elided_named_lifetimes: bless & add tests

src/tools/clippy/tests/ui/needless_lifetimes.stderr

@@ -1,3 +1,14 @@
+error: elided lifetime has a name
+  --> tests/ui/needless_lifetimes.rs:266:52
+   |
+LL | fn named_input_elided_output<'a>(_arg: &'a str) -> &str {
+   |                              --                    ^ this elided lifetime gets resolved as `'a`
+   |                              |
+   |                              lifetime `'a` declared here
+   |
+   = note: `-D elided-named-lifetimes` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(elided_named_lifetimes)]`
+
 error: the following explicit lifetimes could be elided: 'a, 'b
   --> tests/ui/needless_lifetimes.rs:17:23
    |
@@ -553,5 +564,5 @@ LL -         fn one_input<'a>(x: &'a u8) -> &'a u8 {
 LL +         fn one_input(x: &u8) -> &u8 {
    |
 
-error: aborting due to 46 previous errors
+error: aborting due to 47 previous errors
 

src/tools/clippy/tests/ui/ptr_arg.stderr

@@ -1,3 +1,12 @@
+error: elided lifetime has a name
+  --> tests/ui/ptr_arg.rs:295:56
+   |
+LL |     fn cow_good_ret_ty<'a>(input: &'a Cow<'a, str>) -> &str {
+   |                        -- lifetime `'a` declared here  ^ this elided lifetime gets resolved as `'a`
+   |
+   = note: `-D elided-named-lifetimes` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(elided_named_lifetimes)]`
+
 error: writing `&Vec` instead of `&[_]` involves a new object where a slice will do
   --> tests/ui/ptr_arg.rs:13:14
    |
@@ -212,5 +221,5 @@ error: using a reference to `Cow` is not recommended
 LL |     fn cow_bad_ret_ty_2<'a, 'b>(input: &'a Cow<'a, str>) -> &'b str {
    |                                        ^^^^^^^^^^^^^^^^ help: change this to: `&str`
 
-error: aborting due to 24 previous errors
+error: aborting due to 25 previous errors
 

tests/ui/async-await/issues/issue-63388-1.rs

@@ -9,7 +9,7 @@ trait Foo {}
 impl Xyz {
     async fn do_sth<'a>(
         &'a self, foo: &dyn Foo
-    ) -> &dyn Foo
+    ) -> &dyn Foo  //~ WARNING elided lifetime has a name
     {
         //~^ ERROR explicit lifetime required in the type of `foo` [E0621]
         foo

tests/ui/async-await/issues/issue-63388-1.stderr

@@ -1,3 +1,14 @@
+warning: elided lifetime has a name
+  --> $DIR/issue-63388-1.rs:12:10
+   |
+LL |     async fn do_sth<'a>(
+   |                     -- lifetime `'a` declared here
+LL |         &'a self, foo: &dyn Foo
+LL |     ) -> &dyn Foo
+   |          ^ this elided lifetime gets resolved as `'a`
+   |
+   = note: `#[warn(elided_named_lifetimes)]` on by default
+
 error[E0621]: explicit lifetime required in the type of `foo`
   --> $DIR/issue-63388-1.rs:13:5
    |
@@ -10,6 +21,6 @@ LL | |         foo
 LL | |     }
    | |_____^ lifetime `'a` required
 
-error: aborting due to 1 previous error
+error: aborting due to 1 previous error; 1 warning emitted
 
 For more information about this error, try `rustc --explain E0621`.

tests/ui/const-generics/type-dependent/issue-71348.full.stderr

@@ -0,0 +1,10 @@
+warning: elided lifetime has a name
+  --> $DIR/issue-71348.rs:18:68
+   |
+LL |     fn ask<'a, const N: &'static str>(&'a self) -> &'a <Self as Get<N>>::Target
+   |            -- lifetime `'a` declared here                          ^ this elided lifetime gets resolved as `'a`
+   |
+   = note: `#[warn(elided_named_lifetimes)]` on by default
+
+warning: 1 warning emitted
+

tests/ui/const-generics/type-dependent/issue-71348.min.stderr

@@ -1,3 +1,11 @@
+warning: elided lifetime has a name
+  --> $DIR/issue-71348.rs:18:68
+   |
+LL |     fn ask<'a, const N: &'static str>(&'a self) -> &'a <Self as Get<N>>::Target
+   |            -- lifetime `'a` declared here                          ^ this elided lifetime gets resolved as `'a`
+   |
+   = note: `#[warn(elided_named_lifetimes)]` on by default
+
 error: `&'static str` is forbidden as the type of a const generic parameter
   --> $DIR/issue-71348.rs:10:24
    |
@@ -30,5 +38,5 @@ help: add `#![feature(unsized_const_params)]` to the crate attributes to enable
 LL + #![feature(unsized_const_params)]
    |
 
-error: aborting due to 2 previous errors
+error: aborting due to 2 previous errors; 1 warning emitted
 

tests/ui/const-generics/type-dependent/issue-71348.rs

@@ -17,6 +17,7 @@ trait Get<'a, const N: &'static str> {
 impl Foo {
     fn ask<'a, const N: &'static str>(&'a self) -> &'a <Self as Get<N>>::Target
     //[min]~^ ERROR `&'static str` is forbidden as the type of a const generic parameter
+    //~^^ WARNING elided lifetime has a name
     where
         Self: Get<'a, N>,
     {

tests/ui/consts/min_const_fn/min_const_fn.rs

@@ -44,8 +44,8 @@ impl<T> Foo<T> {
 impl<'a, T> Foo<T> {
     const fn new_lt(t: T) -> Self { Foo(t) }
     const fn into_inner_lt(self) -> T { self.0 } //~ destructor of
-    const fn get_lt(&'a self) -> &T { &self.0 }
-    const fn get_mut_lt(&'a mut self) -> &mut T { &mut self.0 }
+    const fn get_lt(&'a self) -> &T { &self.0 } //~ WARNING elided lifetime has a name
+    const fn get_mut_lt(&'a mut self) -> &mut T { &mut self.0 } //~ WARNING elided lifetime has a name
     //~^ mutable references
     //~| mutable references
     //~| mutable references

tests/ui/consts/min_const_fn/min_const_fn.stderr

@@ -1,3 +1,23 @@
+warning: elided lifetime has a name
+  --> $DIR/min_const_fn.rs:47:34
+   |
+LL | impl<'a, T> Foo<T> {
+   |      -- lifetime `'a` declared here
+...
+LL |     const fn get_lt(&'a self) -> &T { &self.0 }
+   |                                  ^ this elided lifetime gets resolved as `'a`
+   |
+   = note: `#[warn(elided_named_lifetimes)]` on by default
+
+warning: elided lifetime has a name
+  --> $DIR/min_const_fn.rs:48:42
+   |
+LL | impl<'a, T> Foo<T> {
+   |      -- lifetime `'a` declared here
+...
+LL |     const fn get_mut_lt(&'a mut self) -> &mut T { &mut self.0 }
+   |                                          ^ this elided lifetime gets resolved as `'a`
+
 error[E0493]: destructor of `Foo<T>` cannot be evaluated at compile-time
   --> $DIR/min_const_fn.rs:37:25
    |
@@ -228,7 +248,7 @@ LL | const fn no_apit(_x: impl std::fmt::Debug) {}
    |                  |
    |                  the destructor for this type cannot be evaluated in constant functions
 
-error: aborting due to 24 previous errors
+error: aborting due to 24 previous errors; 2 warnings emitted
 
 Some errors have detailed explanations: E0493, E0658.
 For more information about an error, try `rustc --explain E0493`.

tests/ui/generics/generic-no-mangle.fixed

@@ -1,5 +1,5 @@
 //@ run-rustfix
-#![allow(dead_code)]
+#![allow(dead_code, elided_named_lifetimes)]
 #![deny(no_mangle_generic_items)]
 
 pub fn foo<T>() {} //~ ERROR functions generic over types or consts must be mangled

tests/ui/generics/generic-no-mangle.rs

@@ -1,5 +1,5 @@
 //@ run-rustfix
-#![allow(dead_code)]
+#![allow(dead_code, elided_named_lifetimes)]
 #![deny(no_mangle_generic_items)]
 
 #[no_mangle]

tests/ui/impl-trait/impl-fn-hrtb-bounds.rs

@@ -13,6 +13,7 @@ fn b() -> impl for<'a> Fn(&'a u8) -> (impl Debug + 'a) {
 
 fn c() -> impl for<'a> Fn(&'a u8) -> (impl Debug + '_) {
     //~^ ERROR `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
+    //~| WARNING elided lifetime has a name
     |x| x
 }
 

tests/ui/impl-trait/impl-fn-hrtb-bounds.stderr

@@ -1,5 +1,5 @@
 error[E0106]: missing lifetime specifier
-  --> $DIR/impl-fn-hrtb-bounds.rs:19:38
+  --> $DIR/impl-fn-hrtb-bounds.rs:20:38
    |
 LL | fn d() -> impl Fn() -> (impl Debug + '_) {
    |                                      ^^ expected named lifetime parameter
@@ -10,6 +10,14 @@ help: consider using the `'static` lifetime, but this is uncommon unless you're
 LL | fn d() -> impl Fn() -> (impl Debug + 'static) {
    |                                      ~~~~~~~
 
+warning: elided lifetime has a name
+  --> $DIR/impl-fn-hrtb-bounds.rs:14:52
+   |
+LL | fn c() -> impl for<'a> Fn(&'a u8) -> (impl Debug + '_) {
+   |                    -- lifetime `'a` declared here  ^^ this elided lifetime gets resolved as `'a`
+   |
+   = note: `#[warn(elided_named_lifetimes)]` on by default
+
 error[E0657]: `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
   --> $DIR/impl-fn-hrtb-bounds.rs:4:41
    |
@@ -46,7 +54,7 @@ note: lifetime declared here
 LL | fn c() -> impl for<'a> Fn(&'a u8) -> (impl Debug + '_) {
    |                    ^^
 
-error: aborting due to 4 previous errors
+error: aborting due to 4 previous errors; 1 warning emitted
 
 Some errors have detailed explanations: E0106, E0657.
 For more information about an error, try `rustc --explain E0106`.

tests/ui/impl-trait/impl-fn-predefined-lifetimes.rs

@@ -3,6 +3,7 @@ use std::fmt::Debug;
 
 fn a<'a>() -> impl Fn(&'a u8) -> (impl Debug + '_) {
     //~^ ERROR cannot resolve opaque type
+    //~| WARNING elided lifetime has a name
     |x| x
     //~^ ERROR expected generic lifetime parameter, found `'_`
 }

tests/ui/impl-trait/impl-fn-predefined-lifetimes.stderr

@@ -1,9 +1,17 @@
+warning: elided lifetime has a name
+  --> $DIR/impl-fn-predefined-lifetimes.rs:4:48
+   |
+LL | fn a<'a>() -> impl Fn(&'a u8) -> (impl Debug + '_) {
+   |      -- lifetime `'a` declared here            ^^ this elided lifetime gets resolved as `'a`
+   |
+   = note: `#[warn(elided_named_lifetimes)]` on by default
+
 error[E0792]: expected generic lifetime parameter, found `'_`
-  --> $DIR/impl-fn-predefined-lifetimes.rs:6:9
+  --> $DIR/impl-fn-predefined-lifetimes.rs:7:9
    |
 LL | fn a<'a>() -> impl Fn(&'a u8) -> (impl Debug + '_) {
    |                                                -- this generic parameter must be used with a generic lifetime parameter
-LL |
+...
 LL |     |x| x
    |         ^
 
@@ -13,7 +21,7 @@ error[E0720]: cannot resolve opaque type
 LL | fn a<'a>() -> impl Fn(&'a u8) -> (impl Debug + '_) {
    |                                   ^^^^^^^^^^^^^^^ cannot resolve opaque type
 
-error: aborting due to 2 previous errors
+error: aborting due to 2 previous errors; 1 warning emitted
 
 Some errors have detailed explanations: E0720, E0792.
 For more information about an error, try `rustc --explain E0720`.

tests/ui/impl-trait/rpit-assoc-pair-with-lifetime.rs

@@ -1,6 +1,7 @@
 //@ check-pass
 
 pub fn iter<'a>(v: Vec<(u32, &'a u32)>) -> impl DoubleEndedIterator<Item = (u32, &u32)> {
+    //~^ WARNING elided lifetime has a name
     v.into_iter()
 }
 

tests/ui/impl-trait/rpit-assoc-pair-with-lifetime.stderr

@@ -0,0 +1,10 @@
+warning: elided lifetime has a name
+  --> $DIR/rpit-assoc-pair-with-lifetime.rs:3:82
+   |
+LL | pub fn iter<'a>(v: Vec<(u32, &'a u32)>) -> impl DoubleEndedIterator<Item = (u32, &u32)> {
+   |             -- lifetime `'a` declared here                                       ^ this elided lifetime gets resolved as `'a`
+   |
+   = note: `#[warn(elided_named_lifetimes)]` on by default
+
+warning: 1 warning emitted
+

tests/ui/lifetimes/lifetime-elision-return-type-requires-explicit-lifetime.rs

@@ -47,5 +47,6 @@ fn l<'a>(_: &'a str, _: &'a str) -> &str { "" }
 
 // This is ok because both `'a` are for the same parameter.
 fn m<'a>(_: &'a Foo<'a>) -> &str { "" }
+//~^ WARNING elided lifetime has a name
 
 fn main() {}

tests/ui/lifetimes/lifetime-elision-return-type-requires-explicit-lifetime.stderr

@@ -105,6 +105,16 @@ help: consider using the `'a` lifetime
 LL | fn l<'a>(_: &'a str, _: &'a str) -> &'a str { "" }
    |                                      ++
 
-error: aborting due to 7 previous errors
+warning: elided lifetime has a name
+  --> $DIR/lifetime-elision-return-type-requires-explicit-lifetime.rs:49:29
+   |
+LL | fn m<'a>(_: &'a Foo<'a>) -> &str { "" }
+   |      --                     ^ this elided lifetime gets resolved as `'a`
+   |      |
+   |      lifetime `'a` declared here
+   |
+   = note: `#[warn(elided_named_lifetimes)]` on by default
+
+error: aborting due to 7 previous errors; 1 warning emitted
 
 For more information about this error, try `rustc --explain E0106`.

tests/ui/lifetimes/lifetime-errors/ex1-return-one-existing-name-if-else-using-impl-3.rs

@@ -4,6 +4,7 @@ struct Foo {
 
 impl Foo {
   fn foo<'a>(&'a self, x: &i32) -> &i32 {
+    //~^ WARNING elided lifetime has a name
 
     if true { &self.field } else { x } //~ ERROR explicit lifetime
 

tests/ui/lifetimes/lifetime-errors/ex1-return-one-existing-name-if-else-using-impl-3.stderr

@@ -1,12 +1,22 @@
+warning: elided lifetime has a name
+  --> $DIR/ex1-return-one-existing-name-if-else-using-impl-3.rs:6:36
+   |
+LL |   fn foo<'a>(&'a self, x: &i32) -> &i32 {
+   |          --                        ^ this elided lifetime gets resolved as `'a`
+   |          |
+   |          lifetime `'a` declared here
+   |
+   = note: `#[warn(elided_named_lifetimes)]` on by default
+
 error[E0621]: explicit lifetime required in the type of `x`
-  --> $DIR/ex1-return-one-existing-name-if-else-using-impl-3.rs:8:36
+  --> $DIR/ex1-return-one-existing-name-if-else-using-impl-3.rs:9:36
    |
 LL |   fn foo<'a>(&'a self, x: &i32) -> &i32 {
    |                           ---- help: add explicit lifetime `'a` to the type of `x`: `&'a i32`
-LL |
+...
 LL |     if true { &self.field } else { x }
    |                                    ^ lifetime `'a` required
 
-error: aborting due to 1 previous error
+error: aborting due to 1 previous error; 1 warning emitted
 
 For more information about this error, try `rustc --explain E0621`.

tests/ui/lint/elided-named-lifetimes/example-from-issue48686.rs

@@ -0,0 +1,12 @@
+#![deny(elided_named_lifetimes)]
+
+struct Foo;
+
+impl Foo {
+    pub fn get_mut(&'static self, x: &mut u8) -> &mut u8 {
+        //~^ ERROR elided lifetime has a name
+        unsafe { &mut *(x as *mut _) }
+    }
+}
+
+fn main() {}

tests/ui/lint/elided-named-lifetimes/example-from-issue48686.stderr

@@ -0,0 +1,14 @@
+error: elided lifetime has a name
+  --> $DIR/example-from-issue48686.rs:6:50
+   |
+LL |     pub fn get_mut(&'static self, x: &mut u8) -> &mut u8 {
+   |                                                  ^ this elided lifetime gets resolved as `'static`
+   |
+note: the lint level is defined here
+  --> $DIR/example-from-issue48686.rs:1:9
+   |
+LL | #![deny(elided_named_lifetimes)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 1 previous error
+

tests/ui/lint/elided-named-lifetimes/missing-lifetime-kind.rs

@@ -0,0 +1,27 @@
+#![deny(elided_named_lifetimes)]
+
+fn ampersand<'a>(x: &'a u8) -> &u8 {
+    //~^ ERROR elided lifetime has a name
+    x
+}
+
+struct Brackets<'a>(&'a u8);
+
+fn brackets<'a>(x: &'a u8) -> Brackets {
+    //~^ ERROR elided lifetime has a name
+    Brackets(x)
+}
+
+struct Comma<'a, T>(&'a T);
+
+fn comma<'a>(x: &'a u8) -> Comma<u8> {
+    //~^ ERROR elided lifetime has a name
+    Comma(x)
+}
+
+fn underscore<'a>(x: &'a u8) -> &'_ u8 {
+    //~^ ERROR elided lifetime has a name
+    x
+}
+
+fn main() {}