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resolve: Levenshtein-based suggestions for non-import paths
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4 files changed

+157
-19
lines changed

4 files changed

+157
-19
lines changed

‎src/librustc_resolve/lib.rs

+65-16
Original file line numberDiff line numberDiff line change
@@ -2191,11 +2191,9 @@ impl<'a> Resolver<'a> {
21912191
}
21922192

21932193
// Try Levenshtein if nothing else worked.
2194-
if path.len() == 1 {
2195-
if let Some(candidate) = this.lookup_typo_candidate(name, ns, is_expected) {
2196-
err.span_label(span, &format!("did you mean `{}`?", candidate));
2197-
return err;
2198-
}
2194+
if let Some(candidate) = this.lookup_typo_candidate(path, ns, is_expected) {
2195+
err.span_label(span, &format!("did you mean `{}`?", candidate));
2196+
return err;
21992197
}
22002198

22012199
// Fallback label.
@@ -2649,21 +2647,72 @@ impl<'a> Resolver<'a> {
26492647
}
26502648

26512649
fn lookup_typo_candidate<FilterFn>(&mut self,
2652-
name: Name,
2650+
path: &[Ident],
26532651
ns: Namespace,
26542652
filter_fn: FilterFn)
2655-
-> Option<Name>
2653+
-> Option<String>
26562654
where FilterFn: Fn(Def) -> bool
26572655
{
2658-
// FIXME: bindings in ribs provide quite modest set of candidates,
2659-
// extend it with other names in scope.
2660-
let names = self.ribs[ns].iter().rev().flat_map(|rib| {
2661-
rib.bindings.iter().filter_map(|(ident, def)| {
2662-
if filter_fn(*def) { Some(&ident.name) } else { None }
2663-
})
2664-
});
2665-
match find_best_match_for_name(names, &name.as_str(), None) {
2666-
Some(found) if found != name => Some(found),
2656+
let add_module_candidates = |module: Module, names: &mut Vec<Name>| {
2657+
for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
2658+
if let Some(binding) = resolution.borrow().binding {
2659+
if filter_fn(binding.def()) {
2660+
names.push(ident.name);
2661+
}
2662+
}
2663+
}
2664+
};
2665+
2666+
let mut names = Vec::new();
2667+
let prefix_str = if path.len() == 1 {
2668+
// Search in lexical scope.
2669+
// Walk backwards up the ribs in scope and collect candidates.
2670+
for rib in self.ribs[ns].iter().rev() {
2671+
// Locals and type parameters
2672+
for (ident, def) in &rib.bindings {
2673+
if filter_fn(*def) {
2674+
names.push(ident.name);
2675+
}
2676+
}
2677+
// Items in scope
2678+
if let ModuleRibKind(module) = rib.kind {
2679+
// Items from this module
2680+
add_module_candidates(module, &mut names);
2681+
2682+
if let ModuleKind::Block(..) = module.kind {
2683+
// We can see through blocks
2684+
} else {
2685+
// Items from the prelude
2686+
if let Some(prelude) = self.prelude {
2687+
if !module.no_implicit_prelude {
2688+
add_module_candidates(prelude, &mut names);
2689+
}
2690+
}
2691+
break;
2692+
}
2693+
}
2694+
}
2695+
// Add primitive types to the mix
2696+
if filter_fn(Def::PrimTy(TyBool)) {
2697+
for (name, _) in &self.primitive_type_table.primitive_types {
2698+
names.push(*name);
2699+
}
2700+
}
2701+
String::new()
2702+
} else {
2703+
// Search in module.
2704+
let mod_path = &path[..path.len() - 1];
2705+
if let PathResult::Module(module) = self.resolve_path(mod_path, Some(TypeNS), None) {
2706+
add_module_candidates(module, &mut names);
2707+
}
2708+
names_to_string(mod_path) + "::"
2709+
};
2710+
2711+
let name = path[path.len() - 1].name;
2712+
// Make sure error reporting is deterministic.
2713+
names.sort_by_key(|name| name.as_str());
2714+
match find_best_match_for_name(names.iter(), &name.as_str(), None) {
2715+
Some(found) if found != name => Some(format!("{}{}", prefix_str, found)),
26672716
_ => None,
26682717
}
26692718
}

‎src/test/ui/resolve/levenshtein.rs

+33
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,33 @@
1+
// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
2+
// file at the top-level directory of this distribution and at
3+
// http://rust-lang.org/COPYRIGHT.
4+
//
5+
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6+
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7+
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8+
// option. This file may not be copied, modified, or distributed
9+
// except according to those terms.
10+
11+
const MAX_ITEM: usize = 10;
12+
13+
fn foo_bar() {}
14+
15+
fn foo(c: esize) {} // Misspelled primitive type name.
16+
17+
enum Bar { }
18+
19+
type A = Baz; // Misspelled type name.
20+
type B = Opiton<u8>; // Misspelled type name from the prelude.
21+
22+
mod m {
23+
type A = Baz; // No suggestion here, Bar is not visible
24+
25+
pub struct First;
26+
pub struct Second;
27+
}
28+
29+
fn main() {
30+
let v = [0u32; MAXITEM]; // Misspelled constant name.
31+
foobar(); // Misspelled function name.
32+
let b: m::first = m::second; // Misspelled item in module.
33+
}

‎src/test/ui/resolve/levenshtein.stderr

+56
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,56 @@
1+
error[E0412]: cannot find type `esize` in this scope
2+
--> $DIR/levenshtein.rs:15:11
3+
|
4+
15 | fn foo(c: esize) {} // Misspelled primitive type name.
5+
| ^^^^^ did you mean `isize`?
6+
7+
error[E0412]: cannot find type `Baz` in this scope
8+
--> $DIR/levenshtein.rs:19:10
9+
|
10+
19 | type A = Baz; // Misspelled type name.
11+
| ^^^ did you mean `Bar`?
12+
13+
error[E0412]: cannot find type `Opiton` in this scope
14+
--> $DIR/levenshtein.rs:20:10
15+
|
16+
20 | type B = Opiton<u8>; // Misspelled type name from the prelude.
17+
| ^^^^^^^^^^ did you mean `Option`?
18+
19+
error[E0412]: cannot find type `Baz` in this scope
20+
--> $DIR/levenshtein.rs:23:14
21+
|
22+
23 | type A = Baz; // No suggestion here, Bar is not visible
23+
| ^^^ not found in this scope
24+
25+
error[E0425]: cannot find value `MAXITEM` in this scope
26+
--> $DIR/levenshtein.rs:30:20
27+
|
28+
30 | let v = [0u32; MAXITEM]; // Misspelled constant name.
29+
| ^^^^^^^ did you mean `MAX_ITEM`?
30+
31+
error[E0425]: cannot find function `foobar` in this scope
32+
--> $DIR/levenshtein.rs:31:5
33+
|
34+
31 | foobar(); // Misspelled function name.
35+
| ^^^^^^ did you mean `foo_bar`?
36+
37+
error[E0412]: cannot find type `first` in module `m`
38+
--> $DIR/levenshtein.rs:32:12
39+
|
40+
32 | let b: m::first = m::second; // Misspelled item in module.
41+
| ^^^^^^^^ did you mean `m::First`?
42+
43+
error[E0425]: cannot find value `second` in module `m`
44+
--> $DIR/levenshtein.rs:32:23
45+
|
46+
32 | let b: m::first = m::second; // Misspelled item in module.
47+
| ^^^^^^^^^ did you mean `m::Second`?
48+
49+
error[E0080]: constant evaluation error
50+
--> $DIR/levenshtein.rs:30:20
51+
|
52+
30 | let v = [0u32; MAXITEM]; // Misspelled constant name.
53+
| ^^^^^^^ unresolved path in constant expression
54+
55+
error: aborting due to previous error
56+

‎src/test/ui/resolve/suggest-path-instead-of-mod-dot-item.stderr

+3-3
Original file line numberDiff line numberDiff line change
@@ -32,7 +32,7 @@ error[E0423]: expected value, found module `a::b`
3232
--> $DIR/suggest-path-instead-of-mod-dot-item.rs:55:12
3333
|
3434
55 | v.push(a::b);
35-
| ^^^^ not a value
35+
| ^^^^ did you mean `a::I`?
3636

3737
error[E0423]: expected value, found module `a::b`
3838
--> $DIR/suggest-path-instead-of-mod-dot-item.rs:61:5
@@ -44,13 +44,13 @@ error[E0423]: expected value, found module `a::b`
4444
--> $DIR/suggest-path-instead-of-mod-dot-item.rs:67:5
4545
|
4646
67 | a::b
47-
| ^^^^ not a value
47+
| ^^^^ did you mean `a::I`?
4848

4949
error[E0423]: expected function, found module `a::b`
5050
--> $DIR/suggest-path-instead-of-mod-dot-item.rs:73:5
5151
|
5252
73 | a::b()
53-
| ^^^^ not a function
53+
| ^^^^ did you mean `a::I`?
5454

5555
error: main function not found
5656

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