56 lines
2.2 KiB
Rust
56 lines
2.2 KiB
Rust
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// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use rustc::infer::canonical::{Canonical, QueryResult};
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use rustc::traits::{self, FulfillmentContext, Normalized, ObligationCause,
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SelectionContext};
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use rustc::traits::query::{CanonicalProjectionGoal, NoSolution, normalize::NormalizationResult};
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use rustc::ty::{ParamEnvAnd, TyCtxt};
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use rustc::util::common::CellUsizeExt;
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use std::rc::Rc;
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use syntax::ast::DUMMY_NODE_ID;
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use syntax_pos::DUMMY_SP;
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use util;
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crate fn normalize_projection_ty<'tcx>(
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tcx: TyCtxt<'_, 'tcx, 'tcx>,
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goal: CanonicalProjectionGoal<'tcx>,
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) -> Result<Rc<Canonical<'tcx, QueryResult<'tcx, NormalizationResult<'tcx>>>>, NoSolution> {
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debug!("normalize_provider(goal={:#?})", goal);
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tcx.sess.perf_stats.normalize_projection_ty.increment();
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tcx.infer_ctxt().enter(|ref infcx| {
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let (
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ParamEnvAnd {
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param_env,
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value: goal,
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},
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canonical_inference_vars,
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) = infcx.instantiate_canonical_with_fresh_inference_vars(DUMMY_SP, &goal);
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let fulfill_cx = &mut FulfillmentContext::new();
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let selcx = &mut SelectionContext::new(infcx);
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let cause = ObligationCause::misc(DUMMY_SP, DUMMY_NODE_ID);
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let Normalized {
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value: answer,
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obligations,
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} = traits::normalize_projection_type(selcx, param_env, goal, cause, 0);
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fulfill_cx.register_predicate_obligations(infcx, obligations);
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// Now that we have fulfilled as much as we can, create a solution
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// from what we've learned.
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util::make_query_response(
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infcx,
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canonical_inference_vars,
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NormalizationResult { normalized_ty: answer },
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fulfill_cx,
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)
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})
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}
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