Skip to content

Commit

Permalink
Add note linking to Rust 2018 path semantics docs.
Browse files Browse the repository at this point in the history 
This commit extends existing path suggestions to link to documentation
on the changed semantics of `use` in Rust 2018.
  • Loading branch information
@davidtwco
davidtwco committed Oct 26, 2018
1 parent 82239b0 commit 8d5fb4c
Show file tree
Hide file tree
Showing 3 changed files with 63 additions and 29 deletions.
25 changes: 16 additions & 9 deletions src/librustc_resolve/error_reporting.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -24,7 +24,7 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
&mut self,
span: Span,
path: Vec<Segment>
) -> Option<Vec<Segment>> {
) -> Option<(Vec<Segment>, Option<String>)> {
debug!("make_path_suggestion: span={:?} path={:?}", span, path);
// If we don't have a path to suggest changes to, then return.
if path.is_empty() {
Expand Down Expand Up @@ -60,13 +60,13 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
&mut self,
span: Span,
mut path: Vec<Segment>
) -> Option<Vec<Segment>> {
) -> Option<(Vec<Segment>, Option<String>)> {
// Replace first ident with `self` and check if that is valid.
path[0].ident.name = keywords::SelfValue.name();
let result = self.resolve_path(None, &path, None, false, span, CrateLint::No);
debug!("make_missing_self_suggestion: path={:?} result={:?}", path, result);
if let PathResult::Module(..) = result {
Some(path)
Some((path, None))
} else {
None
}
Expand All @@ -83,13 +83,20 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
&mut self,
span: Span,
mut path: Vec<Segment>
) -> Option<Vec<Segment>> {
) -> Option<(Vec<Segment>, Option<String>)> {
// Replace first ident with `crate` and check if that is valid.
path[0].ident.name = keywords::Crate.name();
let result = self.resolve_path(None, &path, None, false, span, CrateLint::No);
debug!("make_missing_crate_suggestion: path={:?} result={:?}", path, result);
if let PathResult::Module(..) = result {
Some(path)
Some((
path,
Some(
"`use` statements changed in Rust 2018; read more at \
<https://doc.rust-lang.org/edition-guide/rust-2018/module-system/path-\
clarity.html>".to_string()
),
))
} else {
None
}
Expand All @@ -106,13 +113,13 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
&mut self,
span: Span,
mut path: Vec<Segment>
) -> Option<Vec<Segment>> {
) -> Option<(Vec<Segment>, Option<String>)> {
// Replace first ident with `crate` and check if that is valid.
path[0].ident.name = keywords::Super.name();
let result = self.resolve_path(None, &path, None, false, span, CrateLint::No);
debug!("make_missing_super_suggestion: path={:?} result={:?}", path, result);
if let PathResult::Module(..) = result {
Some(path)
Some((path, None))
} else {
None
}
Expand All @@ -132,7 +139,7 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
&mut self,
span: Span,
mut path: Vec<Segment>
) -> Option<Vec<Segment>> {
) -> Option<(Vec<Segment>, Option<String>)> {
// Need to clone else we can't call `resolve_path` without a borrow error. We also store
// into a `BTreeMap` so we can get consistent ordering (and therefore the same diagnostic)
// each time.
Expand All @@ -153,7 +160,7 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
debug!("make_external_crate_suggestion: name={:?} path={:?} result={:?}",
name, path, result);
if let PathResult::Module(..) = result {
return Some(path)
return Some((path, None));
}
}

Expand Down
65 changes: 45 additions & 20 deletions src/librustc_resolve/resolve_imports.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -703,7 +703,7 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
}
}
});
} else if let Some((span, err)) = error {
} else if let Some((span, err, note)) = error {
errors = true;

if let SingleImport { source, ref result, .. } = import.subclass {
Expand Down Expand Up @@ -733,7 +733,7 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
&import.subclass,
span,
);
error_vec.push((span, path, err));
error_vec.push((span, path, err, note));
seen_spans.insert(span);
prev_root_id = import.root_id;
}
Expand Down Expand Up @@ -825,27 +825,45 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
}
}

fn throw_unresolved_import_error(&self, error_vec: Vec<(Span, String, String)>,
span: Option<MultiSpan>) {
fn throw_unresolved_import_error(
&self,
error_vec: Vec<(Span, String, String, Option<String>)>,
span: Option<MultiSpan>,
) {
let max_span_label_msg_count = 10; // upper limit on number of span_label message.
let (span, msg) = if error_vec.is_empty() {
(span.unwrap(), "unresolved import".to_string())
let (span, msg, note) = if error_vec.is_empty() {
(span.unwrap(), "unresolved import".to_string(), None)
} else {
let span = MultiSpan::from_spans(error_vec.clone().into_iter()
.map(|elem: (Span, String, String)| { elem.0 })
.collect());
let span = MultiSpan::from_spans(
error_vec.clone().into_iter()
.map(|elem: (Span, String, String, Option<String>)| elem.0)
.collect()
);

let note: Option<String> = error_vec.clone().into_iter()
.filter_map(|elem: (Span, String, String, Option<String>)| elem.3)
.last();

let path_vec: Vec<String> = error_vec.clone().into_iter()
.map(|elem: (Span, String, String)| { format!("`{}`", elem.1) })
.map(|elem: (Span, String, String, Option<String>)| format!("`{}`", elem.1))
.collect();
let path = path_vec.join(", ");
let msg = format!("unresolved import{} {}",
if path_vec.len() > 1 { "s" } else { "" }, path);
(span, msg)
let msg = format!(
"unresolved import{} {}",
if path_vec.len() > 1 { "s" } else { "" },
path
);

(span, msg, note)
};

let mut err = struct_span_err!(self.resolver.session, span, E0432, "{}", &msg);
for span_error in error_vec.into_iter().take(max_span_label_msg_count) {
err.span_label(span_error.0, span_error.2);
}
if let Some(note) = note {
err.note(&note);
}
err.emit();
}

Expand Down Expand Up @@ -941,7 +959,10 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
}

// If appropriate, returns an error to report.
fn finalize_import(&mut self, directive: &'b ImportDirective<'b>) -> Option<(Span, String)> {
fn finalize_import(
&mut self,
directive: &'b ImportDirective<'b>
) -> Option<(Span, String, Option<String>)> {
self.current_module = directive.parent;
let ImportDirective { ref module_path, span, .. } = *directive;

Expand All @@ -964,15 +985,16 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
return None;
}
PathResult::Failed(span, msg, true) => {
return if let Some(suggested_path) = self.make_path_suggestion(
return if let Some((suggested_path, note)) = self.make_path_suggestion(
span, module_path.clone()
) {
Some((
span,
format!("Did you mean `{}`?", Segment::names_to_string(&suggested_path))
format!("Did you mean `{}`?", Segment::names_to_string(&suggested_path)),
note,
))
} else {
Some((span, msg))
Some((span, msg, None))
};
},
_ => return None,
Expand All @@ -997,8 +1019,11 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
if let ModuleOrUniformRoot::Module(module) = module {
if module.def_id() == directive.parent.def_id() {
// Importing a module into itself is not allowed.
return Some((directive.span,
"Cannot glob-import a module into itself.".to_string()));
return Some((
directive.span,
"Cannot glob-import a module into itself.".to_string(),
None,
));
}
}
if !is_prelude &&
Expand Down Expand Up @@ -1096,7 +1121,7 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
}
}
};
Some((span, msg))
Some((span, msg, None))
} else {
// `resolve_ident_in_module` reported a privacy error.
self.import_dummy_binding(directive);
Expand Down
2 changes: 2 additions & 0 deletions src/test/ui/rust-2018/local-path-suggestions-2018.stderr
View file
Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,8 @@ error[E0432]: unresolved import `foo`
|
LL | use foo::Bar;
| ^^^ Did you mean `crate::foo`?
|
= note: `use` statements changed in Rust 2018; read more at <https://doc.rust-lang.org/edition-guide/rust-2018/module-system/path-clarity.html>

error[E0432]: unresolved import `foo`
--> $DIR/local-path-suggestions-2018.rs:27:5
Expand Down

0 comments on commit 8d5fb4c

Please sign in to comment.