Make the GATS self outlives error take into GATs in the inputs

Author: jackh726

compiler/rustc_typeck/src/check/wfcheck.rs

@@ -383,7 +383,7 @@ fn check_gat_where_clauses(tcx: TyCtxt<'_>, associated_items: &[hir::TraitItemRe
                             tcx,
                             param_env,
                             item_hir_id,
-                            sig.output(),
+                            sig.inputs_and_output,
                             // We also assume that all of the function signature's parameter types
                             // are well formed.
                             &sig.inputs().iter().copied().collect(),

src/test/ui/generic-associated-types/self-outlives-lint.rs

@@ -210,4 +210,17 @@ trait StaticReturnAndTakes<'a> {
     fn bar<'b>(&self, arg: Self::Y<'b>);
 }
 
+// We require bounds when the GAT appears in the inputs
+trait Input {
+    type Item<'a>;
+    //~^ missing required
+    fn takes_item<'a>(&'a self, item: Self::Item<'a>);
+}
+
+// We don't require bounds when the GAT appears in the where clauses
+trait WhereClause {
+    type Item<'a>;
+    fn takes_item<'a>(&'a self) where Self::Item<'a>: ;
+}
+
 fn main() {}

src/test/ui/generic-associated-types/self-outlives-lint.stderr

@@ -163,5 +163,16 @@ LL |     type Fut<'out>;
    = note: this bound is currently required to ensure that impls have maximum flexibility
    = note: we are soliciting feedback, see issue #87479 <https://github.com/rust-lang/rust/issues/87479> for more information
 
-error: aborting due to 15 previous errors
+error: missing required bound on `Item`
+  --> $DIR/self-outlives-lint.rs:215:5
+   |
+LL |     type Item<'a>;
+   |     ^^^^^^^^^^^^^-
+   |                  |
+   |                  help: add the required where clause: `where Self: 'a`
+   |
+   = note: this bound is currently required to ensure that impls have maximum flexibility
+   = note: we are soliciting feedback, see issue #87479 <https://github.com/rust-lang/rust/issues/87479> for more information
+
+error: aborting due to 16 previous errors