replace usages of fn_sig query with bound_fn_sig

clippy_utils/src/eager_or_lazy.rs

@@ -79,7 +79,7 @@ fn fn_eagerness(cx: &LateContext<'_>, fn_id: DefId, name: Symbol, have_one_arg:
             && subs.types().all(|x| matches!(x.peel_refs().kind(), ty::Param(_)))
         {
             // Limit the function to either `(self) -> bool` or `(&self) -> bool`
-            match &**cx.tcx.fn_sig(fn_id).skip_binder().inputs_and_output {
+            match &**cx.tcx.bound_fn_sig(fn_id).subst_identity().skip_binder().inputs_and_output {
                 [arg, res] if !arg.is_mutable_ptr() && arg.peel_refs() == ty && res.is_bool() => NoChange,
                 _ => Lazy,
             }

clippy_utils/src/lib.rs

@@ -1379,7 +1379,7 @@ pub fn get_enclosing_loop_or_multi_call_closure<'tcx>(
                                     .chain(args.iter())
                                     .position(|arg| arg.hir_id == id)?;
                                 let id = cx.typeck_results().type_dependent_def_id(e.hir_id)?;
-                                let ty = cx.tcx.fn_sig(id).skip_binder().inputs()[i];
+                                let ty = cx.tcx.bound_fn_sig(id).subst_identity().skip_binder().inputs()[i];
                                 ty_is_fn_once_param(cx.tcx, ty, cx.tcx.param_env(id).caller_bounds()).then_some(())
                             },
                             _ => None,
@@ -1580,14 +1580,14 @@ pub fn is_direct_expn_of(span: Span, name: &str) -> Option<Span> {
 /// Convenience function to get the return type of a function.
 pub fn return_ty<'tcx>(cx: &LateContext<'tcx>, fn_item: hir::HirId) -> Ty<'tcx> {
     let fn_def_id = cx.tcx.hir().local_def_id(fn_item);
-    let ret_ty = cx.tcx.fn_sig(fn_def_id).output();
+    let ret_ty = cx.tcx.bound_fn_sig(fn_def_id.into()).subst_identity().output();
     cx.tcx.erase_late_bound_regions(ret_ty)
 }
 
 /// Convenience function to get the nth argument type of a function.
 pub fn nth_arg<'tcx>(cx: &LateContext<'tcx>, fn_item: hir::HirId, nth: usize) -> Ty<'tcx> {
     let fn_def_id = cx.tcx.hir().local_def_id(fn_item);
-    let arg = cx.tcx.fn_sig(fn_def_id).input(nth);
+    let arg = cx.tcx.bound_fn_sig(fn_def_id.into()).subst_identity().input(nth);
     cx.tcx.erase_late_bound_regions(arg)
 }
 

clippy_utils/src/qualify_min_const_fn.rs

@@ -55,7 +55,7 @@ pub fn is_min_const_fn<'tcx>(tcx: TyCtxt<'tcx>, body: &Body<'tcx>, msrv: &Msrv)
     // impl trait is gone in MIR, so check the return type manually
     check_ty(
         tcx,
-        tcx.fn_sig(def_id).output().skip_binder(),
+        tcx.bound_fn_sig(def_id).subst_identity().output().skip_binder(),
         body.local_decls.iter().next().unwrap().source_info.span,
     )?;
 

clippy_utils/src/sugg.rs

@@ -885,7 +885,7 @@ impl<'tcx> DerefDelegate<'_, 'tcx> {
                     .cx
                     .typeck_results()
                     .type_dependent_def_id(parent_expr.hir_id)
-                    .map(|did| self.cx.tcx.fn_sig(did).skip_binder())
+                    .map(|did| self.cx.tcx.bound_fn_sig(did).subst_identity().skip_binder())
                 {
                     std::iter::once(receiver)
                         .chain(call_args.iter())

clippy_utils/src/ty.rs

@@ -628,7 +628,7 @@ impl<'tcx> ExprFnSig<'tcx> {
 /// If the expression is function like, get the signature for it.
 pub fn expr_sig<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'_>) -> Option<ExprFnSig<'tcx>> {
     if let Res::Def(DefKind::Fn | DefKind::Ctor(_, CtorKind::Fn) | DefKind::AssocFn, id) = path_res(cx, expr) {
-        Some(ExprFnSig::Sig(cx.tcx.fn_sig(id), Some(id)))
+        Some(ExprFnSig::Sig(cx.tcx.bound_fn_sig(id).subst_identity(), Some(id)))
     } else {
         ty_sig(cx, cx.typeck_results().expr_ty_adjusted(expr).peel_refs())
     }

clippy_utils/src/visitors.rs

@@ -392,12 +392,12 @@ pub fn is_expr_unsafe<'tcx>(cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) -> bool {
                         .cx
                         .typeck_results()
                         .type_dependent_def_id(e.hir_id)
-                        .map_or(false, |id| self.cx.tcx.fn_sig(id).unsafety() == Unsafety::Unsafe) =>
+                        .map_or(false, |id| self.cx.tcx.bound_fn_sig(id).skip_binder().unsafety() == Unsafety::Unsafe) =>
                 {
                     self.is_unsafe = true;
                 },
                 ExprKind::Call(func, _) => match *self.cx.typeck_results().expr_ty(func).peel_refs().kind() {
-                    ty::FnDef(id, _) if self.cx.tcx.fn_sig(id).unsafety() == Unsafety::Unsafe => self.is_unsafe = true,
+                    ty::FnDef(id, _) if self.cx.tcx.bound_fn_sig(id).skip_binder().unsafety() == Unsafety::Unsafe => self.is_unsafe = true,
                     ty::FnPtr(sig) if sig.unsafety() == Unsafety::Unsafe => self.is_unsafe = true,
                     _ => walk_expr(self, e),
                 },