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
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
|
//! Trait solving using Chalk.
use std::{env::var, sync::Arc};
use chalk_ir::GoalData;
use chalk_recursive::Cache;
use chalk_solve::{logging_db::LoggingRustIrDatabase, Solver};
use base_db::CrateId;
use hir_def::{
lang_item::{LangItem, LangItemTarget},
TraitId,
};
use stdx::panic_context;
use crate::{
db::HirDatabase, infer::unify::InferenceTable, AliasEq, AliasTy, Canonical, DomainGoal, Goal,
Guidance, InEnvironment, Interner, ProjectionTy, ProjectionTyExt, Solution, TraitRefExt, Ty,
TyKind, WhereClause,
};
/// This controls how much 'time' we give the Chalk solver before giving up.
const CHALK_SOLVER_FUEL: i32 = 1000;
#[derive(Debug, Copy, Clone)]
pub(crate) struct ChalkContext<'a> {
pub(crate) db: &'a dyn HirDatabase,
pub(crate) krate: CrateId,
}
fn create_chalk_solver() -> chalk_recursive::RecursiveSolver<Interner> {
let overflow_depth =
var("CHALK_OVERFLOW_DEPTH").ok().and_then(|s| s.parse().ok()).unwrap_or(500);
let max_size = var("CHALK_SOLVER_MAX_SIZE").ok().and_then(|s| s.parse().ok()).unwrap_or(150);
chalk_recursive::RecursiveSolver::new(overflow_depth, max_size, Some(Cache::new()))
}
/// A set of clauses that we assume to be true. E.g. if we are inside this function:
/// ```rust
/// fn foo<T: Default>(t: T) {}
/// ```
/// we assume that `T: Default`.
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub struct TraitEnvironment {
pub krate: CrateId,
// FIXME make this a BTreeMap
pub(crate) traits_from_clauses: Vec<(Ty, TraitId)>,
pub env: chalk_ir::Environment<Interner>,
}
impl TraitEnvironment {
pub fn empty(krate: CrateId) -> Self {
TraitEnvironment {
krate,
traits_from_clauses: Vec::new(),
env: chalk_ir::Environment::new(Interner),
}
}
pub fn traits_in_scope_from_clauses(&self, ty: Ty) -> impl Iterator<Item = TraitId> + '_ {
self.traits_from_clauses
.iter()
.filter_map(move |(self_ty, trait_id)| (*self_ty == ty).then_some(*trait_id))
}
}
pub(crate) fn normalize_projection_query(
db: &dyn HirDatabase,
projection: ProjectionTy,
env: Arc<TraitEnvironment>,
) -> Ty {
let mut table = InferenceTable::new(db, env);
let ty = table.normalize_projection_ty(projection);
table.resolve_completely(ty)
}
/// Solve a trait goal using Chalk.
pub(crate) fn trait_solve_query(
db: &dyn HirDatabase,
krate: CrateId,
goal: Canonical<InEnvironment<Goal>>,
) -> Option<Solution> {
let _p = profile::span("trait_solve_query").detail(|| match &goal.value.goal.data(Interner) {
GoalData::DomainGoal(DomainGoal::Holds(WhereClause::Implemented(it))) => {
db.trait_data(it.hir_trait_id()).name.to_string()
}
GoalData::DomainGoal(DomainGoal::Holds(WhereClause::AliasEq(_))) => "alias_eq".to_string(),
_ => "??".to_string(),
});
tracing::info!("trait_solve_query({:?})", goal.value.goal);
if let GoalData::DomainGoal(DomainGoal::Holds(WhereClause::AliasEq(AliasEq {
alias: AliasTy::Projection(projection_ty),
..
}))) = &goal.value.goal.data(Interner)
{
if let TyKind::BoundVar(_) = projection_ty.self_type_parameter(db).kind(Interner) {
// Hack: don't ask Chalk to normalize with an unknown self type, it'll say that's impossible
return Some(Solution::Ambig(Guidance::Unknown));
}
}
// We currently don't deal with universes (I think / hope they're not yet
// relevant for our use cases?)
let u_canonical = chalk_ir::UCanonical { canonical: goal, universes: 1 };
solve(db, krate, &u_canonical)
}
fn solve(
db: &dyn HirDatabase,
krate: CrateId,
goal: &chalk_ir::UCanonical<chalk_ir::InEnvironment<chalk_ir::Goal<Interner>>>,
) -> Option<chalk_solve::Solution<Interner>> {
let context = ChalkContext { db, krate };
tracing::debug!("solve goal: {:?}", goal);
let mut solver = create_chalk_solver();
let fuel = std::cell::Cell::new(CHALK_SOLVER_FUEL);
let should_continue = || {
db.unwind_if_cancelled();
let remaining = fuel.get();
fuel.set(remaining - 1);
if remaining == 0 {
tracing::debug!("fuel exhausted");
}
remaining > 0
};
let mut solve = || {
let _ctx = if is_chalk_debug() || is_chalk_print() {
Some(panic_context::enter(format!("solving {goal:?}")))
} else {
None
};
let solution = if is_chalk_print() {
let logging_db =
LoggingRustIrDatabaseLoggingOnDrop(LoggingRustIrDatabase::new(context));
solver.solve_limited(&logging_db.0, goal, &should_continue)
} else {
solver.solve_limited(&context, goal, &should_continue)
};
tracing::debug!("solve({:?}) => {:?}", goal, solution);
solution
};
// don't set the TLS for Chalk unless Chalk debugging is active, to make
// extra sure we only use it for debugging
if is_chalk_debug() {
crate::tls::set_current_program(db, solve)
} else {
solve()
}
}
struct LoggingRustIrDatabaseLoggingOnDrop<'a>(LoggingRustIrDatabase<Interner, ChalkContext<'a>>);
impl<'a> Drop for LoggingRustIrDatabaseLoggingOnDrop<'a> {
fn drop(&mut self) {
eprintln!("chalk program:\n{}", self.0);
}
}
fn is_chalk_debug() -> bool {
std::env::var("CHALK_DEBUG").is_ok()
}
fn is_chalk_print() -> bool {
std::env::var("CHALK_PRINT").is_ok()
}
#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
pub enum FnTrait {
FnOnce,
FnMut,
Fn,
}
impl FnTrait {
const fn lang_item(self) -> LangItem {
match self {
FnTrait::FnOnce => LangItem::FnOnce,
FnTrait::FnMut => LangItem::FnMut,
FnTrait::Fn => LangItem::Fn,
}
}
pub fn get_id(&self, db: &dyn HirDatabase, krate: CrateId) -> Option<TraitId> {
let target = db.lang_item(krate, self.lang_item())?;
match target {
LangItemTarget::Trait(t) => Some(t),
_ => None,
}
}
}
|
