diff options
Diffstat (limited to 'compiler/rustc_trait_selection/src/traits/codegen.rs')
-rw-r--r-- | compiler/rustc_trait_selection/src/traits/codegen.rs | 89 |
1 files changed, 0 insertions, 89 deletions
diff --git a/compiler/rustc_trait_selection/src/traits/codegen.rs b/compiler/rustc_trait_selection/src/traits/codegen.rs deleted file mode 100644 index 8a62bf015..000000000 --- a/compiler/rustc_trait_selection/src/traits/codegen.rs +++ /dev/null @@ -1,89 +0,0 @@ -// This file contains various trait resolution methods used by codegen. -// They all assume regions can be erased and monomorphic types. It -// seems likely that they should eventually be merged into more -// general routines. - -use crate::infer::{DefiningAnchor, TyCtxtInferExt}; -use crate::traits::error_reporting::TypeErrCtxtExt; -use crate::traits::{ - ImplSource, Obligation, ObligationCause, SelectionContext, TraitEngine, TraitEngineExt, - Unimplemented, -}; -use rustc_infer::traits::FulfillmentErrorCode; -use rustc_middle::traits::CodegenObligationError; -use rustc_middle::ty::{self, TyCtxt}; - -/// Attempts to resolve an obligation to an `ImplSource`. The result is -/// a shallow `ImplSource` resolution, meaning that we do not -/// (necessarily) resolve all nested obligations on the impl. Note -/// that type check should guarantee to us that all nested -/// obligations *could be* resolved if we wanted to. -/// -/// This also expects that `trait_ref` is fully normalized. -pub fn codegen_select_candidate<'tcx>( - tcx: TyCtxt<'tcx>, - (param_env, trait_ref): (ty::ParamEnv<'tcx>, ty::PolyTraitRef<'tcx>), -) -> Result<&'tcx ImplSource<'tcx, ()>, CodegenObligationError> { - // We expect the input to be fully normalized. - debug_assert_eq!(trait_ref, tcx.normalize_erasing_regions(param_env, trait_ref)); - - // Do the initial selection for the obligation. This yields the - // shallow result we are looking for -- that is, what specific impl. - let infcx = tcx - .infer_ctxt() - .ignoring_regions() - .with_opaque_type_inference(DefiningAnchor::Bubble) - .build(); - //~^ HACK `Bubble` is required for - // this test to pass: type-alias-impl-trait/assoc-projection-ice.rs - let mut selcx = SelectionContext::new(&infcx); - - let obligation_cause = ObligationCause::dummy(); - let obligation = - Obligation::new(obligation_cause, param_env, trait_ref.to_poly_trait_predicate()); - - let selection = match selcx.select(&obligation) { - Ok(Some(selection)) => selection, - Ok(None) => return Err(CodegenObligationError::Ambiguity), - Err(Unimplemented) => return Err(CodegenObligationError::Unimplemented), - Err(e) => { - bug!("Encountered error `{:?}` selecting `{:?}` during codegen", e, trait_ref) - } - }; - - debug!(?selection); - - // Currently, we use a fulfillment context to completely resolve - // all nested obligations. This is because they can inform the - // inference of the impl's type parameters. - let mut fulfill_cx = <dyn TraitEngine<'tcx>>::new(tcx); - let impl_source = selection.map(|predicate| { - fulfill_cx.register_predicate_obligation(&infcx, predicate); - }); - - // In principle, we only need to do this so long as `impl_source` - // contains unbound type parameters. It could be a slight - // optimization to stop iterating early. - let errors = fulfill_cx.select_all_or_error(&infcx); - if !errors.is_empty() { - // `rustc_monomorphize::collector` assumes there are no type errors. - // Cycle errors are the only post-monomorphization errors possible; emit them now so - // `rustc_ty_utils::resolve_associated_item` doesn't return `None` post-monomorphization. - for err in errors { - if let FulfillmentErrorCode::CodeCycle(cycle) = err.code { - infcx.err_ctxt().report_overflow_error_cycle(&cycle); - } - } - return Err(CodegenObligationError::FulfillmentError); - } - - let impl_source = infcx.resolve_vars_if_possible(impl_source); - let impl_source = infcx.tcx.erase_regions(impl_source); - - // Opaque types may have gotten their hidden types constrained, but we can ignore them safely - // as they will get constrained elsewhere, too. - // (ouz-a) This is required for `type-alias-impl-trait/assoc-projection-ice.rs` to pass - let _ = infcx.inner.borrow_mut().opaque_type_storage.take_opaque_types(); - - Ok(&*tcx.arena.alloc(impl_source)) -} |