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Account for fn() types in lifetime suggestions

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This commit is contained in:
Esteban Küber 2020-01-27 16:13:45 -08:00
parent ba3b44c508
commit 92505df338
20 changed files with 211 additions and 154 deletions
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24
src/librustc_resolve/diagnostics.rs
View File

@ -19,7 +19,7 @@
use syntax::util::lev_distance::find_best_match_for_name;
use crate::imports::{ImportDirective, ImportDirectiveSubclass, ImportResolver};
use crate::lifetimes::{ElisionFailureInfo, HRLTSpanType, MissingLifetimeSpot};
use crate::lifetimes::{ElisionFailureInfo, ForLifetimeSpanType, MissingLifetimeSpot};
use crate::path_names_to_string;
use crate::{AmbiguityError, AmbiguityErrorMisc, AmbiguityKind};
use crate::{BindingError, CrateLint, HasGenericParams, LegacyScope, Module, ModuleOrUniformRoot};
@ -1495,7 +1495,7 @@ fn find_span_immediately_after_crate_name(
let should_break;
introduce_suggestion.push(match missing {
MissingLifetimeSpot::Generics(generics) => {
msg = "consider introducing a named lifetime parameter";
msg = "consider introducing a named lifetime parameter".to_string();
should_break = true;
match &generics.params {
[] => (generics.span, "<'a>".to_string()),
@ -1503,15 +1503,27 @@ fn find_span_immediately_after_crate_name(
}
}
MissingLifetimeSpot::HRLT { span, span_type } => {
msg = "consider introducing a higher-ranked lifetime";
msg = format!(
"consider making the {} lifetime-generic with a new `'a` lifetime",
match span_type {
ForLifetimeSpanType::BoundEmpty
| ForLifetimeSpanType::BoundTail => "bound",
ForLifetimeSpanType::TypeEmpty | ForLifetimeSpanType::TypeTail =>
"type",
}
);
should_break = false;
err.note(
"for more information on higher-ranked lifetimes, visit \
https://doc.rust-lang.org/nomicon/hrtb.html",
);
let suggestion = match span_type {
HRLTSpanType::Empty => "for<'a> ",
HRLTSpanType::Tail => ", 'a",
ForLifetimeSpanType::BoundEmpty | ForLifetimeSpanType::TypeEmpty => {
"for<'a> "
}
ForLifetimeSpanType::BoundTail | ForLifetimeSpanType::TypeTail => {
", 'a"
}
};
(*span, suggestion.to_string())
}
@ -1528,7 +1540,7 @@ fn find_span_immediately_after_crate_name(
}
}
introduce_suggestion.push((span, sugg.to_string()));
err.multipart_suggestion(msg, introduce_suggestion, Applicability::MaybeIncorrect);
err.multipart_suggestion(&msg, introduce_suggestion, Applicability::MaybeIncorrect);
if should_break {
break;
}

64
src/librustc_resolve/lifetimes.rs
View File

@ -155,12 +155,14 @@ struct NamedRegionMap {
crate enum MissingLifetimeSpot<'tcx> {
Generics(&'tcx hir::Generics<'tcx>),
HRLT { span: Span, span_type: HRLTSpanType },
HRLT { span: Span, span_type: ForLifetimeSpanType },
}
crate enum HRLTSpanType {
Empty,
Tail,
crate enum ForLifetimeSpanType {
BoundEmpty,
BoundTail,
TypeEmpty,
TypeTail,
}
impl<'tcx> Into<MissingLifetimeSpot<'tcx>> for &'tcx hir::Generics<'tcx> {
@ -509,6 +511,21 @@ fn visit_ty(&mut self, ty: &'tcx hir::Ty<'tcx>) {
let next_early_index = self.next_early_index();
let was_in_fn_syntax = self.is_in_fn_syntax;
self.is_in_fn_syntax = true;
let lifetime_span: Option<Span> = c
.generic_params
.iter()
.filter_map(|param| match param.kind {
GenericParamKind::Lifetime { .. } => Some(param.span),
_ => None,
})
.last();
let (span, span_type) = if let Some(span) = lifetime_span {
(span.shrink_to_hi(), ForLifetimeSpanType::TypeTail)
} else {
(ty.span.shrink_to_lo(), ForLifetimeSpanType::TypeEmpty)
};
self.missing_named_lifetime_spots
.push(MissingLifetimeSpot::HRLT { span, span_type });
let scope = Scope::Binder {
lifetimes: c
.generic_params
@ -531,6 +548,7 @@ fn visit_ty(&mut self, ty: &'tcx hir::Ty<'tcx>) {
this.check_lifetime_params(old_scope, &c.generic_params);
intravisit::walk_ty(this, ty);
});
self.missing_named_lifetime_spots.pop();
self.is_in_fn_syntax = was_in_fn_syntax;
}
hir::TyKind::TraitObject(bounds, ref lifetime) => {
@ -1873,12 +1891,23 @@ fn resolve_lifetime_ref(&mut self, lifetime_ref: &'tcx hir::Lifetime) {
err.span_suggestion(
*span,
&format!(
"consider introducing a higher-ranked lifetime `{}` here",
"consider making the {} lifetime-generic with a new `{}` lifetime",
match span_type {
ForLifetimeSpanType::BoundEmpty
| ForLifetimeSpanType::BoundTail => "bound",
ForLifetimeSpanType::TypeEmpty
| ForLifetimeSpanType::TypeTail => "type",
},
lifetime_ref
),
match span_type {
HRLTSpanType::Empty => format!("for<{}> ", lifetime_ref),
HRLTSpanType::Tail => format!(", {}", lifetime_ref),
ForLifetimeSpanType::TypeEmpty
| ForLifetimeSpanType::BoundEmpty => {
format!("for<{}> ", lifetime_ref)
}
ForLifetimeSpanType::TypeTail | ForLifetimeSpanType::BoundTail => {
format!(", {}", lifetime_ref)
}
}
.to_string(),
Applicability::MaybeIncorrect,
@ -2487,13 +2516,12 @@ fn report_elision_failure(
params.iter().cloned().filter(|info| info.lifetime_count > 0).collect();
let elided_len = elided_params.len();
let mut spans = vec![];
for (i, info) in elided_params.into_iter().enumerate() {
let ElisionFailureInfo { parent, index, lifetime_count: n, have_bound_regions, span } =
info;
spans.push(span);
db.span_label(span, "");
let help_name = if let Some(ident) =
parent.and_then(|body| self.tcx.hir().body(body).params[index].pat.simple_ident())
{
@ -2524,14 +2552,6 @@ fn report_elision_failure(
}
}
let help = |msg| {
if spans.is_empty() {
db.help(msg);
} else {
db.span_help(spans, msg);
}
};
if len == 0 {
db.help(
"this function's return type contains a borrowed value, \
@ -2539,7 +2559,7 @@ fn report_elision_failure(
);
self.suggest_lifetime(db, span, "consider giving it a 'static lifetime")
} else if elided_len == 0 {
help(
db.help(
"this function's return type contains a borrowed value with \
an elided lifetime, but the lifetime cannot be derived from \
the arguments",
@ -2547,14 +2567,14 @@ fn report_elision_failure(
let msg = "consider giving it an explicit bounded or 'static lifetime";
self.suggest_lifetime(db, span, msg)
} else if elided_len == 1 {
help(&format!(
db.help(&format!(
"this function's return type contains a borrowed value, \
but the signature does not say which {} it is borrowed from",
m
));
true
} else {
help(&format!(
db.help(&format!(
"this function's return type contains a borrowed value, \
but the signature does not say whether it is borrowed from {}",
m
@ -2816,8 +2836,8 @@ fn is_trait_ref_fn_scope(&mut self, trait_ref: &'tcx hir::PolyTraitRef<'tcx>) ->
.contains(&Some(did))
{
let (span, span_type) = match &trait_ref.bound_generic_params {
[] => (trait_ref.span.shrink_to_lo(), HRLTSpanType::Empty),
[.., bound] => (bound.span.shrink_to_hi(), HRLTSpanType::Tail),
[] => (trait_ref.span.shrink_to_lo(), ForLifetimeSpanType::BoundEmpty),
[.., bound] => (bound.span.shrink_to_hi(), ForLifetimeSpanType::BoundTail),
};
self.missing_named_lifetime_spots
.push(MissingLifetimeSpot::HRLT { span, span_type });

8
src/test/ui/async-await/issues/issue-63388-2.stderr
View File

@ -1,14 +1,12 @@
error[E0106]: missing lifetime specifier
--> $DIR/issue-63388-2.rs:12:10
|
LL | foo: &dyn Foo, bar: &'a dyn Foo
| -------- -----------
LL | ) -> &dyn Foo
| ^ help: consider using the named lifetime: `&'a`
|
help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from `foo` or `bar`
--> $DIR/issue-63388-2.rs:11:14
|
LL | foo: &dyn Foo, bar: &'a dyn Foo
| ^^^^^^^^ ^^^^^^^^^^^
= help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from `foo` or `bar`
error: cannot infer an appropriate lifetime
--> $DIR/issue-63388-2.rs:11:9

12
src/test/ui/generic/generic-extern-lifetime.stderr
View File

@ -9,12 +9,24 @@ error[E0261]: use of undeclared lifetime name `'a`
|
LL | pub fn life4<'b>(x: for<'c> fn(&'a i32));
| ^^ undeclared lifetime
|
= note: for more information on higher-ranked lifetimes, visit https://doc.rust-lang.org/nomicon/hrtb.html
help: consider making the type lifetime-generic with a new `'a` lifetime
|
LL | pub fn life4<'b>(x: for<'c, 'a> fn(&'a i32));
| ^^^^
error[E0261]: use of undeclared lifetime name `'a`
--> $DIR/generic-extern-lifetime.rs:11:38
|
LL | pub fn life7<'b>() -> for<'c> fn(&'a i32);
| ^^ undeclared lifetime
|
= note: for more information on higher-ranked lifetimes, visit https://doc.rust-lang.org/nomicon/hrtb.html
help: consider making the type lifetime-generic with a new `'a` lifetime
|
LL | pub fn life7<'b>() -> for<'c, 'a> fn(&'a i32);
| ^^^^
error: aborting due to 3 previous errors

12
src/test/ui/in-band-lifetimes/no_introducing_in_band_in_locals.stderr
View File

@ -9,10 +9,18 @@ LL | let y: &'test u32 = x;
error[E0261]: use of undeclared lifetime name `'test`
--> $DIR/no_introducing_in_band_in_locals.rs:10:16
|
LL | fn bar() {
| - help: consider introducing lifetime `'test` here: `<'test>`
LL | let y: fn(&'test u32) = foo2;
| ^^^^^ undeclared lifetime
|
= note: for more information on higher-ranked lifetimes, visit https://doc.rust-lang.org/nomicon/hrtb.html
help: consider introducing lifetime `'test` here
|
LL | fn bar<'test>() {
| ^^^^^^^
help: consider making the type lifetime-generic with a new `'test` lifetime
|
LL | let y: for<'test> fn(&'test u32) = foo2;
| ^^^^^^^^^^
error: aborting due to 2 previous errors

21
src/test/ui/issues/issue-19707.stderr
View File

@ -2,13 +2,14 @@ error[E0106]: missing lifetime specifier
--> $DIR/issue-19707.rs:3:28
|
LL | type Foo = fn(&u8, &u8) -> &u8;
| ^ expected named lifetime parameter
| --- --- ^ expected named lifetime parameter
|
help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from argument 1 or argument 2
--> $DIR/issue-19707.rs:3:15
= help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from argument 1 or argument 2
= note: for more information on higher-ranked lifetimes, visit https://doc.rust-lang.org/nomicon/hrtb.html
help: consider making the type lifetime-generic with a new `'a` lifetime
|
LL | type Foo = fn(&u8, &u8) -> &u8;
| ^^^ ^^^
LL | type Foo = for<'a> fn(&'a u8, &'a u8) -> &'a u8;
| ^^^^^^^ ^^^^^^ ^^^^^^ ^^^
help: consider introducing a named lifetime parameter
|
LL | type Foo<'a> = fn(&'a u8, &'a u8) -> &'a u8;
@ -18,15 +19,11 @@ error[E0106]: missing lifetime specifier
--> $DIR/issue-19707.rs:5:27
|
LL | fn bar<F: Fn(&u8, &u8) -> &u8>(f: &F) {}
| ^ expected named lifetime parameter
| --- --- ^ expected named lifetime parameter
|
help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from argument 1 or argument 2
--> $DIR/issue-19707.rs:5:14
|
LL | fn bar<F: Fn(&u8, &u8) -> &u8>(f: &F) {}
| ^^^ ^^^
= help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from argument 1 or argument 2
= note: for more information on higher-ranked lifetimes, visit https://doc.rust-lang.org/nomicon/hrtb.html
help: consider introducing a higher-ranked lifetime
help: consider making the bound lifetime-generic with a new `'a` lifetime
|
LL | fn bar<F: for<'a> Fn(&'a u8, &'a u8) -> &'a u8>(f: &F) {}
| ^^^^^^^ ^^^^^^ ^^^^^^ ^^^

8
src/test/ui/issues/issue-26638.stderr
View File

@ -2,13 +2,9 @@ error[E0106]: missing lifetime specifier
--> $DIR/issue-26638.rs:1:62
|
LL | fn parse_type(iter: Box<dyn Iterator<Item=&str>+'static>) -> &str { iter.next() }
| ^ expected named lifetime parameter
| ------------------------------------ ^ expected named lifetime parameter
|
help: this function's return type contains a borrowed value, but the signature does not say which one of `iter`'s 2 lifetimes it is borrowed from
--> $DIR/issue-26638.rs:1:21
|
LL | fn parse_type(iter: Box<dyn Iterator<Item=&str>+'static>) -> &str { iter.next() }
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
= help: this function's return type contains a borrowed value, but the signature does not say which one of `iter`'s 2 lifetimes it is borrowed from
help: consider introducing a named lifetime parameter
|
LL | fn parse_type<'a>(iter: Box<dyn Iterator<Item=&str>+'static>) -> &'a str { iter.next() }

24
src/test/ui/issues/issue-30255.stderr
View File

@ -2,13 +2,9 @@ error[E0106]: missing lifetime specifier
--> $DIR/issue-30255.rs:9:24
|
LL | fn f(a: &S, b: i32) -> &i32 {
| ^ expected named lifetime parameter
| -- ^ expected named lifetime parameter
|
help: this function's return type contains a borrowed value, but the signature does not say which one of `a`'s 2 lifetimes it is borrowed from
--> $DIR/issue-30255.rs:9:9
|
LL | fn f(a: &S, b: i32) -> &i32 {
| ^^
= help: this function's return type contains a borrowed value, but the signature does not say which one of `a`'s 2 lifetimes it is borrowed from
help: consider introducing a named lifetime parameter
|
LL | fn f<'a>(a: &'a S, b: i32) -> &'a i32 {
@ -18,13 +14,9 @@ error[E0106]: missing lifetime specifier
--> $DIR/issue-30255.rs:14:34
|
LL | fn g(a: &S, b: bool, c: &i32) -> &i32 {
| ^ expected named lifetime parameter
| -- ---- ^ expected named lifetime parameter
|
help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from one of `a`'s 2 lifetimes or `c`
--> $DIR/issue-30255.rs:14:9
|
LL | fn g(a: &S, b: bool, c: &i32) -> &i32 {
| ^^ ^^^^
= help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from one of `a`'s 2 lifetimes or `c`
help: consider introducing a named lifetime parameter
|
LL | fn g<'a>(a: &'a S, b: bool, c: &'a i32) -> &'a i32 {
@ -34,13 +26,9 @@ error[E0106]: missing lifetime specifier
--> $DIR/issue-30255.rs:19:44
|
LL | fn h(a: &bool, b: bool, c: &S, d: &i32) -> &i32 {
| ^ expected named lifetime parameter
| ----- -- ---- ^ expected named lifetime parameter
|
help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from `a`, one of `c`'s 2 lifetimes, or `d`
--> $DIR/issue-30255.rs:19:9
|
LL | fn h(a: &bool, b: bool, c: &S, d: &i32) -> &i32 {
| ^^^^^ ^^ ^^^^
= help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from `a`, one of `c`'s 2 lifetimes, or `d`
help: consider introducing a named lifetime parameter
|
LL | fn h<'a>(a: &'a bool, b: bool, c: &'a S, d: &'a i32) -> &'a i32 {

16
src/test/ui/lifetimes/lifetime-elision-return-type-requires-explicit-lifetime.stderr
View File

@ -10,13 +10,9 @@ error[E0106]: missing lifetime specifier
--> $DIR/lifetime-elision-return-type-requires-explicit-lifetime.rs:7:33
|
LL | fn g(_x: &isize, _y: &isize) -> &isize {
| ^ expected named lifetime parameter
| ------ ------ ^ expected named lifetime parameter
|
help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from `_x` or `_y`
--> $DIR/lifetime-elision-return-type-requires-explicit-lifetime.rs:7:10
|
LL | fn g(_x: &isize, _y: &isize) -> &isize {
| ^^^^^^ ^^^^^^
= help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from `_x` or `_y`
help: consider introducing a named lifetime parameter
|
LL | fn g<'a>(_x: &'a isize, _y: &'a isize) -> &'a isize {
@ -26,13 +22,9 @@ error[E0106]: missing lifetime specifier
--> $DIR/lifetime-elision-return-type-requires-explicit-lifetime.rs:17:19
|
LL | fn h(_x: &Foo) -> &isize {
| ^ expected named lifetime parameter
| ---- ^ expected named lifetime parameter
|
help: this function's return type contains a borrowed value, but the signature does not say which one of `_x`'s 2 lifetimes it is borrowed from
--> $DIR/lifetime-elision-return-type-requires-explicit-lifetime.rs:17:10
|
LL | fn h(_x: &Foo) -> &isize {
| ^^^^
= help: this function's return type contains a borrowed value, but the signature does not say which one of `_x`'s 2 lifetimes it is borrowed from
help: consider introducing a named lifetime parameter
|
LL | fn h<'a>(_x: &'a Foo) -> &'a isize {

8
src/test/ui/lifetimes/lifetime-errors/ex1b-return-no-names-if-else.stderr
View File

@ -2,13 +2,9 @@ error[E0106]: missing lifetime specifier
--> $DIR/ex1b-return-no-names-if-else.rs:1:29
|
LL | fn foo(x: &i32, y: &i32) -> &i32 {
| ^ expected named lifetime parameter
| ---- ---- ^ expected named lifetime parameter
|
help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from `x` or `y`
--> $DIR/ex1b-return-no-names-if-else.rs:1:11
|
LL | fn foo(x: &i32, y: &i32) -> &i32 {
| ^^^^ ^^^^
= help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from `x` or `y`
help: consider introducing a named lifetime parameter
|
LL | fn foo<'a>(x: &'a i32, y: &'a i32) -> &'a i32 {

4
src/test/ui/regions/regions-name-undeclared.stderr
View File

@ -94,7 +94,7 @@ help: consider introducing lifetime `'b` here
|
LL | fn fn_types<'b>(a: &'a isize,
| ^^^^
help: consider introducing a higher-ranked lifetime `'b` here
help: consider making the bound lifetime-generic with a new `'b` lifetime
|
LL | b: Box<dyn for<'a, 'b> FnOnce(&'a isize,
| ^^^^
@ -110,7 +110,7 @@ help: consider introducing lifetime `'b` here
|
LL | fn fn_types<'b>(a: &'a isize,
| ^^^^
help: consider introducing a higher-ranked lifetime `'b` here
help: consider making the bound lifetime-generic with a new `'b` lifetime
|
LL | b: Box<dyn for<'a, 'b> FnOnce(&'a isize,
| ^^^^

13
src/test/ui/rfc1623-2.rs Normal file
View File

@ -0,0 +1,13 @@
#![allow(dead_code)]
fn non_elidable<'a, 'b>(a: &'a u8, b: &'b u8) -> &'a u8 {
a
}
// the boundaries of elision
static NON_ELIDABLE_FN: &fn(&u8, &u8) -> &u8 =
//~^ ERROR missing lifetime specifier [E0106]
&(non_elidable as fn(&u8, &u8) -> &u8);
//~^ ERROR missing lifetime specifier [E0106]
fn main() {}

29
src/test/ui/rfc1623-2.stderr Normal file
View File

@ -0,0 +1,29 @@
error[E0106]: missing lifetime specifier
--> $DIR/rfc1623-2.rs:8:42
|
LL | static NON_ELIDABLE_FN: &fn(&u8, &u8) -> &u8 =
| --- --- ^ expected named lifetime parameter
|
= help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from argument 1 or argument 2
= note: for more information on higher-ranked lifetimes, visit https://doc.rust-lang.org/nomicon/hrtb.html
help: consider making the type lifetime-generic with a new `'a` lifetime
|
LL | static NON_ELIDABLE_FN: &for<'a> fn(&'a u8, &'a u8) -> &'a u8 =
| ^^^^^^^ ^^^^^^ ^^^^^^ ^^^
error[E0106]: missing lifetime specifier
--> $DIR/rfc1623-2.rs:10:39
|
LL | &(non_elidable as fn(&u8, &u8) -> &u8);
| --- --- ^ expected named lifetime parameter
|
= help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from argument 1 or argument 2
= note: for more information on higher-ranked lifetimes, visit https://doc.rust-lang.org/nomicon/hrtb.html
help: consider making the type lifetime-generic with a new `'a` lifetime
|
LL | &(non_elidable as for<'a> fn(&'a u8, &'a u8) -> &'a u8);
| ^^^^^^^ ^^^^^^ ^^^^^^ ^^^
error: aborting due to 2 previous errors
For more information about this error, try `rustc --explain E0106`.

13
src/test/ui/rfc1623.rs
View File

@ -4,11 +4,10 @@ fn non_elidable<'a, 'b>(a: &'a u8, b: &'b u8) -> &'a u8 {
a
}
// the boundaries of elision
static NON_ELIDABLE_FN: &fn(&u8, &u8) -> &u8 =
//~^ ERROR missing lifetime specifier [E0106]
&(non_elidable as fn(&u8, &u8) -> &u8);
//~^ ERROR missing lifetime specifier [E0106]
// The incorrect case without `for<'a>` is tested for in `rfc1623-2.rs`
static NON_ELIDABLE_FN: &for<'a> fn(&'a u8, &'a u8) -> &'a u8 =
&(non_elidable as for<'a> fn(&'a u8, &'a u8) -> &'a u8);
struct SomeStruct<'x, 'y, 'z: 'x> {
foo: &'x Foo<'z>,
@ -20,10 +19,12 @@ fn id<T>(t: T) -> T {
t
}
static SOME_STRUCT: &SomeStruct = SomeStruct {
static SOME_STRUCT: &SomeStruct = SomeStruct { //~ ERROR mismatched types
foo: &Foo { bools: &[false, true] },
bar: &Bar { bools: &[true, true] },
f: &id,
//~^ ERROR type mismatch in function arguments
//~| ERROR type mismatch resolving
};
// very simple test for a 'static static with default lifetime

57
src/test/ui/rfc1623.stderr
View File

@ -1,27 +1,46 @@
error[E0106]: missing lifetime specifier
--> $DIR/rfc1623.rs:8:42
error[E0308]: mismatched types
--> $DIR/rfc1623.rs:22:35
|
LL | static NON_ELIDABLE_FN: &fn(&u8, &u8) -> &u8 =
| ^ expected named lifetime parameter
LL | static SOME_STRUCT: &SomeStruct = SomeStruct {
| ___________________________________^
LL | | foo: &Foo { bools: &[false, true] },
LL | | bar: &Bar { bools: &[true, true] },
LL | | f: &id,
LL | |
LL | |
LL | | };
| |_^ expected `&SomeStruct<'static, 'static, 'static>`, found struct `SomeStruct`
|
help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from argument 1 or argument 2
--> $DIR/rfc1623.rs:8:29
help: consider borrowing here
|
LL | static NON_ELIDABLE_FN: &fn(&u8, &u8) -> &u8 =
| ^^^ ^^^
LL | static SOME_STRUCT: &SomeStruct = &SomeStruct {
LL | foo: &Foo { bools: &[false, true] },
LL | bar: &Bar { bools: &[true, true] },
LL | f: &id,
LL |
LL |
...
error[E0106]: missing lifetime specifier
--> $DIR/rfc1623.rs:10:39
error[E0631]: type mismatch in function arguments
--> $DIR/rfc1623.rs:25:8
|
LL | &(non_elidable as fn(&u8, &u8) -> &u8);
| ^ expected named lifetime parameter
LL | fn id<T>(t: T) -> T {
| ------------------- found signature of `fn(_) -> _`
...
LL | f: &id,
| ^^^ expected signature of `for<'a, 'b> fn(&'a Foo<'b>) -> _`
|
help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from argument 1 or argument 2
--> $DIR/rfc1623.rs:10:26
|
LL | &(non_elidable as fn(&u8, &u8) -> &u8);
| ^^^ ^^^
= note: required for the cast to the object type `dyn for<'a, 'b> std::ops::Fn(&'a Foo<'b>) -> &'a Foo<'b>`
error: aborting due to 2 previous errors
error[E0271]: type mismatch resolving `for<'a, 'b> <fn(_) -> _ {id::<_>} as std::ops::FnOnce<(&'a Foo<'b>,)>>::Output == &'a Foo<'b>`
--> $DIR/rfc1623.rs:25:8
|
LL | f: &id,
| ^^^ expected bound lifetime parameter 'a, found concrete lifetime
|
= note: required for the cast to the object type `dyn for<'a, 'b> std::ops::Fn(&'a Foo<'b>) -> &'a Foo<'b>`
For more information about this error, try `rustc --explain E0106`.
error: aborting due to 3 previous errors
Some errors have detailed explanations: E0271, E0308, E0631.
For more information about an error, try `rustc --explain E0271`.

12
src/test/ui/suggestions/fn-missing-lifetime-in-item.stderr
View File

@ -9,7 +9,7 @@ help: consider introducing lifetime `'a` here
|
LL | struct S1<'a, F: Fn(&i32, &i32) -> &'a i32>(F);
| ^^^
help: consider introducing a higher-ranked lifetime `'a` here
help: consider making the bound lifetime-generic with a new `'a` lifetime
|
LL | struct S1<F: for<'a> Fn(&i32, &i32) -> &'a i32>(F);
| ^^^^^^^
@ -18,15 +18,11 @@ error[E0106]: missing lifetime specifier
--> $DIR/fn-missing-lifetime-in-item.rs:2:32
|
LL | struct S2<F: Fn(&i32, &i32) -> &i32>(F);
| ^ expected named lifetime parameter
| ---- ---- ^ expected named lifetime parameter
|
help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from argument 1 or argument 2
--> $DIR/fn-missing-lifetime-in-item.rs:2:17
|
LL | struct S2<F: Fn(&i32, &i32) -> &i32>(F);
| ^^^^ ^^^^
= help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from argument 1 or argument 2
= note: for more information on higher-ranked lifetimes, visit https://doc.rust-lang.org/nomicon/hrtb.html
help: consider introducing a higher-ranked lifetime
help: consider making the bound lifetime-generic with a new `'a` lifetime
|
LL | struct S2<F: for<'a> Fn(&'a i32, &'a i32) -> &'a i32>(F);
| ^^^^^^^ ^^^^^^^ ^^^^^^^ ^^^

16
src/test/ui/suggestions/return-without-lifetime.stderr
View File

@ -8,25 +8,17 @@ error[E0106]: missing lifetime specifier
--> $DIR/return-without-lifetime.rs:5:34
|
LL | fn func1<'a>(_arg: &'a Thing) -> &() { unimplemented!() }
| ^ help: consider using the named lifetime: `&'a`
| --------- ^ help: consider using the named lifetime: `&'a`
|
help: this function's return type contains a borrowed value, but the signature does not say which one of `_arg`'s 2 lifetimes it is borrowed from
--> $DIR/return-without-lifetime.rs:5:20
|
LL | fn func1<'a>(_arg: &'a Thing) -> &() { unimplemented!() }
| ^^^^^^^^^
= help: this function's return type contains a borrowed value, but the signature does not say which one of `_arg`'s 2 lifetimes it is borrowed from
error[E0106]: missing lifetime specifier
--> $DIR/return-without-lifetime.rs:7:35
|
LL | fn func2<'a>(_arg: &Thing<'a>) -> &() { unimplemented!() }
| ^ help: consider using the named lifetime: `&'a`
| ---------- ^ help: consider using the named lifetime: `&'a`
|
help: this function's return type contains a borrowed value, but the signature does not say which one of `_arg`'s 2 lifetimes it is borrowed from
--> $DIR/return-without-lifetime.rs:7:20
|
LL | fn func2<'a>(_arg: &Thing<'a>) -> &() { unimplemented!() }
| ^^^^^^^^^^
= help: this function's return type contains a borrowed value, but the signature does not say which one of `_arg`'s 2 lifetimes it is borrowed from
error: aborting due to 3 previous errors

8
src/test/ui/unboxed-closures/unboxed-closure-sugar-lifetime-elision.stderr
View File

@ -2,13 +2,9 @@ error[E0106]: missing lifetime specifier
--> $DIR/unboxed-closure-sugar-lifetime-elision.rs:26:39
|
LL | let _: dyn Foo(&isize, &usize) -> &usize;
| ^ expected named lifetime parameter
| ------ ------ ^ expected named lifetime parameter
|
help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from argument 1 or argument 2
--> $DIR/unboxed-closure-sugar-lifetime-elision.rs:26:20
|
LL | let _: dyn Foo(&isize, &usize) -> &usize;
| ^^^^^^ ^^^^^^
= help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from argument 1 or argument 2
help: consider introducing a named lifetime parameter
|
LL | fn main<'a>() {

8
src/test/ui/underscore-lifetime/in-fn-return-illegal.stderr
View File

@ -2,13 +2,9 @@ error[E0106]: missing lifetime specifier
--> $DIR/in-fn-return-illegal.rs:5:30
|
LL | fn foo(x: &u32, y: &u32) -> &'_ u32 { loop { } }
| ^^ expected named lifetime parameter
| ---- ---- ^^ expected named lifetime parameter
|
help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from `x` or `y`
--> $DIR/in-fn-return-illegal.rs:5:11
|
LL | fn foo(x: &u32, y: &u32) -> &'_ u32 { loop { } }
| ^^^^ ^^^^
= help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from `x` or `y`
help: consider introducing a named lifetime parameter
|
LL | fn foo<'a>(x: &'a u32, y: &'a u32) -> &'a u32 { loop { } }

8
src/test/ui/underscore-lifetime/underscore-lifetime-binders.stderr
View File

@ -28,13 +28,9 @@ error[E0106]: missing lifetime specifier
--> $DIR/underscore-lifetime-binders.rs:16:35
|
LL | fn foo2(_: &'_ u8, y: &'_ u8) -> &'_ u8 { y }
| ^^ expected named lifetime parameter
| ------ ------ ^^ expected named lifetime parameter
|
help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from argument 1 or `y`
--> $DIR/underscore-lifetime-binders.rs:16:12
|
LL | fn foo2(_: &'_ u8, y: &'_ u8) -> &'_ u8 { y }
| ^^^^^^ ^^^^^^
= help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from argument 1 or `y`
help: consider introducing a named lifetime parameter
|
LL | fn foo2<'a>(_: &'a u8, y: &'a u8) -> &'a u8 { y }