Rollup merge of rust-lang#89504 - Aaron1011:rpit-nll-static, r=nikomatsakis

Don't suggest replacing region with 'static in NLL

Fixes rust-lang#73159

This is similar to rust-lang#69350 - if the user didn't initially
write out a 'static lifetime, adding 'static in response to
a lifetime error is usually the wrong thing to do.

Author: Manishearth

compiler/rustc_borrowck/src/diagnostics/outlives_suggestion.rs

@@ -171,9 +171,7 @@ impl OutlivesSuggestionBuilder {
         let outlived_fr_name = self.region_vid_to_name(mbcx, errci.outlived_fr);
 
         if let (Some(fr_name), Some(outlived_fr_name)) = (fr_name, outlived_fr_name) {
-            if let RegionNameSource::Static = outlived_fr_name.source {
-                diag.help(&format!("consider replacing `{}` with `'static`", fr_name));
-            } else {
+            if !matches!(outlived_fr_name.source, RegionNameSource::Static) {
                 diag.help(&format!(
                     "consider adding the following bound: `{}: {}`",
                     fr_name, outlived_fr_name

src/test/ui/associated-types/cache/project-fn-ret-contravariant.transmute.nll.stderr

@@ -5,8 +5,6 @@ LL | fn baz<'a,'b>(x: &'a u32) -> &'static u32 {
    |        -- lifetime `'a` defined here
 LL |    bar(foo, x)
    |    ^^^^^^^^^^^ returning this value requires that `'a` must outlive `'static`
-   |
-   = help: consider replacing `'a` with `'static`
 
 error: aborting due to previous error
 

src/test/ui/associated-types/cache/project-fn-ret-invariant.transmute.nll.stderr

@@ -6,8 +6,6 @@ LL | fn baz<'a, 'b>(x: Type<'a>) -> Type<'static> {
 ...
 LL |     bar(foo, x)
    |     ^^^^^^^^^^^ returning this value requires that `'a` must outlive `'static`
-   |
-   = help: consider replacing `'a` with `'static`
 
 error: aborting due to previous error
 

src/test/ui/closure-expected-type/expect-fn-supply-fn.nll.stderr

@@ -18,8 +18,6 @@ LL | fn expect_free_supply_free_from_fn<'x>(x: &'x u32) {
 ...
 LL |     with_closure_expecting_fn_with_free_region(|x: fn(&'x u32), y| {});
    |                                                 ^ requires that `'x` must outlive `'static`
-   |
-   = help: consider replacing `'x` with `'static`
 
 error[E0308]: mismatched types
   --> $DIR/expect-fn-supply-fn.rs:32:49

src/test/ui/closures/closure-expected-type/expect-region-supply-region-2.nll.stderr

@@ -17,8 +17,6 @@ LL | fn expect_bound_supply_named<'x>() {
 ...
 LL |     closure_expecting_bound(|x: &'x u32| {
    |                              ^ requires that `'x` must outlive `'static`
-   |
-   = help: consider replacing `'x` with `'static`
 
 error: aborting due to 2 previous errors
 

src/test/ui/hrtb/hrtb-just-for-static.nll.stderr

@@ -14,8 +14,6 @@ LL | fn give_some<'a>() {
    |              -- lifetime `'a` defined here
 LL |     want_hrtb::<&'a u32>()
    |     ^^^^^^^^^^^^^^^^^^^^ requires that `'a` must outlive `'static`
-   |
-   = help: consider replacing `'a` with `'static`
 
 error: implementation of `Foo` is not general enough
   --> $DIR/hrtb-just-for-static.rs:30:5

src/test/ui/hrtb/hrtb-perfect-forwarding.nll.stderr

@@ -54,8 +54,6 @@ LL | fn foo_hrtb_bar_not<'b, T>(mut t: T)
 ...
 LL |     foo_hrtb_bar_not(&mut t);
    |     ^^^^^^^^^^^^^^^^^^^^^^^^ requires that `'b` must outlive `'static`
-   |
-   = help: consider replacing `'b` with `'static`
 
 error: implementation of `Bar` is not general enough
   --> $DIR/hrtb-perfect-forwarding.rs:43:5

src/test/ui/impl-header-lifetime-elision/dyn-trait.nll.stderr

@@ -5,8 +5,6 @@ LL | fn with_dyn_debug_static<'a>(x: Box<dyn Debug + 'a>) {
    |                              - `x` is a reference that is only valid in the function body
 LL |     static_val(x);
    |     ^^^^^^^^^^^^^ `x` escapes the function body here
-   |
-   = help: consider replacing `'a` with `'static`
 
 error: aborting due to previous error
 

src/test/ui/impl-trait/must_outlive_least_region_or_bound.nll.stderr

@@ -19,7 +19,6 @@ LL | fn explicit<'a>(x: &'a i32) -> impl Copy { x }
    |             |
    |             lifetime `'a` defined here
    |
-   = help: consider replacing `'a` with `'static`
 help: to allow this `impl Trait` to capture borrowed data with lifetime `'a`, add `'a` as a bound
    |
 LL | fn explicit<'a>(x: &'a i32) -> impl Copy + 'a { x }
@@ -42,7 +41,6 @@ LL | fn explicit2<'a>(x: &'a i32) -> impl Copy + 'static { x }
    |              -- lifetime `'a` defined here            ^ returning this value requires that `'a` must outlive `'static`
    |
    = help: consider replacing `'a` with `'static`
-   = help: consider replacing `'a` with `'static`
 
 error[E0621]: explicit lifetime required in the type of `x`
   --> $DIR/must_outlive_least_region_or_bound.rs:11:41
@@ -67,7 +65,6 @@ LL | fn with_bound<'a>(x: &'a i32) -> impl LifetimeTrait<'a> + 'static { x }
    |               -- lifetime `'a` defined here                         ^ returning this value requires that `'a` must outlive `'static`
    |
    = help: consider replacing `'a` with `'static`
-   = help: consider replacing `'a` with `'static`
 
 error: lifetime may not live long enough
   --> $DIR/must_outlive_least_region_or_bound.rs:32:61

src/test/ui/impl-trait/static-return-lifetime-infered.nll.stderr

@@ -19,7 +19,6 @@ LL |     fn iter_values<'a>(&'a self) -> impl Iterator<Item=u32> {
    |                    |
    |                    lifetime `'a` defined here
    |
-   = help: consider replacing `'a` with `'static`
 help: to allow this `impl Trait` to capture borrowed data with lifetime `'a`, add `'a` as a bound
    |
 LL |     fn iter_values<'a>(&'a self) -> impl Iterator<Item=u32> + 'a {

src/test/ui/issues/issue-10291.nll.stderr

@@ -6,8 +6,6 @@ LL | fn test<'x>(x: &'x isize) {
 LL |     drop::<Box<dyn for<'z> FnMut(&'z isize) -> &'z isize>>(Box::new(|z| {
 LL |         x
    |         ^ returning this value requires that `'x` must outlive `'static`
-   |
-   = help: consider replacing `'x` with `'static`
 
 error: aborting due to previous error
 

src/test/ui/issues/issue-26217.nll.stderr

@@ -5,8 +5,6 @@ LL | fn bar<'a>() {
    |        -- lifetime `'a` defined here
 LL |     foo::<&'a i32>();
    |     ^^^^^^^^^^^^^^ requires that `'a` must outlive `'static`
-   |
-   = help: consider replacing `'a` with `'static`
 
 error: aborting due to previous error
 

src/test/ui/issues/issue-54943.nll.stderr

@@ -6,8 +6,6 @@ LL | fn boo<'a>() {
 ...
 LL |     let x = foo::<&'a u32>();
    |             ^^^^^^^^^^^^^^ requires that `'a` must outlive `'static`
-   |
-   = help: consider replacing `'a` with `'static`
 
 error: aborting due to previous error
 

src/test/ui/issues/issue-55796.nll.stderr

@@ -6,8 +6,6 @@ LL | pub trait Graph<'a> {
 ...
 LL |         Box::new(self.out_edges(u).map(|e| e.target()))
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ returning this value requires that `'a` must outlive `'static`
-   |
-   = help: consider replacing `'a` with `'static`
 
 error: lifetime may not live long enough
   --> $DIR/issue-55796.rs:23:9
@@ -17,8 +15,6 @@ LL | pub trait Graph<'a> {
 ...
 LL |         Box::new(self.in_edges(u).map(|e| e.target()))
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ returning this value requires that `'a` must outlive `'static`
-   |
-   = help: consider replacing `'a` with `'static`
 
 error: aborting due to 2 previous errors
 

src/test/ui/issues/issue-75777.nll.stderr

@@ -6,8 +6,6 @@ LL | fn inject<'a, Env: 'a, A: 'a + Send>(v: A) -> Box<dyn FnOnce(&'a Env) -> Bo
 LL |     let fut: BoxFuture<'a, A> = Box::pin(future::ready(v));
 LL |     Box::new(move |_| fut)
    |     ^^^^^^^^^^^^^^^^^^^^^^ returning this value requires that `'a` must outlive `'static`
-   |
-   = help: consider replacing `'a` with `'static`
 
 error: aborting due to previous error
 

src/test/ui/lifetimes/lifetime-bound-will-change-warning.nll.stderr

@@ -6,8 +6,6 @@ LL | fn test2<'a>(x: &'a Box<dyn Fn() + 'a>) {
 LL |     // but ref_obj will not, so warn.
 LL |     ref_obj(x)
    |     ^^^^^^^^^^ `x` escapes the function body here
-   |
-   = help: consider replacing `'a` with `'static`
 
 error[E0521]: borrowed data escapes outside of function
   --> $DIR/lifetime-bound-will-change-warning.rs:39:5
@@ -17,8 +15,6 @@ LL | fn test2cc<'a>(x: &'a Box<dyn Fn() + 'a>) {
 LL |     // same as test2, but cross crate
 LL |     lib::ref_obj(x)
    |     ^^^^^^^^^^^^^^^ `x` escapes the function body here
-   |
-   = help: consider replacing `'a` with `'static`
 
 error: aborting due to 2 previous errors
 

src/test/ui/lub-if.nll.stderr

@@ -6,8 +6,6 @@ LL | pub fn opt_str2<'a>(maybestr: &'a Option<String>) -> &'static str {
 ...
 LL |         s
    |         ^ returning this value requires that `'a` must outlive `'static`
-   |
-   = help: consider replacing `'a` with `'static`
 
 error: lifetime may not live long enough
   --> $DIR/lub-if.rs:35:9
@@ -17,8 +15,6 @@ LL | pub fn opt_str3<'a>(maybestr: &'a Option<String>) -> &'static str {
 ...
 LL |         s
    |         ^ returning this value requires that `'a` must outlive `'static`
-   |
-   = help: consider replacing `'a` with `'static`
 
 error: aborting due to 2 previous errors
 

src/test/ui/lub-match.nll.stderr

@@ -6,8 +6,6 @@ LL | pub fn opt_str2<'a>(maybestr: &'a Option<String>) -> &'static str {
 ...
 LL |             s
    |             ^ returning this value requires that `'a` must outlive `'static`
-   |
-   = help: consider replacing `'a` with `'static`
 
 error: lifetime may not live long enough
   --> $DIR/lub-match.rs:39:13
@@ -17,8 +15,6 @@ LL | pub fn opt_str3<'a>(maybestr: &'a Option<String>) -> &'static str {
 ...
 LL |             s
    |             ^ returning this value requires that `'a` must outlive `'static`
-   |
-   = help: consider replacing `'a` with `'static`
 
 error: aborting due to 2 previous errors
 

src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-no-bound.stderr

@@ -46,8 +46,6 @@ LL | |         // Only works if 'x: 'y:
 LL | |         demand_y(x, y, x.get())
 LL | |     });
    | |______^ `cell_a` escapes the function body here
-   |
-   = help: consider replacing `'a` with `'static`
 
 error: aborting due to previous error
 

src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-wrong-bound.stderr

@@ -46,8 +46,6 @@ LL | |         // Only works if 'x: 'y:
 LL | |         demand_y(x, y, x.get())
 LL | |     });
    | |______^ `cell_a` escapes the function body here
-   |
-   = help: consider replacing `'a` with `'static`
 
 error: aborting due to previous error
 

src/test/ui/nll/closure-requirements/region-lbr-named-does-not-outlive-static.stderr

@@ -5,8 +5,6 @@ LL | fn foo<'a>(x: &'a u32) -> &'static u32 {
    |        -- lifetime `'a` defined here
 LL |     &*x
    |     ^^^ returning this value requires that `'a` must outlive `'static`
-   |
-   = help: consider replacing `'a` with `'static`
 
 error: aborting due to previous error
 

src/test/ui/nll/issue-50716.nll.stderr

@@ -6,8 +6,6 @@ LL | fn foo<'a, T: 'static>(s: Box<<&'a T as A>::X>)
 ...
 LL |     let _x = *s;
    |              ^^ proving this value is `Sized` requires that `'a` must outlive `'static`
-   |
-   = help: consider replacing `'a` with `'static`
 
 error: aborting due to previous error
 

src/test/ui/nll/issue-55401.nll.stderr

@@ -6,8 +6,6 @@ LL | fn static_to_a_to_static_through_ref_in_tuple<'a>(x: &'a u32) -> &'static u
 LL |     let (ref y, _z): (&'a u32, u32) = (&22, 44);
 LL |     *y
    |     ^^ returning this value requires that `'a` must outlive `'static`
-   |
-   = help: consider replacing `'a` with `'static`
 
 error: aborting due to previous error
 

src/test/ui/nll/issue-58299.stderr

@@ -6,8 +6,6 @@ LL | fn foo<'a>(x: i32) {
 ...
 LL |         A::<'a>::X..=A::<'static>::X => (),
    |         ^^^^^^^^^^ requires that `'a` must outlive `'static`
-   |
-   = help: consider replacing `'a` with `'static`
 
 error: lifetime may not live long enough
   --> $DIR/issue-58299.rs:24:27
@@ -17,8 +15,6 @@ LL | fn bar<'a>(x: i32) {
 ...
 LL |         A::<'static>::X..=A::<'a>::X => (),
    |                           ^^^^^^^^^^ requires that `'a` must outlive `'static`
-   |
-   = help: consider replacing `'a` with `'static`
 
 error: aborting due to 2 previous errors
 

src/test/ui/nll/issue-73159-rpit-static.rs

@@ -0,0 +1,14 @@
+// Regression test for issue #73159
+// Tests thar we don't suggest replacing 'a with 'static'
+
+#![feature(nll)]
+
+struct Foo<'a>(&'a [u8]);
+
+impl<'a> Foo<'a> {
+    fn make_it(&self) -> impl Iterator<Item = u8> { //~ ERROR lifetime may not live
+        self.0.iter().copied()
+    }
+}
+
+fn main() {}

src/test/ui/nll/issue-73159-rpit-static.stderr

@@ -0,0 +1,10 @@
+error: lifetime may not live long enough
+  --> $DIR/issue-73159-rpit-static.rs:9:26
+   |
+LL | impl<'a> Foo<'a> {
+   |      -- lifetime `'a` defined here
+LL |     fn make_it(&self) -> impl Iterator<Item = u8> {
+   |                          ^^^^^^^^^^^^^^^^^^^^^^^^ opaque type requires that `'a` must outlive `'static`
+
+error: aborting due to previous error
+

src/test/ui/nll/mir_check_cast_reify.stderr

@@ -6,8 +6,6 @@ LL | fn bar<'a>(x: &'a u32) -> &'static u32 {
 ...
 LL |     f(x)
    |     ^^^^ returning this value requires that `'a` must outlive `'static`
-   |
-   = help: consider replacing `'a` with `'static`
 
 error: aborting due to previous error
 

src/test/ui/nll/mir_check_cast_unsafe_fn.stderr

@@ -6,8 +6,6 @@ LL | fn bar<'a>(input: &'a u32, f: fn(&'a u32) -> &'a u32) -> &'static u32 {
 ...
 LL |     unsafe { g(input) }
    |              ^^^^^^^^ returning this value requires that `'a` must outlive `'static`
-   |
-   = help: consider replacing `'a` with `'static`
 
 error: aborting due to previous error
 

src/test/ui/nll/mir_check_cast_unsize.stderr

@@ -5,8 +5,6 @@ LL | fn bar<'a>(x: &'a u32) -> &'static dyn Debug {
    |        -- lifetime `'a` defined here
 LL |     x
    |     ^ returning this value requires that `'a` must outlive `'static`
-   |
-   = help: consider replacing `'a` with `'static`
 
 error: aborting due to previous error
 

src/test/ui/nll/outlives-suggestion-more.stderr

@@ -46,8 +46,6 @@ LL | fn foo2<'a, 'b, 'c>(x: &'a usize, y: &'b usize) -> (&'c usize, &'static usi
    |             -- lifetime `'b` defined here
 LL |     (x, y)
    |     ^^^^^^ returning this value requires that `'b` must outlive `'static`
-   |
-   = help: consider replacing `'b` with `'static`
 
 help: the following changes may resolve your lifetime errors
    |
@@ -88,8 +86,6 @@ LL | fn foo3<'a, 'b, 'c, 'd, 'e>(
 ...
 LL |     (x, y, z)
    |     ^^^^^^^^^ returning this value requires that `'c` must outlive `'static`
-   |
-   = help: consider replacing `'c` with `'static`
 
 help: the following changes may resolve your lifetime errors
    |

src/test/ui/nll/outlives-suggestion-simple.stderr

@@ -17,8 +17,6 @@ LL | fn foo2<'a>(x: &'a usize) -> &'static usize {
    |         -- lifetime `'a` defined here
 LL |     x
    |     ^ returning this value requires that `'a` must outlive `'static`
-   |
-   = help: consider replacing `'a` with `'static`
 
 error: lifetime may not live long enough
   --> $DIR/outlives-suggestion-simple.rs:14:5
@@ -66,8 +64,6 @@ LL |     pub fn foo<'a>(x: &'a usize) -> Self {
    |                -- lifetime `'a` defined here
 LL |         Foo { x }
    |         ^^^^^^^^^ returning this value requires that `'a` must outlive `'static`
-   |
-   = help: consider replacing `'a` with `'static`
 
 error: lifetime may not live long enough
   --> $DIR/outlives-suggestion-simple.rs:41:9