From 546ba3d310ae2d795b43188ce1b9980b33e690e5 Mon Sep 17 00:00:00 2001 From: dianne Date: Sun, 17 Nov 2024 00:11:34 -0800 Subject: [PATCH] `suggest_borrow_generic_arg`: instantiate clauses properly Fixes issue 133118. This also modifies `tests/ui/moves/moved-value-on-as-ref-arg.rs` to have more useful bounds on the tests for suggestions to borrow `Borrow` and `BorrowMut` arguments. With its old tautological `T: BorrowMut` bound, this fix would make it suggest a shared borrow for that argument. --- .../src/diagnostics/conflict_errors.rs | 26 +++++++------------ .../ui/moves/moved-value-on-as-ref-arg.fixed | 4 +-- tests/ui/moves/moved-value-on-as-ref-arg.rs | 4 +-- .../region-var-in-moved-ty-issue-133118.rs | 25 ++++++++++++++++++ ...region-var-in-moved-ty-issue-133118.stderr | 21 +++++++++++++++ 5 files changed, 60 insertions(+), 20 deletions(-) create mode 100644 tests/ui/moves/region-var-in-moved-ty-issue-133118.rs create mode 100644 tests/ui/moves/region-var-in-moved-ty-issue-133118.stderr diff --git a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs index 454fd14ea74..51c2282422e 100644 --- a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs +++ b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs @@ -27,7 +27,7 @@ use rustc_middle::mir::{ }; use rustc_middle::ty::print::PrintTraitRefExt as _; use rustc_middle::ty::{ - self, ClauseKind, PredicateKind, Ty, TyCtxt, TypeSuperVisitable, TypeVisitor, Upcast, + self, PredicateKind, Ty, TyCtxt, TypeSuperVisitable, TypeVisitor, Upcast, suggest_constraining_type_params, }; use rustc_middle::util::CallKind; @@ -649,11 +649,11 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> { ) -> Option { let tcx = self.infcx.tcx; let sig = tcx.fn_sig(callee_did).instantiate_identity().skip_binder(); - let clauses = tcx.predicates_of(callee_did).instantiate_identity(self.infcx.tcx).predicates; + let clauses = tcx.predicates_of(callee_did); // First, is there at least one method on one of `param`'s trait bounds? // This keeps us from suggesting borrowing the argument to `mem::drop`, e.g. - if !clauses.iter().any(|clause| { + if !clauses.instantiate_identity(tcx).predicates.iter().any(|clause| { clause.as_trait_clause().is_some_and(|tc| { tc.self_ty().skip_binder().is_param(param.index) && tc.polarity() == ty::PredicatePolarity::Positive @@ -700,23 +700,17 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> { return false; } - // Test the callee's predicates, substituting a reference in for the self ty - // in bounds on `param`. - clauses.iter().all(|&clause| { - let clause_for_ref = clause.kind().map_bound(|kind| match kind { - ClauseKind::Trait(c) if c.self_ty().is_param(param.index) => { - ClauseKind::Trait(c.with_self_ty(tcx, ref_ty)) - } - ClauseKind::Projection(c) if c.self_ty().is_param(param.index) => { - ClauseKind::Projection(c.with_self_ty(tcx, ref_ty)) - } - _ => kind, - }); + // Test the callee's predicates, substituting in `ref_ty` for the moved argument type. + clauses.instantiate(tcx, new_args).predicates.iter().all(|&(mut clause)| { + // Normalize before testing to see through type aliases and projections. + if let Ok(normalized) = tcx.try_normalize_erasing_regions(self.param_env, clause) { + clause = normalized; + } self.infcx.predicate_must_hold_modulo_regions(&Obligation::new( tcx, ObligationCause::dummy(), self.param_env, - ty::EarlyBinder::bind(clause_for_ref).instantiate(tcx, generic_args), + clause, )) }) }) { diff --git a/tests/ui/moves/moved-value-on-as-ref-arg.fixed b/tests/ui/moves/moved-value-on-as-ref-arg.fixed index 292fa98a3f7..97bfe094ce5 100644 --- a/tests/ui/moves/moved-value-on-as-ref-arg.fixed +++ b/tests/ui/moves/moved-value-on-as-ref-arg.fixed @@ -18,8 +18,8 @@ impl AsMut for Bar { fn foo>(_: T) {} fn qux>(_: T) {} -fn bat>(_: T) {} -fn baz>(_: T) {} +fn bat>(_: T) {} +fn baz>(_: T) {} pub fn main() { let bar = Bar; diff --git a/tests/ui/moves/moved-value-on-as-ref-arg.rs b/tests/ui/moves/moved-value-on-as-ref-arg.rs index 632af9efcda..fed41cf710d 100644 --- a/tests/ui/moves/moved-value-on-as-ref-arg.rs +++ b/tests/ui/moves/moved-value-on-as-ref-arg.rs @@ -18,8 +18,8 @@ impl AsMut for Bar { fn foo>(_: T) {} fn qux>(_: T) {} -fn bat>(_: T) {} -fn baz>(_: T) {} +fn bat>(_: T) {} +fn baz>(_: T) {} pub fn main() { let bar = Bar; diff --git a/tests/ui/moves/region-var-in-moved-ty-issue-133118.rs b/tests/ui/moves/region-var-in-moved-ty-issue-133118.rs new file mode 100644 index 00000000000..a49370e315d --- /dev/null +++ b/tests/ui/moves/region-var-in-moved-ty-issue-133118.rs @@ -0,0 +1,25 @@ +//! regression test for #133118 + +pub trait Alpha { + fn y(self) -> usize; +} + +pub trait Beta { + type Gamma; + fn gamma(&self) -> Self::Gamma; +} + +pub fn a(_x: T) -> usize { + todo!(); +} + +pub fn x(beta: &B) -> usize +where + for<'a> &'a B: Beta, + for<'a> <&'a B as Beta>::Gamma: Alpha, +{ + let g1 = beta.gamma(); + a(g1) + a(g1) //~ ERROR use of moved value: `g1` [E0382] +} + +pub fn main() {} diff --git a/tests/ui/moves/region-var-in-moved-ty-issue-133118.stderr b/tests/ui/moves/region-var-in-moved-ty-issue-133118.stderr new file mode 100644 index 00000000000..691625d042d --- /dev/null +++ b/tests/ui/moves/region-var-in-moved-ty-issue-133118.stderr @@ -0,0 +1,21 @@ +error[E0382]: use of moved value: `g1` + --> $DIR/region-var-in-moved-ty-issue-133118.rs:22:15 + | +LL | let g1 = beta.gamma(); + | -- move occurs because `g1` has type `<&B as Beta>::Gamma`, which does not implement the `Copy` trait +LL | a(g1) + a(g1) + | -- ^^ value used here after move + | | + | value moved here + | +note: consider changing this parameter type in function `a` to borrow instead if owning the value isn't necessary + --> $DIR/region-var-in-moved-ty-issue-133118.rs:12:24 + | +LL | pub fn a(_x: T) -> usize { + | - ^ this parameter takes ownership of the value + | | + | in this function + +error: aborting due to 1 previous error + +For more information about this error, try `rustc --explain E0382`.