1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
|
// Copyright 2018 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 rustc::traits::query::CanonicalPredicateGoal;
use rustc::traits::{
EvaluationResult, Obligation, ObligationCause, OverflowError, SelectionContext, TraitQueryMode,
};
use rustc::ty::query::Providers;
use rustc::ty::{ParamEnvAnd, TyCtxt};
use syntax::source_map::DUMMY_SP;
crate fn provide(p: &mut Providers) {
*p = Providers {
evaluate_obligation,
..*p
};
}
fn evaluate_obligation<'tcx>(
tcx: TyCtxt<'_, 'tcx, 'tcx>,
canonical_goal: CanonicalPredicateGoal<'tcx>,
) -> Result<EvaluationResult, OverflowError> {
tcx.infer_ctxt().enter_with_canonical(
DUMMY_SP,
&canonical_goal,
|ref infcx, goal, _canonical_inference_vars| {
let ParamEnvAnd {
param_env,
value: predicate,
} = goal;
let mut selcx = SelectionContext::with_query_mode(&infcx, TraitQueryMode::Canonical);
let obligation = Obligation::new(ObligationCause::dummy(), param_env, predicate);
selcx.evaluate_obligation_recursively(&obligation)
},
)
}
|
