Auto merge of #30676 - nikomatsakis:issue-29857, r=arielb1
This is an alternative to https://github.com/rust-lang/rust/pull/29954 for fixing #29857 that seems to me to be more inline with the general strategy around `TyError`. It also includes the fix for #30589 -- in fact, just the minimal change of making `ty_is_local` tolerate `TyError` avoids the ICE, but you get a lot of duplicate error reports, so in the case where the impl's trait reference already includes `TyError`, we just ignore the impl altogether. cc @arielb1 @sanxiyn Fixes #29857. Fixes #30589.
This commit is contained in:
bors
commit
d01ed8ad8e
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@ -63,9 +63,9 @@ fn overlap<'cx, 'tcx>(selcx: &mut SelectionContext<'cx, 'tcx>,
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b_def_id,
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util::fresh_type_vars_for_impl);
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debug!("overlap: a_trait_ref={:?}", a_trait_ref);
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debug!("overlap: a_trait_ref={:?} a_obligations={:?}", a_trait_ref, a_obligations);
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debug!("overlap: b_trait_ref={:?}", b_trait_ref);
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debug!("overlap: b_trait_ref={:?} b_obligations={:?}", b_trait_ref, b_obligations);
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// Do `a` and `b` unify? If not, no overlap.
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if let Err(_) = infer::mk_eq_trait_refs(selcx.infcx(),
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@ -330,8 +330,11 @@ fn ty_is_local_constructor<'tcx>(tcx: &ty::ctxt<'tcx>,
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tt.principal_def_id().is_local()
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}
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ty::TyClosure(..) |
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ty::TyError => {
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true
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}
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ty::TyClosure(..) => {
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tcx.sess.bug(
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&format!("ty_is_local invoked on unexpected type: {:?}",
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ty))
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@ -426,11 +426,25 @@ fn opt_normalize_projection_type<'a,'b,'tcx>(
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}
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}
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/// in various error cases, we just set TyError and return an obligation
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/// that, when fulfilled, will lead to an error.
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/// If we are projecting `<T as Trait>::Item`, but `T: Trait` does not
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/// hold. In various error cases, we cannot generate a valid
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/// normalized projection. Therefore, we create an inference variable
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/// return an associated obligation that, when fulfilled, will lead to
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/// an error.
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///
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/// FIXME: the TyError created here can enter the obligation we create,
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/// leading to error messages involving TyError.
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/// Note that we used to return `TyError` here, but that was quite
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/// dubious -- the premise was that an error would *eventually* be
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/// reported, when the obligation was processed. But in general once
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/// you see a `TyError` you are supposed to be able to assume that an
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/// error *has been* reported, so that you can take whatever heuristic
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/// paths you want to take. To make things worse, it was possible for
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/// cycles to arise, where you basically had a setup like `<MyType<$0>
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/// as Trait>::Foo == $0`. Here, normalizing `<MyType<$0> as
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/// Trait>::Foo> to `[type error]` would lead to an obligation of
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/// `<MyType<[type error]> as Trait>::Foo`. We are supposed to report
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/// an error for this obligation, but we legitimately should not,
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/// because it contains `[type error]`. Yuck! (See issue #29857 for
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/// one case where this arose.)
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fn normalize_to_error<'a,'tcx>(selcx: &mut SelectionContext<'a,'tcx>,
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projection_ty: ty::ProjectionTy<'tcx>,
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cause: ObligationCause<'tcx>,
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@ -441,8 +455,9 @@ fn normalize_to_error<'a,'tcx>(selcx: &mut SelectionContext<'a,'tcx>,
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let trait_obligation = Obligation { cause: cause,
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recursion_depth: depth,
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predicate: trait_ref.to_predicate() };
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let new_value = selcx.infcx().next_ty_var();
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Normalized {
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value: selcx.tcx().types.err,
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value: new_value,
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obligations: vec!(trait_obligation)
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}
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}
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@ -210,8 +210,6 @@ enum SelectionCandidate<'tcx> {
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BuiltinObjectCandidate,
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BuiltinUnsizeCandidate,
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ErrorCandidate,
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}
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struct SelectionCandidateSet<'tcx> {
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@ -753,8 +751,15 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
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stack: &TraitObligationStack<'o, 'tcx>)
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-> SelectionResult<'tcx, SelectionCandidate<'tcx>>
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{
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if stack.obligation.predicate.0.self_ty().references_error() {
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return Ok(Some(ErrorCandidate));
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if stack.obligation.predicate.references_error() {
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// If we encounter a `TyError`, we generally prefer the
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// most "optimistic" result in response -- that is, the
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// one least likely to report downstream errors. But
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// because this routine is shared by coherence and by
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// trait selection, there isn't an obvious "right" choice
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// here in that respect, so we opt to just return
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// ambiguity and let the upstream clients sort it out.
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return Ok(None);
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}
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if !self.is_knowable(stack) {
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@ -1587,7 +1592,6 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
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true
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},
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&ParamCandidate(..) => false,
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&ErrorCandidate => false // propagate errors
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},
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_ => false
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}
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@ -1998,10 +2002,6 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
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try!(self.confirm_builtin_candidate(obligation, builtin_bound))))
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}
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ErrorCandidate => {
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Ok(VtableBuiltin(VtableBuiltinData { nested: vec![] }))
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}
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ParamCandidate(param) => {
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let obligations = self.confirm_param_candidate(obligation, param);
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Ok(VtableParam(obligations))
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@ -69,6 +69,7 @@ use middle::ty::adjustment::{AutoAdjustment, AutoDerefRef, AdjustDerefRef};
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use middle::ty::adjustment::{AutoPtr, AutoUnsafe, AdjustReifyFnPointer};
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use middle::ty::adjustment::{AdjustUnsafeFnPointer};
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use middle::ty::{self, LvaluePreference, TypeAndMut, Ty};
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use middle::ty::fold::TypeFoldable;
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use middle::ty::error::TypeError;
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use middle::ty::relate::RelateResult;
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use util::common::indent;
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@ -110,10 +111,15 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
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a,
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b);
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let a = self.fcx.infcx().shallow_resolve(a);
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// Just ignore error types.
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if a.references_error() || b.references_error() {
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return Ok(None);
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}
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// Consider coercing the subtype to a DST
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let unsize = self.unpack_actual_value(a, |a| {
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self.coerce_unsized(a, b)
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});
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let unsize = self.coerce_unsized(a, b);
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if unsize.is_ok() {
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return unsize;
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}
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@ -124,39 +130,33 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
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// See above for details.
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match b.sty {
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ty::TyRawPtr(mt_b) => {
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return self.unpack_actual_value(a, |a| {
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self.coerce_unsafe_ptr(a, b, mt_b.mutbl)
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});
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return self.coerce_unsafe_ptr(a, b, mt_b.mutbl);
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}
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ty::TyRef(_, mt_b) => {
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return self.unpack_actual_value(a, |a| {
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self.coerce_borrowed_pointer(expr_a, a, b, mt_b.mutbl)
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});
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return self.coerce_borrowed_pointer(expr_a, a, b, mt_b.mutbl);
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}
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_ => {}
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}
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self.unpack_actual_value(a, |a| {
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match a.sty {
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ty::TyBareFn(Some(_), a_f) => {
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// Function items are coercible to any closure
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// type; function pointers are not (that would
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// require double indirection).
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self.coerce_from_fn_item(a, a_f, b)
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}
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ty::TyBareFn(None, a_f) => {
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// We permit coercion of fn pointers to drop the
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// unsafe qualifier.
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self.coerce_from_fn_pointer(a, a_f, b)
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}
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_ => {
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// Otherwise, just use subtyping rules.
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self.subtype(a, b)
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}
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match a.sty {
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ty::TyBareFn(Some(_), a_f) => {
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// Function items are coercible to any closure
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// type; function pointers are not (that would
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// require double indirection).
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self.coerce_from_fn_item(a, a_f, b)
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}
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})
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ty::TyBareFn(None, a_f) => {
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// We permit coercion of fn pointers to drop the
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// unsafe qualifier.
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self.coerce_from_fn_pointer(a, a_f, b)
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}
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_ => {
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// Otherwise, just use subtyping rules.
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self.subtype(a, b)
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}
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}
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}
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/// Reborrows `&mut A` to `&mut B` and `&(mut) A` to `&B`.
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@ -1038,6 +1038,9 @@ fn report_cast_to_unsized_type<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
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t_cast: Ty<'tcx>,
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t_expr: Ty<'tcx>,
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id: ast::NodeId) {
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if t_cast.references_error() || t_expr.references_error() {
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return;
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}
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let tstr = fcx.infcx().ty_to_string(t_cast);
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let mut err = fcx.type_error_struct(span, |actual| {
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format!("cast to unsized type: `{}` as `{}`", actual, tstr)
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@ -3511,9 +3514,10 @@ fn check_expr_with_unifier<'a, 'tcx, F>(fcx: &FnCtxt<'a, 'tcx>,
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let t_cast = structurally_resolved_type(fcx, expr.span, t_cast);
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check_expr_with_expectation(fcx, e, ExpectCastableToType(t_cast));
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let t_expr = fcx.expr_ty(e);
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let t_cast = fcx.infcx().resolve_type_vars_if_possible(&t_cast);
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// Eagerly check for some obvious errors.
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if t_expr.references_error() {
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if t_expr.references_error() || t_cast.references_error() {
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fcx.write_error(id);
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} else if !fcx.type_is_known_to_be_sized(t_cast, expr.span) {
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report_cast_to_unsized_type(fcx, expr.span, t.span, e.span, t_cast, t_expr, id);
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|
|
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@ -149,11 +149,23 @@ impl<'a, 'tcx> CoherenceChecker<'a, 'tcx> {
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trait_ref,
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item.name);
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// Skip impls where one of the self type is an error type.
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// This occurs with e.g. resolve failures (#30589).
|
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if trait_ref.references_error() {
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return;
|
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}
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enforce_trait_manually_implementable(self.crate_context.tcx,
|
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item.span,
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trait_ref.def_id);
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self.add_trait_impl(trait_ref, impl_did);
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} else {
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// Skip inherent impls where the self type is an error
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// type. This occurs with e.g. resolve failures (#30589).
|
||||
if self_type.ty.references_error() {
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return;
|
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}
|
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|
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// Add the implementation to the mapping from implementation to base
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// type def ID, if there is a base type for this implementation and
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// the implementation does not have any associated traits.
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|
|
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|
|
@ -0,0 +1,28 @@
|
|||
// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
|
||||
// file at the top-level directory of this distribution and at
|
||||
// http://rust-lang.org/COPYRIGHT.
|
||||
//
|
||||
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
|
||||
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
|
||||
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
|
||||
// option. This file may not be copied, modified, or distributed
|
||||
// except according to those terms.
|
||||
|
||||
#![feature(rustc_attrs)]
|
||||
|
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// Here we expect a coherence conflict because, even though `i32` does
|
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// not implement `Iterator`, we cannot rely on that negative reasoning
|
||||
// due to the orphan rules. Therefore, `A::Item` may yet turn out to
|
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// be `i32`.
|
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|
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pub trait Foo<P> {}
|
||||
|
||||
pub trait Bar {
|
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type Output: 'static;
|
||||
}
|
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|
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impl Foo<i32> for i32 { } //~ ERROR E0119
|
||||
|
||||
impl<A:Iterator> Foo<A::Item> for A { }
|
||||
|
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fn main() {}
|
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|
|
@ -0,0 +1,22 @@
|
|||
// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
|
||||
// file at the top-level directory of this distribution and at
|
||||
// http://rust-lang.org/COPYRIGHT.
|
||||
//
|
||||
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
|
||||
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
|
||||
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
|
||||
// option. This file may not be copied, modified, or distributed
|
||||
// except according to those terms.
|
||||
|
||||
// Coherence error results because we do not know whether `T: Foo<P>` or not
|
||||
// for the second impl.
|
||||
|
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use std::marker::PhantomData;
|
||||
|
||||
pub trait Foo<P> {}
|
||||
|
||||
impl <P, T: Foo<P>> Foo<P> for Option<T> {} //~ ERROR E0119
|
||||
|
||||
impl<T, U> Foo<T> for Option<U> { }
|
||||
|
||||
fn main() {}
|
||||
|
|
@ -0,0 +1,27 @@
|
|||
// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
|
||||
// file at the top-level directory of this distribution and at
|
||||
// http://rust-lang.org/COPYRIGHT.
|
||||
//
|
||||
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
|
||||
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
|
||||
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
|
||||
// option. This file may not be copied, modified, or distributed
|
||||
// except according to those terms.
|
||||
|
||||
use std::marker::PhantomData;
|
||||
|
||||
pub trait Foo<P> {}
|
||||
|
||||
pub trait Bar {
|
||||
type Output: 'static;
|
||||
}
|
||||
|
||||
impl Foo<i32> for i32 { } //~ ERROR E0119
|
||||
|
||||
impl<A:Bar> Foo<A::Output> for A { }
|
||||
|
||||
impl Bar for i32 {
|
||||
type Output = i32;
|
||||
}
|
||||
|
||||
fn main() {}
|
||||
|
|
@ -0,0 +1,29 @@
|
|||
// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
|
||||
// file at the top-level directory of this distribution and at
|
||||
// http://rust-lang.org/COPYRIGHT.
|
||||
//
|
||||
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
|
||||
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
|
||||
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
|
||||
// option. This file may not be copied, modified, or distributed
|
||||
// except according to those terms.
|
||||
|
||||
#![feature(rustc_attrs)]
|
||||
#![allow(dead_code)]
|
||||
|
||||
// Here we do not get a coherence conflict because `Baz: Iterator`
|
||||
// does not hold and (due to the orphan rules), we can rely on that.
|
||||
|
||||
pub trait Foo<P> {}
|
||||
|
||||
pub trait Bar {
|
||||
type Output: 'static;
|
||||
}
|
||||
|
||||
struct Baz;
|
||||
impl Foo<i32> for Baz { }
|
||||
|
||||
impl<A:Iterator> Foo<A::Item> for A { }
|
||||
|
||||
#[rustc_error]
|
||||
fn main() {} //~ ERROR compilation successful
|
||||
|
|
@ -0,0 +1,28 @@
|
|||
// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
|
||||
// file at the top-level directory of this distribution and at
|
||||
// http://rust-lang.org/COPYRIGHT.
|
||||
//
|
||||
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
|
||||
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
|
||||
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
|
||||
// option. This file may not be copied, modified, or distributed
|
||||
// except according to those terms.
|
||||
|
||||
#![feature(rustc_attrs)]
|
||||
|
||||
pub trait Foo<P> {}
|
||||
|
||||
pub trait Bar {
|
||||
type Output: 'static;
|
||||
}
|
||||
|
||||
impl Foo<i32> for i32 { }
|
||||
|
||||
impl<A:Bar> Foo<A::Output> for A { }
|
||||
|
||||
impl Bar for i32 {
|
||||
type Output = u32;
|
||||
}
|
||||
|
||||
#[rustc_error]
|
||||
fn main() {} //~ ERROR compilation successful
|
||||
|
|
@ -22,7 +22,7 @@ use std::{u8, u16, u32, u64, usize};
|
|||
const A_I8_T
|
||||
: [u32; (i8::MAX as i8 + 1u8) as usize]
|
||||
//~^ ERROR mismatched types
|
||||
//~| the trait `core::ops::Add<u8>` is not implemented for the type `i8`
|
||||
//~| ERROR the trait `core::ops::Add<u8>` is not implemented for the type `i8`
|
||||
= [0; (i8::MAX as usize) + 1];
|
||||
|
||||
fn main() {
|
||||
|
|
|
|||
|
|
@ -12,7 +12,7 @@ struct Homura;
|
|||
|
||||
fn akemi(homura: Homura) {
|
||||
let Some(ref madoka) = Some(homura.kaname()); //~ ERROR no method named `kaname` found
|
||||
madoka.clone(); //~ ERROR the type of this value must be known in this context
|
||||
madoka.clone(); //~ ERROR the type of this value must be known
|
||||
}
|
||||
|
||||
fn main() { }
|
||||
|
|
|
|||
|
|
@ -16,5 +16,5 @@ fn main() {
|
|||
let x = &10 as
|
||||
&Add;
|
||||
//~^ ERROR the type parameter `RHS` must be explicitly specified in an object type because its default value `Self` references the type `Self`
|
||||
//~^^ ERROR the value of the associated type `Output` (from the trait `core::ops::Add`) must be specified
|
||||
//~| ERROR the value of the associated type `Output` (from the trait `core::ops::Add`) must be specified
|
||||
}
|
||||
|
|
|
|||
|
|
@ -9,5 +9,7 @@
|
|||
// except according to those terms.
|
||||
|
||||
fn main() {
|
||||
"".chars().fold(|_, _| (), ()); //~ ERROR is not implemented for the type `()`
|
||||
"".chars().fold(|_, _| (), ());
|
||||
//~^ ERROR E0277
|
||||
//~| ERROR E0277
|
||||
}
|
||||
|
|
|
|||
|
|
@ -10,5 +10,5 @@
|
|||
|
||||
fn main() {
|
||||
1.0f64 - 1.0;
|
||||
1.0f64 - 1 //~ ERROR: is not implemented
|
||||
1.0f64 - 1 //~ ERROR E0277
|
||||
}
|
||||
|
|
|
|||
|
|
@ -0,0 +1,31 @@
|
|||
// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
|
||||
// file at the top-level directory of this distribution and at
|
||||
// http://rust-lang.org/COPYRIGHT.
|
||||
//
|
||||
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
|
||||
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
|
||||
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
|
||||
// option. This file may not be copied, modified, or distributed
|
||||
// except according to those terms.
|
||||
|
||||
|
||||
#![feature(rustc_attrs)]
|
||||
|
||||
use std::marker::PhantomData;
|
||||
|
||||
pub trait Foo<P> {}
|
||||
|
||||
impl <P, T: Foo<P>> Foo<P> for Option<T> {}
|
||||
|
||||
pub struct Qux<T> (PhantomData<*mut T>);
|
||||
|
||||
impl<T> Foo<*mut T> for Option<Qux<T>> {}
|
||||
|
||||
pub trait Bar {
|
||||
type Output: 'static;
|
||||
}
|
||||
|
||||
impl<T: 'static, W: Bar<Output = T>> Foo<*mut T> for W {}
|
||||
|
||||
#[rustc_error]
|
||||
fn main() {} //~ ERROR compilation successful
|
||||
|
|
@ -0,0 +1,19 @@
|
|||
// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
|
||||
// file at the top-level directory of this distribution and at
|
||||
// http://rust-lang.org/COPYRIGHT.
|
||||
//
|
||||
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
|
||||
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
|
||||
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
|
||||
// option. This file may not be copied, modified, or distributed
|
||||
// except according to those terms.
|
||||
|
||||
use std::fmt;
|
||||
|
||||
impl fmt::Display for DecoderError { //~ ERROR E0412
|
||||
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
|
||||
write!(f, "Missing data: {}", self.0)
|
||||
}
|
||||
}
|
||||
fn main() {
|
||||
}
|
||||
|
|
@ -31,6 +31,5 @@ impl ToString_ for Point {
|
|||
fn main() {
|
||||
let p = Point::new(0.0, 0.0);
|
||||
//~^ ERROR no associated item named `new` found for type `Point` in the current scope
|
||||
println!("{}", p.to_string());
|
||||
//~^ ERROR the type of this value must be known in this context
|
||||
println!("{}", p.to_string()); //~ ERROR type of this value must be known
|
||||
}
|
||||
|
|
|
|||
Loading…
Reference in New Issue