Fix incorrect lifetime suggestion

Author: estebank

compiler/rustc_resolve/src/late/diagnostics.rs

@@ -2654,8 +2654,8 @@ impl<'a: 'ast, 'ast, 'tcx> LateResolutionVisitor<'a, '_, 'ast, 'tcx> {
                     "this function's return type contains a borrowed value, but there is no value \
                      for it to be borrowed from",
                 );
-                maybe_static = true;
                 if in_scope_lifetimes.is_empty() {
+                    maybe_static = true;
                     in_scope_lifetimes = vec![(
                         Ident::with_dummy_span(kw::StaticLifetime),
                         (DUMMY_NODE_ID, LifetimeRes::Static),
@@ -2666,8 +2666,8 @@ impl<'a: 'ast, 'ast, 'tcx> LateResolutionVisitor<'a, '_, 'ast, 'tcx> {
                     "this function's return type contains a borrowed value with an elided \
                      lifetime, but the lifetime cannot be derived from the arguments",
                 );
-                maybe_static = true;
                 if in_scope_lifetimes.is_empty() {
+                    maybe_static = true;
                     in_scope_lifetimes = vec![(
                         Ident::with_dummy_span(kw::StaticLifetime),
                         (DUMMY_NODE_ID, LifetimeRes::Static),

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

@@ -88,19 +88,10 @@ LL | fn k<'a, T: WithLifetime<'a>>(_x: T::Output) -> &isize {
    |                                                 ^ expected named lifetime parameter
    |
    = help: this function's return type contains a borrowed value, but there is no value for it to be borrowed from
-help: consider using the `'a` lifetime, but this is uncommon unless you're returning a borrowed value from a `const` or a `static`
+help: consider using the `'a` lifetime
    |
 LL | fn k<'a, T: WithLifetime<'a>>(_x: T::Output) -> &'a isize {
    |                                                  ++
-help: instead, you are more likely to want to change the argument to be borrowed...
-   |
-LL | fn k<'a, T: WithLifetime<'a>>(_x: &T::Output) -> &isize {
-   |                                   +
-help: ...or alternatively, you might want to return an owned value
-   |
-LL - fn k<'a, T: WithLifetime<'a>>(_x: T::Output) -> &isize {
-LL + fn k<'a, T: WithLifetime<'a>>(_x: T::Output) -> isize {
-   |
 
 error[E0106]: missing lifetime specifier
   --> $DIR/lifetime-elision-return-type-requires-explicit-lifetime.rs:45:37
@@ -109,18 +100,10 @@ LL | fn l<'a>(_: &'a str, _: &'a str) -> &str { "" }
    |             -------     -------     ^ expected named lifetime parameter
    |
    = help: this function's return type contains a borrowed value with an elided lifetime, but the lifetime cannot be derived from the arguments
-help: consider using the `'a` lifetime, but this is uncommon unless you're returning a borrowed value from a `const` or a `static`
+help: consider using the `'a` lifetime
    |
 LL | fn l<'a>(_: &'a str, _: &'a str) -> &'a str { "" }
    |                                      ++
-help: instead, you are more likely to want to change one of the arguments to be borrowed...
-   |
-LL | fn l<'a>(_: &&'a str, _: &&'a str) -> &str { "" }
-   |             +            +
-help: ...or alternatively, you might want to return an owned value
-   |
-LL | fn l<'a>(_: &'a str, _: &'a str) -> String { "" }
-   |                                     ~~~~~~
 
 error: aborting due to 7 previous errors