Remove a duplicate branch

Author: dianqk

compiler/rustc_ty_utils/src/abi.rs

@@ -560,20 +560,15 @@ fn fn_abi_new_uncached<'tcx>(
     let extra_args = if sig.abi == ExternAbi::RustCall {
         assert!(!sig.c_variadic && extra_args.is_empty());
 
-        if let Some(input) = sig.inputs().last() {
-            if let ty::Tuple(tupled_arguments) = input.kind() {
-                inputs = &sig.inputs()[0..sig.inputs().len() - 1];
-                tupled_arguments
-            } else {
-                bug!(
-                    "argument to function with \"rust-call\" ABI \
-                        is not a tuple"
-                );
-            }
+        if let Some(input) = sig.inputs().last()
+            && let ty::Tuple(tupled_arguments) = input.kind()
+        {
+            inputs = &sig.inputs()[0..sig.inputs().len() - 1];
+            tupled_arguments
         } else {
             bug!(
                 "argument to function with \"rust-call\" ABI \
-                    is not a tuple"
+                        is not a tuple"
             );
         }
     } else {