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davidtwcopietroalbini
davidtwco
authored and
pietroalbini
committed
Add note linking to Rust 2018 path semantics docs.
This commit extends existing path suggestions to link to documentation on the changed semantics of `use` in Rust 2018.
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3 files changed

+65
-31
lines changed

3 files changed

+65
-31
lines changed

‎src/librustc_resolve/error_reporting.rs

Lines changed: 19 additions & 12 deletions
Original file line numberDiff line numberDiff line change
@@ -26,7 +26,7 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
2626
span: Span,
2727
path: Vec<Ident>
2828
parent_scope: &ParentScope<'b>,
29-
) -> Option<Vec<Ident>> {
29+
) -> Option<(Vec<Ident>, Option<String>)> {
3030
debug!("make_path_suggestion: span={:?} path={:?}", span, path);
3131
// If we don't have a path to suggest changes to, then return.
3232
if path.is_empty() {
@@ -65,13 +65,13 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
6565
span: Span,
6666
mut path: Vec<Ident>
6767
parent_scope: &ParentScope<'b>,
68-
) -> Option<Vec<Ident>> {
68+
) -> Option<(Vec<Ident>, Option<String>)> {
6969
// Replace first ident with `self` and check if that is valid.
70-
path[0].name = keywords::SelfValue.name();
70+
path[0] = keywords::SelfValue.name();
7171
let result = self.resolve_path(None, &path, None, parent_scope, false, span, CrateLint::No);
7272
debug!("make_missing_self_suggestion: path={:?} result={:?}", path, result);
7373
if let PathResult::Module(..) = result {
74-
Some(path)
74+
Some((path, None))
7575
} else {
7676
None
7777
}
@@ -89,13 +89,20 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
8989
span: Span,
9090
mut path: Vec<Ident>
9191
parent_scope: &ParentScope<'b>,
92-
) -> Option<Vec<Ident>> {
92+
) -> Option<(Vec<Ident>, Option<String>)> {
9393
// Replace first ident with `crate` and check if that is valid.
94-
path[0].name = keywords::Crate.name();
94+
path[0] = keywords::Crate.name();
9595
let result = self.resolve_path(None, &path, None, parent_scope, false, span, CrateLint::No);
9696
debug!("make_missing_crate_suggestion: path={:?} result={:?}", path, result);
9797
if let PathResult::Module(..) = result {
98-
Some(path)
98+
Some((
99+
path,
100+
Some(
101+
"`use` statements changed in Rust 2018; read more at \
102+
<https://doc.rust-lang.org/edition-guide/rust-2018/module-system/path-\
103+
clarity.html>".to_string()
104+
),
105+
))
99106
} else {
100107
None
101108
}
@@ -113,14 +120,14 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
113120
span: Span,
114121
mut path: Vec<Ident>
115122
parent_scope: &ParentScope<'b>,
116-
) -> Option<Vec<Ident>> {
123+
) -> Option<(Vec<Ident>, Option<String>)> {
117124
// Replace first ident with `crate` and check if that is valid.
118-
path[0].name = keywords::Super.name();
125+
path[0] = keywords::Super.name();
119126
let result = self.resolve_path(None, &path, None, false, span, CrateLint::No);
120127
let result = self.resolve_path(None, &path, None, parent_scope, false, span, CrateLint::No);
121128
debug!("make_missing_super_suggestion: path={:?} result={:?}", path, result);
122129
if let PathResult::Module(..) = result {
123-
Some(path)
130+
Some((path, None))
124131
} else {
125132
None
126133
}
@@ -141,7 +148,7 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
141148
span: Span,
142149
mut path: Vec<Ident>
143150
parent_scope: &ParentScope<'b>,
144-
) -> Option<Vec<Ident>> {
151+
) -> Option<(Vec<Ident>, Option<String>)> {
145152
// Need to clone else we can't call `resolve_path` without a borrow error. We also store
146153
// into a `BTreeMap` so we can get consistent ordering (and therefore the same diagnostic)
147154
// each time.
@@ -163,7 +170,7 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
163170
debug!("make_external_crate_suggestion: name={:?} path={:?} result={:?}",
164171
name, path, result);
165172
if let PathResult::Module(..) = result {
166-
return Some(path)
173+
return Some((path, None));
167174
}
168175
}
169176

‎src/librustc_resolve/resolve_imports.rs

Lines changed: 44 additions & 19 deletions
Original file line numberDiff line numberDiff line change
@@ -707,7 +707,7 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
707707
}
708708
}
709709
});
710-
} else if let Some((span, err)) = error {
710+
} else if let Some((span, err, note)) = error {
711711
errors = true;
712712

713713
if let SingleImport { source, ref result, .. } = import.subclass {
@@ -735,7 +735,7 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
735735
let path = import_path_to_string(&import.module_path[..],
736736
&import.subclass,
737737
span);
738-
error_vec.push((span, path, err));
738+
error_vec.push((span, path, err, note));
739739
seen_spans.insert(span);
740740
prev_root_id = import.root_id;
741741
}
@@ -827,27 +827,45 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
827827
}
828828
}
829829

830-
fn throw_unresolved_import_error(&self, error_vec: Vec<(Span, String, String)>,
831-
span: Option<MultiSpan>) {
830+
fn throw_unresolved_import_error(
831+
&self,
832+
error_vec: Vec<(Span, String, String, Option<String>)>,
833+
span: Option<MultiSpan>,
834+
) {
832835
let max_span_label_msg_count = 10; // upper limit on number of span_label message.
833-
let (span, msg) = if error_vec.is_empty() {
834-
(span.unwrap(), "unresolved import".to_string())
836+
let (span, msg, note) = if error_vec.is_empty() {
837+
(span.unwrap(), "unresolved import".to_string(), None)
835838
} else {
836-
let span = MultiSpan::from_spans(error_vec.clone().into_iter()
837-
.map(|elem: (Span, String, String)| { elem.0 })
838-
.collect());
839+
let span = MultiSpan::from_spans(
840+
error_vec.clone().into_iter()
841+
.map(|elem: (Span, String, String, Option<String>)| elem.0)
842+
.collect()
843+
);
844+
845+
let note: Option<String> = error_vec.clone().into_iter()
846+
.filter_map(|elem: (Span, String, String, Option<String>)| elem.3)
847+
.last();
848+
839849
let path_vec: Vec<String> = error_vec.clone().into_iter()
840-
.map(|elem: (Span, String, String)| { format!("`{}`", elem.1) })
850+
.map(|elem: (Span, String, String, Option<String>)| format!("`{}`", elem.1))
841851
.collect();
842852
let path = path_vec.join(", ");
843-
let msg = format!("unresolved import{} {}",
844-
if path_vec.len() > 1 { "s" } else { "" }, path);
845-
(span, msg)
853+
let msg = format!(
854+
"unresolved import{} {}",
855+
if path_vec.len() > 1 { "s" } else { "" },
856+
path
857+
);
858+
859+
(span, msg, note)
846860
};
861+
847862
let mut err = struct_span_err!(self.resolver.session, span, E0432, "{}", &msg);
848863
for span_error in error_vec.into_iter().take(max_span_label_msg_count) {
849864
err.span_label(span_error.0, span_error.2);
850865
}
866+
if let Some(note) = note {
867+
err.note(&note);
868+
}
851869
err.emit();
852870
}
853871

@@ -943,7 +961,10 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
943961
}
944962

945963
// If appropriate, returns an error to report.
946-
fn finalize_import(&mut self, directive: &'b ImportDirective<'b>) -> Option<(Span, String)> {
964+
fn finalize_import(
965+
&mut self,
966+
directive: &'b ImportDirective<'b>
967+
) -> Option<(Span, String, Option<String>)> {
947968
self.current_module = directive.parent_scope.module;
948969
let ImportDirective { ref module_path, span, .. } = *directive;
949970

@@ -967,15 +988,16 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
967988
return None;
968989
}
969990
PathResult::Failed(span, msg, true) => {
970-
return if let Some(suggested_path) = self.make_path_suggestion(
991+
return if let Some((suggested_path, note)) = self.make_path_suggestion(
971992
span, module_path.clone(), &directive.parent_scope
972993
) {
973994
Some((
974995
span,
975996
format!("Did you mean `{}`?", names_to_string(&suggested_path[..]))
997+
note,
976998
))
977999
} else {
978-
Some((span, msg))
1000+
Some((span, msg, None))
9791001
};
9801002
},
9811003
_ => return None,
@@ -1000,8 +1022,11 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
10001022
if let ModuleOrUniformRoot::Module(module) = module {
10011023
if module.def_id() == directive.parent_scope.module.def_id() {
10021024
// Importing a module into itself is not allowed.
1003-
return Some((directive.span,
1004-
"Cannot glob-import a module into itself.".to_string()));
1025+
return Some((
1026+
directive.span,
1027+
"Cannot glob-import a module into itself.".to_string(),
1028+
None,
1029+
));
10051030
}
10061031
}
10071032
if !is_prelude &&
@@ -1099,7 +1124,7 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
10991124
}
11001125
}
11011126
};
1102-
Some((span, msg))
1127+
Some((span, msg, None))
11031128
} else {
11041129
// `resolve_ident_in_module` reported a privacy error.
11051130
self.import_dummy_binding(directive);

‎src/test/ui/rust-2018/local-path-suggestions-2018.stderr

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -3,6 +3,8 @@ error[E0432]: unresolved import `foo`
33
|
44
LL | use foo::Bar;
55
| ^^^ Did you mean `crate::foo`?
6+
|
7+
= note: `use` statements changed in Rust 2018; read more at <https://doc.rust-lang.org/edition-guide/rust-2018/module-system/path-clarity.html>
68

79
error[E0432]: unresolved import `foo`
810
--> $DIR/local-path-suggestions-2018.rs:27:5

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