Tweak suggested lifetimes to modify return type instead of &self receiver

estebank · estebank · commit 1775e7b93d41 · 2024-05-17T20:31:13.000Z
Do not suggest constraining the `&amp;self` param, but rather the return type.
If that is wrong (because it is not sufficient), a follow up error will tell the
user to fix it. This way we lower the chances of *over* constraining, but still
get the cake of "correctly" contrained in two steps.

This is a correct suggestion:

```
error: lifetime may not live long enough
  --&gt; $DIR/ex3-both-anon-regions-return-type-is-anon.rs:9:9
   |
LL |     fn foo&lt;'a&gt;(&amp;self, x: &amp;i32) -&gt; &amp;i32 {
   |                -         - let's call the lifetime of this reference `'1`
   |                |
   |                let's call the lifetime of this reference `'2`
LL |         x
   |         ^ method was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
   |
help: consider introducing a named lifetime parameter and update trait if needed
   |
LL |     fn foo&lt;'a&gt;(&amp;self, x: &amp;'a i32) -&gt; &amp;'a i32 {
   |                           ++          ++
```

While this is incomplete because it should suggestino `&amp;'a self`

```
error: lifetime may not live long enough
  --&gt; $DIR/ex3-both-anon-regions-self-is-anon.rs:7:19
   |
LL |     fn foo&lt;'a&gt;(&amp;self, x: &amp;Foo) -&gt; &amp;Foo {
   |                -         - let's call the lifetime of this reference `'1`
   |                |
   |                let's call the lifetime of this reference `'2`
LL |         if true { x } else { self }
   |                   ^ method was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
   |
help: consider introducing a named lifetime parameter and update trait if needed
   |
LL |     fn foo&lt;'a&gt;(&amp;self, x: &amp;'a Foo) -&gt; &amp;'a Foo {
   |                           ++          ++
```

but the follow up error is

```
error: lifetime may not live long enough
 --&gt; tests/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-self-is-anon.rs:7:30
  |
6 |     fn foo&lt;'a&gt;(&amp;self, x: &amp;'a Foo) -&gt; &amp;'a Foo {
  |            --  - let's call the lifetime of this reference `'1`
  |            |
  |            lifetime `'a` defined here
7 |         if true { x } else { self }
  |                              ^^^^ method was supposed to return data with lifetime `'a` but it is returning data with lifetime `'1`
  |
help: consider introducing a named lifetime parameter and update trait if needed
  |
6 |     fn foo&lt;'a&gt;(&amp;'a self, x: &amp;'a Foo) -&gt; &amp;'a Foo {
  |                 ++
```
diff --git a/compiler/rustc_infer/src/errors/mod.rs b/compiler/rustc_infer/src/errors/mod.rs
@@ -484,13 +484,19 @@ impl Subdiagnostic for AddLifetimeParamsSuggestion<'_> {
                 suggestions: vec![],
                 suggestion_param_name: suggestion_param_name.clone(),
             };
-            visitor.visit_ty(self.ty_sub);
-            visitor.visit_ty(self.ty_sup);
             if let Some(fn_decl) = node.fn_decl()
                 && let hir::FnRetTy::Return(ty) = fn_decl.output
             {
                 visitor.visit_ty(ty);
             }
+            if visitor.suggestions.is_empty() {
+                // Do not suggest constraining the `&self` param, but rather the return type.
+                // If that is wrong (because it is not sufficient), a follow up error will tell the
+                // user to fix it. This way we lower the chances of *over* constraining, but still
+                // get the cake of "correctly" contrained in two steps.
+                visitor.visit_ty(self.ty_sup);
+            }
+            visitor.visit_ty(self.ty_sub);
             if visitor.suggestions.is_empty() {
                 return false;
             }
diff --git a/tests/ui/lifetimes/issue-17728.stderr b/tests/ui/lifetimes/issue-17728.stderr
@@ -29,8 +29,8 @@ LL |             Some(entry) => Ok(entry),
    |
 help: consider introducing a named lifetime parameter
    |
-LL |     fn attemptTraverse<'a>(&'a self, room: &'a Room, directionStr: &str) -> Result<&'a Room, &'a str> {
-   |                       ++++  ++              ++                                      ++        ++
+LL |     fn attemptTraverse<'a>(&self, room: &'a Room, directionStr: &str) -> Result<&'a Room, &'a str> {
+   |                       ++++               ++                                      ++        ++
 
 error: aborting due to 2 previous errors
 
diff --git a/tests/ui/lifetimes/lifetime-errors/ex1-return-one-existing-name-return-type-is-anon.fixed b/tests/ui/lifetimes/lifetime-errors/ex1-return-one-existing-name-return-type-is-anon.fixed
@@ -5,7 +5,7 @@ struct Foo {
 }
 
 impl Foo {
-    fn foo<'a>(&'a self, x: &'a i32) -> &'a i32 {
+    fn foo<'a>(&self, x: &'a i32) -> &'a i32 {
         x
         //~^ ERROR lifetime may not live long enough
     }
diff --git a/tests/ui/lifetimes/lifetime-errors/ex1-return-one-existing-name-return-type-is-anon.stderr b/tests/ui/lifetimes/lifetime-errors/ex1-return-one-existing-name-return-type-is-anon.stderr
@@ -10,8 +10,8 @@ LL |         x
    |
 help: consider introducing a named lifetime parameter and update trait if needed
    |
-LL |     fn foo<'a>(&'a self, x: &'a i32) -> &'a i32 {
-   |                 ++                       ++
+LL |     fn foo<'a>(&self, x: &'a i32) -> &'a i32 {
+   |                                       ++
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-return-type-is-anon.fixed b/tests/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-return-type-is-anon.fixed
@@ -5,7 +5,7 @@ struct Foo {
 }
 
 impl Foo {
-    fn foo<'a>(&'a self, x: &'a i32) -> &'a i32 {
+    fn foo<'a>(&self, x: &'a i32) -> &'a i32 {
         x
         //~^ ERROR lifetime may not live long enough
     }
diff --git a/tests/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-return-type-is-anon.stderr b/tests/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-return-type-is-anon.stderr
@@ -10,8 +10,8 @@ LL |         x
    |
 help: consider introducing a named lifetime parameter and update trait if needed
    |
-LL |     fn foo<'a>(&'a self, x: &'a i32) -> &'a i32 {
-   |                 ++           ++          ++
+LL |     fn foo<'a>(&self, x: &'a i32) -> &'a i32 {
+   |                           ++          ++
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-self-is-anon.stderr b/tests/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-self-is-anon.stderr
@@ -10,8 +10,8 @@ LL |         if true { x } else { self }
    |
 help: consider introducing a named lifetime parameter and update trait if needed
    |
-LL |     fn foo<'a>(&'a self, x: &'a Foo) -> &'a Foo {
-   |                 ++           ++          ++
+LL |     fn foo<'a>(&self, x: &'a Foo) -> &'a Foo {
+   |                           ++          ++
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/self/arbitrary_self_types_pin_lifetime_mismatch.stderr b/tests/ui/self/arbitrary_self_types_pin_lifetime_mismatch.stderr
@@ -10,8 +10,8 @@ LL |         f
    |
 help: consider introducing a named lifetime parameter and update trait if needed
    |
-LL |     fn a<'a>(self: Pin<&'a Foo>, f: &'a Foo) -> &'a Foo {
-   |         ++++            ++           ++          ++
+LL |     fn a<'a>(self: Pin<&Foo>, f: &'a Foo) -> &'a Foo {
+   |         ++++                      ++          ++
 
 error: lifetime may not live long enough
   --> $DIR/arbitrary_self_types_pin_lifetime_mismatch.rs:14:9
@@ -25,8 +25,8 @@ LL |         (self, f)
    |
 help: consider introducing a named lifetime parameter and update trait if needed
    |
-LL |     fn c<'a>(self: Pin<&'a Self>, f: &'a Foo, g: &Foo) -> (Pin<&'a Foo>, &'a Foo) {
-   |         ++++            ++            ++                        ++        ++
+LL |     fn c<'a>(self: Pin<&Self>, f: &'a Foo, g: &Foo) -> (Pin<&'a Foo>, &'a Foo) {
+   |         ++++                       ++                        ++        ++
 
 error: lifetime may not live long enough
   --> $DIR/arbitrary_self_types_pin_lifetime_mismatch.rs:21:9
@@ -40,8 +40,8 @@ LL |         arg
    |
 help: consider introducing a named lifetime parameter and update trait if needed
    |
-LL |     fn bar<'a>(self: Alias<&'a Self>, arg: &'a ()) -> &'a () {
-   |                             ++                         ++
+LL |     fn bar<'a>(self: Alias<&Self>, arg: &'a ()) -> &'a () {
+   |                                                     ++
 
 error: aborting due to 3 previous errors
 
diff --git a/tests/ui/self/elision/lt-ref-self.fixed b/tests/ui/self/elision/lt-ref-self.fixed
@@ -10,34 +10,34 @@ struct Struct<'a> {
 impl<'a> Struct<'a> {
     // Test using `&self` sugar:
 
-    fn ref_self<'b>(&'b self, f: &'b u32) -> &'b u32 {
+    fn ref_self<'b>(&self, f: &'b u32) -> &'b u32 {
         f
         //~^ ERROR lifetime may not live long enough
     }
 
     // Test using `&Self` explicitly:
 
-    fn ref_Self<'b>(self: &'b Self, f: &'b u32) -> &'b u32 {
+    fn ref_Self<'b>(self: &Self, f: &'b u32) -> &'b u32 {
         f
         //~^ ERROR lifetime may not live long enough
     }
 
-    fn box_ref_Self<'b>(self: Box<&'b Self>, f: &'b u32) -> &'b u32 {
+    fn box_ref_Self<'b>(self: Box<&Self>, f: &'b u32) -> &'b u32 {
         f
         //~^ ERROR lifetime may not live long enough
     }
 
-    fn pin_ref_Self<'b>(self: Pin<&'b Self>, f: &'b u32) -> &'b u32 {
+    fn pin_ref_Self<'b>(self: Pin<&Self>, f: &'b u32) -> &'b u32 {
         f
         //~^ ERROR lifetime may not live long enough
     }
 
-    fn box_box_ref_Self<'b>(self: Box<Box<&'b Self>>, f: &'b u32) -> &'b u32 {
+    fn box_box_ref_Self<'b>(self: Box<Box<&Self>>, f: &'b u32) -> &'b u32 {
         f
         //~^ ERROR lifetime may not live long enough
     }
 
-    fn box_pin_Self<'b>(self: Box<Pin<&'b Self>>, f: &'b u32) -> &'b u32 {
+    fn box_pin_Self<'b>(self: Box<Pin<&Self>>, f: &'b u32) -> &'b u32 {
         f
         //~^ ERROR lifetime may not live long enough
     }
diff --git a/tests/ui/self/elision/lt-ref-self.stderr b/tests/ui/self/elision/lt-ref-self.stderr
@@ -10,8 +10,8 @@ LL |         f
    |
 help: consider introducing a named lifetime parameter and update trait if needed
    |
-LL |     fn ref_self<'b>(&'b self, f: &'b u32) -> &'b u32 {
-   |                ++++  ++           ++          ++
+LL |     fn ref_self<'b>(&self, f: &'b u32) -> &'b u32 {
+   |                ++++            ++          ++
 
 error: lifetime may not live long enough
   --> $DIR/lt-ref-self.rs:21:9
@@ -25,8 +25,8 @@ LL |         f
    |
 help: consider introducing a named lifetime parameter and update trait if needed
    |
-LL |     fn ref_Self<'b>(self: &'b Self, f: &'b u32) -> &'b u32 {
-   |                ++++        ++           ++          ++
+LL |     fn ref_Self<'b>(self: &Self, f: &'b u32) -> &'b u32 {
+   |                ++++                  ++          ++
 
 error: lifetime may not live long enough
   --> $DIR/lt-ref-self.rs:26:9
@@ -40,8 +40,8 @@ LL |         f
    |
 help: consider introducing a named lifetime parameter and update trait if needed
    |
-LL |     fn box_ref_Self<'b>(self: Box<&'b Self>, f: &'b u32) -> &'b u32 {
-   |                    ++++            ++            ++          ++
+LL |     fn box_ref_Self<'b>(self: Box<&Self>, f: &'b u32) -> &'b u32 {
+   |                    ++++                       ++          ++
 
 error: lifetime may not live long enough
   --> $DIR/lt-ref-self.rs:31:9
@@ -55,8 +55,8 @@ LL |         f
    |
 help: consider introducing a named lifetime parameter and update trait if needed
    |
-LL |     fn pin_ref_Self<'b>(self: Pin<&'b Self>, f: &'b u32) -> &'b u32 {
-   |                    ++++            ++            ++          ++
+LL |     fn pin_ref_Self<'b>(self: Pin<&Self>, f: &'b u32) -> &'b u32 {
+   |                    ++++                       ++          ++
 
 error: lifetime may not live long enough
   --> $DIR/lt-ref-self.rs:36:9
@@ -70,8 +70,8 @@ LL |         f
    |
 help: consider introducing a named lifetime parameter and update trait if needed
    |
-LL |     fn box_box_ref_Self<'b>(self: Box<Box<&'b Self>>, f: &'b u32) -> &'b u32 {
-   |                        ++++                ++             ++          ++
+LL |     fn box_box_ref_Self<'b>(self: Box<Box<&Self>>, f: &'b u32) -> &'b u32 {
+   |                        ++++                            ++          ++
 
 error: lifetime may not live long enough
   --> $DIR/lt-ref-self.rs:41:9
@@ -85,8 +85,8 @@ LL |         f
    |
 help: consider introducing a named lifetime parameter and update trait if needed
    |
-LL |     fn box_pin_Self<'b>(self: Box<Pin<&'b Self>>, f: &'b u32) -> &'b u32 {
-   |                    ++++                ++             ++          ++
+LL |     fn box_pin_Self<'b>(self: Box<Pin<&Self>>, f: &'b u32) -> &'b u32 {
+   |                    ++++                            ++          ++
 
 error: aborting due to 6 previous errors
 
diff --git a/tests/ui/self/elision/ref-mut-self.fixed b/tests/ui/self/elision/ref-mut-self.fixed
@@ -8,34 +8,34 @@ struct Struct {}
 impl Struct {
     // Test using `&mut self` sugar:
 
-    fn ref_self<'a>(&'a mut self, f: &'a u32) -> &'a u32 {
+    fn ref_self<'a>(&mut self, f: &'a u32) -> &'a u32 {
         f
         //~^ ERROR lifetime may not live long enough
     }
 
     // Test using `&mut Self` explicitly:
 
-    fn ref_Self<'a>(self: &'a mut Self, f: &'a u32) -> &'a u32 {
+    fn ref_Self<'a>(self: &mut Self, f: &'a u32) -> &'a u32 {
         f
         //~^ ERROR lifetime may not live long enough
     }
 
-    fn box_ref_Self<'a>(self: Box<&'a mut Self>, f: &'a u32) -> &'a u32 {
+    fn box_ref_Self<'a>(self: Box<&mut Self>, f: &'a u32) -> &'a u32 {
         f
         //~^ ERROR lifetime may not live long enough
     }
 
-    fn pin_ref_Self<'a>(self: Pin<&'a mut Self>, f: &'a u32) -> &'a u32 {
+    fn pin_ref_Self<'a>(self: Pin<&mut Self>, f: &'a u32) -> &'a u32 {
         f
         //~^ ERROR lifetime may not live long enough
     }
 
-    fn box_box_ref_Self<'a>(self: Box<Box<&'a mut Self>>, f: &'a u32) -> &'a u32 {
+    fn box_box_ref_Self<'a>(self: Box<Box<&mut Self>>, f: &'a u32) -> &'a u32 {
         f
         //~^ ERROR lifetime may not live long enough
     }
 
-    fn box_pin_ref_Self<'a>(self: Box<Pin<&'a mut Self>>, f: &'a u32) -> &'a u32 {
+    fn box_pin_ref_Self<'a>(self: Box<Pin<&mut Self>>, f: &'a u32) -> &'a u32 {
         f
         //~^ ERROR lifetime may not live long enough
     }
diff --git a/tests/ui/self/elision/ref-mut-self.stderr b/tests/ui/self/elision/ref-mut-self.stderr
@@ -10,8 +10,8 @@ LL |         f
    |
 help: consider introducing a named lifetime parameter and update trait if needed
    |
-LL |     fn ref_self<'a>(&'a mut self, f: &'a u32) -> &'a u32 {
-   |                ++++  ++               ++          ++
+LL |     fn ref_self<'a>(&mut self, f: &'a u32) -> &'a u32 {
+   |                ++++                ++          ++
 
 error: lifetime may not live long enough
   --> $DIR/ref-mut-self.rs:19:9
@@ -25,8 +25,8 @@ LL |         f
    |
 help: consider introducing a named lifetime parameter and update trait if needed
    |
-LL |     fn ref_Self<'a>(self: &'a mut Self, f: &'a u32) -> &'a u32 {
-   |                ++++        ++               ++          ++
+LL |     fn ref_Self<'a>(self: &mut Self, f: &'a u32) -> &'a u32 {
+   |                ++++                      ++          ++
 
 error: lifetime may not live long enough
   --> $DIR/ref-mut-self.rs:24:9
@@ -40,8 +40,8 @@ LL |         f
    |
 help: consider introducing a named lifetime parameter and update trait if needed
    |
-LL |     fn box_ref_Self<'a>(self: Box<&'a mut Self>, f: &'a u32) -> &'a u32 {
-   |                    ++++            ++                ++          ++
+LL |     fn box_ref_Self<'a>(self: Box<&mut Self>, f: &'a u32) -> &'a u32 {
+   |                    ++++                           ++          ++
 
 error: lifetime may not live long enough
   --> $DIR/ref-mut-self.rs:29:9
@@ -55,8 +55,8 @@ LL |         f
    |
 help: consider introducing a named lifetime parameter and update trait if needed
    |
-LL |     fn pin_ref_Self<'a>(self: Pin<&'a mut Self>, f: &'a u32) -> &'a u32 {
-   |                    ++++            ++                ++          ++
+LL |     fn pin_ref_Self<'a>(self: Pin<&mut Self>, f: &'a u32) -> &'a u32 {
+   |                    ++++                           ++          ++
 
 error: lifetime may not live long enough
   --> $DIR/ref-mut-self.rs:34:9
@@ -70,8 +70,8 @@ LL |         f
    |
 help: consider introducing a named lifetime parameter and update trait if needed
    |
-LL |     fn box_box_ref_Self<'a>(self: Box<Box<&'a mut Self>>, f: &'a u32) -> &'a u32 {
-   |                        ++++                ++                 ++          ++
+LL |     fn box_box_ref_Self<'a>(self: Box<Box<&mut Self>>, f: &'a u32) -> &'a u32 {
+   |                        ++++                                ++          ++
 
 error: lifetime may not live long enough
   --> $DIR/ref-mut-self.rs:39:9
@@ -85,8 +85,8 @@ LL |         f
    |
 help: consider introducing a named lifetime parameter and update trait if needed
    |
-LL |     fn box_pin_ref_Self<'a>(self: Box<Pin<&'a mut Self>>, f: &'a u32) -> &'a u32 {
-   |                        ++++                ++                 ++          ++
+LL |     fn box_pin_ref_Self<'a>(self: Box<Pin<&mut Self>>, f: &'a u32) -> &'a u32 {
+   |                        ++++                                ++          ++
 
 error: aborting due to 6 previous errors
 
diff --git a/tests/ui/self/elision/ref-mut-struct.fixed b/tests/ui/self/elision/ref-mut-struct.fixed
@@ -8,27 +8,27 @@ struct Struct {}
 impl Struct {
     // Test using `&mut Struct` explicitly:
 
-    fn ref_Struct<'a>(self: &'a mut Struct, f: &'a u32) -> &'a u32 {
+    fn ref_Struct<'a>(self: &mut Struct, f: &'a u32) -> &'a u32 {
         f
         //~^ ERROR lifetime may not live long enough
     }
 
-    fn box_ref_Struct<'a>(self: Box<&'a mut Struct>, f: &'a u32) -> &'a u32 {
+    fn box_ref_Struct<'a>(self: Box<&mut Struct>, f: &'a u32) -> &'a u32 {
         f
         //~^ ERROR lifetime may not live long enough
     }
 
-    fn pin_ref_Struct<'a>(self: Pin<&'a mut Struct>, f: &'a u32) -> &'a u32 {
+    fn pin_ref_Struct<'a>(self: Pin<&mut Struct>, f: &'a u32) -> &'a u32 {
         f
         //~^ ERROR lifetime may not live long enough
     }
 
-    fn box_box_ref_Struct<'a>(self: Box<Box<&'a mut Struct>>, f: &'a u32) -> &'a u32 {
+    fn box_box_ref_Struct<'a>(self: Box<Box<&mut Struct>>, f: &'a u32) -> &'a u32 {
         f
         //~^ ERROR lifetime may not live long enough
     }
 
-    fn box_pin_ref_Struct<'a>(self: Box<Pin<&'a mut Struct>>, f: &'a u32) -> &'a u32 {
+    fn box_pin_ref_Struct<'a>(self: Box<Pin<&mut Struct>>, f: &'a u32) -> &'a u32 {
         f
         //~^ ERROR lifetime may not live long enough
     }
diff --git a/tests/ui/self/elision/ref-mut-struct.stderr b/tests/ui/self/elision/ref-mut-struct.stderr
diff --git a/tests/ui/self/elision/ref-self.fixed b/tests/ui/self/elision/ref-self.fixed
diff --git a/tests/ui/self/elision/ref-self.stderr b/tests/ui/self/elision/ref-self.stderr
diff --git a/tests/ui/self/elision/ref-struct.fixed b/tests/ui/self/elision/ref-struct.fixed
diff --git a/tests/ui/self/elision/ref-struct.stderr b/tests/ui/self/elision/ref-struct.stderr

Original file line number	Diff line number	Diff line change
`@@ -29,8 +29,8 @@ LL \| Some(entry) => Ok(entry),`
`29`	`29`	`\|`
`30`	`30`	`help: consider introducing a named lifetime parameter`
`31`	`31`	`\|`
`32`		`-LL \| fn attemptTraverse<'a>(&'a self, room: &'a Room, directionStr: &str) -> Result<&'a Room, &'a str> {`
`33`		`- \| ++++ ++ ++ ++ ++`
	`32`	`+LL \| fn attemptTraverse<'a>(&self, room: &'a Room, directionStr: &str) -> Result<&'a Room, &'a str> {`
	`33`	`+ \| ++++ ++ ++ ++`
`34`	`34`
`35`	`35`	`error: aborting due to 2 previous errors`
`36`	`36`
Original file line number	Diff line number	Diff line change
`@@ -5,7 +5,7 @@ struct Foo {`
`5`	`5`	`}`
`6`	`6`
`7`	`7`	`impl Foo {`
`8`		`- fn foo<'a>(&'a self, x: &'a i32) -> &'a i32 {`
	`8`	`+ fn foo<'a>(&self, x: &'a i32) -> &'a i32 {`
`9`	`9`	`x`
`10`	`10`	`//~^ ERROR lifetime may not live long enough`
`11`	`11`	`}`
Original file line number	Diff line number	Diff line change
`@@ -10,8 +10,8 @@ LL \| x`
`10`	`10`	`\|`
`11`	`11`	`help: consider introducing a named lifetime parameter and update trait if needed`
`12`	`12`	`\|`
`13`		`-LL \| fn foo<'a>(&'a self, x: &'a i32) -> &'a i32 {`
`14`		`- \| ++ ++`
	`13`	`+LL \| fn foo<'a>(&self, x: &'a i32) -> &'a i32 {`
	`14`	`+ \| ++`
`15`	`15`
`16`	`16`	`error: aborting due to 1 previous error`
`17`	`17`
Original file line number	Diff line number	Diff line change
`@@ -10,8 +10,8 @@ LL \| if true { x } else { self }`
`10`	`10`	`\|`
`11`	`11`	`help: consider introducing a named lifetime parameter and update trait if needed`
`12`	`12`	`\|`
`13`		`-LL \| fn foo<'a>(&'a self, x: &'a Foo) -> &'a Foo {`
`14`		`- \| ++ ++ ++`
	`13`	`+LL \| fn foo<'a>(&self, x: &'a Foo) -> &'a Foo {`
	`14`	`+ \| ++ ++`
`15`	`15`
`16`	`16`	`error: aborting due to 1 previous error`
`17`	`17`
Original file line number	Diff line number	Diff line change
`@@ -10,8 +10,8 @@ LL \| f`
`10`	`10`	`\|`
`11`	`11`	`help: consider introducing a named lifetime parameter and update trait if needed`
`12`	`12`	`\|`
`13`		`-LL \| fn a<'a>(self: Pin<&'a Foo>, f: &'a Foo) -> &'a Foo {`
`14`		`- \| ++++ ++ ++ ++`
	`13`	`+LL \| fn a<'a>(self: Pin<&Foo>, f: &'a Foo) -> &'a Foo {`
	`14`	`+ \| ++++ ++ ++`
`15`	`15`
`16`	`16`	`error: lifetime may not live long enough`
`17`	`17`	`--> $DIR/arbitrary_self_types_pin_lifetime_mismatch.rs:14:9`
`@@ -25,8 +25,8 @@ LL \| (self, f)`
`25`	`25`	`\|`
`26`	`26`	`help: consider introducing a named lifetime parameter and update trait if needed`
`27`	`27`	`\|`
`28`		`-LL \| fn c<'a>(self: Pin<&'a Self>, f: &'a Foo, g: &Foo) -> (Pin<&'a Foo>, &'a Foo) {`
`29`		`- \| ++++ ++ ++ ++ ++`
	`28`	`+LL \| fn c<'a>(self: Pin<&Self>, f: &'a Foo, g: &Foo) -> (Pin<&'a Foo>, &'a Foo) {`
	`29`	`+ \| ++++ ++ ++ ++`
`30`	`30`
`31`	`31`	`error: lifetime may not live long enough`
`32`	`32`	`--> $DIR/arbitrary_self_types_pin_lifetime_mismatch.rs:21:9`
`@@ -40,8 +40,8 @@ LL \| arg`
`40`	`40`	`\|`
`41`	`41`	`help: consider introducing a named lifetime parameter and update trait if needed`
`42`	`42`	`\|`
`43`		`-LL \| fn bar<'a>(self: Alias<&'a Self>, arg: &'a ()) -> &'a () {`
`44`		`- \| ++ ++`
	`43`	`+LL \| fn bar<'a>(self: Alias<&Self>, arg: &'a ()) -> &'a () {`
	`44`	`+ \| ++`
`45`	`45`
`46`	`46`	`error: aborting due to 3 previous errors`
`47`	`47`
Original file line number	Diff line number	Diff line change
`@@ -10,34 +10,34 @@ struct Struct<'a> {`
`10`	`10`	`impl<'a> Struct<'a> {`
`11`	`11`	// Test using `&self` sugar:
`12`	`12`
`13`		`- fn ref_self<'b>(&'b self, f: &'b u32) -> &'b u32 {`
	`13`	`+ fn ref_self<'b>(&self, f: &'b u32) -> &'b u32 {`
`14`	`14`	`f`
`15`	`15`	`//~^ ERROR lifetime may not live long enough`
`16`	`16`	`}`
`17`	`17`
`18`	`18`	// Test using `&Self` explicitly:
`19`	`19`
`20`		`- fn ref_Self<'b>(self: &'b Self, f: &'b u32) -> &'b u32 {`
	`20`	`+ fn ref_Self<'b>(self: &Self, f: &'b u32) -> &'b u32 {`
`21`	`21`	`f`
`22`	`22`	`//~^ ERROR lifetime may not live long enough`
`23`	`23`	`}`
`24`	`24`
`25`		`- fn box_ref_Self<'b>(self: Box<&'b Self>, f: &'b u32) -> &'b u32 {`
	`25`	`+ fn box_ref_Self<'b>(self: Box<&Self>, f: &'b u32) -> &'b u32 {`
`26`	`26`	`f`
`27`	`27`	`//~^ ERROR lifetime may not live long enough`
`28`	`28`	`}`
`29`	`29`
`30`		`- fn pin_ref_Self<'b>(self: Pin<&'b Self>, f: &'b u32) -> &'b u32 {`
	`30`	`+ fn pin_ref_Self<'b>(self: Pin<&Self>, f: &'b u32) -> &'b u32 {`
`31`	`31`	`f`
`32`	`32`	`//~^ ERROR lifetime may not live long enough`
`33`	`33`	`}`
`34`	`34`
`35`		`- fn box_box_ref_Self<'b>(self: Box<Box<&'b Self>>, f: &'b u32) -> &'b u32 {`
	`35`	`+ fn box_box_ref_Self<'b>(self: Box<Box<&Self>>, f: &'b u32) -> &'b u32 {`
`36`	`36`	`f`
`37`	`37`	`//~^ ERROR lifetime may not live long enough`
`38`	`38`	`}`
`39`	`39`
`40`		`- fn box_pin_Self<'b>(self: Box<Pin<&'b Self>>, f: &'b u32) -> &'b u32 {`
	`40`	`+ fn box_pin_Self<'b>(self: Box<Pin<&Self>>, f: &'b u32) -> &'b u32 {`
`41`	`41`	`f`
`42`	`42`	`//~^ ERROR lifetime may not live long enough`
`43`	`43`	`}`