Skip to content
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

Jump to bottom

Use structured suggestion for disambiguating method calls #67127

Merged
merged 2 commits into from
Dec 20, 2019
Merged

Use structured suggestion for disambiguating method calls #67127

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
3980342
Use structured suggestion for disambiguating method calls
estebank Dec 4, 2019
8c4f1d5
review comments
estebank Dec 12, 2019
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
11 changes: 11 additions & 0 deletions src/librustc/ty/mod.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -212,6 +212,17 @@ pub enum AssocKind {
Type
}

impl AssocKind {
pub fn suggestion_descr(&self) -> &'static str {
match self {
ty::AssocKind::Method => "method call",
ty::AssocKind::Type |
ty::AssocKind::OpaqueTy => "associated type",
ty::AssocKind::Const => "associated constant",
}
}
}

impl AssocItem {
pub fn def_kind(&self) -> DefKind {
match self.kind {
Expand Down
3 changes: 1 addition & 2 deletions src/librustc_typeck/check/expr.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1422,8 +1422,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
field: ast::Ident,
) -> Ty<'tcx> {
let expr_t = self.check_expr_with_needs(base, needs);
let expr_t = self.structurally_resolved_type(base.span,
expr_t);
let expr_t = self.structurally_resolved_type(base.span, expr_t);
let mut private_candidate = None;
let mut autoderef = self.autoderef(expr.span, expr_t);
while let Some((base_t, _)) = autoderef.next() {
Expand Down
161 changes: 118 additions & 43 deletions src/librustc_typeck/check/method/suggest.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -15,7 +15,7 @@ use rustc::traits::Obligation;
use rustc::ty::{self, Ty, TyCtxt, ToPolyTraitRef, ToPredicate, TypeFoldable};
use rustc::ty::print::with_crate_prefix;
use syntax_pos::{Span, FileName};
use syntax::ast;
use syntax::{ast, source_map};
use syntax::util::lev_distance;

use rustc_error_codes::*;
Expand Down Expand Up @@ -79,37 +79,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
return None;
}

let print_disambiguation_help = |
err: &mut DiagnosticBuilder<'_>,
trait_name: String,
| {
err.help(&format!(
"to disambiguate the method call, write `{}::{}({}{})` instead",
trait_name,
item_name,
if rcvr_ty.is_region_ptr() && args.is_some() {
if rcvr_ty.is_mutable_ptr() {
"&mut "
} else {
"&"
}
} else {
""
},
args.map(|arg| arg
.iter()
.map(|arg| self.tcx.sess.source_map().span_to_snippet(arg.span)
.unwrap_or_else(|_| "...".to_owned()))
.collect::<Vec<_>>()
.join(", ")
).unwrap_or_else(|| "...".to_owned())
));
};

let report_candidates = |
span: Span,
err: &mut DiagnosticBuilder<'_>,
mut sources: Vec<CandidateSource>,
sugg_span: Span,
| {
sources.sort();
sources.dedup();
Expand Down Expand Up @@ -150,15 +124,19 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
}
};

let note_str = if sources.len() > 1 {
format!("candidate #{} is defined in an impl{} for the type `{}`",
idx + 1,
insertion,
impl_ty)
let (note_str, idx) = if sources.len() > 1 {
(format!(
"candidate #{} is defined in an impl{} for the type `{}`",
idx + 1,
insertion,
impl_ty,
), Some(idx + 1))
} else {
format!("the candidate is defined in an impl{} for the type `{}`",
insertion,
impl_ty)
(format!(
"the candidate is defined in an impl{} for the type `{}`",
insertion,
impl_ty,
), None)
};
if let Some(note_span) = note_span {
// We have a span pointing to the method. Show note with snippet.
Expand All @@ -168,7 +146,31 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
err.note(&note_str);
}
if let Some(trait_ref) = self.tcx.impl_trait_ref(impl_did) {
print_disambiguation_help(err, self.tcx.def_path_str(trait_ref.def_id));
let path = self.tcx.def_path_str(trait_ref.def_id);

let ty = match item.kind {
ty::AssocKind::Const |
ty::AssocKind::Type |
ty::AssocKind::OpaqueTy => rcvr_ty,
ty::AssocKind::Method => self.tcx.fn_sig(item.def_id)
.inputs()
.skip_binder()
.get(0)
.filter(|ty| ty.is_region_ptr() && !rcvr_ty.is_region_ptr())
.map(|ty| *ty)
.unwrap_or(rcvr_ty),
};
print_disambiguation_help(
item_name,
args,
err,
path,
ty,
item.kind,
sugg_span,
idx,
self.tcx.sess.source_map(),
);
}
}
CandidateSource::TraitSource(trait_did) => {
Expand All @@ -182,19 +184,32 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
};
let item_span = self.tcx.sess.source_map()
.def_span(self.tcx.def_span(item.def_id));
if sources.len() > 1 {
let idx = if sources.len() > 1 {
span_note!(err,
item_span,
"candidate #{} is defined in the trait `{}`",
idx + 1,
self.tcx.def_path_str(trait_did));
Some(idx + 1)
} else {
span_note!(err,
item_span,
"the candidate is defined in the trait `{}`",
self.tcx.def_path_str(trait_did));
}
print_disambiguation_help(err, self.tcx.def_path_str(trait_did));
None
};
let path = self.tcx.def_path_str(trait_did);
print_disambiguation_help(
item_name,
args,
err,
path,
rcvr_ty,
item.kind,
sugg_span,
idx,
self.tcx.sess.source_map(),
);
}
}
}
Expand All @@ -203,6 +218,13 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
}
};

let sugg_span = if let SelfSource::MethodCall(expr) = source {
// Given `foo.bar(baz)`, `expr` is `bar`, but we want to point to the whole thing.
self.tcx.hir().expect_expr(self.tcx.hir().get_parent_node(expr.hir_id)).span
} else {
span
};

match error {
MethodError::NoMatch(NoMatchData {
static_candidates: static_sources,
Expand Down Expand Up @@ -495,9 +517,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
));
}

report_candidates(span, &mut err, static_sources);
report_candidates(span, &mut err, static_sources, sugg_span);
} else if static_sources.len() > 1 {
report_candidates(span, &mut err, static_sources);
report_candidates(span, &mut err, static_sources, sugg_span);
}

if !unsatisfied_predicates.is_empty() {
Expand Down Expand Up @@ -584,7 +606,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
"multiple applicable items in scope");
err.span_label(span, format!("multiple `{}` found", item_name));

report_candidates(span, &mut err, sources);
report_candidates(span, &mut err, sources, sugg_span);
err.emit();
}

Expand Down Expand Up @@ -1123,3 +1145,56 @@ impl hir::intravisit::Visitor<'tcx> for UsePlacementFinder<'tcx> {
hir::intravisit::NestedVisitorMap::None
}
}

fn print_disambiguation_help(
item_name: ast::Ident,
args: Option<&'tcx [hir::Expr]>,
err: &mut DiagnosticBuilder<'_>,
trait_name: String,
rcvr_ty: Ty<'_>,
kind: ty::AssocKind,
span: Span,
candidate: Option<usize>,
source_map: &source_map::SourceMap,
) {
let mut applicability = Applicability::MachineApplicable;
let sugg_args = if let (ty::AssocKind::Method, Some(args)) = (kind, args) {
format!(
"({}{})",
if rcvr_ty.is_region_ptr() {
if rcvr_ty.is_mutable_ptr() {
"&mut "
} else {
"&"
}
} else {
""
},
args.iter()
.map(|arg| source_map.span_to_snippet(arg.span)
.unwrap_or_else(|_| {
applicability = Applicability::HasPlaceholders;
"_".to_owned()
}))
.collect::<Vec<_>>()
.join(", "),
)
} else {
String::new()
};
let sugg = format!("{}::{}{}", trait_name, item_name, sugg_args);
err.span_suggestion(
span,
&format!(
"disambiguate the {} for {}",
kind.suggestion_descr(),
if let Some(candidate) = candidate {
format!("candidate #{}", candidate)
} else {
"the candidate".to_string()
},
),
sugg,
applicability,
);
}
10 changes: 8 additions & 2 deletions src/test/ui/associated-const/associated-const-ambiguity-report.stderr
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -9,13 +9,19 @@ note: candidate #1 is defined in an impl of the trait `Foo` for the type `i32`
|
LL | const ID: i32 = 1;
| ^^^^^^^^^^^^^^^^^^
= help: to disambiguate the method call, write `Foo::ID(...)` instead
note: candidate #2 is defined in an impl of the trait `Bar` for the type `i32`
--> $DIR/associated-const-ambiguity-report.rs:14:5
|
LL | const ID: i32 = 3;
| ^^^^^^^^^^^^^^^^^^
= help: to disambiguate the method call, write `Bar::ID(...)` instead
help: disambiguate the associated constant for candidate #1
|
LL | const X: i32 = Foo::ID;
| ^^^^^^^
help: disambiguate the associated constant for candidate #2
|
LL | const X: i32 = Bar::ID;
| ^^^^^^^

error: aborting due to previous error

Expand Down
10 changes: 8 additions & 2 deletions src/test/ui/error-codes/E0034.stderr
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -9,13 +9,19 @@ note: candidate #1 is defined in an impl of the trait `Trait1` for the type `Tes
|
LL | fn foo() {}
| ^^^^^^^^
= help: to disambiguate the method call, write `Trait1::foo(...)` instead
note: candidate #2 is defined in an impl of the trait `Trait2` for the type `Test`
--> $DIR/E0034.rs:16:5
|
LL | fn foo() {}
| ^^^^^^^^
= help: to disambiguate the method call, write `Trait2::foo(...)` instead
help: disambiguate the method call for candidate #1
|
LL | Trait1::foo()
| ^^^^^^^^^^^
help: disambiguate the method call for candidate #2
|
LL | Trait2::foo()
| ^^^^^^^^^^^

error: aborting due to previous error

Expand Down
10 changes: 8 additions & 2 deletions src/test/ui/inference/inference_unstable_featured.stderr
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -5,9 +5,15 @@ LL | assert_eq!('x'.ipu_flatten(), 0);
| ^^^^^^^^^^^ multiple `ipu_flatten` found
|
= note: candidate #1 is defined in an impl of the trait `inference_unstable_iterator::IpuIterator` for the type `char`
= help: to disambiguate the method call, write `inference_unstable_iterator::IpuIterator::ipu_flatten('x')` instead
= note: candidate #2 is defined in an impl of the trait `inference_unstable_itertools::IpuItertools` for the type `char`
= help: to disambiguate the method call, write `inference_unstable_itertools::IpuItertools::ipu_flatten('x')` instead
help: disambiguate the method call for candidate #1
|
LL | assert_eq!(inference_unstable_iterator::IpuIterator::ipu_flatten(&'x'), 0);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
help: disambiguate the method call for candidate #2
|
LL | assert_eq!(inference_unstable_itertools::IpuItertools::ipu_flatten(&'x'), 0);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: aborting due to previous error

Expand Down
6 changes: 4 additions & 2 deletions src/test/ui/issues/issue-18446.stderr
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,10 @@ error[E0034]: multiple applicable items in scope
--> $DIR/issue-18446.rs:18:7
|
LL | x.foo();
| ^^^ multiple `foo` found
| --^^^--
| | |
| | multiple `foo` found
| help: disambiguate the method call for candidate #2: `T::foo(&x)`
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Why is there only one disambiguation suggestion here?

Copy link
Contributor Author

@estebank estebank Dec 13, 2019 •
edited
Loading

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

The code for this is


trait T {
    fn foo(&self);
}

impl<'a> dyn T + 'a {
    fn foo(&self) {}
}

impl T for i32 {
    fn foo(&self) {}
}

fn main() {
    let x: &dyn T = &0i32;
    x.foo(); //~ ERROR multiple applicable items in scope [E0034]
}

I'm not sure what the appropriate syntax would be to call (&dyn T)::foo. Also note that we were already not suggesting it.

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Also note that we were already not suggesting it.

I did notice this. I think we ought to open a new issue — if the user can't specify (&dyn T)::foo, we should at least explain this in the diagnostic. But this PR looks good as it is.

|
note: candidate #1 is defined in an impl for the type `dyn T`
--> $DIR/issue-18446.rs:9:5
Expand All @@ -14,7 +17,6 @@ note: candidate #2 is defined in the trait `T`
|
LL | fn foo(&self);
| ^^^^^^^^^^^^^^
= help: to disambiguate the method call, write `T::foo(&x)` instead

error: aborting due to previous error

Expand Down
10 changes: 8 additions & 2 deletions src/test/ui/issues/issue-3702-2.stderr
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -9,13 +9,19 @@ note: candidate #1 is defined in an impl of the trait `ToPrimitive` for the type
|
LL | fn to_int(&self) -> isize { 0 }
| ^^^^^^^^^^^^^^^^^^^^^^^^^
= help: to disambiguate the method call, write `ToPrimitive::to_int(&self)` instead
note: candidate #2 is defined in an impl of the trait `Add` for the type `isize`
--> $DIR/issue-3702-2.rs:14:5
|
LL | fn to_int(&self) -> isize { *self }
| ^^^^^^^^^^^^^^^^^^^^^^^^^
= help: to disambiguate the method call, write `Add::to_int(&self)` instead
help: disambiguate the method call for candidate #1
|
LL | ToPrimitive::to_int(&self) + other.to_int()
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
help: disambiguate the method call for candidate #2
|
LL | Add::to_int(&self) + other.to_int()
| ^^^^^^^^^^^^^^^^^^

error: aborting due to previous error

Expand Down
10 changes: 8 additions & 2 deletions src/test/ui/issues/issue-65634-raw-ident-suggestion.stderr
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -9,13 +9,19 @@ note: candidate #1 is defined in an impl of the trait `async` for the type `r#fn
|
LL | fn r#struct(&self) {
| ^^^^^^^^^^^^^^^^^^
= help: to disambiguate the method call, write `async::r#struct(r#fn {})` instead
note: candidate #2 is defined in an impl of the trait `await` for the type `r#fn`
--> $DIR/issue-65634-raw-ident-suggestion.rs:10:5
|
LL | fn r#struct(&self) {
| ^^^^^^^^^^^^^^^^^^
= help: to disambiguate the method call, write `await::r#struct(r#fn {})` instead
help: disambiguate the method call for candidate #1
|
LL | async::r#struct(&r#fn {});
| ^^^^^^^^^^^^^^^^^^^^^^^^^
help: disambiguate the method call for candidate #2
|
LL | await::r#struct(&r#fn {});
| ^^^^^^^^^^^^^^^^^^^^^^^^^

error: aborting due to previous error

Expand Down
Loading