Rollup merge of #104732 - WaffleLapkin:from_def_idn't, r=compiler-errors

Refactor `ty::ClosureKind` related stuff

I've tried to fix all duplication and weirdness, but if I missed something do tell :p

r? `@compiler-errors`

compiler/rustc_infer/src/infer/error_reporting/nice_region_error/placeholder_error.rs

@@ -399,10 +399,7 @@ impl<'tcx> NiceRegionError<'_, 'tcx> {
                 self_ty.highlight.maybe_highlighting_region(vid, actual_has_vid);
 
                 if self_ty.value.is_closure()
-                    && self
-                        .tcx()
-                        .fn_trait_kind_from_lang_item(expected_trait_ref.value.def_id)
-                        .is_some()
+                    && self.tcx().is_fn_trait(expected_trait_ref.value.def_id)
                 {
                     let closure_sig = self_ty.map(|closure| {
                         if let ty::Closure(_, substs) = closure.kind() {