Skip to content

Add hint for unresolved associated trait items if the trait has a single item #87775

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 1 commit into from
Aug 6, 2021
Merged

Add hint for unresolved associated trait items if the trait has a single item #87775

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
62 changes: 43 additions & 19 deletions compiler/rustc_resolve/src/diagnostics.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -38,14 +38,25 @@ crate type Suggestion = (Vec<(Span, String)>, String, Applicability);
/// similarly named label and whether or not it is reachable.
crate type LabelSuggestion = (Ident, bool);

crate enum SuggestionTarget {
/// The target has a similar name as the name used by the programmer (probably a typo)
SimilarlyNamed,
/// The target is the only valid item that can be used in the corresponding context
SingleItem,
}

crate struct TypoSuggestion {
pub candidate: Symbol,
pub res: Res,
pub target: SuggestionTarget,
}

impl TypoSuggestion {
crate fn from_res(candidate: Symbol, res: Res) -> TypoSuggestion {
TypoSuggestion { candidate, res }
crate fn typo_from_res(candidate: Symbol, res: Res) -> TypoSuggestion {
Self { candidate, res, target: SuggestionTarget::SimilarlyNamed }
}
crate fn single_item_from_res(candidate: Symbol, res: Res) -> TypoSuggestion {
Self { candidate, res, target: SuggestionTarget::SingleItem }
}
}

Expand Down Expand Up @@ -80,7 +91,7 @@ impl<'a> Resolver<'a> {
if let Some(binding) = resolution.borrow().binding {
let res = binding.res();
if filter_fn(res) {
names.push(TypoSuggestion::from_res(key.ident.name, res));
names.push(TypoSuggestion::typo_from_res(key.ident.name, res));
}
}
}
Expand Down Expand Up @@ -623,7 +634,7 @@ impl<'a> Resolver<'a> {
.get(&expn_id)
.into_iter()
.flatten()
.map(|ident| TypoSuggestion::from_res(ident.name, res)),
.map(|ident| TypoSuggestion::typo_from_res(ident.name, res)),
);
}
}
Expand All @@ -642,7 +653,7 @@ impl<'a> Resolver<'a> {
suggestions.extend(
ext.helper_attrs
.iter()
.map(|name| TypoSuggestion::from_res(*name, res)),
.map(|name| TypoSuggestion::typo_from_res(*name, res)),
);
}
}
Expand All @@ -652,8 +663,10 @@ impl<'a> Resolver<'a> {
if let MacroRulesScope::Binding(macro_rules_binding) = macro_rules_scope.get() {
let res = macro_rules_binding.binding.res();
if filter_fn(res) {
suggestions
.push(TypoSuggestion::from_res(macro_rules_binding.ident.name, res))
suggestions.push(TypoSuggestion::typo_from_res(
macro_rules_binding.ident.name,
res,
))
}
}
}
Expand All @@ -671,15 +684,15 @@ impl<'a> Resolver<'a> {
suggestions.extend(
this.registered_attrs
.iter()
.map(|ident| TypoSuggestion::from_res(ident.name, res)),
.map(|ident| TypoSuggestion::typo_from_res(ident.name, res)),
);
}
}
Scope::MacroUsePrelude => {
suggestions.extend(this.macro_use_prelude.iter().filter_map(
|(name, binding)| {
let res = binding.res();
filter_fn(res).then_some(TypoSuggestion::from_res(*name, res))
filter_fn(res).then_some(TypoSuggestion::typo_from_res(*name, res))
},
));
}
Expand All @@ -689,22 +702,22 @@ impl<'a> Resolver<'a> {
suggestions.extend(
BUILTIN_ATTRIBUTES
.iter()
.map(|(name, ..)| TypoSuggestion::from_res(*name, res)),
.map(|(name, ..)| TypoSuggestion::typo_from_res(*name, res)),
);
}
}
Scope::ExternPrelude => {
suggestions.extend(this.extern_prelude.iter().filter_map(|(ident, _)| {
let res = Res::Def(DefKind::Mod, DefId::local(CRATE_DEF_INDEX));
filter_fn(res).then_some(TypoSuggestion::from_res(ident.name, res))
filter_fn(res).then_some(TypoSuggestion::typo_from_res(ident.name, res))
}));
}
Scope::ToolPrelude => {
let res = Res::NonMacroAttr(NonMacroAttrKind::Tool);
suggestions.extend(
this.registered_tools
.iter()
.map(|ident| TypoSuggestion::from_res(ident.name, res)),
.map(|ident| TypoSuggestion::typo_from_res(ident.name, res)),
);
}
Scope::StdLibPrelude => {
Expand All @@ -721,7 +734,7 @@ impl<'a> Resolver<'a> {
Scope::BuiltinTypes => {
suggestions.extend(PrimTy::ALL.iter().filter_map(|prim_ty| {
let res = Res::PrimTy(*prim_ty);
filter_fn(res).then_some(TypoSuggestion::from_res(prim_ty.name(), res))
filter_fn(res).then_some(TypoSuggestion::typo_from_res(prim_ty.name(), res))
}))
}
}
Expand Down Expand Up @@ -993,20 +1006,31 @@ impl<'a> Resolver<'a> {
// | ^
return false;
}
let prefix = match suggestion.target {
SuggestionTarget::SimilarlyNamed => "similarly named ",
SuggestionTarget::SingleItem => "",
};

err.span_label(
self.session.source_map().guess_head_span(def_span),
&format!(
"similarly named {} `{}` defined here",
"{}{} `{}` defined here",
prefix,
suggestion.res.descr(),
suggestion.candidate.as_str(),
),
);
}
let msg = format!(
"{} {} with a similar name exists",
suggestion.res.article(),
suggestion.res.descr()
);
let msg = match suggestion.target {
SuggestionTarget::SimilarlyNamed => format!(
"{} {} with a similar name exists",
suggestion.res.article(),
suggestion.res.descr()
),
SuggestionTarget::SingleItem => {
format!("maybe you meant this {}", suggestion.res.descr())
}
};
err.span_suggestion(
span,
&msg,
Expand Down
52 changes: 45 additions & 7 deletions compiler/rustc_resolve/src/late/diagnostics.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -541,6 +541,10 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
}
_ => {}
}

// If the trait has a single item (which wasn't matched by Levenshtein), suggest it
let suggestion = self.get_single_associated_item(&path, span, &source, is_expected);
self.r.add_typo_suggestion(&mut err, suggestion, ident_span);
}
if fallback {
// Fallback label.
Expand Down Expand Up @@ -585,6 +589,40 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
(err, candidates)
}

fn get_single_associated_item(
&mut self,
path: &[Segment],
span: Span,
source: &PathSource<'_>,
filter_fn: &impl Fn(Res) -> bool,
) -> Option<TypoSuggestion> {
if let crate::PathSource::TraitItem(_) = source {
let mod_path = &path[..path.len() - 1];
if let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
self.resolve_path(mod_path, None, false, span, CrateLint::No)
{
let resolutions = self.r.resolutions(module).borrow();
let targets: Vec<_> =
resolutions
.iter()
.filter_map(|(key, resolution)| {
resolution.borrow().binding.map(|binding| binding.res()).and_then(
|res| if filter_fn(res) { Some((key, res)) } else { None },
)
})
.collect();
if targets.len() == 1 {
let target = targets[0];
return Some(TypoSuggestion::single_item_from_res(
target.0.ident.name,
target.1,
));
}
}
}
None
}

/// Given `where <T as Bar>::Baz: String`, suggest `where T: Bar<Baz = String>`.
fn restrict_assoc_type_in_where_clause(
&mut self,
Expand Down Expand Up @@ -1208,7 +1246,7 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
// Locals and type parameters
for (ident, &res) in &rib.bindings {
if filter_fn(res) {
names.push(TypoSuggestion::from_res(ident.name, res));
names.push(TypoSuggestion::typo_from_res(ident.name, res));
}
}
// Items in scope
Expand All @@ -1231,7 +1269,9 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
);

if filter_fn(crate_mod) {
Some(TypoSuggestion::from_res(ident.name, crate_mod))
Some(TypoSuggestion::typo_from_res(
ident.name, crate_mod,
))
} else {
None
}
Expand All @@ -1249,11 +1289,9 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
}
// Add primitive types to the mix
if filter_fn(Res::PrimTy(PrimTy::Bool)) {
names.extend(
PrimTy::ALL.iter().map(|prim_ty| {
TypoSuggestion::from_res(prim_ty.name(), Res::PrimTy(*prim_ty))
}),
)
names.extend(PrimTy::ALL.iter().map(|prim_ty| {
TypoSuggestion::typo_from_res(prim_ty.name(), Res::PrimTy(*prim_ty))
}))
}
} else {
// Search in module.
Expand Down
22 changes: 22 additions & 0 deletions src/test/ui/associated-item/issue-87638.fixed
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,22 @@
// run-rustfix

trait Trait {
const FOO: usize;

type Target;
}

struct S;

impl Trait for S {
const FOO: usize = 0;
type Target = ();
}

fn main() {
let _: <S as Trait>::Target; //~ ERROR cannot find associated type `Output` in trait `Trait`
//~^ HELP maybe you meant this associated type

let _ = <S as Trait>::FOO; //~ ERROR cannot find method or associated constant `BAR` in trait `Trait`
//~^ HELP maybe you meant this associated constant
}
22 changes: 22 additions & 0 deletions src/test/ui/associated-item/issue-87638.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,22 @@
// run-rustfix

trait Trait {
const FOO: usize;

type Target;
}

struct S;

impl Trait for S {
const FOO: usize = 0;
type Target = ();
}

fn main() {
let _: <S as Trait>::Output; //~ ERROR cannot find associated type `Output` in trait `Trait`
//~^ HELP maybe you meant this associated type

let _ = <S as Trait>::BAR; //~ ERROR cannot find method or associated constant `BAR` in trait `Trait`
//~^ HELP maybe you meant this associated constant
}
27 changes: 27 additions & 0 deletions src/test/ui/associated-item/issue-87638.stderr
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,27 @@
error[E0576]: cannot find associated type `Output` in trait `Trait`
--> $DIR/issue-87638.rs:17:26
|
LL | type Target;
| ------------ associated type `Target` defined here
...
LL | let _: <S as Trait>::Output;
| ^^^^^^
| |
| not found in `Trait`
| help: maybe you meant this associated type: `Target`

error[E0576]: cannot find method or associated constant `BAR` in trait `Trait`
--> $DIR/issue-87638.rs:20:27
|
LL | const FOO: usize;
| ----------------- associated constant `FOO` defined here
...
LL | let _ = <S as Trait>::BAR;
| ^^^
| |
| not found in `Trait`
| help: maybe you meant this associated constant: `FOO`

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0576`.
7 changes: 6 additions & 1 deletion src/test/ui/associated-types/issue-22037.stderr
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,8 +1,13 @@
error[E0576]: cannot find associated type `X` in trait `A`
--> $DIR/issue-22037.rs:3:33
|
LL | type Output;
| ------------ associated type `Output` defined here
LL | fn a(&self) -> <Self as A>::X;
| ^ not found in `A`
| ^
| |
| not found in `A`
| help: maybe you meant this associated type: `Output`

error: aborting due to previous error

Expand Down
8 changes: 7 additions & 1 deletion src/test/ui/issues/issue-19883.stderr
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,8 +1,14 @@
error[E0576]: cannot find associated type `Dst` in trait `From`
--> $DIR/issue-19883.rs:9:30
|
LL | type Output;
| ------------ associated type `Output` defined here
...
LL | <Dst as From<Self>>::Dst
| ^^^ not found in `From`
| ^^^
| |
| not found in `From`
| help: maybe you meant this associated type: `Output`

error: aborting due to previous error

Expand Down