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@estebank
estebank committed Oct 22, 2018
1 parent e1e52eb commit d0bd69a
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Showing 9 changed files with 54 additions and 105 deletions.
99 changes: 42 additions & 57 deletions src/librustc/middle/resolve_lifetime.rs
View file
Expand Up @@ -2235,22 +2235,46 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
};

let mut err = report_missing_lifetime_specifiers(self.tcx.sess, span, lifetime_refs.len());
let mut add_label = true;

if let Some(params) = error {
if lifetime_refs.len() == 1 {
self.report_elision_failure(&mut err, params, span);
add_label = add_label && self.report_elision_failure(&mut err, params, span);
}
}
if add_label {
add_missing_lifetime_specifiers_label(&mut err, span, lifetime_refs.len());
}

err.emit();
}

fn suggest_lifetime(&self, db: &mut DiagnosticBuilder<'_>, span: Span, msg: &str) -> bool {
match self.tcx.sess.source_map().span_to_snippet(span) {
Ok(ref snippet) => {
let (sugg, applicability) = if &snippet[..] == "&" {
("&'static ".to_owned(), Applicability::MachineApplicable)
} else if snippet == "'_" {
("'static".to_owned(), Applicability::MachineApplicable)
} else {
(format!("{} + 'static", snippet), Applicability::MaybeIncorrect)
};
db.span_suggestion_with_applicability(span, msg, sugg, applicability);
false
}
Err(_) => {
db.help(msg);
true
}
}
}

fn report_elision_failure(
&mut self,
db: &mut DiagnosticBuilder<'_>,
params: &[ElisionFailureInfo],
span: Span,
) {
) -> bool {
let mut m = String::new();
let len = params.len();

Expand Down Expand Up @@ -2305,29 +2329,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
"this function's return type contains a borrowed value, but \
there is no value for it to be borrowed from"
);
let msg = "consider giving it a 'static lifetime";
match self.tcx.sess.source_map().span_to_snippet(span) {
Ok(ref snippet) if snippet == "&" => db.span_suggestion_with_applicability(
span,
msg,
"&'static ".to_owned(),
Applicability::MachineApplicable,
),
Ok(ref snippet)
if snippet == "'_" => db.span_suggestion_with_applicability(
span,
msg,
"'static".to_owned(),
Applicability::MachineApplicable,
),
Ok(ref snippet) => db.span_suggestion_with_applicability(
span,
msg,
format!("{} + 'static", snippet),
Applicability::MaybeIncorrect,
),
Err(_) => db.help(msg),
};
self.suggest_lifetime(db, span, "consider giving it a 'static lifetime")
} else if elided_len == 0 {
help!(
db,
Expand All @@ -2336,42 +2338,23 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
the arguments"
);
let msg = "consider giving it an explicit bounded or 'static lifetime";
match self.tcx.sess.source_map().span_to_snippet(span) {
Ok(ref snippet) if snippet == "&" => db.span_suggestion_with_applicability(
span,
msg,
"&'static ".to_owned(),
Applicability::MachineApplicable,
),
Ok(ref snippet)
if snippet == "'_" => db.span_suggestion_with_applicability(
span,
msg,
"'static".to_owned(),
Applicability::MachineApplicable,
),
Ok(ref snippet) => db.span_suggestion_with_applicability(
span,
msg,
format!("{} + 'static", snippet),
Applicability::MaybeIncorrect,
),
Err(_) => db.help(msg),
};
self.suggest_lifetime(db, span, msg)
} else if elided_len == 1 {
help!(
db,
"this function's return type contains a borrowed value, but \
the signature does not say which {} it is borrowed from",
m
);
true
} else {
help!(
db,
"this function's return type contains a borrowed value, but \
the signature does not say whether it is borrowed from {}",
m
);
true
}
}

Expand Down Expand Up @@ -2785,26 +2768,28 @@ fn insert_late_bound_lifetimes(
}
}

pub fn report_missing_lifetime_specifiers(
fn report_missing_lifetime_specifiers(
sess: &Session,
span: Span,
count: usize,
) -> DiagnosticBuilder<'_> {
let mut err = struct_span_err!(
struct_span_err!(
sess,
span,
E0106,
"missing lifetime specifier{}",
if count > 1 { "s" } else { "" }
);
)
}

let msg: Cow<'static, str> = if count > 1 {
format!("expected {} lifetime parameters", count).into()
fn add_missing_lifetime_specifiers_label(
err: &mut DiagnosticBuilder<'_>,
span: Span,
count: usize,
) {
if count > 1 {
err.span_label(span, format!("expected {} lifetime parameters", count));
} else {
"expected lifetime parameter".into()
err.span_label(span, "expected lifetime parameter");
};

err.span_label(span, msg);

err
}
5 changes: 1 addition & 4 deletions src/test/ui/associated-types/bound-lifetime-in-binding-only.elision.stderr
View file
Expand Up @@ -2,10 +2,7 @@ error[E0106]: missing lifetime specifier
--> $DIR/bound-lifetime-in-binding-only.rs:62:23
|
LL | fn elision<T: Fn() -> &i32>() {
| ^
| |
| expected lifetime parameter
| help: consider giving it a 'static lifetime: `&'static`
| ^ help: consider giving it a 'static lifetime: `&'static`
|
= help: this function's return type contains a borrowed value, but there is no value for it to be borrowed from

Expand Down
5 changes: 1 addition & 4 deletions src/test/ui/associated-types/bound-lifetime-in-return-only.elision.stderr
View file
Expand Up @@ -2,10 +2,7 @@ error[E0106]: missing lifetime specifier
--> $DIR/bound-lifetime-in-return-only.rs:44:23
|
LL | fn elision(_: fn() -> &i32) {
| ^
| |
| expected lifetime parameter
| help: consider giving it a 'static lifetime: `&'static`
| ^ help: consider giving it a 'static lifetime: `&'static`
|
= help: this function's return type contains a borrowed value, but there is no value for it to be borrowed from

Expand Down
5 changes: 1 addition & 4 deletions src/test/ui/foreign-fn-return-lifetime.stderr
View file
Expand Up @@ -2,10 +2,7 @@ error[E0106]: missing lifetime specifier
--> $DIR/foreign-fn-return-lifetime.rs:15:19
|
LL | pub fn f() -> &u8; //~ ERROR missing lifetime specifier
| ^
| |
| expected lifetime parameter
| help: consider giving it a 'static lifetime: `&'static`
| ^ help: consider giving it a 'static lifetime: `&'static`
|
= help: this function's return type contains a borrowed value, but there is no value for it to be borrowed from

Expand Down
5 changes: 1 addition & 4 deletions src/test/ui/issues/issue-13497.stderr
View file
Expand Up @@ -2,10 +2,7 @@ error[E0106]: missing lifetime specifier
--> $DIR/issue-13497.rs:12:5
|
LL | &str //~ ERROR missing lifetime specifier
| ^
| |
| expected lifetime parameter
| help: consider giving it a 'static lifetime: `&'static`
| ^ help: consider giving it a 'static lifetime: `&'static`
|
= help: this function's return type contains a borrowed value, but there is no value for it to be borrowed from

Expand Down
10 changes: 2 additions & 8 deletions src/test/ui/issues/issue-26638.stderr
View file
Expand Up @@ -10,21 +10,15 @@ error[E0106]: missing lifetime specifier
--> $DIR/issue-26638.rs:14:40
|
LL | fn parse_type_2(iter: fn(&u8)->&u8) -> &str { iter() }
| ^
| |
| expected lifetime parameter
| help: consider giving it an explicit bounded or 'static lifetime: `&'static`
| ^ help: consider giving it an explicit bounded or 'static lifetime: `&'static`
|
= help: this function's return type contains a borrowed value with an elided lifetime, but the lifetime cannot be derived from the arguments

error[E0106]: missing lifetime specifier
--> $DIR/issue-26638.rs:17:22
|
LL | fn parse_type_3() -> &str { unimplemented!() }
| ^
| |
| expected lifetime parameter
| help: consider giving it a 'static lifetime: `&'static`
| ^ help: consider giving it a 'static lifetime: `&'static`
|
= help: this function's return type contains a borrowed value, but there is no value for it to be borrowed from

Expand Down
20 changes: 4 additions & 16 deletions src/test/ui/lifetimes/lifetime-elision-return-type-requires-explicit-lifetime.stderr
View file
Expand Up @@ -2,10 +2,7 @@ error[E0106]: missing lifetime specifier
--> $DIR/lifetime-elision-return-type-requires-explicit-lifetime.rs:12:11
|
LL | fn f() -> &isize { //~ ERROR missing lifetime specifier
| ^
| |
| expected lifetime parameter
| help: consider giving it a 'static lifetime: `&'static`
| ^ help: consider giving it a 'static lifetime: `&'static`
|
= help: this function's return type contains a borrowed value, but there is no value for it to be borrowed from

Expand All @@ -29,32 +26,23 @@ error[E0106]: missing lifetime specifier
--> $DIR/lifetime-elision-return-type-requires-explicit-lifetime.rs:31:20
|
LL | fn i(_x: isize) -> &isize { //~ ERROR missing lifetime specifier
| ^
| |
| expected lifetime parameter
| help: consider giving it an explicit bounded or 'static lifetime: `&'static`
| ^ help: consider giving it an explicit bounded or 'static lifetime: `&'static`
|
= help: this function's return type contains a borrowed value with an elided lifetime, but the lifetime cannot be derived from the arguments

error[E0106]: missing lifetime specifier
--> $DIR/lifetime-elision-return-type-requires-explicit-lifetime.rs:44:24
|
LL | fn j(_x: StaticStr) -> &isize { //~ ERROR missing lifetime specifier
| ^
| |
| expected lifetime parameter
| help: consider giving it an explicit bounded or 'static lifetime: `&'static`
| ^ help: consider giving it an explicit bounded or 'static lifetime: `&'static`
|
= help: this function's return type contains a borrowed value with an elided lifetime, but the lifetime cannot be derived from the arguments

error[E0106]: missing lifetime specifier
--> $DIR/lifetime-elision-return-type-requires-explicit-lifetime.rs:50:49
|
LL | fn k<'a, T: WithLifetime<'a>>(_x: T::Output) -> &isize {
| ^
| |
| expected lifetime parameter
| help: consider giving it an explicit bounded or 'static lifetime: `&'static`
| ^ help: consider giving it an explicit bounded or 'static lifetime: `&'static`
|
= help: this function's return type contains a borrowed value with an elided lifetime, but the lifetime cannot be derived from the arguments

Expand Down
5 changes: 1 addition & 4 deletions src/test/ui/lifetimes/lifetime-elision-return-type-trait.stderr
View file
Expand Up @@ -6,10 +6,7 @@ error[E0106]: missing lifetime specifier
--> $DIR/lifetime-elision-return-type-trait.rs:8:44
|
LL | fn foo() -> impl Future<Item=(), Error=Box<Error>> {
| ^^^^^
| |
| expected lifetime parameter
| help: consider giving it a 'static lifetime: `Error + 'static`
| ^^^^^ help: consider giving it a 'static lifetime: `Error + 'static`
|
= help: this function's return type contains a borrowed value, but there is no value for it to be borrowed from

Expand Down
5 changes: 1 addition & 4 deletions src/test/ui/underscore-lifetime/underscore-lifetime-binders.stderr
View file
Expand Up @@ -26,10 +26,7 @@ error[E0106]: missing lifetime specifier
--> $DIR/underscore-lifetime-binders.rs:24:29
|
LL | fn meh() -> Box<for<'_> Meh<'_>> //~ ERROR cannot be used here
| ^^
| |
| expected lifetime parameter
| help: consider giving it a 'static lifetime: `'static`
| ^^ help: consider giving it a 'static lifetime: `'static`
|
= help: this function's return type contains a borrowed value, but there is no value for it to be borrowed from

Expand Down

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