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Add tactic for associated item constants
1 parent 1ad33f9 commit d3d840b

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5 files changed

+118
-20
lines changed

5 files changed

+118
-20
lines changed

‎src/tools/rust-analyzer/crates/hir/src/term_search.rs

+1
Original file line numberDiff line numberDiff line change
@@ -325,6 +325,7 @@ pub fn term_search<DB: HirDatabase>(ctx: &TermSearchCtx<'_, DB>) -> Vec<Expr> {
325325
let mut solutions: Vec<Expr> = tactics::trivial(ctx, &defs, &mut lookup).collect();
326326
// Use well known types tactic before iterations as it does not depend on other tactics
327327
solutions.extend(tactics::famous_types(ctx, &defs, &mut lookup));
328+
solutions.extend(tactics::assoc_const(ctx, &defs, &mut lookup));
328329

329330
while should_continue() {
330331
lookup.new_round();

‎src/tools/rust-analyzer/crates/hir/src/term_search/expr.rs

+36-19
Original file line numberDiff line numberDiff line change
@@ -9,8 +9,8 @@ use hir_ty::{
99
use itertools::Itertools;
1010

1111
use crate::{
12-
Adt, AsAssocItem, Const, ConstParam, Field, Function, GenericDef, Local, ModuleDef,
13-
SemanticsScope, Static, Struct, StructKind, Trait, Type, Variant,
12+
Adt, AsAssocItem, AssocItemContainer, Const, ConstParam, Field, Function, GenericDef, Local,
13+
ModuleDef, SemanticsScope, Static, Struct, StructKind, Trait, Type, Variant,
1414
};
1515

1616
/// Helper function to get path to `ModuleDef`
@@ -138,7 +138,17 @@ impl Expr {
138138
let db = sema_scope.db;
139139
let mod_item_path_str = |s, def| mod_item_path_str(s, def, cfg);
140140
match self {
141-
Expr::Const(it) => mod_item_path_str(sema_scope, &ModuleDef::Const(*it)),
141+
Expr::Const(it) => match it.as_assoc_item(db).map(|it| it.container(db)) {
142+
Some(container) => {
143+
let container_name = container_name(container, sema_scope, cfg)?;
144+
let const_name = it
145+
.name(db)
146+
.map(|c| c.display(db.upcast()).to_string())
147+
.unwrap_or(String::new());
148+
Ok(format!("{container_name}::{const_name}"))
149+
}
150+
None => mod_item_path_str(sema_scope, &ModuleDef::Const(*it)),
151+
},
142152
Expr::Static(it) => mod_item_path_str(sema_scope, &ModuleDef::Static(*it)),
143153
Expr::Local(it) => Ok(it.name(db).display(db.upcast()).to_string()),
144154
Expr::ConstParam(it) => Ok(it.name(db).display(db.upcast()).to_string()),
@@ -153,22 +163,7 @@ impl Expr {
153163

154164
match func.as_assoc_item(db).map(|it| it.container(db)) {
155165
Some(container) => {
156-
let container_name = match container {
157-
crate::AssocItemContainer::Trait(trait_) => {
158-
mod_item_path_str(sema_scope, &ModuleDef::Trait(trait_))?
159-
}
160-
crate::AssocItemContainer::Impl(imp) => {
161-
let self_ty = imp.self_ty(db);
162-
// Should it be guaranteed that `mod_item_path` always exists?
163-
match self_ty
164-
.as_adt()
165-
.and_then(|adt| mod_item_path(sema_scope, &adt.into(), cfg))
166-
{
167-
Some(path) => path.display(sema_scope.db.upcast()).to_string(),
168-
None => self_ty.display(db).to_string(),
169-
}
170-
}
171-
};
166+
let container_name = container_name(container, sema_scope, cfg)?;
172167
let fn_name = func.name(db).display(db.upcast()).to_string();
173168
Ok(format!("{container_name}::{fn_name}({args})"))
174169
}
@@ -414,3 +409,25 @@ impl Expr {
414409
matches!(self, Expr::Many(_))
415410
}
416411
}
412+
413+
/// Helper function to find name of container
414+
fn container_name(
415+
container: AssocItemContainer,
416+
sema_scope: &SemanticsScope<'_>,
417+
cfg: ImportPathConfig,
418+
) -> Result<String, DisplaySourceCodeError> {
419+
let container_name = match container {
420+
crate::AssocItemContainer::Trait(trait_) => {
421+
mod_item_path_str(sema_scope, &ModuleDef::Trait(trait_), cfg)?
422+
}
423+
crate::AssocItemContainer::Impl(imp) => {
424+
let self_ty = imp.self_ty(sema_scope.db);
425+
// Should it be guaranteed that `mod_item_path` always exists?
426+
match self_ty.as_adt().and_then(|adt| mod_item_path(sema_scope, &adt.into(), cfg)) {
427+
Some(path) => path.display(sema_scope.db.upcast()).to_string(),
428+
None => self_ty.display(sema_scope.db).to_string(),
429+
}
430+
}
431+
};
432+
Ok(container_name)
433+
}

‎src/tools/rust-analyzer/crates/hir/src/term_search/tactics.rs

+50-1
Original file line numberDiff line numberDiff line change
@@ -80,14 +80,63 @@ pub(super) fn trivial<'a, DB: HirDatabase>(
8080
lookup.insert(ty.clone(), std::iter::once(expr.clone()));
8181

8282
// Don't suggest local references as they are not valid for return
83-
if matches!(expr, Expr::Local(_)) && ty.contains_reference(db) {
83+
if matches!(expr, Expr::Local(_))
84+
&& ty.contains_reference(db)
85+
&& ctx.config.enable_borrowcheck
86+
{
8487
return None;
8588
}
8689

8790
ty.could_unify_with_deeply(db, &ctx.goal).then_some(expr)
8891
})
8992
}
9093

94+
/// # Associated constant tactic
95+
///
96+
/// Attempts to fulfill the goal by trying constants defined as associated items.
97+
/// Only considers them on types that are in scope.
98+
///
99+
/// # Arguments
100+
/// * `ctx` - Context for the term search
101+
/// * `defs` - Set of items in scope at term search target location
102+
/// * `lookup` - Lookup table for types
103+
///
104+
/// Returns iterator that yields elements that unify with `goal`.
105+
///
106+
/// _Note that there is no use of calling this tactic in every iteration as the output does not
107+
/// depend on the current state of `lookup`_
108+
pub(super) fn assoc_const<'a, DB: HirDatabase>(
109+
ctx: &'a TermSearchCtx<'a, DB>,
110+
defs: &'a FxHashSet<ScopeDef>,
111+
lookup: &'a mut LookupTable,
112+
) -> impl Iterator<Item = Expr> + 'a {
113+
let db = ctx.sema.db;
114+
let module = ctx.scope.module();
115+
116+
defs.iter()
117+
.filter_map(|def| match def {
118+
ScopeDef::ModuleDef(ModuleDef::Adt(it)) => Some(it),
119+
_ => None,
120+
})
121+
.flat_map(|it| Impl::all_for_type(db, it.ty(db)))
122+
.filter(|it| !it.is_unsafe(db))
123+
.flat_map(|it| it.items(db))
124+
.filter(move |it| it.is_visible_from(db, module))
125+
.filter_map(AssocItem::as_const)
126+
.filter_map(|it| {
127+
let expr = Expr::Const(it);
128+
let ty = it.ty(db);
129+
130+
if ty.contains_unknown() {
131+
return None;
132+
}
133+
134+
lookup.insert(ty.clone(), std::iter::once(expr.clone()));
135+
136+
ty.could_unify_with_deeply(db, &ctx.goal).then_some(expr)
137+
})
138+
}
139+
91140
/// # Data constructor tactic
92141
///
93142
/// Attempts different data constructors for enums and structs in scope

‎src/tools/rust-analyzer/crates/ide-assists/src/handlers/term_search.rs

+30
Original file line numberDiff line numberDiff line change
@@ -290,4 +290,34 @@ fn f() { let a = 1; let b: Foo<i32> = todo$0!(); }"#,
290290
fn f() { let a = 1; let b: Foo<i32> = Foo(a); }"#,
291291
)
292292
}
293+
294+
#[test]
295+
fn test_struct_assoc_item() {
296+
check_assist(
297+
term_search,
298+
r#"//- minicore: todo, unimplemented
299+
struct Foo;
300+
impl Foo { const FOO: i32 = 0; }
301+
fn f() { let a: i32 = todo$0!(); }"#,
302+
r#"struct Foo;
303+
impl Foo { const FOO: i32 = 0; }
304+
fn f() { let a: i32 = Foo::FOO; }"#,
305+
)
306+
}
307+
308+
#[test]
309+
fn test_trait_assoc_item() {
310+
check_assist(
311+
term_search,
312+
r#"//- minicore: todo, unimplemented
313+
struct Foo;
314+
trait Bar { const BAR: i32; }
315+
impl Bar for Foo { const BAR: i32 = 0; }
316+
fn f() { let a: i32 = todo$0!(); }"#,
317+
r#"struct Foo;
318+
trait Bar { const BAR: i32; }
319+
impl Bar for Foo { const BAR: i32 = 0; }
320+
fn f() { let a: i32 = Foo::BAR; }"#,
321+
)
322+
}
293323
}

‎src/tools/rust-analyzer/crates/ide-completion/src/render.rs

+1
Original file line numberDiff line numberDiff line change
@@ -1799,6 +1799,7 @@ fn go(world: &WorldSnapshot) { go(w$0) }
17991799
"#,
18001800
expect![[r#"
18011801
lc world [type+name+local]
1802+
ex world [type]
18021803
st WorldSnapshot {…} []
18031804
st &WorldSnapshot {…} [type]
18041805
st WorldSnapshot []

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