Rollup merge of #91308 - BGR360:issue-88586, r=jackh726

Fix ICE when lowering `trait A where for<'a> Self: 'a`

Fixes #88586.

r? `@jackh726`

Jack, this fix is much smaller in scope than what I think you were proposing in the issue. Let me know if you had a vision for a larger refactor here.

cc `@JohnTitor`

2 files changed, 30 insertions, 0 deletions

diff --git a/src/test/ui/higher-rank-trait-bounds/issue-88586-hr-self-outlives-in-trait-def.rs b/src/test/ui/higher-rank-trait-bounds/issue-88586-hr-self-outlives-in-trait-def.rs
new file mode 100644
index 00000000000..b50f56b03d9
--- /dev/null
+++ b/src/test/ui/higher-rank-trait-bounds/issue-88586-hr-self-outlives-in-trait-def.rs
@@ -0,0 +1,11 @@
+// Regression test for #88586: a higher-ranked outlives bound on Self in a trait
+// definition caused an ICE when debug_assertions were enabled.
+//
+// FIXME: The error output in the absence of the ICE is unhelpful; this should be improved.
+
+trait A where for<'a> Self: 'a
+//~^ ERROR the parameter type `Self` may not live long enough
+{
+}
+
+fn main() {}
diff --git a/src/test/ui/higher-rank-trait-bounds/issue-88586-hr-self-outlives-in-trait-def.stderr b/src/test/ui/higher-rank-trait-bounds/issue-88586-hr-self-outlives-in-trait-def.stderr
new file mode 100644
index 00000000000..18618ffcc86
--- /dev/null
+++ b/src/test/ui/higher-rank-trait-bounds/issue-88586-hr-self-outlives-in-trait-def.stderr
@@ -0,0 +1,19 @@
+error[E0311]: the parameter type `Self` may not live long enough
+  --> $DIR/issue-88586-hr-self-outlives-in-trait-def.rs:6:1
+   |
+LL | / trait A where for<'a> Self: 'a
+LL | |
+LL | | {
+LL | | }
+   | |_^
+   |
+   = help: consider adding an explicit lifetime bound `Self: 'a`...
+   = note: ...so that the type `Self` will meet its required lifetime bounds...
+note: ...that is required by this bound
+  --> $DIR/issue-88586-hr-self-outlives-in-trait-def.rs:6:29
+   |
+LL | trait A where for<'a> Self: 'a
+   |                             ^^
+
+error: aborting due to previous error
+