Auto merge of #107727 - Dylan-DPC:rollup-b1yexcl, r=Dylan-DPC

Rollup of 5 pull requests

Successful merges:

 - #107553 (Suggest std::ptr::null if literal 0 is given to a raw pointer function argument)
 - #107580 (Recover from lifetimes with default lifetimes in generic args)
 - #107669 (rustdoc: combine duplicate rules in ayu CSS)
 - #107685 (Suggest adding a return type for async functions)
 - #107687 (Adapt SROA MIR opt for aggregated MIR)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

1 files changed, 16 insertions, 1 deletions

diff --git a/compiler/rustc_parse/src/parser/generics.rs b/compiler/rustc_parse/src/parser/generics.rs
index 585dfc518b3..23f49ec55a1 100644
--- a/compiler/rustc_parse/src/parser/generics.rs
+++ b/compiler/rustc_parse/src/parser/generics.rs
@@ -1,5 +1,6 @@
 use crate::errors::{
-    MultipleWhereClauses, UnexpectedSelfInGenericParameters, WhereClauseBeforeTupleStructBody,
+    MultipleWhereClauses, UnexpectedDefaultValueForLifetimeInGenericParameters,
+    UnexpectedSelfInGenericParameters, WhereClauseBeforeTupleStructBody,
     WhereClauseBeforeTupleStructBodySugg,
 };
 
@@ -145,6 +146,20 @@ impl<'a> Parser<'a> {
                         } else {
                             (None, Vec::new())
                         };
+
+                        if this.check_noexpect(&token::Eq)
+                            && this.look_ahead(1, |t| t.is_lifetime())
+                        {
+                            let lo = this.token.span;
+                            // Parse `= 'lifetime`.
+                            this.bump(); // `=`
+                            this.bump(); // `'lifetime`
+                            let span = lo.to(this.prev_token.span);
+                            this.sess.emit_err(
+                                UnexpectedDefaultValueForLifetimeInGenericParameters { span },
+                            );
+                        }
+
                         Some(ast::GenericParam {
                             ident: lifetime.ident,
                             id: lifetime.id,