/
input_output.rs
178 lines (160 loc) · 7.07 KB
/
input_output.rs
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
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
//! This module contains code to equate the input/output types appearing
//! in the MIR with the expected input/output types from the function
//! signature. This requires a bit of processing, as the expected types
//! are supplied to us before normalization and may contain opaque
//! `impl Trait` instances. In contrast, the input/output types found in
//! the MIR (specifically, in the special local variables for the
//! `RETURN_PLACE` the MIR arguments) are always fully normalized (and
//! contain revealed `impl Trait` values).
use rustc_infer::infer::LateBoundRegionConversionTime;
use rustc_middle::mir::*;
use rustc_middle::ty::Ty;
use rustc_index::vec::Idx;
use rustc_span::Span;
use crate::borrow_check::universal_regions::UniversalRegions;
use super::{Locations, TypeChecker};
impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
pub(super) fn equate_inputs_and_outputs(
&mut self,
body: &Body<'tcx>,
universal_regions: &UniversalRegions<'tcx>,
normalized_inputs_and_output: &[Ty<'tcx>],
) {
let (&normalized_output_ty, normalized_input_tys) =
normalized_inputs_and_output.split_last().unwrap();
let mir_def_id = body.source.def_id().expect_local();
// If the user explicitly annotated the input types, extract
// those.
//
// e.g., `|x: FxHashMap<_, &'static u32>| ...`
let user_provided_sig;
if !self.tcx().is_closure(mir_def_id.to_def_id()) {
user_provided_sig = None;
} else {
let typeck_results = self.tcx().typeck(mir_def_id);
user_provided_sig = typeck_results.user_provided_sigs.get(&mir_def_id.to_def_id()).map(
|user_provided_poly_sig| {
// Instantiate the canonicalized variables from
// user-provided signature (e.g., the `_` in the code
// above) with fresh variables.
let (poly_sig, _) = self.infcx.instantiate_canonical_with_fresh_inference_vars(
body.span,
&user_provided_poly_sig,
);
// Replace the bound items in the fn sig with fresh
// variables, so that they represent the view from
// "inside" the closure.
self.infcx
.replace_bound_vars_with_fresh_vars(
body.span,
LateBoundRegionConversionTime::FnCall,
poly_sig,
)
.0
},
);
}
debug!(
"equate_inputs_and_outputs: normalized_input_tys = {:?}, local_decls = {:?}",
normalized_input_tys, body.local_decls
);
// Equate expected input tys with those in the MIR.
for (argument_index, &normalized_input_ty) in normalized_input_tys.iter().enumerate() {
if argument_index + 1 >= body.local_decls.len() {
self.tcx()
.sess
.delay_span_bug(body.span, "found more normalized_input_ty than local_decls");
break;
}
// In MIR, argument N is stored in local N+1.
let local = Local::new(argument_index + 1);
let mir_input_ty = body.local_decls[local].ty;
let mir_input_span = body.local_decls[local].source_info.span;
self.equate_normalized_input_or_output(
normalized_input_ty,
mir_input_ty,
mir_input_span,
);
}
if let Some(user_provided_sig) = user_provided_sig {
for (argument_index, &user_provided_input_ty) in
user_provided_sig.inputs().iter().enumerate()
{
// In MIR, closures begin an implicit `self`, so
// argument N is stored in local N+2.
let local = Local::new(argument_index + 2);
let mir_input_ty = body.local_decls[local].ty;
let mir_input_span = body.local_decls[local].source_info.span;
// If the user explicitly annotated the input types, enforce those.
let user_provided_input_ty =
self.normalize(user_provided_input_ty, Locations::All(mir_input_span));
self.equate_normalized_input_or_output(
user_provided_input_ty,
mir_input_ty,
mir_input_span,
);
}
}
assert!(body.yield_ty().is_some() == universal_regions.yield_ty.is_some());
if let Some(mir_yield_ty) = body.yield_ty() {
let ur_yield_ty = universal_regions.yield_ty.unwrap();
let yield_span = body.local_decls[RETURN_PLACE].source_info.span;
self.equate_normalized_input_or_output(ur_yield_ty, mir_yield_ty, yield_span);
}
// Return types are a bit more complex. They may contain opaque `impl Trait` types.
let mir_output_ty = body.local_decls[RETURN_PLACE].ty;
let output_span = body.local_decls[RETURN_PLACE].source_info.span;
if let Err(terr) = self.eq_opaque_type_and_type(
mir_output_ty,
normalized_output_ty,
Locations::All(output_span),
ConstraintCategory::BoringNoLocation,
) {
span_mirbug!(
self,
Location::START,
"equate_inputs_and_outputs: `{:?}=={:?}` failed with `{:?}`",
normalized_output_ty,
mir_output_ty,
terr
);
};
// If the user explicitly annotated the output types, enforce those.
// Note that this only happens for closures.
if let Some(user_provided_sig) = user_provided_sig {
let user_provided_output_ty = user_provided_sig.output();
let user_provided_output_ty =
self.normalize(user_provided_output_ty, Locations::All(output_span));
if let Err(err) = self.eq_opaque_type_and_type(
mir_output_ty,
user_provided_output_ty,
Locations::All(output_span),
ConstraintCategory::BoringNoLocation,
) {
span_mirbug!(
self,
Location::START,
"equate_inputs_and_outputs: `{:?}=={:?}` failed with `{:?}`",
mir_output_ty,
user_provided_output_ty,
err
);
}
}
}
fn equate_normalized_input_or_output(&mut self, a: Ty<'tcx>, b: Ty<'tcx>, span: Span) {
debug!("equate_normalized_input_or_output(a={:?}, b={:?})", a, b);
if let Err(terr) =
self.eq_types(a, b, Locations::All(span), ConstraintCategory::BoringNoLocation)
{
span_mirbug!(
self,
Location::START,
"equate_normalized_input_or_output: `{:?}=={:?}` failed with `{:?}`",
a,
b,
terr
);
}
}
}