src/ty/sty.rs @@ -2945,6 +2945,33 @@ impl<'tcx> Ty<'tcx> { _ => false, } } + + pub fn is_known_rigid(self) -> bool { + match self.kind() { + Bool + | Char + | Int(_) + | Uint(_) + | Float(_) + | Adt(_, _) + | Foreign(_) + | Str + | Array(_, _) + | Slice(_) + | RawPtr(_) + | Ref(_, _, _) + | FnDef(_, _) + | FnPtr(_) + | Dynamic(_, _, _) + | Closure(_, _) + | Generator(_, _, _) + | GeneratorWitness(_) + | GeneratorWitnessMIR(_, _) + | Never + | Tuple(_) => true, + Error(_) | Infer(_) | Alias(_, _) | Param(_) | Bound(_, _) | Placeholder(_) => false, + } + } } /// Extra information about why we ended up with a particular variance. diff --git a/compiler/rustc_ty_utils/src/instance.rs b/compiler/rustc_ty_utils/src/instance.rs index da2958bf56e8c..91f1c21310e30 100644 --- a/compiler/rustc_ty_utils/src/instance.rs +++ b/compiler/rustc_ty_utils/src/instance.rs @@ -141,11 +141,34 @@ fn resolve_associated_item<'tcx>( false } }; - if !eligible { return Ok(None); } + // HACK: We may have overlapping `dyn Trait` built-in impls and + // user-provided blanket impls. Detect that case here, and return + // ambiguity. + // + // This should not affect totally monomorphized contexts, only + // resolve calls that happen polymorphically, such as the mir-inliner + // and const-prop (and also some lints). + let self_ty = rcvr_args.type_at(0); + if !self_ty.is_known_rigid() { + let predicates = tcx + .predicates_of(impl_data.impl_def_id) + .instantiate(tcx, impl_data.args) + .predicates; + let sized_def_id = tcx.lang_items().sized_trait(); + // If we find a `Self: Sized` bound on the item, then we know + // that `dyn Trait` can certainly never apply here. + if !predicates.into_iter().filter_map(ty::Clause::as_trait_clause).any(|clause| { + Some(clause.def_id()) == sized_def_id + && clause.skip_binder().self_ty() == self_ty + }) { + return Ok(None); + } + } + // Any final impl is required to define all associated items. if !leaf_def.item.defaultness(tcx).has_value() { let guard = tcx.sess.delay_span_bug( diff --git a/tests/mir-opt/dont_inline_type_id.call.Inline.diff b/tests/mir-opt/dont_inline_type_id.call.Inline.diff new file mode 100644 index 0000000000000..80cfe07b0cbf6 --- /dev/null +++ b/tests/mir-opt/dont_inline_type_id.call.Inline.diff @@ -0,0 +1,20 @@ +- // MIR for `call` before Inline ++ // MIR for `call` after Inline + + fn call(_1: &T) -> TypeId { + debug s => _1; + let mut _0: std::any::TypeId; + let mut _2: &T; + + bb0: { + StorageLive(_2); + _2 = &(*_1); + _0 = ::type_id(move _2) -> [return: bb1, unwind unreachable]; + } + + bb1: { + StorageDead(_2); + return; + } + } + diff --git a/tests/mir-opt/dont_inline_type_id.rs b/tests/mir-opt/dont_inline_type_id.rs new file mode 100644 index 0000000000000..d8a5663609443 --- /dev/null +++ b/tests/mir-opt/dont_inline_type_id.rs @@ -0,0 +1,15 @@ +// unit-test: Inline +// compile-flags: --crate-type=lib -C panic=abort + +use std::any::Any; +use std::any::TypeId; + +struct A { + a: i32, + b: T, +} + +// EMIT_MIR dont_inline_type_id.call.Inline.diff +pub fn call(s: &T) -> TypeId { + s.type_id() +} diff --git a/tests/mir-opt/inline_generically_if_sized.call.Inline.diff b/tests/mir-opt/inline_generically_if_sized.call.Inline.diff new file mode 100644 index 0000000000000..0cf4565dc994c --- /dev/null +++ b/tests/mir-opt/inline_generically_if_sized.call.Inline.diff @@ -0,0 +1,24 @@ +- // MIR for `call` before Inline ++ // MIR for `call` after Inline + + fn call(_1: &T) -> i32 { + debug s => _1; + let mut _0: i32; + let mut _2: &T; ++ scope 1 (inlined ::bar) { ++ debug self => _2; ++ } + + bb0: { + StorageLive(_2); + _2 = &(*_1); +- _0 = ::bar(move _2) -> [return: bb1, unwind unreachable]; +- } +- +- bb1: { ++ _0 = const 0_i32; + StorageDead(_2); + return; + } + } + diff --git a/tests/mir-opt/inline_generically_if_sized.rs b/tests/mir-opt/inline_generically_if_sized.rs new file mode 100644 index 0000000000000..1acfff7a56b7c --- /dev/null +++ b/tests/mir-opt/inline_generically_if_sized.rs @@ -0,0 +1,17 @@ +// unit-test: Inline +// compile-flags: --crate-type=lib -C panic=abort + +trait Foo { + fn bar(&self) -> i32; +} + +impl Foo for T { + fn bar(&self) -> i32 { + 0 + } +} + +// EMIT_MIR inline_generically_if_sized.call.Inline.diff +pub fn call(s: &T) -> i32 { + s.bar() +} diff --git a/tests/ui/const_prop/dont-propagate-generic-instance-2.rs b/tests/ui/const_prop/dont-propagate-generic-instance-2.rs new file mode 100644 index 0000000000000..e5525af23f0e6 --- /dev/null +++ b/tests/ui/const_prop/dont-propagate-generic-instance-2.rs @@ -0,0 +1,26 @@ +// run-pass + +#![feature(inline_const)] + +// Makes sure we don't propagate generic instances of `Self: ?Sized` blanket impls. +// This is relevant when we have an overlapping impl and builtin dyn instance. +// See for more context. + +trait Trait { + fn foo(&self) -> &'static str; +} + +impl Trait for T { + fn foo(&self) -> &'static str { + std::any::type_name::() + } +} + +fn bar() -> fn(&T) -> &'static str { + const { Trait::foo as fn(&T) -> &'static str } + // If const prop were to propagate the instance +} + +fn main() { + assert_eq!("i32", bar::()(&1i32)); +} diff --git a/tests/ui/const_prop/dont-propagate-generic-instance.rs b/tests/ui/const_prop/dont-propagate-generic-instance.rs new file mode 100644 index 0000000000000..5994961b887b1 --- /dev/null +++ b/tests/ui/const_prop/dont-propagate-generic-instance.rs @@ -0,0 +1,24 @@ +// run-pass + +// Makes sure we don't propagate generic instances of `Self: ?Sized` blanket impls. +// This is relevant when we have an overlapping impl and builtin dyn instance. +// See for more context. + +trait Trait { + fn foo(&self) -> &'static str; +} + +impl Trait for T { + fn foo(&self) -> &'static str { + std::any::type_name::() + } +} + +const fn bar() -> fn(&T) -> &'static str { + Trait::foo + // If const prop were to propagate the instance +} + +fn main() { + assert_eq!("i32", bar::()(&1i32)); +}