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Rollup merge of #131751 - compiler-errors:structurally-resolve, r=lcnr
Rename `can_coerce` to `may_coerce`, and then structurally resolve correctly in the probe We need to structurally resolve the lhs and rhs of the coercion. Also, renaming the method so it's less ambiguous about what it's doing... the word "may" gives more clear signal that it has false positives imo. r? lcnr
This commit is contained in:
Matthias Krüger
GitHub
commit
3b8fd5f895
@ -235,8 +235,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
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Some(ret_coercion) => {
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let ret_ty = ret_coercion.borrow().expected_ty();
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let ret_ty = self.infcx.shallow_resolve(ret_ty);
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self.can_coerce(arm_ty, ret_ty)
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&& prior_arm.is_none_or(|(_, ty, _)| self.can_coerce(ty, ret_ty))
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self.may_coerce(arm_ty, ret_ty)
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&& prior_arm.is_none_or(|(_, ty, _)| self.may_coerce(ty, ret_ty))
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// The match arms need to unify for the case of `impl Trait`.
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&& !matches!(ret_ty.kind(), ty::Alias(ty::Opaque, ..))
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}
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@ -409,7 +409,7 @@ impl<'a, 'tcx> CastCheck<'tcx> {
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let mut sugg_mutref = false;
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if let ty::Ref(reg, cast_ty, mutbl) = *self.cast_ty.kind() {
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if let ty::RawPtr(expr_ty, _) = *self.expr_ty.kind()
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&& fcx.can_coerce(
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&& fcx.may_coerce(
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Ty::new_ref(fcx.tcx, fcx.tcx.lifetimes.re_erased, expr_ty, mutbl),
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self.cast_ty,
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)
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@ -418,14 +418,14 @@ impl<'a, 'tcx> CastCheck<'tcx> {
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} else if let ty::Ref(expr_reg, expr_ty, expr_mutbl) = *self.expr_ty.kind()
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&& expr_mutbl == Mutability::Not
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&& mutbl == Mutability::Mut
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&& fcx.can_coerce(Ty::new_mut_ref(fcx.tcx, expr_reg, expr_ty), self.cast_ty)
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&& fcx.may_coerce(Ty::new_mut_ref(fcx.tcx, expr_reg, expr_ty), self.cast_ty)
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{
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sugg_mutref = true;
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}
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if !sugg_mutref
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&& sugg == None
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&& fcx.can_coerce(
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&& fcx.may_coerce(
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Ty::new_ref(fcx.tcx, reg, self.expr_ty, mutbl),
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self.cast_ty,
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)
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@ -433,7 +433,7 @@ impl<'a, 'tcx> CastCheck<'tcx> {
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sugg = Some((format!("&{}", mutbl.prefix_str()), false));
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}
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} else if let ty::RawPtr(_, mutbl) = *self.cast_ty.kind()
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&& fcx.can_coerce(
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&& fcx.may_coerce(
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Ty::new_ref(fcx.tcx, fcx.tcx.lifetimes.re_erased, self.expr_ty, mutbl),
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self.cast_ty,
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)
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@ -1084,24 +1084,42 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
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})
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}
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/// Same as `coerce()`, but without side-effects.
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/// Probe whether `expr_ty` can be coerced to `target_ty`. This has no side-effects,
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/// and may return false positives if types are not yet fully constrained by inference.
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///
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/// Returns false if the coercion creates any obligations that result in
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/// errors.
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pub(crate) fn can_coerce(&self, expr_ty: Ty<'tcx>, target: Ty<'tcx>) -> bool {
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// FIXME(-Znext-solver): We need to structurally resolve both types here.
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let source = self.resolve_vars_with_obligations(expr_ty);
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debug!("coercion::can_with_predicates({:?} -> {:?})", source, target);
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/// Returns false if the coercion is not possible, or if the coercion creates any
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/// sub-obligations that result in errors.
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///
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/// This should only be used for diagnostics.
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pub(crate) fn may_coerce(&self, expr_ty: Ty<'tcx>, target_ty: Ty<'tcx>) -> bool {
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let cause = self.cause(DUMMY_SP, ObligationCauseCode::ExprAssignable);
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// We don't ever need two-phase here since we throw out the result of the coercion.
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// We also just always set `coerce_never` to true, since this is a heuristic.
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let coerce = Coerce::new(self, cause, AllowTwoPhase::No, true);
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let coerce = Coerce::new(self, cause.clone(), AllowTwoPhase::No, true);
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self.probe(|_| {
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let Ok(ok) = coerce.coerce(source, target) else {
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// Make sure to structurally resolve the types, since we use
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// the `TyKind`s heavily in coercion.
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let ocx = ObligationCtxt::new(self);
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let structurally_resolve = |ty| {
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let ty = self.shallow_resolve(ty);
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if self.next_trait_solver()
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&& let ty::Alias(..) = ty.kind()
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{
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ocx.structurally_normalize(&cause, self.param_env, ty)
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} else {
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Ok(ty)
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}
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};
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let Ok(expr_ty) = structurally_resolve(expr_ty) else {
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return false;
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};
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let Ok(target_ty) = structurally_resolve(target_ty) else {
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return false;
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};
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let Ok(ok) = coerce.coerce(expr_ty, target_ty) else {
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return false;
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};
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let ocx = ObligationCtxt::new(self);
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ocx.register_obligations(ok.obligations);
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ocx.select_where_possible().is_empty()
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})
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@ -1370,7 +1388,7 @@ pub fn can_coerce<'tcx>(
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) -> bool {
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let root_ctxt = crate::typeck_root_ctxt::TypeckRootCtxt::new(tcx, body_id);
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let fn_ctxt = FnCtxt::new(&root_ctxt, param_env, body_id);
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fn_ctxt.can_coerce(ty, output_ty)
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fn_ctxt.may_coerce(ty, output_ty)
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}
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/// CoerceMany encapsulates the pattern you should use when you have
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@ -1330,9 +1330,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
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let refs_can_coerce = |lhs: Ty<'tcx>, rhs: Ty<'tcx>| {
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let lhs = Ty::new_imm_ref(self.tcx, self.tcx.lifetimes.re_erased, lhs.peel_refs());
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let rhs = Ty::new_imm_ref(self.tcx, self.tcx.lifetimes.re_erased, rhs.peel_refs());
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self.can_coerce(rhs, lhs)
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self.may_coerce(rhs, lhs)
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};
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let (applicability, eq) = if self.can_coerce(rhs_ty, lhs_ty) {
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let (applicability, eq) = if self.may_coerce(rhs_ty, lhs_ty) {
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(Applicability::MachineApplicable, true)
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} else if refs_can_coerce(rhs_ty, lhs_ty) {
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// The lhs and rhs are likely missing some references in either side. Subsequent
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@ -1349,7 +1349,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
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let actual_lhs_ty = self.check_expr(rhs_expr);
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(
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Applicability::MaybeIncorrect,
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self.can_coerce(rhs_ty, actual_lhs_ty)
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self.may_coerce(rhs_ty, actual_lhs_ty)
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|| refs_can_coerce(rhs_ty, actual_lhs_ty),
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)
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} else if let ExprKind::Binary(
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@ -1363,7 +1363,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
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let actual_rhs_ty = self.check_expr(lhs_expr);
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(
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Applicability::MaybeIncorrect,
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self.can_coerce(actual_rhs_ty, lhs_ty)
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self.may_coerce(actual_rhs_ty, lhs_ty)
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|| refs_can_coerce(actual_rhs_ty, lhs_ty),
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)
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} else {
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@ -1414,7 +1414,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
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self.param_env,
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)
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.may_apply();
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if lhs_deref_ty_is_sized && self.can_coerce(rhs_ty, lhs_deref_ty) {
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if lhs_deref_ty_is_sized && self.may_coerce(rhs_ty, lhs_deref_ty) {
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err.span_suggestion_verbose(
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lhs.span.shrink_to_lo(),
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"consider dereferencing here to assign to the mutably borrowed value",
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@ -658,7 +658,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
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&& fn_sig.inputs()[1..]
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.iter()
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.zip(input_types.iter())
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.all(|(expected, found)| self.can_coerce(*expected, *found))
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.all(|(expected, found)| self.may_coerce(*expected, *found))
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&& fn_sig.inputs()[1..].len() == input_types.len()
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{
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err.span_suggestion_verbose(
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@ -722,7 +722,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
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let expectation = Expectation::rvalue_hint(self, expected_input_ty);
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let coerced_ty = expectation.only_has_type(self).unwrap_or(formal_input_ty);
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let can_coerce = self.can_coerce(arg_ty, coerced_ty);
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let can_coerce = self.may_coerce(arg_ty, coerced_ty);
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if !can_coerce {
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return Compatibility::Incompatible(Some(ty::error::TypeError::Sorts(
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ty::error::ExpectedFound::new(true, coerced_ty, arg_ty),
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@ -802,7 +802,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
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provided_arg_tys.iter().map(|(ty, _)| *ty).skip(mismatch_idx + tys.len()),
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),
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) {
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if !self.can_coerce(provided_ty, *expected_ty) {
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if !self.may_coerce(provided_ty, *expected_ty) {
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satisfied = false;
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break;
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}
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@ -1023,7 +1023,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
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std::iter::zip(formal_and_expected_inputs.iter(), removed_arg_tys.iter()).all(
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|((expected_ty, _), (provided_ty, _))| {
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!provided_ty.references_error()
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&& self.can_coerce(*provided_ty, *expected_ty)
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&& self.may_coerce(*provided_ty, *expected_ty)
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},
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)
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};
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@ -2124,7 +2124,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
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let expr_ty = self.typeck_results.borrow().expr_ty(expr);
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let return_ty = fn_sig.output();
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if !matches!(expr.kind, hir::ExprKind::Ret(..))
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&& self.can_coerce(expr_ty, return_ty)
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&& self.may_coerce(expr_ty, return_ty)
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{
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found_semi = true;
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}
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@ -261,7 +261,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
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if let hir::ExprKind::MethodCall(hir::PathSegment { ident: method, .. }, recv_expr, &[], _) =
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expr.kind
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&& let Some(recv_ty) = self.typeck_results.borrow().expr_ty_opt(recv_expr)
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&& self.can_coerce(recv_ty, expected)
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&& self.may_coerce(recv_ty, expected)
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&& let name = method.name.as_str()
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&& (name.starts_with("to_") || name.starts_with("as_") || name == "into")
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{
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@ -349,7 +349,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
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return true;
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}
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if self.suggest_fn_call(err, expr, found, |output| self.can_coerce(output, expected))
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if self.suggest_fn_call(err, expr, found, |output| self.may_coerce(output, expected))
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&& let ty::FnDef(def_id, ..) = *found.kind()
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&& let Some(sp) = self.tcx.hir().span_if_local(def_id)
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{
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@ -568,7 +568,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
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if self.tcx.hir().is_inside_const_context(hir_id) || !expected.is_box() || found.is_box() {
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return false;
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}
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if self.can_coerce(Ty::new_box(self.tcx, found), expected) {
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if self.may_coerce(Ty::new_box(self.tcx, found), expected) {
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let suggest_boxing = match found.kind() {
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ty::Tuple(tuple) if tuple.is_empty() => {
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errors::SuggestBoxing::Unit { start: span.shrink_to_lo(), end: span }
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@ -663,7 +663,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
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};
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match expected.kind() {
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ty::Adt(def, _) if Some(def.did()) == pin_did => {
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if self.can_coerce(pin_box_found, expected) {
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if self.may_coerce(pin_box_found, expected) {
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debug!("can coerce {:?} to {:?}, suggesting Box::pin", pin_box_found, expected);
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match found.kind() {
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ty::Adt(def, _) if def.is_box() => {
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@ -689,7 +689,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
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}
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}
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true
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} else if self.can_coerce(pin_found, expected) {
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} else if self.may_coerce(pin_found, expected) {
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match found.kind() {
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ty::Adt(def, _) if def.is_box() => {
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err.help("use `Box::pin`");
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@ -701,7 +701,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
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false
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}
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}
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ty::Adt(def, _) if def.is_box() && self.can_coerce(box_found, expected) => {
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ty::Adt(def, _) if def.is_box() && self.may_coerce(box_found, expected) => {
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// Check if the parent expression is a call to Pin::new. If it
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// is and we were expecting a Box, ergo Pin<Box<expected>>, we
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// can suggest Box::pin.
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@ -884,7 +884,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
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let ty = Binder::bind_with_vars(ty, bound_vars);
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let ty = self.normalize(hir_ty.span, ty);
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let ty = self.tcx.instantiate_bound_regions_with_erased(ty);
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if self.can_coerce(expected, ty) {
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if self.may_coerce(expected, ty) {
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err.subdiagnostic(errors::ExpectedReturnTypeLabel::Other {
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span: hir_ty.span,
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expected,
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@ -1141,12 +1141,12 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
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ty::Asyncness::No => ty,
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};
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let ty = self.normalize(expr.span, ty);
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self.can_coerce(found, ty)
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self.may_coerce(found, ty)
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}
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hir::FnRetTy::DefaultReturn(_) if in_closure => {
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self.ret_coercion.as_ref().map_or(false, |ret| {
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let ret_ty = ret.borrow().expected_ty();
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self.can_coerce(found, ret_ty)
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self.may_coerce(found, ret_ty)
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})
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}
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_ => false,
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@ -1510,7 +1510,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
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provided_ty
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};
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if !self.can_coerce(expected_ty, dummy_ty) {
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if !self.may_coerce(expected_ty, dummy_ty) {
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return;
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}
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let msg = format!("use `{adt_name}::map_or` to deref inner value of `{adt_name}`");
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@ -1534,7 +1534,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
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expected_ty: Ty<'tcx>,
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) {
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if let ty::Slice(elem_ty) | ty::Array(elem_ty, _) = expected_ty.kind() {
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if self.can_coerce(blk_ty, *elem_ty)
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if self.may_coerce(blk_ty, *elem_ty)
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&& blk.stmts.is_empty()
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&& blk.rules == hir::BlockCheckMode::DefaultBlock
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{
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@ -1744,7 +1744,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
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if item_ty.has_param() {
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return false;
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}
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if self.can_coerce(item_ty, expected_ty) {
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if self.may_coerce(item_ty, expected_ty) {
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err.span_suggestion_verbose(
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segment.ident.span,
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format!("try referring to the associated const `{capitalized_name}` instead",),
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@ -1804,7 +1804,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
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// diagnostic in cases where we have `(&&T).clone()` and we expect `T`).
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&& !results.expr_adjustments(callee_expr).iter().any(|adj| matches!(adj.kind, ty::adjustment::Adjust::Deref(..)))
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// Check that we're in fact trying to clone into the expected type
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&& self.can_coerce(*pointee_ty, expected_ty)
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&& self.may_coerce(*pointee_ty, expected_ty)
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&& let trait_ref = ty::TraitRef::new(self.tcx, clone_trait_did, [expected_ty])
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// And the expected type doesn't implement `Clone`
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&& !self.predicate_must_hold_considering_regions(&traits::Obligation::new(
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@ -2022,7 +2022,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
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} else {
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return false;
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};
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if is_ctor || !self.can_coerce(args.type_at(0), expected) {
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if is_ctor || !self.may_coerce(args.type_at(0), expected) {
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return false;
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}
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@ -2293,7 +2293,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
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.then(|| " (its field is private, but it's local to this crate and its privacy can be changed)".to_string());
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let sole_field_ty = sole_field.ty(self.tcx, args);
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if self.can_coerce(expr_ty, sole_field_ty) {
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if self.may_coerce(expr_ty, sole_field_ty) {
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let variant_path =
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with_no_trimmed_paths!(self.tcx.def_path_str(variant.def_id));
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// FIXME #56861: DRYer prelude filtering
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@ -2401,7 +2401,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
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}
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|
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let int_type = args.type_at(0);
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if !self.can_coerce(expr_ty, int_type) {
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if !self.may_coerce(expr_ty, int_type) {
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return false;
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}
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@ -2585,7 +2585,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
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Ty::new_imm_ref(self.tcx, self.tcx.lifetimes.re_static, checked_ty)
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}
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};
|
||||
if self.can_coerce(ref_ty, expected) {
|
||||
if self.may_coerce(ref_ty, expected) {
|
||||
let mut sugg_sp = sp;
|
||||
if let hir::ExprKind::MethodCall(segment, receiver, args, _) = expr.kind {
|
||||
let clone_trait =
|
||||
|
||||
@ -1934,7 +1934,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
|
||||
&& fn_sig.inputs()[1..]
|
||||
.iter()
|
||||
.zip(args.into_iter())
|
||||
.all(|(expected, found)| self.can_coerce(*expected, *found))
|
||||
.all(|(expected, found)| self.may_coerce(*expected, *found))
|
||||
&& fn_sig.inputs()[1..].len() == args.len()
|
||||
{
|
||||
err.span_suggestion_verbose(
|
||||
@ -4148,7 +4148,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
|
||||
return false;
|
||||
};
|
||||
|
||||
if !self.can_coerce(output, expected) {
|
||||
if !self.may_coerce(output, expected) {
|
||||
return false;
|
||||
}
|
||||
|
||||
|
||||
@ -1767,7 +1767,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
|
||||
} else if inexistent_fields.len() == 1 {
|
||||
match pat_field.pat.kind {
|
||||
PatKind::Lit(expr)
|
||||
if !self.can_coerce(
|
||||
if !self.may_coerce(
|
||||
self.typeck_results.borrow().expr_ty(expr),
|
||||
self.field_ty(field.span, field_def, args),
|
||||
) => {}
|
||||
|
||||
@ -0,0 +1,19 @@
|
||||
//@ compile-flags: -Znext-solver
|
||||
|
||||
trait Mirror {
|
||||
type Assoc;
|
||||
}
|
||||
impl<T> Mirror for T {
|
||||
type Assoc = T;
|
||||
}
|
||||
|
||||
fn arg() -> &'static [i32; 1] { todo!() }
|
||||
|
||||
fn arg_error(x: <fn() as Mirror>::Assoc, y: ()) { todo!() }
|
||||
|
||||
fn main() {
|
||||
// Should suggest to reverse the args...
|
||||
// but if we don't normalize the expected, then we don't.
|
||||
arg_error((), || ());
|
||||
//~^ ERROR arguments to this function are incorrect
|
||||
}
|
||||
@ -0,0 +1,21 @@
|
||||
error[E0308]: arguments to this function are incorrect
|
||||
--> $DIR/coerce-in-may-coerce.rs:17:5
|
||||
|
|
||||
LL | arg_error((), || ());
|
||||
| ^^^^^^^^^ -- ----- expected `()`, found `{closure@$DIR/coerce-in-may-coerce.rs:17:19: 17:21}`
|
||||
| |
|
||||
| expected `<fn() as Mirror>::Assoc`, found `()`
|
||||
|
|
||||
note: function defined here
|
||||
--> $DIR/coerce-in-may-coerce.rs:12:4
|
||||
|
|
||||
LL | fn arg_error(x: <fn() as Mirror>::Assoc, y: ()) { todo!() }
|
||||
| ^^^^^^^^^ -------------------------- -----
|
||||
help: swap these arguments
|
||||
|
|
||||
LL | arg_error(|| (), ());
|
||||
| ~~~~~~~~~~~
|
||||
|
||||
error: aborting due to 1 previous error
|
||||
|
||||
For more information about this error, try `rustc --explain E0308`.
|
||||
@ -1,3 +1,15 @@
|
||||
error[E0308]: mismatched types
|
||||
--> $DIR/lazy_subtyping_of_opaques.rs:11:5
|
||||
|
|
||||
LL | fn reify_as_tait() -> Thunk<Tait> {
|
||||
| ----------- expected `Thunk<_>` because of return type
|
||||
LL |
|
||||
LL | Thunk::new(|cont| cont)
|
||||
| ^^^^^^^^^^^^^^^^^^^^^^^ expected `Thunk<_>`, found `()`
|
||||
|
|
||||
= note: expected struct `Thunk<_>`
|
||||
found unit type `()`
|
||||
|
||||
error[E0277]: expected a `FnOnce()` closure, found `()`
|
||||
--> $DIR/lazy_subtyping_of_opaques.rs:11:23
|
||||
|
|
||||
@ -12,19 +24,13 @@ error[E0277]: expected a `FnOnce()` closure, found `()`
|
||||
|
|
||||
LL | fn reify_as_tait() -> Thunk<Tait> {
|
||||
| ^^^^^^^^^^^ expected an `FnOnce()` closure, found `()`
|
||||
LL |
|
||||
LL | Thunk::new(|cont| cont)
|
||||
| ----------------------- return type was inferred to be `{type error}` here
|
||||
|
|
||||
= help: the trait `FnOnce()` is not implemented for `()`
|
||||
= note: wrap the `()` in a closure with no arguments: `|| { /* code */ }`
|
||||
|
||||
error[E0308]: mismatched types
|
||||
--> $DIR/lazy_subtyping_of_opaques.rs:11:5
|
||||
|
|
||||
LL | Thunk::new(|cont| cont)
|
||||
| ^^^^^^^^^^^^^^^^^^^^^^^ expected `Thunk<_>`, found `()`
|
||||
|
|
||||
= note: expected struct `Thunk<_>`
|
||||
found unit type `()`
|
||||
|
||||
error: aborting due to 3 previous errors
|
||||
|
||||
Some errors have detailed explanations: E0277, E0308.
|
||||
|
||||
Loading…
Reference in New Issue
Block a user