From fb9e171ab7b0303fc983b6955e684ebb2a0f5944 Mon Sep 17 00:00:00 2001 From: Oli Scherer Date: Tue, 21 Mar 2023 11:11:32 +0000 Subject: [PATCH] Only implement Fn* traits for extern "Rust" safe function pointers. --- .../solve/trait_goals/structural_traits.rs | 16 ++++- .../src/traits/select/candidate_assembly.rs | 3 + tests/ui/traits/new-solver/fn-trait.rs | 17 ++++- tests/ui/traits/new-solver/fn-trait.stderr | 64 +++++++++++++++++++ 4 files changed, 98 insertions(+), 2 deletions(-) create mode 100644 tests/ui/traits/new-solver/fn-trait.stderr diff --git a/compiler/rustc_trait_selection/src/solve/trait_goals/structural_traits.rs b/compiler/rustc_trait_selection/src/solve/trait_goals/structural_traits.rs index d7d93377cf1..51a1a88f8e7 100644 --- a/compiler/rustc_trait_selection/src/solve/trait_goals/structural_traits.rs +++ b/compiler/rustc_trait_selection/src/solve/trait_goals/structural_traits.rs @@ -2,6 +2,7 @@ use rustc_data_structures::fx::FxHashMap; use rustc_hir::{def_id::DefId, Movability, Mutability}; use rustc_infer::traits::query::NoSolution; use rustc_middle::ty::{self, Ty, TyCtxt, TypeFoldable, TypeFolder, TypeSuperFoldable}; +use rustc_target::spec::abi::Abi; use crate::solve::EvalCtxt; @@ -194,7 +195,20 @@ pub(crate) fn extract_tupled_inputs_and_output_from_callable<'tcx>( .subst(tcx, substs) .map_bound(|sig| (tcx.mk_tup(sig.inputs()), sig.output())), )), - ty::FnPtr(sig) => Ok(Some(sig.map_bound(|sig| (tcx.mk_tup(sig.inputs()), sig.output())))), + // keep this in sync with assemble_fn_pointer_candidates until the old solver is removed. + ty::FnPtr(sig) => { + if let ty::FnSig { + unsafety: rustc_hir::Unsafety::Normal, + abi: Abi::Rust, + c_variadic: false, + .. + } = sig.skip_binder() + { + Ok(Some(sig.map_bound(|sig| (tcx.mk_tup(sig.inputs()), sig.output())))) + } else { + Err(NoSolution) + } + } ty::Closure(_, substs) => { let closure_substs = substs.as_closure(); match closure_substs.kind_ty().to_opt_closure_kind() { diff --git a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs index 3182af989f0..2b3f003353c 100644 --- a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs +++ b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs @@ -291,6 +291,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { return; } + // Keep this funtion in sync with extract_tupled_inputs_and_output_from_callable + // until the old solver (and thus this function) is removed. + // Okay to skip binder because what we are inspecting doesn't involve bound regions. let self_ty = obligation.self_ty().skip_binder(); match *self_ty.kind() { diff --git a/tests/ui/traits/new-solver/fn-trait.rs b/tests/ui/traits/new-solver/fn-trait.rs index d566ead105c..8967858a8ba 100644 --- a/tests/ui/traits/new-solver/fn-trait.rs +++ b/tests/ui/traits/new-solver/fn-trait.rs @@ -1,5 +1,4 @@ // compile-flags: -Ztrait-solver=next -// check-pass fn require_fn(_: impl Fn() -> i32) {} @@ -7,7 +6,23 @@ fn f() -> i32 { 1i32 } +extern "C" fn g() -> i32 { + 2i32 +} + +unsafe fn h() -> i32 { + 2i32 +} + fn main() { require_fn(f); require_fn(f as fn() -> i32); + require_fn(f as unsafe fn() -> i32); + //~^ ERROR: expected a `Fn<()>` closure, found `unsafe fn() -> i32` + //~| ERROR: type mismatch resolving ` i32 as FnOnce<()>>::Output == i32` + require_fn(g); + require_fn(g as extern "C" fn() -> i32); + //~^ ERROR: expected a `Fn<()>` closure, found `extern "C" fn() -> i32` + //~| ERROR: type mismatch resolving ` i32 as FnOnce<()>>::Output == i32` + require_fn(h); } diff --git a/tests/ui/traits/new-solver/fn-trait.stderr b/tests/ui/traits/new-solver/fn-trait.stderr new file mode 100644 index 00000000000..01f1b64be20 --- /dev/null +++ b/tests/ui/traits/new-solver/fn-trait.stderr @@ -0,0 +1,64 @@ +error[E0277]: expected a `Fn<()>` closure, found `unsafe fn() -> i32` + --> $DIR/fn-trait.rs:20:16 + | +LL | require_fn(f as unsafe fn() -> i32); + | ---------- ^^^^^^^^^^^^^^^^^^^^^^^ call the function in a closure: `|| unsafe { /* code */ }` + | | + | required by a bound introduced by this call + | + = help: the trait `Fn<()>` is not implemented for `unsafe fn() -> i32` + = note: wrap the `unsafe fn() -> i32` in a closure with no arguments: `|| { /* code */ }` +note: required by a bound in `require_fn` + --> $DIR/fn-trait.rs:3:23 + | +LL | fn require_fn(_: impl Fn() -> i32) {} + | ^^^^^^^^^^^ required by this bound in `require_fn` + +error[E0271]: type mismatch resolving ` i32 as FnOnce<()>>::Output == i32` + --> $DIR/fn-trait.rs:20:16 + | +LL | require_fn(f as unsafe fn() -> i32); + | ---------- ^^^^^^^^^^^^^^^^^^^^^^^ types differ + | | + | required by a bound introduced by this call + | +note: required by a bound in `require_fn` + --> $DIR/fn-trait.rs:3:31 + | +LL | fn require_fn(_: impl Fn() -> i32) {} + | ^^^ required by this bound in `require_fn` + +error[E0277]: expected a `Fn<()>` closure, found `extern "C" fn() -> i32` + --> $DIR/fn-trait.rs:24:16 + | +LL | require_fn(g as extern "C" fn() -> i32); + | ---------- ^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected an `Fn<()>` closure, found `extern "C" fn() -> i32` + | | + | required by a bound introduced by this call + | + = help: the trait `Fn<()>` is not implemented for `extern "C" fn() -> i32` + = note: wrap the `extern "C" fn() -> i32` in a closure with no arguments: `|| { /* code */ }` +note: required by a bound in `require_fn` + --> $DIR/fn-trait.rs:3:23 + | +LL | fn require_fn(_: impl Fn() -> i32) {} + | ^^^^^^^^^^^ required by this bound in `require_fn` + +error[E0271]: type mismatch resolving ` i32 as FnOnce<()>>::Output == i32` + --> $DIR/fn-trait.rs:24:16 + | +LL | require_fn(g as extern "C" fn() -> i32); + | ---------- ^^^^^^^^^^^^^^^^^^^^^^^^^^^ types differ + | | + | required by a bound introduced by this call + | +note: required by a bound in `require_fn` + --> $DIR/fn-trait.rs:3:31 + | +LL | fn require_fn(_: impl Fn() -> i32) {} + | ^^^ required by this bound in `require_fn` + +error: aborting due to 4 previous errors + +Some errors have detailed explanations: E0271, E0277. +For more information about an error, try `rustc --explain E0271`.