Fix an ICE on rust-lang#96738

Author: JohnTitor

compiler/rustc_typeck/src/check/method/suggest.rs

@@ -367,8 +367,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
                 if self.is_fn_ty(rcvr_ty, span) {
                     if let SelfSource::MethodCall(expr) = source {
-                        let suggest = if let ty::FnDef(def_id, _) = rcvr_ty.kind() {
-                            let local_id = def_id.expect_local();
+                        let suggest = if let ty::FnDef(def_id, _) = rcvr_ty.kind() && let Some(local_id) = def_id.as_local() {
                             let hir_id = tcx.hir().local_def_id_to_hir_id(local_id);
                             let node = tcx.hir().get(hir_id);
                             let fields = node.tuple_fields();

src/test/ui/typeck/issue-96738.rs

@@ -0,0 +1,3 @@
+fn main() {
+    Some.nonexistent_method(); //~ ERROR: no method named `nonexistent_method` found
+}

src/test/ui/typeck/issue-96738.stderr

@@ -0,0 +1,11 @@
+error[E0599]: no method named `nonexistent_method` found for fn item `fn(_) -> Option<_> {Option::<_>::Some}` in the current scope
+  --> $DIR/issue-96738.rs:2:10
+   |
+LL |     Some.nonexistent_method();
+   |     ---- ^^^^^^^^^^^^^^^^^^ method not found in `fn(_) -> Option<_> {Option::<_>::Some}`
+   |     |
+   |     this is a function, perhaps you wish to call it
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0599`.