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davidtwcodavidtwco
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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

+63
-29
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3 files changed

+63
-29
lines changed

‎src/librustc_resolve/error_reporting.rs‎

Lines changed: 16 additions & 9 deletions
Original file line numberDiff line numberDiff line change
@@ -24,7 +24,7 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
2424
&mut self,
2525
span: Span,
2626
path: Vec<Segment>
27-
) -> Option<Vec<Segment>> {
27+
) -> Option<(Vec<Segment>, Option<String>)> {
2828
debug!("make_path_suggestion: span={:?} path={:?}", span, path);
2929
// If we don't have a path to suggest changes to, then return.
3030
if path.is_empty() {
@@ -60,13 +60,13 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
6060
&mut self,
6161
span: Span,
6262
mut path: Vec<Segment>
63-
) -> Option<Vec<Segment>> {
63+
) -> Option<(Vec<Segment>, Option<String>)> {
6464
// Replace first ident with `self` and check if that is valid.
6565
path[0].ident.name = keywords::SelfValue.name();
6666
let result = self.resolve_path(None, &path, None, false, span, CrateLint::No);
6767
debug!("make_missing_self_suggestion: path={:?} result={:?}", path, result);
6868
if let PathResult::Module(..) = result {
69-
Some(path)
69+
Some((path, None))
7070
} else {
7171
None
7272
}
@@ -83,13 +83,20 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
8383
&mut self,
8484
span: Span,
8585
mut path: Vec<Segment>
86-
) -> Option<Vec<Segment>> {
86+
) -> Option<(Vec<Segment>, Option<String>)> {
8787
// Replace first ident with `crate` and check if that is valid.
8888
path[0].ident.name = keywords::Crate.name();
8989
let result = self.resolve_path(None, &path, None, false, span, CrateLint::No);
9090
debug!("make_missing_crate_suggestion: path={:?} result={:?}", path, result);
9191
if let PathResult::Module(..) = result {
92-
Some(path)
92+
Some((
93+
path,
94+
Some(
95+
"`use` statements changed in Rust 2018; read more at \
96+
<https://doc.rust-lang.org/edition-guide/rust-2018/module-system/path-\
97+
clarity.html>".to_string()
98+
),
99+
))
93100
} else {
94101
None
95102
}
@@ -106,13 +113,13 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
106113
&mut self,
107114
span: Span,
108115
mut path: Vec<Segment>
109-
) -> Option<Vec<Segment>> {
116+
) -> Option<(Vec<Segment>, Option<String>)> {
110117
// Replace first ident with `crate` and check if that is valid.
111118
path[0].ident.name = keywords::Super.name();
112119
let result = self.resolve_path(None, &path, None, false, span, CrateLint::No);
113120
debug!("make_missing_super_suggestion: path={:?} result={:?}", path, result);
114121
if let PathResult::Module(..) = result {
115-
Some(path)
122+
Some((path, None))
116123
} else {
117124
None
118125
}
@@ -132,7 +139,7 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
132139
&mut self,
133140
span: Span,
134141
mut path: Vec<Segment>
135-
) -> Option<Vec<Segment>> {
142+
) -> Option<(Vec<Segment>, Option<String>)> {
136143
// Need to clone else we can't call `resolve_path` without a borrow error. We also store
137144
// into a `BTreeMap` so we can get consistent ordering (and therefore the same diagnostic)
138145
// each time.
@@ -153,7 +160,7 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
153160
debug!("make_external_crate_suggestion: name={:?} path={:?} result={:?}",
154161
name, path, result);
155162
if let PathResult::Module(..) = result {
156-
return Some(path)
163+
return Some((path, None));
157164
}
158165
}
159166

‎src/librustc_resolve/resolve_imports.rs‎

Lines changed: 45 additions & 20 deletions
Original file line numberDiff line numberDiff line change
@@ -703,7 +703,7 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
703703
}
704704
}
705705
});
706-
} else if let Some((span, err)) = error {
706+
} else if let Some((span, err, note)) = error {
707707
errors = true;
708708

709709
if let SingleImport { source, ref result, .. } = import.subclass {
@@ -733,7 +733,7 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
733733
&import.subclass,
734734
span,
735735
);
736-
error_vec.push((span, path, err));
736+
error_vec.push((span, path, err, note));
737737
seen_spans.insert(span);
738738
prev_root_id = import.root_id;
739739
}
@@ -825,27 +825,45 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
825825
}
826826
}
827827

828-
fn throw_unresolved_import_error(&self, error_vec: Vec<(Span, String, String)>,
829-
span: Option<MultiSpan>) {
828+
fn throw_unresolved_import_error(
829+
&self,
830+
error_vec: Vec<(Span, String, String, Option<String>)>,
831+
span: Option<MultiSpan>,
832+
) {
830833
let max_span_label_msg_count = 10; // upper limit on number of span_label message.
831-
let (span, msg) = if error_vec.is_empty() {
832-
(span.unwrap(), "unresolved import".to_string())
834+
let (span, msg, note) = if error_vec.is_empty() {
835+
(span.unwrap(), "unresolved import".to_string(), None)
833836
} else {
834-
let span = MultiSpan::from_spans(error_vec.clone().into_iter()
835-
.map(|elem: (Span, String, String)| { elem.0 })
836-
.collect());
837+
let span = MultiSpan::from_spans(
838+
error_vec.clone().into_iter()
839+
.map(|elem: (Span, String, String, Option<String>)| elem.0)
840+
.collect()
841+
);
842+
843+
let note: Option<String> = error_vec.clone().into_iter()
844+
.filter_map(|elem: (Span, String, String, Option<String>)| elem.3)
845+
.last();
846+
837847
let path_vec: Vec<String> = error_vec.clone().into_iter()
838-
.map(|elem: (Span, String, String)| { format!("`{}`", elem.1) })
848+
.map(|elem: (Span, String, String, Option<String>)| format!("`{}`", elem.1))
839849
.collect();
840850
let path = path_vec.join(", ");
841-
let msg = format!("unresolved import{} {}",
842-
if path_vec.len() > 1 { "s" } else { "" }, path);
843-
(span, msg)
851+
let msg = format!(
852+
"unresolved import{} {}",
853+
if path_vec.len() > 1 { "s" } else { "" },
854+
path
855+
);
856+
857+
(span, msg, note)
844858
};
859+
845860
let mut err = struct_span_err!(self.resolver.session, span, E0432, "{}", &msg);
846861
for span_error in error_vec.into_iter().take(max_span_label_msg_count) {
847862
err.span_label(span_error.0, span_error.2);
848863
}
864+
if let Some(note) = note {
865+
err.note(&note);
866+
}
849867
err.emit();
850868
}
851869

@@ -941,7 +959,10 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
941959
}
942960

943961
// If appropriate, returns an error to report.
944-
fn finalize_import(&mut self, directive: &'b ImportDirective<'b>) -> Option<(Span, String)> {
962+
fn finalize_import(
963+
&mut self,
964+
directive: &'b ImportDirective<'b>
965+
) -> Option<(Span, String, Option<String>)> {
945966
self.current_module = directive.parent;
946967
let ImportDirective { ref module_path, span, .. } = *directive;
947968

@@ -964,15 +985,16 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
964985
return None;
965986
}
966987
PathResult::Failed(span, msg, true) => {
967-
return if let Some(suggested_path) = self.make_path_suggestion(
988+
return if let Some((suggested_path, note)) = self.make_path_suggestion(
968989
span, module_path.clone()
969990
) {
970991
Some((
971992
span,
972-
format!("Did you mean `{}`?", Segment::names_to_string(&suggested_path))
993+
format!("Did you mean `{}`?", Segment::names_to_string(&suggested_path)),
994+
note,
973995
))
974996
} else {
975-
Some((span, msg))
997+
Some((span, msg, None))
976998
};
977999
},
9781000
_ => return None,
@@ -997,8 +1019,11 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
9971019
if let ModuleOrUniformRoot::Module(module) = module {
9981020
if module.def_id() == directive.parent.def_id() {
9991021
// Importing a module into itself is not allowed.
1000-
return Some((directive.span,
1001-
"Cannot glob-import a module into itself.".to_string()));
1022+
return Some((
1023+
directive.span,
1024+
"Cannot glob-import a module into itself.".to_string(),
1025+
None,
1026+
));
10021027
}
10031028
}
10041029
if !is_prelude &&
@@ -1096,7 +1121,7 @@ impl<'a, 'b:'a, 'c: 'b> ImportResolver<'a, 'b, 'c> {
10961121
}
10971122
}
10981123
};
1099-
Some((span, msg))
1124+
Some((span, msg, None))
11001125
} else {
11011126
// `resolve_ident_in_module` reported a privacy error.
11021127
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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