Skip to content

Commit

Permalink
Auto merge of rust-lang#124944 - estebank:multiple-crate-versions, r=…
Browse files Browse the repository at this point in the history
…fee1-dead

On trait bound mismatch, detect multiple crate versions in dep tree

When encountering an E0277, if the type and the trait both come from a crate with the same name but different crate number, we explain that there are multiple crate versions in the dependency tree.

If there's a type that fulfills the bound, and it has the same name as the passed in type and has the same crate name, we explain that the same type in two different versions of the same crate *are different*.

```
error[E0277]: the trait bound `Type: dependency::Trait` is not satisfied
 --> src/main.rs:4:18
  |
4 |     do_something(Type);
  |     ------------ ^^^^ the trait `dependency::Trait` is not implemented for `Type`
  |     |
  |     required by a bound introduced by this call
  |
help: you have multiple different versions of crate `dependency` in your dependency graph
 --> src/main.rs:1:5
  |
1 | use bar::do_something;
  |     ^^^ one version of crate `dependency` is used here, as a dependency of crate `bar`
2 | use dependency::Type;
  |     ^^^^^^^^^^ one version of crate `dependency` is used here, as a direct dependency of the current crate
note: two types coming from two different versions of the same crate are different types even if they look the same
 --> /home/gh-estebank/crate_versions/baz-2/src/lib.rs:1:1
  |
1 | pub struct Type;
  | ^^^^^^^^^^^^^^^ this type doesn't implement the required trait
  |
 ::: /home/gh-estebank/crate_versions/baz/src/lib.rs:1:1
  |
1 | pub struct Type;
  | ^^^^^^^^^^^^^^^ this type implements the required trait
2 | pub trait Trait {}
  | --------------- this is the required trait
note: required by a bound in `bar::do_something`
 --> /home/gh-estebank/crate_versions/baz/src/lib.rs:4:24
  |
4 | pub fn do_something<X: Trait>(_: X) {}
  |                        ^^^^^ required by this bound in `do_something`
```

Address rust-lang#22750.
  • Loading branch information
bors committed May 13, 2024
2 parents 982c9c1 + 782cba8 commit 3a9190b
Show file tree
Hide file tree
Showing 8 changed files with 280 additions and 35 deletions.
21 changes: 21 additions & 0 deletions compiler/rustc_errors/src/diagnostic.rs
Original file line number Diff line number Diff line change
Expand Up @@ -737,6 +737,16 @@ impl<'a, G: EmissionGuarantee> Diag<'a, G> {
self
}

#[rustc_lint_diagnostics]
pub fn highlighted_span_note(
&mut self,
span: impl Into<MultiSpan>,
msg: Vec<StringPart>,
) -> &mut Self {
self.sub_with_highlights(Level::Note, msg, span.into());
self
}

/// This is like [`Diag::note()`], but it's only printed once.
#[rustc_lint_diagnostics]
pub fn note_once(&mut self, msg: impl Into<SubdiagMessage>) -> &mut Self {
Expand Down Expand Up @@ -811,6 +821,17 @@ impl<'a, G: EmissionGuarantee> Diag<'a, G> {
self
}

/// Add a help message attached to this diagnostic with a customizable highlighted message.
#[rustc_lint_diagnostics]
pub fn highlighted_span_help(
&mut self,
span: impl Into<MultiSpan>,
msg: Vec<StringPart>,
) -> &mut Self {
self.sub_with_highlights(Level::Help, msg, span.into());
self
}

/// Prints the span with some help above it.
/// This is like [`Diag::help()`], but it gets its own span.
#[rustc_lint_diagnostics]
Expand Down
7 changes: 5 additions & 2 deletions compiler/rustc_errors/src/emitter.rs
Original file line number Diff line number Diff line change
Expand Up @@ -1328,7 +1328,7 @@ impl HumanEmitter {
buffer.append(0, ": ", header_style);
label_width += 2;
}
for (text, _) in msgs.iter() {
for (text, style) in msgs.iter() {
let text = self.translate_message(text, args).map_err(Report::new).unwrap();
// Account for newlines to align output to its label.
for (line, text) in normalize_whitespace(&text).lines().enumerate() {
Expand All @@ -1339,7 +1339,10 @@ impl HumanEmitter {
if line == 0 { String::new() } else { " ".repeat(label_width) },
text
),
header_style,
match style {
Style::Highlight => *style,
_ => header_style,
},
);
}
}
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -1939,9 +1939,125 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
other: bool,
param_env: ty::ParamEnv<'tcx>,
) -> bool {
// If we have a single implementation, try to unify it with the trait ref
// that failed. This should uncover a better hint for what *is* implemented.
let alternative_candidates = |def_id: DefId| {
let mut impl_candidates: Vec<_> = self
.tcx
.all_impls(def_id)
// Ignore automatically derived impls and `!Trait` impls.
.filter_map(|def_id| self.tcx.impl_trait_header(def_id))
.filter_map(|header| {
(header.polarity != ty::ImplPolarity::Negative
|| self.tcx.is_automatically_derived(def_id))
.then(|| header.trait_ref.instantiate_identity())
})
.filter(|trait_ref| {
let self_ty = trait_ref.self_ty();
// Avoid mentioning type parameters.
if let ty::Param(_) = self_ty.kind() {
false
}
// Avoid mentioning types that are private to another crate
else if let ty::Adt(def, _) = self_ty.peel_refs().kind() {
// FIXME(compiler-errors): This could be generalized, both to
// be more granular, and probably look past other `#[fundamental]`
// types, too.
self.tcx.visibility(def.did()).is_accessible_from(body_def_id, self.tcx)
} else {
true
}
})
.collect();

impl_candidates.sort_by_key(|tr| tr.to_string());
impl_candidates.dedup();
impl_candidates
};

// We'll check for the case where the reason for the mismatch is that the trait comes from
// one crate version and the type comes from another crate version, even though they both
// are from the same crate.
let trait_def_id = trait_ref.def_id();
if let ty::Adt(def, _) = trait_ref.self_ty().skip_binder().peel_refs().kind()
&& let found_type = def.did()
&& trait_def_id.krate != found_type.krate
&& self.tcx.crate_name(trait_def_id.krate) == self.tcx.crate_name(found_type.krate)
{
let name = self.tcx.crate_name(trait_def_id.krate);
let spans: Vec<_> = [trait_def_id, found_type]
.into_iter()
.filter_map(|def_id| self.tcx.extern_crate(def_id))
.map(|data| {
let dependency = if data.dependency_of == LOCAL_CRATE {
"direct dependency of the current crate".to_string()
} else {
let dep = self.tcx.crate_name(data.dependency_of);
format!("dependency of crate `{dep}`")
};
(
data.span,
format!("one version of crate `{name}` is used here, as a {dependency}"),
)
})
.collect();
let mut span: MultiSpan = spans.iter().map(|(sp, _)| *sp).collect::<Vec<Span>>().into();
for (sp, label) in spans.into_iter() {
span.push_span_label(sp, label);
}
err.highlighted_span_help(
span,
vec![
StringPart::normal("you have ".to_string()),
StringPart::highlighted("multiple different versions".to_string()),
StringPart::normal(" of crate `".to_string()),
StringPart::highlighted(format!("{name}")),
StringPart::normal("` in your dependency graph".to_string()),
],
);
let candidates = if impl_candidates.is_empty() {
alternative_candidates(trait_def_id)
} else {
impl_candidates.into_iter().map(|cand| cand.trait_ref).collect()
};
if let Some((sp_candidate, sp_found)) = candidates.iter().find_map(|trait_ref| {
if let ty::Adt(def, _) = trait_ref.self_ty().peel_refs().kind()
&& let candidate_def_id = def.did()
&& let Some(name) = self.tcx.opt_item_name(candidate_def_id)
&& let Some(found) = self.tcx.opt_item_name(found_type)
&& name == found
&& candidate_def_id.krate != found_type.krate
&& self.tcx.crate_name(candidate_def_id.krate)
== self.tcx.crate_name(found_type.krate)
{
// A candidate was found of an item with the same name, from two separate
// versions of the same crate, let's clarify.
Some((self.tcx.def_span(candidate_def_id), self.tcx.def_span(found_type)))
} else {
None
}
}) {
let mut span: MultiSpan = vec![sp_candidate, sp_found].into();
span.push_span_label(self.tcx.def_span(trait_def_id), "this is the required trait");
span.push_span_label(sp_candidate, "this type implements the required trait");
span.push_span_label(sp_found, "this type doesn't implement the required trait");
err.highlighted_span_note(
span,
vec![
StringPart::normal(
"two types coming from two different versions of the same crate are \
different types "
.to_string(),
),
StringPart::highlighted("even if they look the same".to_string()),
],
);
}
err.help("you can use `cargo tree` to explore your dependency tree");
return true;
}

if let [single] = &impl_candidates {
// If we have a single implementation, try to unify it with the trait ref
// that failed. This should uncover a better hint for what *is* implemented.
if self.probe(|_| {
let ocx = ObligationCtxt::new(self);

Expand Down Expand Up @@ -2096,37 +2212,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
// Mentioning implementers of `Copy`, `Debug` and friends is not useful.
return false;
}
let mut impl_candidates: Vec<_> = self
.tcx
.all_impls(def_id)
// Ignore automatically derived impls and `!Trait` impls.
.filter_map(|def_id| self.tcx.impl_trait_header(def_id))
.filter_map(|header| {
(header.polarity != ty::ImplPolarity::Negative
|| self.tcx.is_automatically_derived(def_id))
.then(|| header.trait_ref.instantiate_identity())
})
.filter(|trait_ref| {
let self_ty = trait_ref.self_ty();
// Avoid mentioning type parameters.
if let ty::Param(_) = self_ty.kind() {
false
}
// Avoid mentioning types that are private to another crate
else if let ty::Adt(def, _) = self_ty.peel_refs().kind() {
// FIXME(compiler-errors): This could be generalized, both to
// be more granular, and probably look past other `#[fundamental]`
// types, too.
self.tcx.visibility(def.did()).is_accessible_from(body_def_id, self.tcx)
} else {
true
}
})
.collect();

impl_candidates.sort_by_key(|tr| tr.to_string());
impl_candidates.dedup();
return report(impl_candidates, err);
return report(alternative_candidates(def_id), err);
}

// Sort impl candidates so that ordering is consistent for UI tests.
Expand Down
4 changes: 4 additions & 0 deletions tests/ui/crate-loading/auxiliary/dep-2-reexport.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,4 @@
//@ edition:2021
//@ aux-build:multiple-dep-versions-2.rs
extern crate dependency;
pub use dependency::do_something;
7 changes: 7 additions & 0 deletions tests/ui/crate-loading/auxiliary/multiple-dep-versions-1.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,7 @@
#![crate_name="dependency"]
//@ edition:2021
//@ compile-flags: -C metadata=1 -C extra-filename=-1
pub struct Type;
pub trait Trait {}
impl Trait for Type {}
pub fn do_something<X: Trait>(_: X) { }
7 changes: 7 additions & 0 deletions tests/ui/crate-loading/auxiliary/multiple-dep-versions-2.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,7 @@
#![crate_name="dependency"]
//@ edition:2021
//@ compile-flags: -C metadata=2 -C extra-filename=-2
pub struct Type(pub i32);
pub trait Trait {}
impl Trait for Type {}
pub fn do_something<X: Trait>(_: X) {}
14 changes: 14 additions & 0 deletions tests/ui/crate-loading/multiple-dep-versions.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,14 @@
//@ aux-build:dep-2-reexport.rs
//@ aux-build:multiple-dep-versions-1.rs
//@ edition:2021
//@ compile-flags: --error-format=human --color=always --crate-type bin --extern dependency={{build-base}}/crate-loading/multiple-dep-versions/auxiliary/libdependency-1.so --extern dep_2_reexport={{build-base}}/crate-loading/multiple-dep-versions/auxiliary/libdep_2_reexport.so
//@ ignore-windows

extern crate dependency;
extern crate dep_2_reexport;
use dependency::Type;
use dep_2_reexport::do_something;

fn main() {
do_something(Type);
}
103 changes: 103 additions & 0 deletions tests/ui/crate-loading/multiple-dep-versions.svg
Loading
Sorry, something went wrong. Reload?
Sorry, we cannot display this file.
Sorry, this file is invalid so it cannot be displayed.

0 comments on commit 3a9190b

Please sign in to comment.